(first posted 2/25/2017. Original pictures and some text by Paul N.) Over the past several months, we’ve reviewed several different motor coach manufacturers that went toe-to-toe with General Motors in the intercity bus market of the 1950’s – ACF Brill, Beck, Fitzjohn, Aerocoach. All fought the good fight, but ended up on the canvas. OK, enough boxing metaphors – let’s look at the bus that vanquished all of these challengers, and set the template for all buses to come. All hail the GM PD-4104 Highway Traveler.
Paul’s post on the 4104’s predecessor, the GM 3751 and 4151 “Silversides” coaches detail how GM first became a powerhouse in the coach field, thanks to innovative alloy semi-monocoque construction and GM’s new light but powerful 2-stroke diesel engine. That engine was so eminently well suited for buses with its transverse location at the very rear and angle drive to the rear wheels.
These and their predecessors were radically new before the war, and were given minor updates when introduced in the post-war market. They were excellent buses; well built and profitable to operate with the GM/DD 6-71 engine. But they weren’t the sweeping, all-new bus that Greyhound, GM’s largest customer, desired for the post-war era. It took a few more years for that model to be introduced – but when it was in 1953, it shook the intercity bus market to its core.
What made the 4104 so special, and how did it come to utterly dominate the market? Several factors, but first and foremost, it was just plainly superior to any other bus being offered at the time. Let’s look at the details.
Weight. Rather than use a separate body and chassis, 4104’s were fully monocoque-bodied (similar to the Gar Wood coaches we looked at in our Aerocoach post). High strength aluminum panels over the monocoque frame made for an extremely light yet rigid coach, easily able to stand-up to the constant over-the-road pounding an intercity bus endures.
Power and mileage. The relatively light weight 2-stroke 210 hp Detroit Diesel 6-71 engine, which was then an exclusive to GM coaches, combined with the light weight of the coach, made the 4104 North America’s most fuel efficient bus, and most likely one of its faster ones. A 4104 could typically get 8-10 miles per gallon of cheap diesel fuel compared to 2-3 mpg for the ACF Brill using the Hall-Scott gas engine, or 7-8 mpg for the Fitzjohn and Aerocoach which used the four stroke Cummins diesel. And it had a cruising/maximum speed of 65 mph.
The Roots-type blower on the side of the engine is necessary for a two-stroke diesel to scavenge the cylinders quickly as well as fill the cylinders with fresh air for the intake stroke.
A two stroke diesel operates rather differently than a gas-oil fed two stroke engine, as the diesel has two or four exhaust valves in the cylinder head. This shows its operation.
The Spicer unsynchronized four speed manual transmission was also more efficient than later automatics, but it was not exactly “slick-shifting”
The long gear shift lever was some 30 feet away from the transmission, so it required a deft hand. Upshifts were relatively easy, and the better drivers managed it without a clutch. Downshifts required double clutching and revving up the engine to the required speed in order to match the rotation speed of the gears on the output shaft. Pulling off a downshift without any hint of gear grinding was the sign of a superior driver.
Ride. While other coaches were experimenting with air suspension systems, GM had theirs ready for use on both its urban transit and intercity models – it provided an extremely smooth ride, no matter how many passengers were on-board, and just as importantly was very reliable.
These reinforced rubber bellow-type springs are utterly ubiquitous now on buses and a high percentage of trucks and trailers, but in 1953, this was a big deal. The improvement in ride quality was very significant, as steel-spring buses had to use quite stiff springs in order to cope with a full load. The air springs rode the same now matter how many passengers. I can remember riding on Marmon-Herrington trolley coaches in the early ’60s in my hometown of Columbus Ohio – these were steel spring buses and when lightly loaded, there was a cacophony of “Bam, Boom, Rattle” with lots of bouncing in the seats.
Storage. With no longitudinal frame, the 4104 had significantly more underfloor storage capacity than any other coach – more room for luggage and freight, in those pre-FEDEX days.
Appearance. Though somewhat hard to envision now, the 4104 was a revolutionary design when launched – more modern looking than any other bus (or car) on the road. It created as much buzz as the ’63 Stingray or ’66 Toronado. The full aluminum-encapsulated body and forward canted large windows became iconic design elements on buses for the next 30 years or more. Everyone rushed to imitate the 4104.
Quality. The folks who worked the line at the Pontiac Michigan Assembly Plant knew how to build a bus. The key word here is “solid” – GM buses of the 1950’s and 60’s had just a much more solid feel to them than any other coach. I can remember riding Greyhound 4104s in the ‘60s and you could tell they had lots of miles on them. Yet, they still had this “all-of-a-piece” feel.
It explains why the 4104s were still snapped up from Greyhound by smaller operators, and why they became the most favored bus for motorhome conversions for decades. They’re still popular in that role, and it’s relatively easy to keep one on the road.
Put all this together and you get a bus that gave passengers a significantly elevated travel experience while at the same time put more money on operators balance sheets – a win-win…
Their durability and cost efficient attributes were not lost on operators outside North America either.
Testament to the goodness of their overall design, the 4104 was superseded by the 4106 in 1961, which was essentially a 4104 with larger windows, an updated HVAC system, dual headlights, and the more powerful 8V-71 engine.
And the 4104’s advanced lightweight design, construction methods and even the slanted windows were all key aspects to GM’s “New Look” transit buses in 1959.
The 4104 laso had a big brother, the iconic greyhound PD-4105 Scenicruiser. They were essentially co-developed, with the Scenicruiser arriving in 1954, one year after the 4104. Unfortunately, the Scenicruiser did not enjoy the same sterling reputation as the 4104; it quickly became rather problematic, with body cracking issues and problems with the twin engines. Paul’s detailed write-up is here.
I routinely peruse various bus and transportation websites and you find nothing but praise for the 4104; “the perfect bus”, “the best bus ever built”…it still has lots of fans out there.
Over 5000 were built from 1953 to 60 – and their solid construction means many still remain on the road today.
And some have even been restored to their former all-original glory; now that’s what I like to see.
Curbside Classic: GM PD-4104 – My Dream Bus Comes To Visit, With A Formula Ford Racing Car In Its Belly
1947 GM PD-3751 “Silversides”: The First Modern Bus PN
GMC “New Look” Transit Buses PN
Thanks !! I love those old GM buses. I got to drive the New Look (fish bowl) city transit buses when I started in 1980. Cool looking bus. I rode those old Greyhounds with my grandmother. Todays Greyhound buses have no style. They look like bricks. I sent an email to Greyhound management suggesting they go with a retro style bus. I haven’t got an answer. Someone should start a petition.
Wonderful idea.. I own a 1953 4104 and it still runs like a top.. I love America and it’s wonderful bused.
Figuered Is throw up another pick of the 53
I have a 1953 Greyhound bus it’s a good one in 79 it was converted to a motorhome.buss number 191 .CA it’s a nice jbuss
I have a 1958 gm coach conversion PD4104 3I85
It’s in almost perfect condition. Only has 2,700 miles on odometer. Looking to sell it. I paid 20,000 for it ten + years ago.
Any pictures or more info on that 4104 if it’s still for sale?
I am tracking down all the surviving GM PD 4104s left in the world. What is your coach’s serial number?
I have 529 Conversions on the list so far.
Our 4104 serial number 1670 serves as our cabin in the woods
Here’s a picture of 1607. It was one of Bill Monroe’s tour buses
Steven – PD4104-1670 was delivered new as fleet number C-5602 in April of 1956 to Carolina Coach Co, HQ’d in Raleigh, NC. Carolina Coach is/was a Trailways affiliate.
Steven – Since you posted two different VINs, and not knowing which is correct, here’s info on the second:
PD4104-1607 was delivered new as fleet number 255 in March of 1956 to Clifton Buses [dba DeCamp Bus Lines], HQ’d in NJ.
RJ I’m dyslexic and it showed up again.
1670 is correct.
Thanks for the provenance.
Hi, my family also has on of these 4104s, serial number 3715. I was wondering how much information you have on individual buses?
Nick – PD4104-3715 was delivered new as fleet number 297 in February of 1958 to Super Service Bus Co, HQ’d in S Amboy, NJ.
I have an uncle who just purchased one of these PD 4104’s. he would like to restore it and would love to talk to you. (440)-670-6114 his name is Joe Jackson if you have any free time to contact him he would appreciate it.
Bus Grease Monkey. goggle him I think you’ll be happy!
I have a GM PD 4104. I don’t know what the serial number is and I am in another state, not where the bus is at. Where will I find the serial number when I go looking for it?
I am looking for a replacement entry door for my bus. Know of a place for me to find one?
Mark – You can find the VIN in three places:
1) A builder’s plaque riveted to the dash in the front entry above the handrail.
2) Stamped into the “frame rail” inside the exterior compartment underneath the driver.
3) Riveted vertically to the side of the heater/defroster box on the right of the throttle and above the heat control valve.
There is a burned 4104 in Rochester, WA that looks like it has a salvageable front door. S side of Hiway 12 next to the IGA store.
HTH. . . 😉
I am negotiating on Pd 4104 =1211 what can you tell me about it.
Any idea where I could buy Right rear upper clearance light lens?
This is Rodney Middleton. We own PD4104-4614 and the original delivery on #1211 is as follows:1211-1212 147773-774 06/54 Missouri,Kansas & Oklahoma Coach Lines 542-543 (Tulsa OK). Hope this helps.
I think I found your bus on Google Earth, RJ. I think it needs roof work also!
Do you have 4104 867 on your list?
Jon, I have a4104 conversion it’s number 821, you have any info on it
I AM LOOKING FOR PD4104 WITH THE SERIAL #4818 1960
GREYHOUND… I AM INTERESTED IN BUYING IT BACK..
I own PD 4014-3354. It’s currently in Tyler, Texas, not in use at the moment. It’s been fully converted years ago. Not sure what I’m going to do with it at this point. The engine has less that 100k, it has the upgraded power steering, (Crawford Coach in Pennsylvania installed the conversion)> The transmission has been rebuild, the brakes exceed original specs. It was always a joy to drive!
Hi! We have GM PD 4104 4066. Would you have any history on this bus? I’d love any info! email@example.com Thanks! Sara
I found 1957 PD4104-1969
Is in Conover, NC.
Going to check it out tomorrow.
It is a converted bus that is for sale.
The owner/seller has owned it for over 20 years
Hello Mr. Fox,
Sorry to bother you, but I saw your post and noticed we live close (Greensboro).
I dont know if you are interested in purchasing a gmc 4104 or have already.
If you have, thats great news…….these are wonderful toys.
Anyway….I currently have a 1956 gmc 4104 that I kept in the mountains near Blowing Rock. Unfortunately it was vandalized and gutted, and I am not going to restore it again. Knowing how hard it is to find parts, and how expensive they are to ship, I thought I would check to see if there was anything you were interested in before I scrap it out?
Please let me know.
Good Morning Jon,
I have a 53 gmc but i believe it is a pd4103 according to the title. My guess is the last four digits on the title are the serial number, 1195. I just pulled out of the sellers backyard where it sat for I guess about 20 years. It runs but needs alot of tlc. Any advice on where to get assistance putting it back on the road would be greatly appreciated and is there a sight to join. I attached a couple pics. I am located in the middle of Michigan just south of Lansing. thanks
Hi, 2054 here. High block 671 with N-65 injectors and 5″ blower inlet. Was converted by George Thornhill in the ’70s. He picked the best Arizona Charter coach and then proceeded to do many upgrades including air clutch, shepherd power steering, two speed box between Spicer and rear end, Walker oil recovery unit, split exhaust manifolds, $15,000 worth of engine work done 10 years ago which included replacement of worn non machinable crank with one from Craig Craddock out of his low mileage rebuilt after he replaced the 671 in his 04 with an 8V71 TA. Am considering adding Propane for climbing and would like any who have done that to share. Bill Thomas 408 307-1593
I realize that this topic is aged and that shoutbacks are tricky on Curbside Classic, but I’d REALLY like to hear more about a splitter box located between trans and diff of a V-drive.
I have Larry Sparks 1960 4 .I’ve owner it for about 35 years…love it…contact me please.,Kent
Rogers City Mi. I have 1953 4104 pd 636. Single mom driving it with my kids just like my dad with me when I was a kid. A family treasure that I hope my kids drive one day with their kids. My kids love listening to 50’s music in it while going down the road. Love it.
Folks, I have 04 2054 and 06 1685. We have now arrived at tomorrow when these coaches are only as good as the condition each is in. Specially mechanically as that is where you are going to wish you had checked if you buy one that has been screwed up. There are very few out there that know what they are doing when it comes to repairs and upgrades. A lot buy new sophisticated stick and staple impressive diesel rigs. Rest assured that these old coaches are infinitely safer than those new contraptions and the untized construction on a 35 foot platform with reasonable window area is by far the strongest in case of major accidents.
I have four 4104s in Maine
i have a 1960 4104-4719 in washington state
A 1953 PD 4104 parked along side a road with a ‘for sale’ sign on it reeled me in and is now parked in my drive way. I’m wondering if you can tell its history. serial number 4104-388.
This is the GM delivery record. Hope this helps. 384-391 144642-649 08/53 Kerrville Bus Co V471-V478 (TX). We own PD4104-4614
We have a 4104 in the family inherited from my grandmother.
Serial number in the picture.
It’s actually for sale as we’re moving out of state ( Currently in Bakersfield CA) and can’t take it with us.
Hi Brad. Your photo didn’t load. I realize this post is now a year old, but have you sold it?
I have one and would like to sell it Totally refurbished overhaul motor with a new power steering pump. a new air filter system
No vin number
Hi Justin. I realize this post is nearly a year old, but is your bus still for sale? thanks
Is this link still current? I have gotten ahold of a PD 4104 bus I’m trying to track down information on it. If you could help point me towards n the right direction it would be much appreciated. Thank you.
What is your serial number and I can see who it was originally sold to and let you know. Thanks, Rodney
I have a 56/57 PD 4104 #3293
it served the Great Lakes route into Canada and an eastern seaboard route.
I have found info indicating it was one of only 2 Greyhound buses to have a dual route.
It still has the original destination scroll and there are 2 sewn together along with inserted patches such as “Race Track” and “Charter”
It was probably a minor league baseball team bus in the 60’s and professionally converted to an RV by Liberty Coach in the 70’s. the 90’s saw it as a band bus with bunks installed in the rear section. I bought it in about 2005 and turned it into more of a mobile shop complete with solar power.
It has sat for 10 years (Indoors) after using it to move back to Az. and I am now getting it on the road again. Not sure if I will keep it or not. It has been insulated has a later 6-71 and gets a solid 10mpg going 75mph down the road.
My 4104 conversion is for sale. Glenn Holland, 803/687-3966
I have a 1951 mci coach PD 4§04 and I’m looking to sell for very cheap must go in 10 days
Great article tying it all together, thanks! For some reason I had always thought that there was never a vehicle actually badged just as a “GM”, I never thought of the buses though.
There was the GM EV1, but I can’t find a picture detailed enough to show the GM badge. But I bet it had one.
Oh yeah, of course! You are absolutely correct. It had the little chiclet thing IIRC.
You can just make out the GM badge in the first photo.
The badge says “GM Coach”, which was its own brand, as was “GMC Truck”, both under the GM Truck and Coach Division.
GM Coaches have a different history than the GMC trucks, as GMC bought Yellow Coach in 1925, and continued to use the Yellow name until 1943. “GMC” trucks go back to 1912. The two divisions were eventually folded into the GM Truck and Coach Division, but kept their separate brands.
I always knew that these had dominated, but had always assumed that it was on the basis of price and low running costs. I miss a world where GM could build the very best in the business and could be successful from building quality instead of building and selling cheap.
Wow… 12-13 MPG from such a massive vehicle, albeit with no electronic controls whatsoever- that’s amazing.
Where did you get the “12-13 MPG” from?
The article originally this morning said “up to 10-12 mpg”, which is a number I had heard years ago and Jim got that from me. With a bit more research this morning, 8-10 mpg is actually correct. Which is still mighty good, considering large American cars often didn’t get much more.
Oops! That’s what I get for typing without being fully awake LOL. 8-10 MPG is still mighty impressive for something so large.
Fwiw taking it easy you can get 10-12 mpg out of a lightly loaded 4104 running at 55-60 mph. I averaged 10.5 over hilly terrain on a 1000 mile run, towing a Eurovan.
Hey Patrick, I am buying a couple PD-3751s that will need some work, wondering if I could pick your brain. I believe they have the same drive train… not sure what else crosses over. Paulvel@gmail.com
Thanks for this Jim. We hardly had them in Israel – they arrived on the market too early and, like the Flxibles, scared operators who were used to simple school bus (really bus-bodied truck chassis) types – the below is what a GMC bus meant in Israel. When the time came for Israeli bus operators to be dragged kicking and screaming into the second half of the 20th century, they first went for the ever more primitive French Chausson and then the Leyland Royal Tiger, itself an iconic design although – with its full chassis and spring suspension – more suitable for Israeli conditions and the need to ensure local body builders had some work…
I wouldn’t want to take anything away from the epic PD 4104, but the PD 4106 was quite a coach as well. In many ways an improved and modernized 4104, the 4106 featured the 8V-71, which made for a rather fast coach and did away with the 4104’s auxiliary engine to power the A/C.
Of course it was, as it was an improved 4104. The point is that the 4104 in its time was the best, not ten years later.
Another great bus post. For a few years we had a 2 axle Crown Coach school bus with a NA 6-71 210 and Fuller 5 speed that was the mileage champ of the fleet at 8MPG. Great driving motor.
Love that mail truck. What is it?
Looks like a Dodge step van. meaning the body was built by a step van builder. i can’t tell which one exactly.
I’m not really much of a bus fan – not my preferred mode of transportation if I have a choice – but the 4104’s surely were the nicest-looking buses ever built, and I am a fan of these.
When my wife worked for Trailways in the 1970s, she referred to these as “air riders”. I don’t know where that term came from, but apparently she heard it from other Trailways personnel.
She was a secretary in the Trailways St. Louis garage.
Still, I’ll take the train whenever possible, thank you…
If you had ridden GM’s Aerotrain, two lightweight “concept trains” that demonstrated on many railroads across the country, including regular scheduled stints as Pennsylvania Railroad’s New York-Pittsburgh “Pennsy Aerotrain” and as Union Pacific’s “City of Las Vegas” between its namesake city and Los Angeles, you’d have been looking out through the windows of the PD-4104, and riding in coaches built using its basic monocoque construction and air suspension. The Aerotrain was a train whose carbodies were based on the PD-4104 bus! The Aerotrains finished up in Chicago commuter service on the Rock Island, retiring in the mid-1960s, and two museums each now have one Aerotrain locomotive and two coaches, preserved.
Would one of those museums be the National Railroad Museum in Green Bay, Wisconsin? It looks familiar.
Post-retirement photo shows how the PD-4104-based coaches of the GM Aerotrain compare in size to conventional streamlined rail passenger cars.
GM Fishbowl based coaches not 4104.
Since the “fishbowl” buses didn’t arrive until 1959, and the Aerotrain was built in 1954-1955, it’s quite safe to say that they were 4101 based, right?
Maybe you could take a minute and Google the subject before you tell someone they’re incorrect.
And here is a photo of the GM Aerotrain as Union Pacific’s City of Las Vegas, showing its bus-body coach construction. The Aerotrain was unfortunately underpowered, and here on the steep Cajon Pass in California, it is being assisted by another GM product, an ElectroMotive GP-9 diesel locomotive.
Also it appears from the open door that the air conditioning has failed in one of the coaches.
I own a 1958 GM 4104 conversion, PD-4104-3576. Owning my bus was a lifelong dream since I was in my teens. I am 66 and somewhat disabled now which makes shifting very painful. So, I’ll probably sell my beauty and buy something newer with an automatic transmission. I am a better person for having owned “3576”. Thank you, Glenn Holland, 803/687-3966: G1Z1@aol.com
Glenn – PD4104-3576 was delivered new as fleet number 6149 in February of 1958 to American Buslines, HQ’d in Lincoln, NE.
Sorry to hear that you’re having to sell your beloved ’04, but certainly understand. We all get to that point eventually. . .
Hello, I am very impressed to see that you have documentation on the 4104. I live in Quebec, Canada and I just bought a 1957 conversion, # 2195. Do you know where it was sold at the time or any other information?
I’d love, if someday (!!) licensed and wealthy, enough,to buy one of those 4101’s with original double clutch-needed non-synchro 4-speed Spicer manual, and Detroit 6-cylinder Diesel engine, and if possible, if already find one that’s already still a (non-motorhome) bus.
Would you believe that over 556 of the 5,065 coaches originally manufactured are still on the road today in the USA, Canada, Mexico, Uraguay, Brazil and Germany.
I’m looking for a wiring diagram for the 4104. I have bus #11
If you own PD4104-011, you’ve definitely got one of the very early ones! It was delivered new in April of 1953 as fleet number S-908 to Southwestern Greyhound Lines, HQ’d in Ft Worth, TX.
Do you still need a wiring diagram?
I AM LOOKING FOR 1960 PD 4104 WITH SERIAL #4817..I PREVIOUSLY
MADE A MISTAKE IN USING THE WRONG SERIAL #4818..IT IS ACTUALLY
#4817..IT WAS SOLD IN WASHINGTON STATE A FEW YEARS BACK TO A
CONSTRUCTION WORKER??. ANYWAY I AM INTERESTED IN KNOWING
WHERE THIS BUS IS AS I AM INTERESTED IN POSSIBLY BUYING IT BACK..
WE LIVED IN THIS BUS FULL TIME FOR 7 YEARS…THANKS.
This is #4777 out of the 5065 produced and its still going smooth in 2019.Ill post again in another 20 years!
PD4104-4777 was delivered new as fleet number P-7687 in May of 1960 to Western Greyhound Lines, HQ’d in San Francisco, CA. WGL had the reputation of having the BEST maintenance facility throughout the Greyhound divisions, so for at least the first 10 years of it’s life, it was well taken care of.
We had a 1956 4104 that we drove for eleven years before an idiot ( and I mean that ) drove a smoking ford truck into the storage unit next to ours Memorial day weekend last year where his Chinese fire extinguishers did even fart at which point it burned down all 10 storage unit in a half hour. He could of let it burn in the plenty of gravel out front of the unit. Bunch of stuff lost including our 4104 which stranded us only once in Unity OR. because of 107 degree weather which a relay did not like. Anyway she is way missed and lots of looking in the past year has not produced a replacement- she is irreplaceable. The guy I bought her from in Idaho had put a 6-92 in her & a 3 speed Allison w/ power steering. Great combination. And the 4104 was also designed for safety like no other even in today’s terms I believe. I did feel safe in her. We went to a class C for a moment, not right- sold that and now have a 1995 Hawkins 36′ Great Cat motor in it but would not like to get in a wreck in it. And no engine compares to the Detroit sound. 4104 is the bus to have so if you all have one take care of her as irreplaceable.
I have a GM 4104 number 51. Is in very good condition n runs great. I unfortunately have to sell this beautiful bus. Any takers? Contact me at firstname.lastname@example.org if interested in purchasing. Thank you
PD4104-051 was delivered new as fleet number S-918 in May of 1953 to Southwestern Greyhound Lines, HQ’d in Ft Worth, TX.
Sorry to hear that you have to sell your coach, but I’m sure it will happen. The venerable ’04 is still popular among busnuts. It may take awhile, but hang in there, somebody will eventually choose to love it as you have.
I’m needing info on a 1963 GMC bus. Can you help.
My name is kalani and I have
PD 4104 – 4741 conversion.
I would love any info on this.
Thank you very much.
This bus is awesome!
I have a 1956 gmc pd4104 what I’m looking for is a breakdown of the manual transmission. Starting to get a noise in first its the loudest and by the time you get into high gear it is barley noticeable. Any help will be greatly appreciated.
My sister has number 304, a 1957 PD4104 in Austin, Tx. She inherited from her husband who was converting it and he unfortunately passed away in 2017. Now she doesn’t know what to do with it. It hasn’t moved from her yard in over 10 years and she needs to sell her house.
I looking at that 4106 in Austin Texas lam jeff jackson 720 364 5415 call Any time thankyou jeff
Are you actively looking for a GM 4104 bus? My sister has No. 304 near Lakeway, close to Austin. She is looking to give it to someone if they can remove it. As I mentioned in my previous post, it was being converted to an RV when her husband passed away in 2017 but he had to quit working on it some years before that.
Is it still available? Thanks Rodney Middleton
Single mom of four in need if available
This is the GM delivery record. We own PD4104-4614. Hope this helps. 384-391 144642-649 08/53 Kerrville Bus Co V471-V478 (TX). Thanks Rodney Middleton
I currently own an 04 an it is halfway converted. I am interested in selling it. I just need to get the newly charged batteries in and start it up *fingers crossed* It has been almost 2 years since started/driven…is there anything I should be aware beforehand? i.e. drain diesel and put in fresh? anything to check for?
Also, I have never been the one to start, nor drive it! lol, I may be on here to ask for help very soon. Any of you near Saint Louis, MO?
RJ, mine is a 1953 PD4104014 🙂 Any info on this old beauty?
Wow, that’s a low unit number. Probably job #14.
Confirm battery polarity, probably pos ground.
Two years isn’t a very long slumber for a Jimmy.
Stuck injector or fuel rack is a danger, could cause runaway.
Be sure the emergency shut down flap door is limber.
Yeah, I was told it was 14th made! Will find out soon.
Where/what is the emergency shut down flap door?
It’s a spring-loaded flap door located at the blower intake.
When closed, blocks the engine’s air supply to prevent engine overspeed in case of malfunction.
Not very good to trip the “gag” door, but it’s better than an overspeed.
In practice tripping the door sometimes won’t stop the engine but at least the restricted intake keeps the speed down until some other measure can be taken.
The clutch may be stuck and not want to release. Again, two years is not very long, stuck clutch would probably break loose.
It seems as if there is air in the lines. How do I prime this thing?
Without writing a DD manual…
One quick method is to loosen the IN line at the gear pump and then SLIGHTLY pressurize the tank to flood the suction side with fuel. That’s usually enough that a bit of engine cranking will do the rest.
Or the filters can be pre-filled with fuel and then simply crank away.
Another option is to draw vacuum on the return side.
Whatever it takes to get a solid column of fuel to the gear pump. Pressure side and injectors will self-bleed with fuel flow.
Methods vary just depends on the situation and available gear.
I am planning on replacing the fuel filters and I might as well replace the oil filter while at it. I will fill the filters then.
Any suggestions on replacing oil filter and changing oil in general?
Also, where should I list this for sale? Anyone have recomendations or looking for one?
Servicing the oil-bath air filter is probably more important than a crankcase oil change
Lot of water over the dam since your coach left Pontiac.
Engine and filter arrangement may not be original type.
Your favorite DD 2-cycle 40 weight oil and filters compatible with whatever it uses now.
Beware a rotten radiator fan hub. Hub failure can jettison the fan, kill the radiator and make a general mess.
The oil-bath does needs to be serviced. What is that procedure and/or is there a service manual or do you mind helping as you have?
Thank you so much for the info. It has been hard to find.
Remove the bowls via thumb screws and ring clamp.
Wash everything with your favorite solvent.
Fill each bowl to “oil level”.with 30 weight engine oil.
Am still looking for clearance light lens over front door on passenger side front of the my 4104. Can repair the one I have of 3D print one, but maybe someone is parting out a coach and would be willing to sell one. Bill T. 408 307-1593
Hard to find.
Does anyone know where to find a new gas tank or how to repair/restore the current one?
My 4104 is off the road and I’d consider selling the tank. I have no idea how difficult it is to remove or how to do it safely without spilling fuel in my yard.
Tank is constructed of sheet metal.
Of course you know where it’s located.
Straight forward removal, not necessary to raise coach or spill fuel.
Tank is massive and a bit awkward to handle, but not heavy when empty.
A temporary 5 gallon can, or whatever, can be used to keep the coach mobile.
Have a 1956 4104 with 84000 original miles on it. The bevel gears started making a noise about 200 miles from home. We decided to head home just in case. About 50 miles from home lost the clutch( as in pushed it would not disengage). Being a veteran truck driver I just started it with the starter in 1st and just slid the gears. Even with researching the web I can’t find out if the bevel gears caused this or not as the clutch doesnt have 500 miles on it. Going to replace all anyway but wanted to know the answer to this just for wanting to know what happened. Any information anyone could provide or a contact person would be greatly appreciated.
My extensive clutch and bevel-drive reply didn’t post.
And this time I didn’t save a copy. Drat
I may be under some sort of partial gag order around here.
Sometimes my replies are delayed, sometimes they vanish.
I didn’t smell any chloroform this time before I blacked out lol
don’t feel any fresh knots on my skull either, so hopefully the reply is just delayed and will appear.
If not I’ll try again.
No, you’re not under some sort of partial gag order here. Don’t be paranoid. Obviously not, given your very long comments the other day about the James Dandy Academy of Personal Responsibility.
I checked the Trash folder; it’s not there. I don’t know what happened to to. But if you’re having comments disappear, then yes, making a copy before posting might be a good idea.
Yah, but that’s where they didn’t post!
Thank you Paul. Knowing that I feel empowered to really let loose.
Sometimes it takes a somewhat higher word-count to appropriately reply to a high word-count. Other times two will do.
Sometimes my replies post instantly. Sometimes with delay, so I avoid re-sending without a good wait.
That’s when contenders sometimes wrongly think it’s a knock-out and try to deliver one last kick. No wonder sometimes a guy gets back up wielding a boot. LoL
That can be discussed later in Double-Post. This is the place and time for double-clutch. 🙂
I’ll try again.
I’m guessing that with “bevel gears” we mean the angled gears at the transmission end of the driveshaft? The final drive, “pig” “pumpkin” etc. I believe is officially called the bevel gear. Not positive on that this minute. Anyway, we move on hopefully on the same page.
Briefly, the bevel-gears are located “down stream” from a conventional 4-speed transmission. If the transmission is shifting well, it’s unlikely the failing bevel-gears (or bearings?) have anything to do with the stuck clutch.
I’m not considering obvious failures, such as the transmission separating from the engine, broken housing, things like that.
Clutch is a common push-type, no mystery components or movements.
There’s a thumbwheel located at the rear bulkhead, it is used to adjust clutch linkage free travel. Start by making sure the release lever is being pulled far enough to release the clutch cover; “pressure plate” some say. It’s fairly easy to access the release lever to “bar” it towards release position.
Be careful. A slight “rock” is sometimes all it takes to start the engine. The governor will try to keep it running as the coach climbs a wall and there may not be shut-off until air pressure builds.
84,000 miles. Wow. How did that happen? Must be a nice coach. Or is this the ’04 that burned at Alabama? Kidding, that’s ugly.
Also surprised the original clutch was bad. Probably either rusted stuck or too-smoothe operators slipping it. Should get off the clutch fast and at low rpm – it’ll lug up. Well, to a point.
Sorry I havent replied quicker been busy with work. I am going to move the clutch lever by hand and see if that disengages the clutch as a last ditch effort but have my doubts since the adjuster has more than half way to go. I am starting to believe that it is just a clutch failure since parts are nit as good as the once were.
The original clutch was rusted up along with the pressure plate so all was changed. After talking to the garage where work was done they are going to stand tall and go through it again.
As far as mileage up until last year it sat for ten years so after going through the sprinkler system of water lines and upgrading all to pex it works. New hw tank. The only bad spot i found was around the pedals from watery carpet. Replaced floor board then tore all of the 1970 shag out and put spc flooring down. Last is the furnace which likes to backfire while running. Nit good on a propane system.
Question tho would you know where I can find service manual(s) for it. Thanks
En Argentina en la década del 50 la empresa El Cóndor usaba varios buses de 37 asientos. No obstante ser niño recuerdo muy bien el rugido de sus motores y su exquisita apariencia exterior y su lujuso interior. No encuentro fotos de entonces con la pintura de El Cóndor. Por favor si alguien dispone fotos tenga a bien publicarlas. Muchas gracias.
Heres one up for sale on FB marketplace 11/17/2021
I have 4104- 583 don’t know anything about it. Thanks for any information .
1953. 4104-129 here. Pacific Greyhound lines with a 1969 Gray Marine engine. Rebuilt 12,000 mi. ago. Ownership since 1979. Fully converted by yours truly from an in service seated coach.
The older it gets the better it gets. Wish I could say that about me! Lol
My hero Dan!!!!
Morning ,I did find a little bit of information today on my 4104-583 at one point it was at Houston Charter Services Inc. very faint markings where letters were removed . Still searching . Have a great day .
Thank you for this wonderful blog! Great information! We have Coach No. PD4104 3711. We bought it from a band, and fixed it up mechanically a great deal, and used it for our band for years – driving from our home base in New Jersey up and down the East Coast, and out to Ohio and even to Texas. We loved every minute and that bus can tell some stories! We are now looking for someone to adopt it…but it needs to be towed as the throttle cable seized up behind the engine over the winter a few years back and we have not been able to loosen it. Also by now I’m sure the batteries are dead. It was running great before that winter. Has some dents from taking it to shows/festivals that weren’t meant for buses, needs a lot of tender loving care. Free to good home but must tow it out. Thank you.
Any info on 1953 pd 4104-1151?
Left on my brothers boat and trailer storage property twenty years ago, now has about $50,000 in back storage fees for the owner(i dont think he’s coming back). Never was really in the way, but now he’s selling the property and it has to go. I have been hemming and hawing for a long time about taking it on– but the love I’ve read here today has cinched it. Going to DMV today to see about an abandoned/salvage title. Know anything about PD4104-2101?
could milky oil come from veery long time of condensation and not changing oil for very, very, very long time? like never since I had it, 20 years just starting it in drive 4 or 5 times a year?
The positive displacement blower is correctly described as a Roots type, and doesn’t have anything to do with the Rootes car company. The Roots Blower Company initiated this design as an industrial air blower. Currently, the Howden Group manufactures Roots branded blowers.
Thanks for pointing out the typo; fixed now.
That 4106 you posted still looks like a modern bus and it goes back to 1961. Testament to the good styling of the bus.
Hello ,Steve Lloyd here. I have a 1953 Pd 4104 I have decided to sell ,have to fix the barn roof. In good or better condition. New batteries rebuilt starter. Call and I will text pictures. Inside condition is great, paint is nice outside, mostly blue. Thanks