CC Tech: 1991 Mazda 626 LX – After 31 Years It’s Time To Replace A Few Things

Since I last introduced my 626 a couple of years ago there has been some maintenance of things expected and some unexpected. So let’s take a look.

One thing that catches up to a car this old is the power windows. Not the motors as one has never failed. You know you have a problem when you come out one day and see a window has slid down. What happens is that a piece of the plastic anchor for the glass breaks from age and lets the window slide down. Quick fix is to get inside the door and brace it up with a piece of wood. In the past I went to junk yards to pull replacements out. However, those days are over and from the looks of it my 91 626 hatchback maybe one of the last in California. No problem though as I hit eBay and find someone selling two new complete OEM regulators. Below the left is unused for the other side while the right was the broken one I pulled out.

Now the main window control is also made of plastic and here one day a piece under the passenger side switch broke. That caused the window to spontaneously go down and up but more down. First thing I did was go into the door to disconnect main power. I then used some wire clips as a bypass and caused the window to go back up. Then I went hunting for a main switch. I had a bad feeling about this because I knew I had never seen any for sale before. The top color panel can be removed and moved from one to the other. However, I did find one and it turned out to be the most expensive part I have ever had to replace on the car. One needs working windows and one yearns for manual windows.


Next the upper panel where the switches for the sunroof had one of the lights not working for a long time. You push in the lens to turn it on and off but not with one side. Finally found a working panel to install and have everything working.

Next repair is my speed control. It simply stopped working one day and the switch no longer lit up. The Mazda manual has a very long dissertation on how to diagnose the problem with probes. Well my switch fails to light, when pressed, so maybe a new switch. Yeah, right, where will I find that. I already know almost all parts have been now discontinued for these cars so all I can do is eBay. One day a switch pops up for $40 from my favorite parts seller. I replace the switch and also put on a new vacuum speed control unit that I have in the garage.

So in order of repair here is one I wasn’t expecting. I’m driving home from the USS Hornet, Saturday late afternoon at 1730 hours. As I drive through the Posey Tube, a tunnel under the Oakland estuary, there is some stop and go traffic. While shifting I notice my clutch pedal is not completely coming back up and have to raise it with my foot. I get through the tube and then a steady pace on the access street to the freeway and smooth sailing. Smooth sailing for 20 miles where I exit the freeway, it opens up to four lanes with a light, before crossing the intersection. I take the far right lane and put the clutch in at the light. What clutch? I have no clutch!

Now I am dead in the water and have to flip on my emergency flashers. Here is where I got to observe interesting human behavior for the 50 minutes while I awaited AAA. The first car that was behind me with the flashing lights hit his horn several times before deciding to go around. That was one behavior as several came around the corner, some quite fast, and pulled right behind me followed by others. They always hit the horn, it is twilight now, and then realize they can’t back up because there are several cars right behind them. Behavior two were those who came around the bend and saw the flashers. They stopped a decent distance and at first I though good they will go round. No, I gave them too much credit as they then pulled up right behind and used their horn. Finally, the rare third type were those who actually pulled around to the two lanes left of me. Cognitive abilities were rare that evening. Anyway the AAA guy arrives and gets me home where upon he spends an hour noticing all my cars.

So fluid is mostly gone but where. Not the slave cylinder as that is a new one and it was dry. Above my foot there was dampness but not soaking wet. There was also a 10 mm wrench sitting on one of the nuts holding the master on. Someone left it there many years ago.

That night I go into the garage to go through my boxes as I know I must have one of these. Yes, I have both a master brake and master clutch cylinders.

Two bolts off and two bolts on then screw on the lines, fill, and done. It did take some pumping to finally clear the air and get pressure while bleeding through the slave.

Now for the last two months rather than the last year. See that green connector in the above picture sitting above the clutch cylinder? Well, when the car throws a code this is what you have to use. So while driving the last two months a check engine light would flash once in awhile on the dash. Sometimes it would stay on for the whole drive. Now it had been so long since I had to read a code on another 626 that I forgot and had to really search for the answer. My memory said connect a ground wire in the engine compartment and hook it to what? Well it is this single connector as you can see above.

Once connected you go into the car and put the ignition into run. The check engine light will then flash. It can be a long flash or a short flash or combinations of them like Morse code. So I got one long flash and seven short flashes for 17. My Mazda lists 17 as O2 sensor not updating.

Ok, so my sensor is done and I know I have two Densco sensors in the garage. Getting the sucker out, even with anti-seize used and the right socket was tough. The damage you see is due to the O2 sensor socket made for the job. In fact I used a 12 point closed end wrench and tapped it loose much easier. Simply replace with more anti-seize and you’re good to go. I did notice the quiet idle was much more quiet than before. Subtle but it was there.


The last long planned activity for the car was the replacement of the entire rear suspension. That means struts, six various control arms, and sway bar end links. I managed to collect everything over the years and now it is time. Doesn’t ride loose but is 31 years old now.

There are three control arms each side. Two are transverse on either side of the drum and one longitudinal anchored up under the rear door. They are very easy to remove and replace with the new arms seen below. Only one of the longitudinal arms is not Mazda NOS.

Getting at them was much easier than the ones on the Focus.  On one you needed to disconnect the cross member and lower it to get the bolt past the floor pan and another was fiddley to get at on one side because of lines. All one needed to do was match up the new adjustable lateral arm to the old, exactly, since that one controls toe in and toe out for the rear wheels. With that done it was time to move onto the struts.

I actually pondered this for an hour going back and forth. The FSM says nothing about the removal of struts on a hatchback only the sedan. In the sedan, open the trunk, and you can see the three nuts holding the top plate of the struts. Not so in the hatchback and it was obvious where those nuts were and also obvious that panel is going nowhere.

So you need to remove the seat back bolster to get it out of the way and pry away the trunk lining to see the nuts. Slip in your 14 mm wrench and loosen nuts so you can spin off with your fingers.

I was given the car in 2010 and so I have no idea how old those rear struts are unlike the fronts which were replaced five years ago when I rebuilt the front.

Into the vise and compress the spring a bit to get the mounting plate bolt off. Good thing I have that electric impact wrench because that bolt was rusted on. How since it is inside the car I have no idea but it took about one minute for the impact to break it loose on both sides. After that it was simply remove and then replace with new plate and new rubber insulator. Obviously I took the spring out to wash it completely before putting back in the car. Just one of those quirks about me in that everything must go back in clean.

Strut back in along with new rear brake hoses I had in stock for the car. Once again the old ones might have been originals. Out on the road, the car was never unsteady with the old components but she is sure a nice smooth car to drive. Super reliable despite the work I have done since most of it was for expected wear parts. All this work spanned from early this year to last month.


These are my last major parts for the car from my favorite eBay seller. The clutch was $79 as was the Denso OEM compressor. The Mazda throttle body was $49. The throttle body maybe next and then the entire AC system that includes, drier, condenser, and hoses. I have my choice of R-12 or R-134. The clutch will be used when the engine gets pulled for rebuild in the farther future as three others are ahead in line. The 410 is coming out but that is another story.

Oh, and here is a strange update on my Focus. For about two months I noticed that the Focus was just a bit hard to start and it wasn’t the battery. Then there was a new tendency to stumble when accelerating quickly on the freeway. The idle was also a little bit lower and rough. I was suspecting a COP. So two weeks ago I got out to diagnose the issue. I pulled all the spark plug connectors, remove the four COPs and plugs to inspect. Nothing unusual. Get in the car and start. As the car is running and the fast idle settles down the check engine light pops on for the first time. Pull out my reader and see I have a code. Not one, not two, but six codes, P0300, P0301 pending, P0301, P0316, P0351, and P0352. Yep, I guess it is a COP and #1 is shot. So I order four (better safe than sorry) Denso OEM COPs and installed all four. Wow, what a difference in response. Last note that under the Denso sticker on the top of the COP was the Motorcraft number but at half the price.