Rear Brakes and ABS lesson learned

[gamellott]

When I bought my 92', it had many issues. One of which was one of the rear disk rotors was ground down, for whatever reason, halfway through the rotor material on one side. I didn't think much of it until the calipers seized. I rebuilt them using brake fluid as the lubricant to reassemble them. That's what I was taught years ago, and I have been doing it ever since.

 

Every 2 years or so, for the past 10 years, I have been tearing apart the rear calipers, unseizing the piston, cleaning the rust out and reassembling using the same process of using brake fluid to lubricate the assembly process....

 

When the calipers were seizing, the symptoms were pretty obvious sometimes. A smoking rotor is one of them.... One of the things that threw me off a couple of times that I didn't really put 2 and 2 together on for years, was that the ABS light would occasionally light up and stay lit when the calipers were starting to seize, and would go away for a while after the rebuild. I was making an assumption that it's old electronics and mechanical gizmos that are starting to fail.

 

The last time I tore apart the calipers, I reassembled them around the dust boot with a one-time-use packet of synthetic brake caliper grease as recommended by one of my co-workers. I'm not entirely positive that is it's the intended use for it, but it's what I used. Ever since then, the calipers have been working flawlessly and the ABS light no longer lights past the initial POST (Power on Self Test). 

 

What I think was happening is that the Mechanical gizmo on the frame was throwing a fault when it couldn't push fluid.

 

So... With this observation, maybe that ABS light you have on your dash being lit isn't a symptom of your module or gizmo starting to fail. Maybe it's a symptom to something else.... in my case at least. 

 

Just thought I would share one of my experiences that I learned over more than a hot minute.... 

[Slartibartfast]

At least you got it in the end! That must've been a grand old PITA to keep having to go through them.

 

The service manual agrees with your coworker. It says to use brake fluid on the pistons, rubber grease on the piston seals, dust seals, and slide pins, and something called poly butyl cuprysil (or, failing that, a silicone-based grease) on the pad retainers.

 

The ABS does have an "other" code (5), for which the first bit of troubleshooting is "overhaul both rear brakes." I have no idea how it would figure this out, given how limited that system is, but clearly it has tricks that I am not wise to! Weirdly mine did not throw that code when my rear brake circuit had air in it.

[adamzan]

The ABS in these while pretty "dumb" just like the ECU, can sense these things. I had an issue where my brakes needed to be bled several times before the ABS light would stay off.. Strange indeed.