328 89 ABS brake fluid change procedure

I don't believe ABS is any different. If you have been reading around you have read not to deperss the brake all the way to the floor. This is for a vehicle that has not had it's annual brake fluid flushes done throughout it's lifetime. If not done for a long period of time, water can build in system and corrode the areas beyond normal use in the master cylinder. The corrosion will then shred the seal. My car has great records. Running it to the floor was no issue.

If you have never done it before you might try on your daily driver first. I change the fluid on my Euro vehicles annually, all others ever 2 to 3 years. Mostly because I'm not worried about a potential caliper change on the cheap cars.

 

You have to have the ignition switch turned on when bleeding the brakes. This will run the ABS pump and push fluid though the system.

 

The instructions I got from FoD, I passed on to the Anchorage Porsche dealer who repaired a leak in my ABS unit (Bosch parts, so he had no problem). After the repair, he stated that the ABS unit repair went fine and the system worked as intended. That was years ago, and everything still works fine. Mind you, that was a professional mechanic doing it, so I can't guarantee he followed the steps exactly or used his technique.

 

See below (one of the most respected shops in the US!)

 

If you PM me I can send a scan of the tech manual for the Teves MK II system which this is. It contains full info about bleed procedure. It states that the front process is normal but the rear right and left have slightly different procedures. Left is done first with the pump running and pedal fully depressed, then Right is done with the pedal slightly depressed.
Note it also contains a warning that the pump will overheat if left running for more than 2 mins, which could be an expensive issue!

 

This is what I remember reading somewhere as well, although I didn't have quite that much detail on the rear and slightly/fully depressing the pedal. Plus, I did the right rear first and then the left rear.

DO NOT get air into the ABS unit. From what I understand, you'd need a special set-up to get it all out and it's a major pain.