Chrysler Repair: 92 LeBaron: Bendix ABS diagnosis


Question
Hi Roland, I own a 1992 Chrysler Lebaron GTC convertible. It has the 3.0l six cylinder Mitsubishi engine and A604 4spd auto. Just coming on 190,000km. Almost restored, well, most every part replaced it seems! I've had a problem with the ABS since I bought the car. The ABS light was on when I first bought it. Also, it was clear to me it wasn't working; car would lockup driverside rear first and slide and no vibrating or modulating pedal with hard depress.
About a month after I owned it, I was running it very very hard one wet,dark,rainy,evening in a huge parking lot to "test it out" I was pushing on the brake pedal hard, doing skids, accelerating hard...(I was getting new tires next day so a bit of messing around). Anyway, lo and behold, the ABS light went out and the system started working like it should. The brake pedal "modulated and vibrated" under my foot as I could feel the ABS working, and of course the car braked straight - with no skidding. This "fixed" condition lasted for 7 months, and one morning in April, just like that, the light came on, and the ABS disappeared.
I checked all the fuses I could: the one under the hood, and the two relays on the passenger side I cleaned with electrical contact cleaner. I can't remember if I completely ruled them out with a manual test...I could get someone to step on the brake and put my hand on them. I did ask the mechanic to take out the electrical connection going to the pump last time he had it on the hoist, and spray some electrical contact cleaner on that...but I didn't see him actually do it.
Do you have any ideas, Roland on what I could do myself with this before I start laying out the hundreds for a mechanic to look at it? What's your experience with the ABS system on my year Lebaron? I believe the pump says it's a "Bendex"...and it looks like I have to pull a fair bit of stuff to actually get at the pump. I appreciate any insights you'd have on this matter.
Thanks in advance,
Rick

Answer
Hi Rick,
I have no personal experience with the ABS systems. I do show in my '91 service manual that in that year the unit is called the Bendix 6 ABS while in my '94 it is the Bendix 4 ABS. The pages about the ABS system number about 25 in the '91 manual, and about 40 in the '94 manual.
So my first question would be is it the 4 or the 6 ABS; perhaps you can read the labels and verify which.
The best approach I can recommend is to take advantage of the  ABS self-diagnostic capability which is accessed by a blue color 6-pin connector located under the dash near the fuse box. A Chrysler DRB II diagnostic readout box plugs in there and can then determine why the ABS warning lamp has been illuminated. That would be the most efficient way to address this issue.
There may be a similar Snap-on obd-1 readout box.
If you can determine which ABS you have I could Xerox copy the pages from either the '91 or '94 manuals and postal mail those to you. It costs me 10 cents per side.
I have the DRB II and live in the SF Bay area.
Roland