QuestionDuring the past few months, the ABS/brake warning lights on my 92 Classic (80K mi) began to stay on longer and longer when I start the truck. It is now at the point where the lights may stay on 20 minutes when the truck is cold. Additionally, it feels like I am not getting any power assist to the brakes unless I allow the truck to run a minute or two before driving. The wait time for this pressure to build is also increasing slowly over time.
While I have not had it looked at yet, a mechanic that was looking at the A/C commented that this was due to a failing ABS pump. This seems like a reasonable diagnosis, but I am not sure if there could be a separate brake booster that might be failing instead resulting in the delayed power to the brake pedal.
The ABS pump is pretty expensive and I plan on doing the work myself. I just want to avoid buying this expensive part if that isn't what I really need. Any ideas?
Thanks,
George
AnswerHi George,
Wow! Your '92 Rangie has low mileage.
The feeling of no power assistance when applying the brakes could be related to the Rangie's screw-in pressure switch/sender. I not sure where you'd find one in US. In UK you could try this ABS pump rebuilder: http://www.blackboxauto.freeserve.co.uk/
I have read that early ABS systems had problems with their relays. Word has it that if you replace the pump you should also replace the relays. Do you hear too many clicking noises when you start the Rangie? If so, this is a bad sign.
Perhaps you should consider trashing the ABS system and fitting in a standard servo/master cylinder setup. Locating a new ABS pump may be difficult and 2nd hand ones are rare!
As an immediate step, you could consider changing your brake fluid and bleeding your lines. This fluid absorbs moisture and can cause all sorts of problems with age. Air in the line can also display the symptoms you describe.
Always use fresh fluid and change it every two years.
Best of luck,
JohnMc
