1991 classsic abs problem

Ive got a 1991 classic with an ABS problem, after every third press of the brakes, the pump comes on for about 7 seconds. Today, however, the pump stayed on, even with ignition off. Has anyone any ideas?

So what's the problem. That's what it should do

But the pump would not switch off and it started to heat up.

Stuck relay...I had this on my 1993 Classic....sort it else the pump will burnout!!

I disconected the pump and the sensor, and tried to drive home. Then the brakes stopped working. Reconected the pump and the sensor and now it is back to how it was before, ie. pump operates after every third press for about 7 seconds. I have read that this could be the accumulator, or the sensor. If it was the sensor might it have cause the constant running or the pump?

As the pressure drops the pump kicks up so it could be working OK on 3 presses and it can stay on after engine is off due to the timer delay on the system.
If it stays on for a long time check the relay as it may be stuck or the pressure switch could of failed which is a new pump

What are the thoughts on the accumulater?

shauntbh1 said:

Ive got a 1991 classic with an ABS problem, after every third press of the brakes, the pump comes on for about 7 seconds. Today, however, the pump stayed on, even with ignition off. Has anyone any ideas?

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Sounds like potentially two problems. 1 - the accumulator is weak, IIRC you should be able to get 5 presses on the brakes before the pump operates.

2- Pump running with ignition off would be a stuck relay (as already said) or you have a short somewhere (unlikely). Replace the relay as it is the quickest and cheapest option at this point.

I did the accumulator on my '91 RRC a couple of months back, made a noticeable difference, new, genuine accumulator was about £100.00 delivered and was easy to change.

I would also suggest if you change the accumulator you should think about changing the brake fluid especially if the fluid has not been changed in say the last 3 years but do be aware that bleeding the system is time consuming and MUST be done to the letter of the workshop manual. Make sure you have a lot of brake fluid available for bleeding (at least 5l). HTH

I will try the relay, but as I have electric seats, where would I find it?

shauntbh1 said:

I will try the relay, but as I have electric seats, where would I find it?

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Regardless of if you have or haven't got electric seats, the relay will still be in the same place!

It should be under the LH Seat...remove the side trim panel and it should be there!

Thanks.

tried the relay, all is fine. Will a p38 pump fit the classic.