Thread: '93 RRC LSE

The ABS pump doesn't run for long.....only a second or two, and then it cuts out again. But it cycles every minute or so. I don't know how often or how long is normal, so any advice in that area would be appreciated.

In a healthy ABS/ETC system (with ignition left on) the ABS pump will cycle every four to five minutes to top up the lost pressure (which seems to disappear within the bowels of the booster unit somehow). Mine lasts about four minutes and takes about 14 seconds to recharge. I've just completed a complete brake overhaul with new accumulator, overhauled ABS pump and cleaned out booster unit.
I don't see a problem with yours except that the accumulator may be leaking internally and/or it has lost its nitrogen.
When you next go to the car (after leaving it off for more than five minutes) arm yourself with a watch, lift the bonnet and lower the drivers window; turn on the ignition (but not the motor) and time/listen to the pump. After about 30 seconds the sound should change as the accumulator is pressurized up and pump labours away to fully charge the system. The pump should cutout after 45 or so seconds.
Leave the ignition on and time how long it takes for the pump to restart.
Again, leaving the ignition on, press the brake pedal and count how many applications it takes for the pressure to drop and the pump to start up again. In a healthy system this should be 3 to 7 or so applications. I'm getting four, but I think there's still a fraction of air in my system (I only finished it yesterday).
If the pump starts as soon as you press the brake pedal, then the accumulator needs to be immediately replaced. I just imported one for about $250. Make sure you get the right model.
But if you get at least 2 brake applications, and you are sure that the pump cycles every minute and for only five or so seconds, then the check valve in the pump could be leaking, allowing pressure back into the pump.
There's heaps more, but I don't want to frighten you! I've already frightened myself enough over the past month getting to grips with mine.