PM3 acting up. I'm thinking accumulator or pressure switch. Thoughts?

[GOT2B GM]

91 CS International LQ1 with PM3 - 80,xxx kms

Ever since a HARD stop (100km/h to 10km/h full braking) on the Gardiner in downtown Toronto on the way to the Autoshow, my PM3 has been acting up.


When you first apply the brakes (normal pressure application) , everything is normal. After holding that braking pressure for a few seconds as slowing down, the pedal with start clicking away with feedback (similar to ABS engaging), until the pump runs again. Once the pump runs, brakes are fine again.

When the pedal is clicking away, pedal becomes harder, and braking power is slightly reduced although it still slows and stops ok.

I know the car needs an accumulator regardless (pump has always run on EVERY pedal press, and runs every 15-20 seconds with constant pedal pressure. (has ever since I've owned it - a year)

I'm wondering if the accumulator is just degrading more to the point that pressure drops off enough to noticibly affect brake operation between pump runs.

But if thats the case, shouldn't the pump just be running more often? Thats what makes the think about the pressure switch being faulty.


Anyways hope that made some sense.

I want to get this taken care of before I go for the brakes and realize I no longer have any.

Thanks!!


And then theres the question, does GM still have accumulators and pressure switches?

If they do, I'm gonna buy two of each, for the CS and TGP.







Oh and I can't tell if the Antilock and brake lights are on, because the fucker I bought the car off of pulled the bulbs. 

[balkyrollsinred89]

do you have a leak anywhere? SAME thing happen to me, slammed on the brakes to miss a dear and it started leakin just a little at first pedal would fade a little bit but otherwise work fine. but after a little bit it started leakin really bad.

[GOT2B GM]

I dont see any leaks on the garage floor.... I should depressurize the system and check the fluid level at the least.