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Payton
04-22-2014, 09:33 PM
Don't here my pump running at all. Obviously brakes are hard and useless.
What should I be checking beside abs relay or the passenger side?
Thanks

r1dd1ck913
04-22-2014, 10:45 PM
Im going to guess you ABS and Brake light are lite?

Payton
04-23-2014, 06:32 AM
Im going to guess you ABS and Brake light are lite?

That's correct

S_Mazza
04-23-2014, 11:56 AM
Easiest first step is to check for power at the harness side of the pump motor connector. If no power, then check the relay. If the relay checks out, then check the trigger signal from the pressure switch. Now, if you do have power at the pump motor connector and the motor doesn't run, most likely the brushes have gone bad.

Pinouts are here:
http://www.35thatr.org/Tips/ABS.htm

Any evidence of fluid leakage below the motor?

Payton
04-23-2014, 06:31 PM
Easiest first step is to check for power at the harness side of the pump motor connector. If no power, then check the relay. If the relay checks out, then check the trigger signal from the pressure switch. Now, if you do have power at the pump motor connector and the motor doesn't run, most likely the brushes have gone bad.

Pinouts are here:
http://www.35thatr.org/Tips/ABS.htm

Any evidence of fluid leakage below the motor?

No leakage. I will check on the voltage, see if it is getting power

Payton
04-25-2014, 06:58 PM
Easiest first step is to check for power at the harness side of the pump motor connector. If no power, then check the relay. If the relay checks out, then check the trigger signal from the pressure switch. Now, if you do have power at the pump motor connector and the motor doesn't run, most likely the brushes have gone bad.

Pinouts are here:
http://www.35thatr.org/Tips/ABS.htm

Any evidence of fluid leakage below the motor?

I've checked for power at 4 pin pump motor connector. No power. Then I should check the relay. How do I do it?
Thanks

S_Mazza
04-25-2014, 08:00 PM
I've checked for power at 4 pin pump motor connector. No power. Then I should check the relay. How do I do it?
Thanks

Ideally, you would unplug the pressure switch from the harness, then ground pin 4 on the harness side with the key on. However, it's hard to get to, so if you can't reach that, I would take out the relay and bench test it. You can use a 9V battery across pins 1 and 2, and see if it clicks. (Pinout on the 35th Anniversary Registry site linked to earlier.) If it doesn't click, then it's not functional. If it does click and seem to work fine, then it's probably the pressure switch that has gone bad.

In the case that the relay isn't the problem, look at the socket that the relay came out of. Check for power at pins 2, 4, and 5 with key on. All three pins should have it. If not, maybe there is a wiring or fuse problem. If power is there, then look at the trigger side.

Pin 1 of the relay is connected to pin 4 of the pressure switch. With key on and pump not running, there will be no pressure. Therefore, the switch should be closing a ground path ... the power entering at relay pin 2, going through the relay trigger side, out relay pin 1, to the pressure switch, and then to ground. So check for continuity between relay socket pin 1 and ground (negative battery terminal). Or check from power to pin 1 and check for 12V. If there is no ground path open, then either the pressure switch wiring is bad, or the switch itself is bad.

If that is the case, then you will have to go back over to the MC unit. You can just barely remove the pressure switch with the unit in the car, but it takes a special tool and it's very tight. Might be better off pulling the whole unit.

vytas
05-05-2014, 03:19 AM
Hi Payton
i had brake problems a couple times over the years - brake lites would come on when applying brakes -then stayed on when pedal became hard and no brakes -- in my case was accumulator that had to be replaced. But you know all about that i think ! Hope you are doing well !!


Vytas

Payton
05-11-2014, 09:12 PM
Turned out my relay went south. After replacing , pump gets energized, pumps the pressure. Unfortunately, after pressing brake pedal once or twice it comes back on.
Does that mean that my accumulator is getting weak? I had it replaced some time ago with the new one I guess it's been more then 7 years ago

S_Mazza
05-12-2014, 12:27 AM
It sounds like the accumulator might be getting weak again. Still, as long as the brake lights don't come on when you press the brake, it may be fine for a while.

Payton
05-12-2014, 06:33 AM
It sounds like the accumulator might be getting weak again. Still, as long as the brake lights don't come on when you press the brake, it may be fine for a while.

Thanks again