Brake light coming on and going off while applying brakes

[Turbo_D]

Alright, I'll try to keep this short and sweet so noone will get bored:biggrin:

Pump went out, had rock hard pedal and brake light on whenever ignition was on. Replaced brake pump assembly (reman) about a year ago. I only drive it about once a month.

Since replacing the pump, the brake light comes on for about a second when braking and then goes away. It comes on every time you hit the pedal. It always goes off about a second later. If you hit the pedal very slowly it doesn't come on.

Did an accumulator bleed by pumping the pedal 10 times and no air in resevoir. Bled brakes at the caliper in front and at the drum in rear with wheels off, still have brake light coming on.

Unhooked brake switch on the frame under the car (don't know which one it is, saw it on wiring diagram) still have brake light. Unhooked the switch behind the resevoir beside accumulator ball and brake light did not come on.

I don't know if this means that switch is bad, or if something on that side of the brake system is bad. Unhooking it basically unhooks everything.

Any thoughts/ideas appreciated. The pedal feels fine and the car brakes well. I just can't get the brake light to go away and it makes me nervous.

Thanks-D

 

[T Spool]

You described my problem exactly. All the research I have done tells me it's the accumulator. I bought one thinking it was new and would have been able to let you know if it solved my problem, but it turns out to possibly not be new and I don't trust it so back to the drawing board.......

My brakes also feel fine and the light goes out after unplugging the grey switch. Kirban says a flashing light and no other symptoms is usually the accumulator.

 

[aminga]

Correct it is most likley the accumulator. It will get worse.

 

[Turbo_D]

It is kind of strange that it didn't do it until I replaced the pump. I thought it was maybe a defective pump.

Alright, next question. Where can I find an accumulator ball for a 21 year old car? Specialty TB shop like Cottons or an auto parts chain?

 

[my85grandnation]

I would suspect an accumulator on the way out as well. You need to replace it asap before it leaves you without properly working brakes. I would only buy a new accumulaltor from a vendor like the ones Kirban is offering, either that or switch your system over to vacum or hydroboost brakes.

 

[Turbo_D]

I did a google search and found a great post about accumulators over on TB's.com. It seems pretty cheap through gmpartsdirect.com

Cheaper Powermaster Accumulator - TurboBuicks.com

 

[TLIMITED]

It is kind of strange that it didn't do it until I replaced the pump. I thought it was maybe a defective pump.

Alright, next question. Where can I find an accumulator ball for a 21 year old car? Specialty TB shop like Cottons or an auto parts chain?

Should be a weak diaphram in the accumulator,also when you change it be sure to suck out all old fluid out of the unit and replace with fresh fluid,I like synthetic and have never had problems since(about 6 years) but I change fluid once a year.Hope this helps!!!!!!!!!

 

[zeus87gn]

TurboD,

That switch on top of your P/M tells your motor when to turn on and off and sets off the light in your dash when the acc is dying.

That thread you linked to is kind of old.
The second gen acc's have been discontinued for some time now.
Third gen acc are now for sale only at Kirbans and GBodyparts that I am aware of.
You may find a second gen on ebay if you want one.
They aren't cheap.

You should really time your P/M to make sure of what's going on.
Look here: Powermaster Diagnostics
It's the GM testing, but it's valid for the most part.

HTH,
Z

 

[Turbo_D]

TurboD,

That switch on top of your P/M tells your motor when to turn on and off and sets off the light in your dash when the acc is dying.

That thread you linked to is kind of old.
The second gen acc's have been discontinued for some time now.
Third gen acc are now for sale only at Kirbans and GBodyparts that I am aware of.
You may find a second gen on ebay if you want one.
They aren't cheap.

You should really time your P/M to make sure of what's going on.
Look here: Powermaster Diagnostics
It's the GM testing, but it's valid for the most part.

HTH,
Z

Thanks Zeus. I went by your bleeding procedure on Saturday. Very well put together, thank you sir!

I didn't think to look at how old that thread is. What must have been the third gen was $179 at Kirbans. I will check gbodyparts.

D

 

[Turbo_D]

Let me go ahead and ask where I can find the correct procedure for removing the old acc and installing the new one. I am guessing you would need to do some kind of complete bleed down.

 

[aminga]

Let me go ahead and ask where I can find the correct procedure for removing the old acc and installing the new one. I am guessing you would need to do some kind of complete bleed down.

Just depressurize it and unscrew it.

 

[aminga]

Thanks Zeus. I went by your bleeding procedure on Saturday. Very well put together, thank you sir!

I didn't think to look at how old that thread is. What must have been the third gen was $179 at Kirbans. I will check gbodyparts.

D

I believe Brian has to order them. I put one on about 3 months ago and it seems like it took about a month as they were out of stock at the time.

 

[Turbo_D]

When you say depressurize it, do you mean just pump the pedal with the ignition off?

 

[aminga]

When you say depressurize it, do you mean just pump the pedal with the ignition off?

yes.

 

[Turbo_D]

Thanks aminga.

 

[zeus87gn]

Thanks Zeus. I went by your bleeding procedure on Saturday. Very well put together, thank you sir!

I didn't think to look at how old that thread is. What must have been the third gen was $179 at Kirbans. I will check gbodyparts.

D

You're welcome. That thing took some time, but I still need good pics.

Yep, the third gen is all that is available "new" these days.

Feel free to ask if you have questions.

Z