Brake light comes on and bleeder screws won't turn

["Turbo-T"]

Three questions...

1. If air gets in the system on a powermaster, does that typically trigger the brake light to come on when the pedal has been pressed at least a few times?

2. Also the powermaster motor runs everytime the brake pedal is pushed...my understanding it's not always supposed to run?

3. I thought I'd try bleeding the brakes but the bleeder screw on the right caliper can't be turned ccw at all....even with a breaker bar on it....is it common for bleeder screws to seize up? How can i get it unseized?

Thanx in advance

 

[1quick6]

Sounds like you are the victim of a bad accumulator ball. They are pretty expensive. If you had air in the system, you'd know it because the pedal would be harder than normal and require increased travel. Does the light come on and then go off after a bit? It might be time to think about adding a few dollars to the cost of a new accumulator and consider hydroboost or vacuum brakes. Unless you want to remain factory original, there are no downsides to swapping in a better brake system on a budget.

Did you try PB blaster on the bleeder? If not, keep them good and soaked for a while. Heat can work too.

 

[buickruss]

Those were my symptoms of a bad accumulator. The replacements are not 100% stock looking but mine has worked for 2 years now.

 

[salvageV6]

Typical of bad rusty brake cylinders, time for some new ones.

C clips are fun to change out too.

If there's a tool available to remove them it's worth buying.

Only solution to broken or seized bleeders.

Bleed them good after replacing the brake cylinders.

Check the rear lines to make sure they have the potential to come off easy enough PB BLaster in advance or you will need new lines and the cylinders if they get fubar'd.

 

["Turbo-T"]

Sounds like you are the victim of a bad accumulator ball. They are pretty expensive. If you had air in the system, you'd know it because the pedal would be harder than normal and require increased travel. Does the light come on and then go off after a bit? It might be time to think about adding a few dollars to the cost of a new accumulator and consider hydroboost or vacuum brakes. Unless you want to remain factory original, there are no downsides to swapping in a better brake system on a budget.

Did you try PB blaster on the bleeder? If not, keep them good and soaked for a while. Heat can work too.

I have a spare accumulator ball sitting around. However the whole "brake light on" ordeal didn't happen until just now. I removed one of the lines on the proportioning valve and then reconnected it. So a little air might have gotten in the line, but I've never heard of the brake light coming on due to air in the line, which is why I asked.

Also the powermaster motor running whenever the brake is pushed....what's up with that? Is that also the sign of a bad accumulator?

Did I expedite my accumulator's death by letting a small amount of air in the lines?

Also the light only comes on i I apply pedal more than once in a row. If I apply pedal once and let off no brake light....if I pump and then pump again on the 2nd or 3rd pump, I get a brake light.

I haven't tried PB blaster or heat but will try....thoughI read using PB blaster can contaminate the brake fluid and brake fluid I read is flammable so heating the calipers runs the risk of messing something up...????

p.s. I'm considering going to either vacuum brakes or hydroboost this winter if I can afford it (going to HB)...though I've also heard/read that a vacuumunti can't hold boost at he line for a poor man's transbrake launch at the track like a PM or HB can. :frown:

 

[1quick6]

I am no expert on Powermasters, but here's my take. You are hearing the motor run excessively because it is trying to keep pressure in that leaky accumulator ball. If you rely on what's in the ball only, a PM is only good for one or two applications of the brake before it is out of assistance. Since your accumulator is bad, it can't hold the pressure and the motor is trying to charge it all of the time to keep up.

Vacuum is an easier swap and many people have success with that. Some people can hold boost and some can't, but that's usually due to the overall health of the other braking system components. Hydroboost has greater line pressure than vacuum, which is why some people prefer it. It can help "overcome" weaknesses in other system components so to speak.

Hydroboost is more difficult to install, but the payback is nice. Just like Ford vs GM, you will have people on both sides of the fence with vac vs hydro. You have to move a lot of stuff out of the way to get hydroboost plumbed, but any TR owner knows you always have to remove "stuff" to get to the other "stuff."

As far as the bleeders go, most people only apply heat with the caliper OFF of the car. Heating with fluid in the line would just usher the heat away from where you want it anyway. Imagine trying to heat a pipe to loosen a soldered connection with water still in the pipe. Not gonna heat up. Any liquid can contaminate brake fluid, but you will be bleeding the line anyway whether it's because you freed the bleeder or put a rebuilt caliper in.

 

[zeus87gn]

You need to check a couple of things before chainging parts unless you know your accumulator is on it's way out.

1 - Pump your accumulator down and remove the check valve that is just inside the pressure line fitting that connects on the side of the main body of the cylinder. They can get gunky and leak pressure out.

2 - Cycle your accumulator a few times. They can develop air in them from normal operation. It's unfortunate, but true. If you don't know what I mean by cycle, see the link in my signature. It's all explained there.

Having air in your system won't necessarily be the cause of failure. It will contribute to it, but the main cause of failure on these systems is improper maintanence. Preventitive maintanence is the best you can do with these.

The pump should not run very often - maybe every 3rd or 4th pedal push. If you clean the check valve and cycle the acc ball until no air comes back and pump still runs too much, then you need to start running diagnostics to determine what part is bad.

HTH,
Z

 

["Turbo-T"]

1quick6, I plan to eventually convert over, but as of now the PM is all i have to work with so I'm going to keep it alive for now. Especially since I am going to be moving soon and would like to have it work long enough to be moved a few miles and not via a tow truck.

As mentioned up until now the light never really came on, but now I see the light comes on after about the 2nd pump. Now I discovered this sitting in the garage and not while driving/on the road. I'm almost certain a little bit of air got into he line as I unhooked a front caliper line off the prop valve but then put it right back on. It was after this i noticed the issues I'm having.

However as you have pointed out a leaky PM accumulator ball, I have a spare so I'll look into that. Just I thought maybe the air gettng in the line would set off the light. I've never seen it happen.

What is it in the accumulator ball that goes bad?

Also what's the best way to heat the calipers to free the bleeder screws? Would a Bernz-o-matic torch be enough to get the job done?

Zeus thanks for the input. Can you please show some pics of where exactly this valve is located? (I am no where near my car as of now so I can't go out and look) 2 years ago I did have the MC drained/flushed. The fluid in it still looks like a dark amber color. Not blackdark or anything like that. Before the fluid was pretty dark.

I have heard the PM and HB offer more clamping power than vacuum brakes...my question is if I were to install the S-10 rear wheel cylinders with a vacuum brake set up if it would be enough to hold 10 lbs of boost at the line?

 

["Turbo-T"]

Ok here's an update

Today I changed out my accumulator ball (after pumping down the MC) , then turned on the ignition and let the PM motor do it's thing....turned off the ign and pumped it down again, turned it back on and let the PM motor again do it's thing. I did this 3-4 times.

The brake light now comes on and is hit or miss. During the pump down/recycle sometimes the brake light would come on and stay on even after the PM motor was done. Other times it would come on and would go out after a few seconds.

I took the car out and tested it. The brake light sometimes comes on but when you barely touch the pedal it goes out. Sometimes it doesn't come on at all.

The brakes don't feel as good as they used to but also still it seems the pedal has to go at least 1/2 way to the floor before any braking action takes place. I can however stop the car, just it's not a firm stop. i.e. i can't lock up the brakes....not sure if a PM is supposed to be able to do this or not.

Also the motor turns on every 2 pumps of the brake pedal.

I did notice now it takes 8 pump to get the accumulator pumped down as opposed to the 10-15 times it used to take.

Any ideas what/were I should check next?

Thanks.

 

[1quick6]

Sounds to me like you have air in the system. Probably not what you want to hear at this point. Did you watch the fluid in the MC when you were pumping down the accumulator to see if it was frothy?

 

["Turbo-T"]

I wasn't standing over the MC when pumping it down but I did notice at first there were air bubbles in the fluid one of the times after pumping it down and before letting the motor put it all back in. The fluid on the pump side of the PM was pretty clear last time I checked it. (no air bubbles)

 

[1quick6]

The bubbles will appear in the passenger side port of the MC. The best thing to do if you see bubbles on that side is to suck the fluid out, replace it with new and bleed the accumulator again.

 

["Turbo-T"]

Ok I did what you said to do. I did see some bubbles coming from the hole for the hose that feeds to the pump motor. So I pumped it down and then sucked all the fluid out until it was almost to the bottom. I then refilled it with fresh fluid and then let the pump fill up the system.

Then shut it off and pumped it down, turned it on and let it fill up the system....then repeated this a few more times.

I still get the dreaded brake light on.

Here's a youtube clip I made to give you an idea of what's going on....

YouTube - Turbo Buick powermaster woes

 

["Turbo-T"]

Oh yeah...I did another test...pulled the plug for the pressure switch that sits on top of the PM, the light still comes on as seen in the youtube clip. The only other culprit that could cause this would be the proportioning valve, but why?

 

[RmvBfrFlght]

Oh yeah...I did another test...pulled the plug for the pressure switch that sits on top of the PM, the light still comes on as seen in the youtube clip. The only other culprit that could cause this would be the proportioning valve, but why?

The combo valve will activate the light if there is a pressure differential between the front and rear brake circuits (pressure lines). This would be if there is a leak in one of the circuits.

Note that the parking brake pedal assembly also has a brake light switch. This too will cause the light to tun on.

RemoveBeforeFlight

 

["Turbo-T"]

The combo valve will activate the light if there is a pressure differential between the front and rear brake circuits (pressure lines). This would be if there is a leak in one of the circuits.

When you say front and rear brake circuits are you referring to the master cylinder outputs?

I've checked and I do not see any external leaking or any fluid loss in the MC.

 

[RmvBfrFlght]

When you say front and rear brake circuits are you referring to the master cylinder outputs?

I've checked and I do not see any external leaking or any fluid loss in the MC.

Yes, they are a dual system. One M/C outlet feeds the rear brakes. The other M/C outlet feeds the front brakes. Any pressure difference between the two circuits/systems will cause the combo valve to turn on the brake indicator light (not the stop lights for those not following).

The best question to ask is: how do the brakes feel? Are they solid? Does the pedal sink? Both are signs of an issue with seals or such.

Now, as far as the powermaster, if that has a brake light indicator input, then that MUST be looked at. I do not know much about PM systems. And defer to others on these systems.

One test is to have the PM pumped up, accumulator up to pressure. Then at key-off, get in the car and give & hold a decent amount of pressure on the brake pedal. Hold an even amount of pressure and feel for a drop in the pedal over time.

This is a valid test for PM, vac, or manual systems. The pedal should hold at the same position. No drop or sinking is allowed.

RemoveBeforeFlight

 

[salvageV6]

Air trapped in the valve/lines would cause a light problem too I believe.

I'd re-bleed the whole system back to front left to right.

 

["Turbo-T"]

The best question to ask is: how do the brakes feel? Are they solid? Does the pedal sink? Both are signs of an issue with seals or such.

They're not what I'd call solid. At least not as compared to the Regal I had before which wasn't a turbo car but it did have vacuum brakes and would stop on a dime.

On this one the pedal pretty much goes all the way down when stopping but it will still stop the car. Just takes a little longer than I'm used to. So I don't know if there's an internal leak in the MC or what. You might be able to see how far the pedal travel is in the video I posted.

I bled this system (after my caliper replacement) with a reverse bleeder that's supposed to get rid of all the air bubbles. I don't know how all of you do yours but supposedly the 2 man way is not the best in eliminating all the air?

 

[1quick6]

During your accumulator bleed process, you shouldn't see any fluid returning to the rear port on the passenger side of the MC when the accumulator is pressurizing from the motor. If you do, you have an internal leak.

It still does look like you have a large amount of air in the system. Air compresses quite nicely, thus allowing the pedal travel.

I have never used an injection bleeder. The traditional method with speed bleeders worked for me and my pedal has never been better.

If your prop valve gets out of whack, this this:http://www.turbobuick.com/forums/br...-wheels/260603-proportioning-valve-reset.html