well, I guess that my brakes got jealous that everything else on my car was working, so they decided to quit.
The problem is the pedal only goes half way down. No matter how hard I press, the car won't stop. I press really hard but I only get about 5% from the brakes.
The problem started about a month ago. It was real intermittent, but this morning they went big time. Only worked about half the time on the way to work. They work now, but I don't know for how long.
Fluid is fine. I can hear the pump working. Brake light is NOT on and the only code I am getting is 24, but that is unrelated I am sure.
Any ideas?
One idea: Code 24 is Vehicle Speed Sensor circuit failed. So that is not it. Plus, your brakes are not hooked up to the computer, so you won't get a code from them, even if they fall out of the car completely. You should get a brake light though if you are losing pressure in the system, which it sounds like you may be. Are you sure the light works? Try turning the car off, and pump the brakes 10-15 times to depressurize the system. Then turn the ignition on. You should see the light come on while the pump builds pressure.
If the brakes are still working, then you haven't blown the fuse, so I would guess that the pump/motor is going, and that your light is out. Good luck.
Brian
Well, I know my brake light does work. It comes on when my key is in the "start" position. But not the on position. It also comes on when I put the emergency break on.
I did pump it with the key off like you said. When I turned the key on, the brake light did not come on, and I did hear the pump run for 3-4 seconds.
Maybe the pressure switch is messed up. That might be why it isn't turning the light on. Of course, I am out of real ideas, so this is just a guess.
I should've mentioned this earlier. On this site, there is a page on brakes with procedures for diagnosing etc. Here is the link:
http://www.gnttype.org/techarea/brakes/brakespage.html
Brian
Thanks, Brian.
I did check out that page, but it was of no help.
With the key in the "on" position, I press the brake pedal and I can here pump working after every time.
I am just going to replace the accumulator to see if that helps.
BTW, what does the accumlator do?
The brake pedal should take about 10-15 pushes before it gets too hard to push anymore, with the key "off". So basically just shut the car off and push the pedal until you can't push it anymore or that it seems to not get any harder, reached it's "hard" limit so to speak. Then when you turn the key, your brake light should come on while the motor runs for a little while, like 20 seconds or less if I remember right, and the light should shut off towards the end of that time. Try doing that to check the light. As far as the accumulator, from my understanding, it's a just a ball with a diaphragm inside. On one side is the brake fluid and on the other, sealed side, is compressed nitrogen gas. As the motor "pumps" up, it's filling the one side of the ball with brake fluid. Since the other side has a gas already there, the more fluid you push on one side, the more pressure you get. When you hit the pedal, instead of a vacuum-type assist, you get the assist from the now pressurized brake fluid. You hit the pedal, a valve moves allowing the brake fluid, that was forced into the ball against pressure, to shoot out with a nice amount of force and help you stop your car. So more of a gas-assisted brake system as opposed to a vacuum-assist. Atleast I think that's how it works, if it's not right, sure sounds good,
good luck
hmmm.
Sounds like a good explanation, thanks. That would explain why replacing the accumulator fixes most of these brake problems. Sounds like the thing just runs out of the nitrogen...If that is true, it sounds kind of "hokey" to me. LOL.
I am a little curious/concerned as to why the brake light won't come on after I do the pump/key off test.
I plan on replacing the accumulator today, hopefully that will do it.
Shawn,
Good luck with the accumulator, I hope that's all you need, but I think you are going to find your problem is the Powermaster itself. Still, throwing the accumulator on is easy and even if you still have to do the whole Powermaster, you will now have a spare. That's how I ended up with mine. It's weird though, because usually as the accumulator starts to die, you get some brake light flashes and soft pedal, not the hard pedal you describe...
The rock hard pedal and hardly any braking is pretty symptomatic of the Powermaster suddenly [and often with no warning] kicking the bucket and lot of us have experienced it. That not-very-subtle failure keeps my wife from driving my TR. I bought my replacement from Jack Cotton, but there are other vendors out there who have them as well.
I swore to myself this is the last PM on putting on my TR, and that next time I will switch to the vacuum setup instead [I figure why not try it?] and keep all the PM parts in case I want to switch back, which some members have done. [I think it is close to an even split on the list opinion on which is better; PM or vacuum system.]
Good luck…
Mike Elia
SoCal [formerly Upstate NY]
87 T [just did the PM a year ago or so, right before I killed my tranny]
I hope that is all I need. I just got my transmission done and I can't afford the PM right now.
Hoping and praying...
I think the reason the brake sytems go out suddenly is, the only failure I can think of regarding the accumulator, that the diaphragm tears or gets a hole in it just from thinning out being in contact with the brake fluid. So one second you've got a nice charge of nitrogen, the next you don't. Don't forget about Hank Terry, he sells the new pumps for the powermaster at a fraction of what a new PM unit sells for. And, with my limited knowledge of the PM system, I'd say the number one problem is the pump goes out, slowly gets worse and then just plain goes. Then maybe the accumulator. Other than the piston assembly setup in the actual mastercylinder part, the only other parts to the system are the switch and the reservoir. I'm not sure about your light not working, maybe someone else could chime in on that, but if your light isn't coming on when the pressure is low, I'd guess the switch maybe?? The switch turns the pump off and on, and I'm guessing it also has to do with the light, ie if the switch detects a "dangerously" low psi, it turns on the light to let you know that you may have a hell of a time stopping the car. I can throw another guess out, that if your switch is bad, it won't get your system to the amount of charge it needs, probably has it too low and doesn't recognize that it's really too low and turn the pump back on. I can guess all day on the what ifs, I'd just suggest you go back to that page and use the "Fix your PowerMaster Part 3", the diagnostic logic chart. I don't think it will cost you as much as you think, I can't say for sure but I think a switch is maybe $60 (could be wrong but wouldn't guess it to be over $100...sre hope not!), and if I remember right, I think Hank has the motor/pumps for about $130-160, which is hardly the $300 reman price or the $1100(last I heard) GM price. Good luck
Thanks dude. I just replaced the accumulator and so far so good. (drove for 15 minutes in stop and go traffice). There were real bad before, so I take this as a good sign.
I got a quote on a remained unit and switch for $365 from my local shop. (altough I still can't afforted it).
Thanks again-
If I were you I would most certainly replace the PM with the "vacsac". I replaced mine today and they work as if nothing had changed. No anoying whining sound from the elecric motor. $170 and I had to modify the brake pedal. Took about 2 hours. At least I now know something about brakes!