Help diagnosing Hard brake pedal problem


Aug 13, 2004
I have a question about my powermaster I was hoping I could get some help with. I’ve only had this car about a week and I’m just starting to look into a few of the small mechanical issues.

I’ve done a search on the powermaster issues, and read all the diagnostics, but what I’m seeing is inconsistent with what I was told about the car.

The current problem is an intermittent hard pedal. The brake light also comes on for just a second every time you hit the pedal. From what I’ve read it would appear that the problem is a bad accumulator. The confusing thing is that the previous owner indicated that he had just recently replaced the accumulator.

Is it possible the new accumulator was installed incorrectly or some other underlying problem has ruined a second accumulator? Any input is appreciated.
Ill be the first . If you search this forum you will find more than enough information to help you trouble shoot your problem . I was where you are a year ago . First of all it might not be your powermaster that has the problem. How many miles does your car have . Did it sit alot . I would work back to the powermaster first . If the car sat the brake cylinders can be bad . After you check that then go to the front rubber brake hoses . Is the problem happening once the fluid gets hot . When I had this problem I pulled out my powermaster put in vacuum and then I had to buy new calipers wheel cylinders and in the end it was the front left hose that was bad . You have asked the question that is more debated than any other issue .
I will tell you this a hard brake pedal is nothing to ignore . My brakes failed and its not fun when you have all of this money you just spent is not stopping .
Start with the basics change the fluid check the cylinders , hoses than hit search button . Alright guys go at it .
Thanks for the help. I’ve owned Turbo Thunderbirds for several years and hung out on those fox body forums so I knew better than to ask a question on here before searching – especially after learning that the powermaster was such an area of contention. The last thing I need is to be an outcast from the beginning.

The trouble I’m having is that my problem seems to conflict with the information I’ve found. The car has been garage kept and has about 110,000 miles on it. Everything I read says an intermittent hard pedal combined with a brake light that blinks for a second when the brakes are applied is a sign of a bad accumulator. The former owner said the accumulator was recently changed (and gave me the old one with a box of other parts) so I’m just wondering what else it could be. I trust the guy that sold it to me, and I was just looking for answers that seem to be outside the norm of what I came up with on my searches.

I really do appreciate the input and I will start with the motor and go from there. I will also try searching other terms and see what I can come up with.
When the accumulator is chaged, it needs to be cycled to get the air out. If that is not done, it will not function properly. I had the exact same problem you are having. Light coming on when you first touch the pedal and then going off sounds like the accumulator.
My question to the person that installed the accumulator is: new or used? If it's used stock it just be a bad piece. If new then you can tell that because the new ones are slightly different looking than the stock units. I just replaced mine (origial item) with the Kirban one. Took a total of 10 minutes and now I have no brake light coming on for a second or two when the brakes are applied.
Most questions have already been mentioned...possible used acc...possible other problems outside the P/M.

One that hasn't been mentioned is have you actually run the diagnostics yet? You need to put a timepiece against the system and find out if you have an internal leak. A new acc isn't any good if an internal leak is present. You can get the symptoms you are describing.

Stnd diagnostics are here: Powermaster Diagnostics

Get those times back to us and we can tell you what's happening.
It only takes a couple of minutes.....
Sorry. I'm doing this on my Blackberry so sometimes I am too brief.

I ran the diagnostics and really don't get past the accumulator check. The accumulator was replaced with a Delco unit (made in Germany) to address this same problem. I was told the problem remained unchanged.

When I run the diagnostics I checked the fluid (strngely enough the resevoir cover is very tough to get on). After giving the brakes 10 pumps with the ignition off and I turn the ignition on the motor runs (it clicks a few times anyway - I never listened to it so I have no frame of reference). However the brake light only stays on for a second or less.

I could be reading wrong, but that seems to indicate a leaky accumulator.

I know you veterans get tired of the newbies asking the same questions over and over so I really appreciate the help. I just wanted to try and reverify it looks like an accumulator problem before I throw money at a problem that was just recently addressed.

Thanks again.
So you're saying your motor doesn't actually run?
You don't hear it humming when you turn on the key?
It just clicks?

If so, you acc has a blown diaphragm (not just leaking). It's dead. Replace it and test again. If you have the old acc, change back to it and try and test again. If you get the same results, try it with a known good acc. I would hope a fellow TR owner would be willing to swap for diagnostics purposes if you can find someone close to you. And I'll bet the motor goes to humming and the fluid gets sucked down.

Once you get the motor running, you can test and see if you have any other problems.

BTW, that cover should be good and snug (tight).

Edit: 1000 posts now. Do I win a prize?
I don’t hear it humming, it just clicks a couple of times. I will replace the acc with the old one and see what response I get before shelling out $200 for a new one. Its just strange that the new acc would be bad or go bad so quickly. If anyone near Houston has a known good they would let me borrow for a day or so I’d sure appreciate it.

One question – if I do have a blown diaphragm in the acc is pumping the brakes going to relieve the pressure on the acc so I can remove it or is it still going to be under pressure?

Let me try this and if I come up empty I’ll get back on here. Thanks again for the willingness to help. I’ve wanted this car since I was a sophomore in high school so as much as I hate not being able to drive it for a few days, I would ate it even worse if I put it into the back of a car full of kids because my brakes wouldn’t work.
That "new" acc has probably been sitting around for a few years. If I understand you correctly, it's the German made one with the yellow circular printing around the removal nut on the outside of the ball? They haven't been manufactured in quite a while. They don't have a good shelf life.

The latest model acc ball is being sold by Kirbans and GBodyparts. They started selling them just over a year ago (approximately) as they have been able to find a new mfg. I have one myself.

I will keep my fingers crossed for you. I know there are many TR owners in the Houston area. Get on the Texas page here on the board and ask around.

Unplug your P/M motor and turn on your key. If the brake light is on, push the pedal to be sure it's hard and it should be depressurized. It most likely is pumped down anyway, but better to be safe than sorry with 700psi.

I can understand you desire. Just don't mess around with trying to use 'used' parts for maintaining your brakes. They need to be trustworthy. After you get the motor running, do the diagnostics anyway and you can determine the health of your P/M.