Rock Hard Brake Pedal!

ekesz13

Registered User
Driving today and my pedal went rock hard. A minute later it was fine. Turned the radio down and it sounds like the accumulator was buzzing kinda weird. Brakes went back and forth the whole way home. Any ideas or suggestions?

If it is the accumulator, is it a rebuildable part? It looks like a mother to get out, any threads on the procedure?

Thanks guys!! Always appreciate your help and advice.
 
im dont have alot of experience but for what ive been reading u either have to replace the ACCUMULATOR or the RELAY. Or replace both. hope it helps

you can buy them i think at your local autoparts store like KRAGEN or AUTOZONE or any one
 
With it being intermittant, I'd wonder what was going on. Sounds like the pump was being a bit flaky.

I'd start with removing the brown relay (for the hydraulic pump) and checking the contacts. Clean everything up to make sure it has good contact. If that fixes it, you know what the problem was.

If it still is flaky, I'd replace that relay first. Then see how it goes.

An accumulator failure causes the hydraulic pump to have to work more. But as long as the pump is working you shouldn't get a hard pedal. Eventually, that harder working pump will fail. That will get you a hard pedal. But as long as the pump is running, the pedal should still keep assist.
 
Mike-
Okay I will start with that. Is the relay in the fuse block on the drivers side fender well?

Now, just to clarify, when I start the car you hear the pump kick on and the accumulator charges. Rather quickly usually. Yesterday it took quite some time, and sounded sickly while doing it. Does this still sound like the relay? I will check it hopefully tonight or tomorrow. Thanks for the help, both of you guys, and keep the suggestions coming. Hopefully I can fix this without removing the darn thing.
 
The sound you are hearing is the internal relief valve in the system preventing the pump that is running too long from overpressurizing the system. Try the relay first. If you still have a problem it could be the Anti Lock Pressure Switch. You did not share what happens with the Brake Light and Anti Lock (red and amber respectively) so it is hard to tell.
 
Good point. When I step on the pedal, they both come on. I don't know if it was everytime, in fact I am pretty sure it wasn't everytime, but it does happen. I will check that out further also.
 
Anyone know the part number for that relay(s). Guys at Autozone and Kragen have no clue what I am talking about (go figure). Thanks.
 
Mike-
Thanks again. I will pick one up. If I need to replace the accumulator (does that include the hydraulic pump) do the local parts stores carry them?

Also, any posted procedures for pulling that damn thing. Looks buried (as is everything)
 
Ford will carry both the accumulator and the hydraulic master cylinder.

The Accumulator is just the round thing. The hydraulic master cylinder comes with the motor. But from ford it's very expensive.

Prior Remanufacturing builds new accumulators for $99 plus shipping. They rebuild the Master cylinder for around $600 including the pump motor. (From ford it's over a grand)

So hope it's just a relay.

Here is a thread with more info:

http://host.sccoa.com/forums/showthread.php?s=&threadid=25303&highlight=prior+reman

A lot of my understanding on these brakes comes from a great article written by Duffy Floyd with all the information on how the brakes on these cars work. (89-92).

Click the link below for the article hosted at the 35Aniversary website.
http://www.35ththunderbirdregistry.org/Tips/ABS.htm
 
Mike-
Thanks for the continued help! I will take the time and read the article over lunch. I am diving into this problem this weekend, with a new relay in hand, hoping that my problem will be solved. If not, it looks like it will get expensive and I am not willing to dump $600-$700 into this thing right now.
 
Mike-
I worked on the problem this weekend. The first time I turned the key to on, the accumulator charge normally, 1-2 seconds. I turned the key off and then back on a few minutes later. This time the hyd. motor had a real low buzz and it took probably 15-20 seconds to charge. During this I was tapping on the relay to see if it helped. It did not. I pulled the relay and headed to the parts store with no luck. Kragen (special order $21), Autozone (never heard of it), NAPA (no lisitng), Pep Boys (Special order $44). So I have to call Ford this morning. I'll keep you posted. Man I hope this is not the pump.

**EDIT**
Checked another NAPA, they said relay ar240sb (economy) or ar250 (premium) is the ABS relay but for 90-93 SC's. Don't show anything for 89. Was it different??
 
Last edited:
Their book is wrong. 89-92 are the same. 93+ are different though I don't know that the relay is even different.
 
Mike-
Thanks for the info. I just got the same answer from Fast Ed. I decided to go to Napa and purchase the relay and it looks the same (well 5 pins anyway with an inductor and switch on the diagram). I will check it tonight. Thanks again for all your input!
 
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