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1994 ford thunderbird: abs..brake fluid..a faulty master cylinder

Customer Question

I recently replaced the master cylinder on my 1994 ford thunderbird 4.6 without abs, and now the front passenger and rear driver side brakes warm up and eventually get stuck to the point that I can no longer drive until I'm assuming the brake fluid recesses back into the master cylinder. I've gotten two different problem diagnosis, a faulty master cylinder, or faulty proportioning valve. A guy at brake check said that the brakes could be freezing up like that because of a contaminated brake system. Please help me to finally fix my problem so I can drive safely again...
Submitted: 6 years ago.
Category: Ford
Expert:  AMEDEE replied 6 years ago.



9 times out of 10, it is just going to be a caliper that is frozen causing this problem. Its going to be the piston or the slides are hanging up. I have a feeling this might just be a coincidence that it is happening now after the master cylinder is replaced.


Try opening up the bleeder and see if that releases the caliper. If so, then you have a faulty master cylinder or something in the hydraulic brake line causing this problem.

Customer: replied 6 years ago.
I've already replaced the caliper that was giving me problems, and it didn't resolve the problem. It was the driver side rear brake drum locking up too. So right now, it's the passenger-side front brake, and the driver-side rear brake that are getting hot and locking up. The mechanic I used to work for says it sounds like the master cylinder, but the airheads at brake check say it's the proportioning valve, and want to flush my system with alcohol to remove any contaminants.
Expert:  AMEDEE replied 6 years ago.

Sorry for the delay!


THis sounds like a bad master cylinder to me!


Think about. It only started after the master cylinder was replaced.


I think you have a defective master cylinder. Take it back under warranty.


After that, if we still need to dig into this further, let me know... I will be here. But I don't think that we will need to go any further.


I hope this helps! You can always accept my answer now, and repost back again later on if you have any more questions. If you want to discuss it some more just hit "reply", it's free to do so otherwise don't forget to hit "accept" and leave positive feedback if you found my answer helpful.






Customer: replied 6 years ago.
One more thing, if I purchased the master cylinder designed for the T-Bird with ABS by mistake, and my T-Bird doesn't have ABS, would that cause the brakes to lock up criss-cross like it's doing when driving? I wasn't sure whether or not my car had ABS when I purchased the master cylinder, so I assumed that it did. I might not have ABS tho. How can I tell?
Expert:  AMEDEE replied 6 years ago.

I would think this would be a possibility.


TO see if you have abs, just look for an abs motor close to the master cylinder or follow the brake lines from the master cylinder. If you have abs, the brake lines from the master cylinder will go right into the abs unit.


Or, you can look underneath to see if there are any wheel speed sensors or abs rings on the axles or rotors.

Category: Ford
Satisfied Customers: 23959
Experience: ASE CERTIFIED TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
AMEDEE and 4 other Ford Specialists are ready to help you
Customer: replied 6 years ago.

Hey, do you think that this problem occurred because of improper priming of the master cylinder before I placed it on the car? I don't think I primed it at all. The guy I used to work for says I could have ruptured components inside the master cylinder when I installed it without priming it first.

Expert:  AMEDEE replied 6 years ago.

Well, I suppose that is might be possible but I have never seen it. If the brake system is not bleed properly, you would just have a spongy brake pedal.... the master cylinder should not continue to hold pressure on the brake line.

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Category: Ford
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