Hey guys, I am scratching my head at this point but I was hoping you can give some insight before I buy something else that I don't need. Well heres the story.

Was changing pads and rotors the other day on my 91 5 Lug S5. I was only changing them because they were worn and the indicators were going off. While changing the rears, I noticed the driver's side break line had a chunk taken out of the outer rubber. So I bought a set of stainless lines that my friend had at his house. Proceeded with the brake job and now changing the lines at all corners as well. In the process, I also noticed that 2 of the pistons on my passenger front caliper were seized. So I replaced this as well. Bled all the lines with ATE Super Blue and then went for a test drive.

The car drove fine, but after applying the brakes hard, the driver's side rear caliper stuck. It stuck so badly that driving approximately .5 miles back to my house made the rotor blazing red and my brake pads were literally on fire. I put the fire out and then parked the car for the night because it was late. Woke up the next day, took the rear caliper off and inspected. Everything seemed fine. Drove the car again, and would feel that the harder I would brake, the more the caliper would stick. Also note, that after letting the car sit for a few hours, the caliper will release.

So I purchased a new rear caliper and replaced the sticking one. Went for a test drive and sure enough the same exact thing is still happening. So now I am wondering if my master cylinder is shot or if there is something wrong with the proportioning valve.

Keep in mind, the brakes were working fine prior to this, aside from the fact that they felt weak (most likely due to the worn pads and the seized pistons in the front caliper). So what do you guys think? Master Cylinder or Proportioning valve or something else?

Thanks in advance.

 

You could of gotten a bad caliper (i am assuming it was a reman). Aside from this, sticky parking brake cable. Did you also remember to lubricate the slider pins?

Your issue is odd if it is only THE ONE caliper sticking. A proportioning valve only works distributing the load to the front and rear wheels as far as I understand how they work. So if that were to be bad, both wheels would of have to seized up in the rear. Did you double check that you installed the pads correctly by making sure the "notch" on the brake pad matched the "hole" on the piston of the caliper? Also, if it were a bad MC, the brakes are distributed diagonally on modern cars, so if it were sticking the drivers rear, the front passenger would be sticking also.

Jack up the rear, and remove problem tire. Have assistant pump pedal and see how it squeezes (can be clearly seen). When he releases the pedal you should be able to rotate rotor/hub by hand (with car in neutral) and will also be able to see the caliper relieve the force it was holding.

 

Slider pins were greased and move in and out with ease. The notches were also lined up correctly. I just removed the reman caliper and the boot for the piston is burnt to a crisp, so I am going to go exchange it. I hope that this is just a case of bad luck and that the reman I got was no good.

 

If it does it again, open the bleeder to see if the caliper releases, if it does, internal break in the flexible line. Replace the line.

 

What flexible line are you talking about? Are you talking about the brake line from the caliper to the hard line? Or is there a line elsewhere that you are referring to?

 

There is only one flexible line, the hose to the brake caliper....

 

I just replaced it with a stainless line. Do you think there is something wrong with the line? When I bled the caliper, it bled fine....

 

What he was saying is there could be an internal kink in the line causing the fluid to not return when depressing the pedal if it doesn't release with the new caliper (follow my previous instruction and observe the caliper before running it on the street)... But my guess is you probably got a bad reman...

 

does your e-brake work , if you can pull on the ebrake and it feels like its doing nothing its probably stuck/ jammed up causing the brake caliper to stay in position.

I had this problem on mine, it was the passenger side rear caliper, i just got the cable unstuck and put everything back together the way it should be, my ebrake cable was just stuck and wouldnt spring back into position from being pulled too hard.

if thats not your problem then it probably is your caliper is frozen

 

might be the line you have

 

Best question yet.
Disconnect the ebrake cable from the sticking caliper and see if the problem goes away.

 

The Ebrake works for both sides. I confirmed this before road testing.

Just picked up a new caliper and will be installing either tonight or tomorrow. We will see how this one goes.

 

**Update, problem resolved**

Ok, put the replacement caliper in and still was still experiencing the same issue. Having my brother press and release the brakes while I wiggled the wheel, you can see the delay for the caliper trying to loosen up. If he really hit the brakes, the wheel would stay locked solid until I loosened the bleeder. I happen to have had another set of stainless brake lines for one of my Miata's that I hadn't installed yet, so I decided to try changing the line.After changing the line, I immediately noticed that the fluid bled much easier and faster. Sure enough, a road test proved that it was infact the brake line that was causing the issue. Not really sure why, visually it looks OK. My friend suggested that there may have been some debris in the system from before I bought the car and that when bleeding the system it got lodged in the line.

On a side note, does anyone know where I can purchase an individual stainless line for this car? The Miata line I have on there now doesn't fit into the stock bracket and I need it for my other car.

 

Not sure about getting them individually, they come in a set. Try contacting mazdatrix and see if they can hook you up...

That's very unfortunate you had that issue with the line. Could be stuck debris like you said or a plain manufacturer defect. You may be able to send it back to the company you bought it from for a new one. If it were debris, I would say that with the force the braking system sees, it would of got dislodged by now. I would call it a manufacturer's defect...

 

I will see if Mazdatrix can work something out for me. I was also considering contacting someone like Goodridge directly and see if I can purchase 1 line.