Another caliper sticking

Black GT

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Sep 8, 2018
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I was driving my 2001 GT today and I could tell a brake was dragging. I started smelling something strange. I stopped at a store and got out to feel my wheels to see which one it was. Looked at the left front and it was smoking. I decided to drive it home and lost my brakes. Had to drive 5 miles with no brakes. I just replaced the right front caliper because it locked up completely. Can not understand why I lost my brakes though. Have not torn it down yet to see what's going on with it. Why do I keep having calipers lock up? I have been driving over 40 years and never had that happen until I got my mustang.
 
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7991LXnSHO

wanna catch the space herp
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If your caliper locked up and got hot enough to smoke the pads, that could be enough heat to boil the brake fluid. Bubbles (gas) compress much more than the same material in a liquid state. If the pedal has resistance now that everything has cooled off, that’s what happened.
If it got that hot and ruined seals, you would loose brake power on that end of the car with a dual circuit master cylinder.
Does the parking brake still work? I have used that on cars when the master cylinder went out to get it to a safe workspace. It’s not recommended, but I am going to teach my kids how in case they need to know how in an emergency.
 
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Black GT

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I had a chance to pull the tire off today. The rotor turns freely in the caliper and just moving the car it seemed like I had a brake pedal. I checked the brake fluid and it is full. No sign of brake fluid on the caliper. Yesterday when I was driving it I could feel the brake dragging and would hear a clunk and the brakes would release until I applied them again. The brakes were working but dragging before I stopped and saw the smoke coming from the wheel. There was a strong smell from the heat also. After I got back in the car to take it home is when the brakes were completely gone. I was going to drive home using the emergency brake but when I pulled up on the handle it did not even slow the car down. Car has a manual transmission so I used the engine to brake the car as much as I could on the ride home. It got so hot on the way home my center cap came out of the wheel. A couple months ago I had to replace the caliper on the other side because it locked up completely. The car would not move and would just spin the tires. I had to pry the caliper off that time.
 

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7991LXnSHO

wanna catch the space herp
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I would not drive it until I replaced the caliper and hose, and then fixed the parking brake. Hoses can get like cholesterol clogged arteries.
I’d also be suspicious of if the rear pads are also shot.
 
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manicmechanic007

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Black GT,
7991LxnSHO is right
Your brake fluid boiled and the brakes got spongey
Switch to dot 4 or 5 if you can handle the pedal feel and the fluid will not boil near as easy
Keep 2 calipers in the trunk and the tools to change them
Reminds me of vintage 4 piston Corvette calipers
 
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Black GT

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Black GT,
7991LxnSHO is right
Your brake fluid boiled and the brakes got spongey
Switch to dot 4 or 5 if you can handle the pedal feel and the fluid will not boil near as easy
Keep 2 calipers in the trunk and the tools to change them
Reminds me of vintage 4 piston Corvette calipers
Thanks, I will change the fluid. I have never owned a car that I have had brake problems like this car. All the other cars I have just require a pad change occasionally. Thanks for your response.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
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The 99-04 PBRs are notorious for seizing. Anecdotally ive seen them seize up when a car is seldom driven, or in the spring when a lot of guys take their cars out from winter storage.

My feeling is the root cause is poor quality brake fluid, or old brake fluid that has absorbed a lot of moisture and is allowed to sit for a period of time and slowly corrode the inside of the caliper. Having torn down a few seized calipers, it does looks like this is the case.

Replace both calipers, use quality brake fluid, and stay on top of fluid flushes. Bleed all 4 brakes.
 
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weendoggy

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I agree with above statements. Phenolic pistons and aluminum can cause issues if not used on a regular basis. Brake fluid is very susceptible to moisture and should be changed every couple of years. I use Motul 660 DOT4 brake fluid as I do track my car. Also have Cobra brakes all around. If the rear didn't even slow the car down you may need to replace (or at least check) the rear calipers to make sure they're working. Don't try to push the rear piston in, they are threaded and need to be turned (tool) to replace pads. Make sure you bleed the ABS module as well. Some good OBDII scanner/tools will have this option. I don't see the need to keep calipers in the trunk. The longer they sit, the more apt to do the same thing collecting moisture (unless temperature controlled environment). :) jmo
 
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7991LXnSHO

wanna catch the space herp
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Black GT,
7991LxnSHO is right
Your brake fluid boiled and the brakes got spongey
Switch to dot 4 or 5 if you can handle the pedal feel and the fluid will not boil near as easy
Keep 2 calipers in the trunk and the tools to change them
Reminds me of vintage 4 piston Corvette calipers
Dot 5 is silicone brake fluid, and will not work well with ABS. It is not compatible with glycol fluids, so stick with fresh Dot 4.
 
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Black GT

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The 99-04 PBRs are notorious for seizing. Anecdotally ive seen them seize up when a car is seldom driven, or in the spring when a lot of guys take their cars out from winter storage.

My feeling is the root cause is poor quality brake fluid, or old brake fluid that has absorbed a lot of moisture and is allowed to sit for a period of time and slowly corrode the inside of the caliper. Having torn down a few seized calipers, it does looks like this is the case.

Replace both calipers, use quality brake fluid, and stay on top of fluid flushes. Bleed all 4 brakes.
Yeah, The time the caliper locked up completely the car had been sitting for awhile. It usually is a second car but my daily blew a oil cooler line. So I have been driving the GT daily lately until this happened. Thanks for the reply
 

Black GT

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Sep 8, 2018
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I agree with above statements. Phenolic pistons and aluminum can cause issues if not used on a regular basis. Brake fluid is very susceptible to moisture and should be changed every couple of years. I use Modul 660 DOT4 brake fluid as I do track my car. Also have Cobra brakes all around. If the rear didn't even slow the car down you may need to replace (or at least check) the rear calipers to make sure they're working. Don't try to push the rear piston in, they are threaded and need to be turned (tool) to replace pads. Make sure you bleed the ABS module as well. Some good OBDII scanner/tools will have this option. I don't see the need to keep calipers in the trunk. The longer they sit, the more apt to do the same thing collecting moisture (unless temperature controlled environment). :) jmo
Thanks, I will check the rear brakes. I am pretty sure they probably need pads anyway. What type of tool is used on the rear caliper pistons?
 

Black GT

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Mustang5L5

Put lubricant all over the balls
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Black GT

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COramprat

...I can take it. I think.
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I've replaced calipers several times over the years my 96 GT and my 03 Saleen and my son's 02 GT. They are pretty notorious for wearing out over time with use or finiky when sitting a while
 
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