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Discussion Starter · #1 ·
Over the last couple of weeks, after i've driven a few start/stop miles in the city, my left front caliper will lock up and the brake will clamp down over the rotor. I've had very old cars and trucks do this, but this caliper is maybe 7-8 years old. Could the sliding mechanism that the caliper uses be fubard (in other words, perhaps the little rubber bushings inside the caliper are dry and have lost lubricant), or is it likely the caliper piston gets stuck? I'm thinking the latter, because, if it was the sliding mechanism, one pad would be wearing worse.

I'll tell you, the left side got so hot, the whole wheel was hot! I believe even the brake fluid got hot and boiled off, if that is possible
 

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Prior maintenance? How many miles on this set of pads and rotors? Brake hardware replaced w/ pad swap or re-used?

W/ regard to your reasoning, you've it reversed. the piston hanging is far less likely than failed caliper pins and bushings causing the issue.
 

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rubber brake line to that caliper.
torn flap inside acts like check valve.
 

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Discussion Starter · #5 ·
C'mon, is that hose observation really common? I've never seen it and have always done my own brakes since the 70's. The weird thing about this is that it doesn't do it if you're not braking a lot. It sorta takes a lot of start stop driving in city, then it locks down.
 

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C'mon, is that hose observation really common?.
I've seen other post on the subject of the flex hose causing issues and in my case it most definitley was. I think it was causing the brakes to stay clamped to the rotor.

I kept having problems with the rotors warping after a few thousand miles. Replaced everything (calipers, rotors (or turned), and pads and after a bit I would get the shakes in the steering wheel when braking and the rotors were warped again.

Someone mentioned the flex hoses to me and I was skepticle but thought, why not. Redid everything again AND replaced both flex hoses.....Problem solved.
 

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Discussion Starter · #7 ·
I've seen other post on the subject of the flex hose causing issues and in my case it most definitley was. I think it was causing the brakes to stay clamped to the rotor.

I kept having problems with the rotors warping after a few thousand miles. Replaced everything (calipers, rotors (or turned), and pads and after a bit I would get the shakes in the steering wheel when braking and the rotors were warped again.

Someone mentioned the flex hoses to me and I was skepticle but thought, why not. Redid everything again AND replaced both flex hoses.....Problem solved.
Thanks for the input and advice everyone. Yeah, hoses are probably original and 'look' good. It's only the driver side and also only does it after brakes are warm and being used. Also interesting that my fluid level was a little low. Topped it off and the problem was till there. Wondering if maybe the heat actually caused some boiling off of brake fluid. DOT3 boils at about 130 degrees C.
 

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Discussion Starter · #8 ·
Well, it looks like its the caliper after all. I pulled the wheel off, and for posterity sake, lubed the slider mechanism, even pulled out the caliper pins and sleeves, and used some of the good ceram lube. The pads were crystallized from the heat, and even though there's plenty of pad left, believe I'll have to change pads. But looking at the caliper piston, I tried to compress it and the damn thing is truly frozen stuck. It's not out that far (maybe 1 cm), but it will not go back in to bottom position, where I need it to be w/new pads. So guess it was the caliper. The hose actually 'looks' good. Pretty sure caliper is original too.
 

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Could be the caliper, but did you try to compress the piston with the hose disconnected the banjo fitting? If not, it could still be the hose preventing the piston from being compressed. Still a good idea to replace the hoses if they got any miles/years on them.
 

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Discussion Starter · #10 ·
Could be the caliper, but did you try to compress the piston with the hose disconnected the banjo fitting? If not, it could still be the hose preventing the piston from being compressed. Still a good idea to replace the hoses if they got any miles/years on them.
No, I didn't try that, but I can tell you i tried compressing it with a HEAVY C-clamp. Surely you would see the hose bulging some but I'll take your advice and replace hoses. I even had the lid slightly cracked on the Master Cylinder to allow the fluid to move.
 

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No, I didn't try that, but I can tell you i tried compressing it with a HEAVY C-clamp. Surely you would see the hose bulging some but I'll take your advice and replace hoses. I even had the lid slightly cracked on the Master Cylinder to allow the fluid to move.
Get the Russell or Earl's stainless hoses. They're better and cheaper. What's not to like? As for the 20 YEAR OLD hoses, methinks you've effectively gotten your money's worth out of them by now, yes? Peace of mind in replacing them all, walking away and knowing you won't have any further issues for a good long, if not indefinite time.

Couldn't hurt to replace front hardware along w/ the one new caliper and to keep everything balanced, replace the hardware on the other side too. Inexpensive parts, but go a long way to even, efficient braking.

You definitely cooked that one side. When bleeding, make sure all fluid is purged completely and replaced w/ new. Scorched fluid looses it's thermal capabilities, so you want any and all remnants evacuated.

If pads got scorched, correct in replacing them now (both sides).
 

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But looking at the caliper piston, I tried to compress it and the damn thing is truly frozen stuck. It's not out that far (maybe 1 cm), but it will not go back in to bottom position, where I need it to be w/new pads.
the stuck piston could be a result of the caliper overheating and seizing the piston and not the cause.
 

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No, I didn't try that, but I can tell you i tried compressing it with a HEAVY C-clamp. Surely you would see the hose bulging some but I'll take your advice and replace hoses. I even had the lid slightly cracked on the Master Cylinder to allow the fluid to move.
Good to hear you're replacing the hoses. At only $10-$15 per hose for a stock
Replacement, its a no brainier. If your metal lines where the flex hose attaches has any rust/crud/years on them, try to soak them real well first where the metal nut threads into the flex hose.

On metal lines that are bad I've had good success soaking for a couple of days being sure to get the nut and the metal line. Then using some fine grit sand paper to clean the metal line getting as close to the back side of the nut as possible. Do that a few times and keep soaking it which will help wash away the junk. The idea is you want the nut to spin on the metal line without (hopefully) twisting up the steel line. Keep a close eye on the line and make sure it doesn't twist while backing off the nut. A little twist is normal til the nut breaks free. It also helps to try and tighten it a little first and work it back and forth as you go.

I recently replaced my front calipers with some stock replacements and they were only $15. If you want to, you could put a block of wood in the caliper that leaves a 1/4" of space to the piston, seal up the Resevoir and apply the brake. This will push the piston out a little further and see if that frees it up. I would still replace it though since you mentioned they got some years on them too. Word of caution on pushing the piston back in. Its a good idea to open the bleeder when you do this. This way all the old junkie fluid sitting in the caliper gets pushed out and not back up into the system.

It would also be a good idea to gravity bleed out the fluid making sure not to get too low and get air into the MC. Then pressure bleed the system and if you can, do all four corners.
 

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Discussion Starter · #14 ·
Well, not quite. I replaced everything BUT the hoses on Sunday. Went out for a test drive for 30 minutes and all was fine. Monday, all was fine. But Tuesday, I started getting a slight drag on the left caliper, but not nearly as bad as it was. So, lesson to self, listen to the guys on the forum. I've been hearing a sort of burping or depressurization after I shut the car. Next question - could it be something in the ABS module, basically a screwed up valve or something? Never heard of it, but just wondering...
 

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Discussion Starter · #15 ·
Hose put on this weekend and all is well. Thanks for reminding me about the hose - I live in a dry southern climate and the hoses don't get the external wear. But as everyone knows, brake fluid will eventually get to most everything, and the insides of brake hoses is no exception.
 
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