# Any way to free up a stuck caliper piston?



## Windows on Wash (Aug 30, 2011)

Put the good piston back in, use a block of wood, and apply air pressure to loosen the stuck unit.


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## noquacks (Jun 5, 2010)

Windows on Wash said:


> Put the good piston back in, use a block of wood, and apply air pressure to loosen the stuck unit.


thanks, window. Just tried it but I use pressure from a wal mart bicycle pump (usuallly works for me), but maybe I need way more psi? Still stuck. Anybody here against heating the caliper with propane then pressurize??


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## SeniorSitizen (Sep 10, 2012)

noquacks said:


> thanks, window. Just tried it but I use pressure from a wal mart bicycle pump (usuallly works for me), but maybe I need way more psi? Still stuck. Anybody here against heating the caliper with propane then pressurize??


Apply the pressure then the heat and you may be surprised how little heat is required from a small propane torch applied in the correct area.


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## Bondo (Dec 8, 2007)

Ayuh,.... Ya need a new/ rebuilt caliper,.... Yer's is Junk,....

Even if ya get it apart, 'n back together,...

It's Unsafe for the highway,....


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## de-nagorg (Feb 23, 2014)

bondo said:


> ayuh,.... Ya need a new/ rebuilt caliper,.... Yer's is junk,....
> 
> Even if ya get it apart, 'n back together,...
> 
> It's unsafe for the highway,....




*ditto button*


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## noquacks (Jun 5, 2010)

SeniorSitizen said:


> Apply the pressure then the heat and you may be surprised how little heat is required from a small propane torch applied in the correct area.


thanks, senior- got it out! wasnt that bad with a tad of heat......


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## noquacks (Jun 5, 2010)

Bondo said:


> Ayuh,.... Ya need a new/ rebuilt caliper,.... Yer's is Junk,....
> 
> Even if ya get it apart, 'n back together,...
> 
> It's Unsafe for the highway,....


thanks, bond, but why?


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## iamrfixit (Jan 30, 2011)

Are you sure it was a stuck piston that caused the worn pad, the entire caliper body also must slide as the pads wear, and that's more likely the problem. The pistons are on the inboard pad, as the caliper squeezes the pads the caliper slides to tighten the outboard pad. If the caliper is unable to slide freely the caliper won't return to a neutral position so the outboard pad gets held against the rotor and the pad wears premature.

After you take the caliper apart you need new seals and boots to reassemble. Most likely you will need to order the kit because almost nobody rebuilds these parts themselves anymore. It is usually cheaper and quicker to just buy a rebuilt caliper and much more likely for the parts store to keep that in stock. 

Time spent cleaning, inspecting and reassembling the caliper, you may need to replace the pistons due to rust pits or hone the caliper. Getting the boots to stay seated in the grooves as you assemble it while not damaging the boot or the seal can often be a challenge.After reassembly you have no warranty, when you get done and it leaks a rebuilt unit will seem cheap. These are some of the reasons most just buy a reman caliper and be done with it.


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## de-nagorg (Feb 23, 2014)

I am not trying to be mean here.

When an amateur rebuilds those disc brake calipers they run the chance of something being out of specs, and the caliper fails at the most critical time causing severe and permanent damage to the operator and/or their passengers.

And it is obvious to me that you have little experience with them, you had to ask if prying on it could hurt it. YES it can. If the inner lining has even one tiny spot that needs honing, or is damaged in any way, it will fail early and need replaced again.

And the parts store replacements are warranted . 

Me personally: I would buy new parts not re-manufactured ones, due to having re-manufactured parts fail too soon for my desire.

many people have better luck than I with re-man stuff, but I nearly always have to do it again too soon .

I have re-built many of my own that lasted longer than re-man ones. 

But I have nearly 50 years doing that so am confident in my ability to 


DO IT RIGHT THE FIRST TIME.


ED


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## iamrfixit (Jan 30, 2011)

I like new too, but unless you are buying new OEM parts you may be better off with remanufactured. A lot of the new, aftermarket stuff is coming from overseas and can be of questionable quality. I bought a new water pump for my wife's van several years ago, and replaced it almost every year due to failure. After several failures I exchanged it for a reman and it has been on there for 8+ years. 

New OEM is almost always good quality, but the cost is often double or even triple that of a remanufactured part that probably has a better warranty. I have had EXCELLENT luck with Cardone reman parts and most of the area parts stores handle them. Price plays a big part, but availability is another. Parts stores sell more reman parts, often due to price, so they are more likely to have the reman version in stock. 

When my vehicles are down, or my shop is tied up, I want it back on the road. A day or two to order parts is longer than I'm willing to wait. Unless you live in the city, most dealership parts departments are pretty limited. In my town of 10k people we have 3 new car (ford, gm, chrysler) dealerships. They keep only the most common stuff in stock and it takes a few days to get parts, unless you want to pay freight too. Other than something they sell almost every day, it will have to be ordered.

I do all repairs and maintenance on not only my own and my kids, which nearly amounts to a fleet these days; but also friends and family, as well as our work trucks and trailers. I buy and install thousands of dollars in parts over the course of a year.


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## Fix'n it (Mar 12, 2012)

quit screwing around with it and replace it.


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## noquacks (Jun 5, 2010)

iamrfixit said:


> Are you sure it was a stuck piston that caused the worn pad, the entire caliper body also must slide as the pads wear, and that's more likely the problem. The pistons are on the inboard pad, as the caliper squeezes the pads the caliper slides to tighten the outboard pad. If the caliper is unable to slide freely the caliper won't return to a neutral position so the outboard pad gets held against the rotor and the pad wears premature.
> 
> After you take the caliper apart you need new seals and boots to reassemble. Most likely you will need to order the kit because almost nobody rebuilds these parts themselves anymore. It is usually cheaper and quicker to just buy a rebuilt caliper and much more likely for the parts store to keep that in stock.
> 
> Time spent cleaning, inspecting and reassembling the caliper, you may need to replace the pistons due to rust pits or hone the caliper. Getting the boots to stay seated in the grooves as you assemble it while not damaging the boot or the seal can often be a challenge.After reassembly you have no warranty, when you get done and it leaks a rebuilt unit will seem cheap. These are some of the reasons most just buy a reman caliper and be done with it.


thanks, . the caliper does not slide. It is stationary. Solid. rebuild kit: $3.00. warranty? what worth is it- ya gotta prove damage, etc. 

Update: I popped it out!! PB blaster and heat! Not sure if I explaied correctly, but the oputer pad was worn down to the steel rivets. Ground down the outer surface of the disc like mad. I just asumed piston was stuck, but it dod pop out- no visible rust/pitting , am planning to rebuild. Its fun. 

Thanks, iamarfixit


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## noquacks (Jun 5, 2010)

Fix'n it said:


> quit screwing around with it and replace it.


 I appreciate your opinion for my situation, fixn, but do you always just replace stuff? Are you good at fixing stuff? Do you know the condidtion of my caliper?? Have you ever rebuilt a caliper? Have you ever owned a car that ran well with original calipers for 200,000 miles? Do you think once something "breaks" it cant be fixed reliably?


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## Bondo (Dec 8, 2007)

noquacks said:


> I appreciate your opinion for my situation, fixn, but do you always just replace stuff? Are you good at fixing stuff? Do you know the condidtion of my caliper?? Have you ever rebuilt a caliper? Have you ever owned a car that ran well with original calipers for 200,000 miles? Do you think once something "breaks" it cant be fixed reliably?


Ayuh,.... I know I'm considerably older than you are,....

I know I've been Fixin' things since I could walk,....

I know I built a career outa makin' ole iron run alittle longer, 'n gettin' just one more lap, outa broken iron,....

'n I know, I learned many moons ago, that the effort of rebuildin' a caliper by yerself,....
_Never_, _Ever_ pays off in the short, nor long term,.......

I also know that the price of calipers is considerably cheaper than when I was putzin' with a 60s something Cadillac, Decades ago,........

Yer wastin' yer time,.... but it's Yer time, so go for it,...
Or,...
Listen to the "Been there, Done that, 1,000s of times", 'n throw on a rebuilt/ reman, 'n be done with it,....


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## Bondo (Dec 8, 2007)

noquacks said:


> thanks, . *the caliper does not slide.* It is stationary. Solid. rebuild kit: $3.00. warranty? what worth is it- ya gotta prove damage, etc.
> 
> Update: I popped it out!! PB blaster and heat! Not sure if I explaied correctly, but the oputer pad was worn down to the steel rivets. Ground down the outer surface of the disc like mad. I just asumed piston was stuck, but it dod pop out- no visible rust/pitting , am planning to rebuild. Its fun.
> 
> Thanks, iamarfixit


Ayuh,.... Either the Caliper, or it's mount, _*HAS*_ to slide,....

That's the auto-adjust for disc brakes,....


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## Fix'n it (Mar 12, 2012)

noquacks said:


> do you always just replace stuff?
> 
> are you good at fixing stuff?
> 
> ...


of course not. i try to fix most stuff. 

much more than i let on.

of course not. i'm not there.

yep. also = engines, transmissions, differentials, to state a few. i also "make" some engine parts.

nope, i don't drive that much. stuff is pretty close around here. 

of course not. but i do know that sometimes it ain't worth the trouble. 

as always = YMMV


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## Fix'n it (Mar 12, 2012)

Bondo said:


> Ayuh,.... Either the Caliper, or it's mount, _*HAS*_ to slide,....
> 
> That's the auto-adjust for disc brakes,....


nope. there are calipers that have pistons on both sides of the rotor


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## Windows on Wash (Aug 30, 2011)

Fix'n it said:


> nope. there are calipers that have pistons on both sides of the rotor


More and more cars are coming with 4 piston units for the brakes up front.


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## Fix'n it (Mar 12, 2012)

Windows on Wash said:


> More and more cars are coming with 4 piston units for the brakes up front.


more and more cars are coming with a bunch of stuff that is not needed. 
this is why i am shopping for a 20 y/o truck.


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## nap (Dec 4, 2007)

a couple thingsnot mentioned here:

what was the material the piston was made of? IF phenolic, replacing the piston is usually a good idea. They have been known to have a problem with absorbing fluid due to the material degrading and they swell. The only fix is to replace it.

also, whether it is phenolic or metal, that is what you are worried about having any imperfections on the surface as that is what seals against the square cut o-ring in a groove in the caliper body. If there is any pitting or scars on the piston, replace it.


Can't say I have ever applied heat to remove a stuck caliper piston though. Given there is no intimate contact between the piston and the caliper body (at least in a perfect world that is the intent) I don't see what heat would really do. Air pressure (no, not a tire pump) is the way to go BUT there are a some precautions to be taken so you don't pop yourself upside the head or break a finger when the piston comes a poppin' out of its bore. 

the fact the OP actually pushed the "stuck" piston into the caliper body shows it is not "welded" to the caliper body with corrosion. Again, not seeing what heat would do for the issue.


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## noquacks (Jun 5, 2010)

Thanks again, people, for all the info. I appreciate every one's post from the forum "buddies" here.

Update- yes, there are many things yous cant know because of limits to typing/internet/etc. But we can relax a bit, I think, because the sufraces appear quite smooth and more inportantly, feel smooth to the touch. No pitting. They are steel, not plastic/phenolic (a type of plastic)/.

Im rebuilding it no matter what some feel about buying new. I may be younger than some here, but that is not necessarily proof I cant rebuild/pass good judgement on a caliper rebuild. Thats why they sell kits. And a 1987 Alfa Romeo OEM caliper is probably made way better than a new one in 2015 in China. 

So, yes, since fixinit mentiomned it probably was not stuck as in fused/rusted, it was not=- Im not sure why it destroyed that side of the disc- stuck for sure, but probably because it was never bled with fresh moisture free fluid, and sticking. 

Im not afraid to rebuild and test. Its not like its going on an airplane, people. Its a car. I drive safely, no tickets ever , no crashes, just boring ol driver who respects the most prevelant dangers of driving a car- distractions and driving too fast. Still, no one of us is guaranteed to be spared whenever we get in any car.


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## noquacks (Jun 5, 2010)

nap said:


> a couple thingsnot mentioned here:
> 
> what was the material the piston was made of? IF phenolic, replacing the piston is usually a good idea. They have been known to have a problem with absorbing fluid due to the material degrading and they swell. The only fix is to replace it.
> 
> ...


piston doesnt have to be "welded/fused" for heat to benefit. Heat expands the outer caliper body BEFORE it gets absorbed by the pistron. This expansion is what frees the piston up. It helped big time in my situation.......

thaks, nap......


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## noquacks (Jun 5, 2010)

Bondo said:


> Ayuh,.... Either the Caliper, or it's mount, _*HAS*_ to slide,....
> 
> That's the auto-adjust for disc brakes,....


I wish it did slide, bond, but man, im telling ya, there are no sliding bolts with those familiar rubber booties on that caliper. you have to see it. Mounts solid onto the hum "bracket", or whatever you call it.


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## nap (Dec 4, 2007)

noquacks said:


> I wish it did slide, bond, but man, im telling ya, there are no sliding bolts with those familiar rubber booties on that caliper. you have to see it. Mounts solid onto the hum "bracket", or whatever you call it..




since you suggested to bondo; you have to see this, provide the model of car and we can see it with a simple internet search. 


fyi; I worked as a pro mechanic for a decade or two and a hobbyist for 4 1/2 decades. I have rebuilt my share of calipers in my day. :wink:


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## digitalplumber (Jul 8, 2011)

noquacks said:


> thanks, bond, but why?


because your life depends on it!


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## nap (Dec 4, 2007)

digitalplumber said:


> because your life depends on it!


there are floating calipers that must move and there are solidly mounted calipers that are fixed in place. The fixed calipers must have a piston (or 2) on each side of the caliper since the caliper does not move but they are out there. 

If I recall correctly, Corvettes have used fixed calipers for years. No slides, no movement of the caliper. The pistons on each side of the caliper make up for the wear of the pad on that side of the rotor.


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## Fix'n it (Mar 12, 2012)

noquacks said:


> Thanks again, people, for all the info. I appreciate every one's post from the forum "buddies" here.
> 
> Update- yes, there are many things yous cant know because of limits to typing/internet/etc. But we can relax a bit, I think, because the sufraces appear quite smooth and more inportantly, feel smooth to the touch. No pitting. They are steel, not plastic/phenolic (a type of plastic)/.
> 
> ...


if you had said it was an alfa caliper, i would have said rebuild it (if possible). as you would save a bunch of money. i thought you were rebuilding a $20 caliper, thats why i said to stop screwing with it. 

it damaged that side of the disc = because the piston would not return/relax = removing pressure from that pad. 

your age has nothing to do with anything.


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## 47_47 (Sep 11, 2007)

If you have the rotors turned on a fixed caliper car, you must remove the same amount from both the inside and outside faces or you will have uneven pad wear.


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## mske390 (Feb 24, 2015)

noquacks I guess we're the minority, like you I like to do things myself. Is a remanufactured one cheap today...yes but I don't get why others think that this is the answer. I have rebuilt countless calipers over the years and guess what people...I'm still here and have never had an accident. Started my career as a aircraft mechanic then mechanical engineer where evidentially got into assessing systems specifically problems in them. I have no idea who you are but who exactly do you think rebuilds remanufactured calipers? I bet you that they are not certified automotive technicians and the cheaper the reman is the lower paid employees used for them! As others stated this is a saftey part so I am NOT going to put my life in someone elses hands when quite frankly I could do this on my own and more importantly know exactly how the component was put back together! 

The pistons need to move freely so you need to make sure hydraulic passages are clear and the sliding surface are clean/smooth. Brake fluid pushes the piston out and the fluid is held in by an o ring. clean the sliding surfaces very good making sure NO pitting or rust, if so, I have used very fine grit sandpaper with hydraulic fluid to hone them back to where they need to be. Install new o rings, install caliper then depress brakes several times (going to need a second person so you could watch operation) if no leaking what's the problem? 

I've been doing that since I started driving back in the late 80's, have yet to have a brake failure or diminshed braking scenario. I have pulled some apart that beyond repair so had to replace. I don't understand everyone's hesitation to rebuild something? A remanufactured caliper undergoes more or less the same thing, quid est?


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## de-nagorg (Feb 23, 2014)

My recommendation to buy a rebuild was due to not knowing Quacks experience and abilities and not having the Facts. I.E. Alfa Romeo .

And having seen newbies try and fail, then ask me "HELP", 

Have been repairing my own at least 25 years before you started, So I have EXPERIENCE, as well as an A S E certificate. 

Do not use sandpaper to polish the pits and rust. 

EMERY PAPER is much better, and finer. Sold in rolls at most auto parts stores.

I wish you luck with it and hope that you can follow the good advice offered by those that just want to pass along their dos and don'ts. gleaned from trial and errors.

ED


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## mske390 (Feb 24, 2015)

been using 2500 -3000 grit sandpaper for years with no issues, probably shoudl have specified that


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