# brakes



## teepee (Feb 21, 2009)

hello. I went to change the pads and rotors on my 03 envoy but couldn't get the caliper retainer bolts free to access & remove the rotor. I am guessing they are rusted or something. is this common and do you have any recommendations?


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## Aggie67 (Dec 20, 2008)

Aerokroil. Not sure if it's available retail, but our crews are required to keep stock of it in their trucks. Give a little shot to the nut and threads a day before you want to do the brake job. DON'T get any on the rotors or pads.


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## nap (Dec 4, 2007)

Not familiar with an Envoy, specifically but I do know GM uses lock-tite on lots of bolts, including the caliper bracket on lots of various vehicles. 

There are only two remedies I am aware of: heat or lots of torque. I prefer the heat method but it must be done with a lot of forethought and care.

I don;t know if it is applicable to the Envoy but surely wouldn't be surprised if it was.

I've never seen any penetrant that would make a lick of difference on loc-tite. I have never heard of or used Aerokroil. Maybe it is something really different. I don't know.


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## SDC (Feb 18, 2009)

nap said:


> Not familiar with an Envoy, specifically but I do know GM uses lock-tite on lots of bolts, including the caliper bracket on lots of various vehicles.
> 
> There are only two remedies I am aware of: heat or lots of torque. I prefer the heat method but it must be done with a lot of forethought and care.
> 
> ...


X2
impact gun or lots of torque
I just did the ones on my 04 2500HD chevy and used a 20" breaker bar and a 3lb hammer to hit it:thumbsup: it got them loose...finally


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## teepee (Feb 21, 2009)

Thanks all. Aggie67 -- I have never used Aerokroil but I'll see if its available. I did try my impact gun and had a pretty big cheater on the L-wrench -- 2 foot long. I think if I use any more force the bolt will split
I have too give it a go again next weekend or so.

I appreciate your comments and any other.


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## nap (Dec 4, 2007)

teepee said:


> Thanks all. Aggie67 -- I have never used Aerokroil but I'll see if its available. I did try my impact gun and had a pretty big cheater on the L-wrench -- 2 foot long. I think if I use any more force the bolt will split
> I have too give it a go again next weekend or so.
> 
> I appreciate your comments and any other.


then heat may be your solution. Do not heat the bolt but the boss the bolt screws in to. It will enlarge the hole an/or distort is which will break the loc-tite bond.

be very aware of the brake hose, any seals, anything that the heat may damage. Shield with a piece of sheet metal if necessary (careful aim generally is adequate.)


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## teepee (Feb 21, 2009)

Thanks nap: I'll give it a go next weekend. Do you think there is any concern with heat to the piston or seals in the caliper?


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## nap (Dec 4, 2007)

teepee said:


> Thanks nap: I'll give it a go next weekend. Do you think there is any concern with heat to the piston or seals in the caliper?


yes, absolutely, at least to the seals. Iron does not transfer heat well but it still transfers, eventually. an acetylene torch with a small tip is preferred so to heat a small area but heat it quickly. It is not uncommon to heat bleeder screws when they are seized. It is just how you do it more than what you are doing.

The pistons, being a separate piece, generally will not be subject to enough heat to be any problem. Realize that when a brake is being used, it creates a great amount of heat so the materials used are designed to deal with a limited amount of heat. Just don;t overdo things.


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