How to insert dust cover into brake caliper

FOREVERWHALERFAN

MEMBER
1999 BUICK PARK AVENUE
123,000 MILES

I have reinstalled the piston in the G.M. Brake caliper but have ruined one dust boot attempting to insert it. Do I need to blow out the piston again and start over? What is the best procedure for inserting this sucker?

Thanks,

Foreverwhalerfan

6 Replies

CARADIODOC

MECHANIC
33,916 POSTS

My preferred method is to hold the piston over the boot and blow the boot up with compressed air. That takes practice to not rattle your knuckles. You can also buy a special pliers to spread the boot open. They make 'em in two sizes. The third way is to put the boot on the piston first, then use the piston as a handle while you poke the lip of the boot into the groove in the caliper. You also put the boot on the piston first on GM products that use a metal ring around the boot. Slide the piston into the caliper, then pound the ring in with a special tool.

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Monday, August 5th, 2013 AT 11:09 PM

FOREVERWHALERFAN

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Thank you. I brought it to a local garage and he installed it in minutes. Now the issue is disconnecting the caliper brake hose in order to replace it. It is easy at the banjo end the other at the mounting is a different story. Since I am already committed, I thought that I would cut the hose so that I could use a socket where the hose meets the mount and an open end on the bottom. I assume that the bottom nut slides down once the nut end of the hose is loosened. I don't want to have to worry about the metal brake line line getting kinked. You may suggest to bring it somewhere, but it is too late for that. Any expert suggestions? And this is only the right side!

Thank you.

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Tuesday, August 6th, 2013 AT 11:51 AM

CARADIODOC

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There's two problems with the connection you're referring to. The nut gets rusted to the steel line and the nut gets rusted to the brass fitting on the flex hose. The way I always got those free was to heat the nut with an acetylene torch. Use safety glasses and wear old clothes. The rubber is going to soften and squirt out of the crimp with a loud pop and lots of neat smoke. By that time you'll be able to work the nut loose in the brass fitting. Be sure to use a flare-nut wrench, (line wrench) on the nut to prevent rounding it off.

Once you get the nut free in the brass fitting you can remove the clip that holds the fitting to the bracket, pull the fitting down out of that bracket and unscrew it from the nut. Now heat the nut again to expand it, then use the wrench to work it free on the steel line. It's coming free when you hear it squeaking. Don't use any type of penetrating oil or any petroleum product anywhere near where brake fluid can come in contact with it. That will destroy all the rubber seals and o-rings in the brake hydraulic system. As it cools down, spray the nut with Brake Parts Cleaner as you work it back and forth to free it up and wash the rust out.

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Tuesday, August 6th, 2013 AT 1:19 PM

FOREVERWHALERFAN

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11 POSTS

Thanks. I sprayed some blaster on the nut a few times, which is no where near the opening of the brake line, and it came loose. I put the new flex hose in and connected the two lines. Although the flex hose end is completely seated into the bracket there is still a little play at the bracket. I think a new clip is necessary.

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Wednesday, August 7th, 2013 AT 6:10 PM

CARADIODOC

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AGHH! Get all of that penetrating oil washed off right away with brake parts cleaner or carburetor cleaner. Its job is to soak in through threads and it's going to do that and contaminate the brake fluid. Petroleum products should never be used anywhere near a brake hydraulic system. Happy to hear you got the hose off though.