Changing brake pads

[lidunian]

I need to change the front brake pads on my 92 Lesabre


Anyone give me a heads up on how to do this ???



Any help would be appreciated

[buickmastermind]

Take off the wheels, and use a torx to unsrcew the two bolts on the back of the brake caliper. The caliper will slide straight off the rotor, with the old pads still on it. The pads are clipped on, and simply pull off. Keep in mind that the calipers automatically adjust to the level of the current shoes and need to be spread apart to put the calipers with the new shoes back on the rotor. Make sure the caliper is tightly connected to the bracket. put the wheels back on and you should be done.

If I forgot to mention somethink, please post it.

[Jed Rule]

Mastermind, you have overy-simplified this repair.
How about opening the bleeder screw to release the dirty brake fluid when retracting the caliper piston? It could contaminate the ABS. Also, examine the piston boot for leakage. Inspect and lube the caliper mounting bolts and sleeves where they slide on the spindle. Inspect the brake hoses (the car is 13 years old). Never let the caliper hang from the hose. Measure the thickness of the rotors. Brake parts may contain asbestos, use caution when handling parts or breathing dust. Brake fluid can iritate eyes or skin.
This is NOT a job for an amateur. I wouldn't want to be on the road in front of this car.

[buickmastermind]

I don't have ABS, so I haven't had to bleed the line. You shouldn't need to, anyways. As long as there are no leaks, there are no contaminates in the fluid. Not saying you should try this, but my car is 18 years old, and I haven't had a problem letting the brake calipers hang by the hose, but my hose may be a different type. Heck, they hung on the hoses for over 3 months, and didn't get ruined. Maybe it was luck. Don't try it though. I might have made it sound simple because it really is, if you take care to notice what goes where. I had never changed the brakes before a few months ago, and mine work the way they are supposed to. In fact, compared to rebuilding a tranny, it is one of the simplest mechanical repairs you can make.

Anyway, is there anything else that needs to be done?

Oh, check the brake fluid level when finished...that might help...

[Jed Rule]

Have you looked at the color of the fluid in your master? It certainly does get contaminated. I hope I don't see you in my rear view mirror on a steep hill.

[avatar307]

Retracting the caliper piston is not as easy as just retracting the caliper piston. Nor is getting the caliper off in many cases.

To get the caliper off, it may be necessary to compress the caliper piston before removing the caliper. There should be a tab sticking up on the in-board pad. A large pair of slide-lock pliers can be used to apply force to this tab and the back of caliper to retract the piston enough to remove the caliper.

Once the caliper is removed, the piston will not simply go back in. At the very least you'll need a large C-clamp and one of the old pads to press it back in. They also make a tool that's basically the same thing, but reversed. Slide lock pliers can also be used... if you're very careful.

Once the piston is pressed far enough back to allow the new pads room, the edge of the piston boot should be lifted to remove any air from within the boot. The boot should be inspected, and care should be taken to tuck it into place correctly. Be sure the boot edge does not touch the back of the new pads.

If the piston puts up a large fight (with ABS systems, it oftens does, even with the cap removed from the brake fluid reservor) it may be necessary to open the bleeder valve. Remove the protective cap on the bleeder screw, and clean it of any debris. Connect a piece of clear tube, and submurse the other end of the tube in a container of NEW DOT-3 brake fluid. Then open the bleeder valve. This will help prevent contaminants from entering the brake lines, and keep too much air from being sucked in. I usually prime the tube as well... but then again... I usually take 4 times as long as most people when working on my car.

And suspending anything that weighs 20 lbs from a rubber hose is just NOT a good idea.... EVER.

Nevermind that a hydralic braking system uses hundreds of pounds of force to apply the brakes. Think about it, when testing brake pedel travel, the diagnostic procedure is to press down on the brake pedel with 100 lbs of force and measure the distance it moves. (Should be less than 2.5 inches.)

Figure you normally press with 50 lbs when slamming on your brakes at a stop light, then figure in how much the power booster multiplies that force, plus a little more force from the ABS pumps. Hell, a hydralic braking accumulator can store something like 500 lbs of hydralic pressure... Little rubber hoses, 500 PSI of hydralic fluid, 20 lbs of dead weight swinging in the wind kinked over a metal connector. (Brake fluid is really sticky when it leaks... it doesn't make braking fun. Involves your head hitting the steering wheel a lot. Oh, and then there's the whole flushing and bleeding the entire brake system and replacing half of components.)