how to fix sticky caliper

[Thrice1825]

i jacked my car up today and took off the right front wheel, and my suspisions where right. My caliper is tight and is causing the brake pads to rub against the rotor. Do i need to get a whole new caliper? :help

[norcalbmw]

new caliper or rebuild does it leak at all?

[scottycs]

teh brake pad is almost always rubbing the rotor. Or can u not turn it?

[supark]

you should be able to get new seals and such to repair the caliper - I think EAP4Parts.com has them - part number: 34111153202

When I was doing my front suspension, I think the pads were dragging the tiniest bit - but it shouldn't be enough that it creates resistance when you're turning it.

How does your brake fluid look? If it's dirty, might be a good time to flush out the brake system too - the stuff breaks down over time.

[Thrice1825]

well i dont know how my brake fluid is becaue i dont know how to check it (knew to cars, just turned 16 awhile back) but ill figure out to check it and yes it does cause quite a bit of resistance. thanks alot for all the replys and help

[Don Nguyen]

If you want I can sell you the caliper as shown in number 1.

[leaftye]

well i dont know how my brake fluid is becaue i dont know how to check it (knew to cars, just turned 16 awhile back) but ill figure out to check it and yes it does cause quite a bit of resistance. thanks alot for all the replys and help

The fluid in the reservoir should be clear (yellow, maybe blue). If it's cloudy or brown, you need to flush the system. Unfortunately this does nothing to tell you about how the fluid is right by the caliper. To check that, do a few braking tests. Once the brakes begin to bite, it should require a neglible amount of pedal movement to apply full braking force. Now keep in mind that you'll have to press much harder, but if the brakes have been flushed properly, only the effort should go up dramatically, but the movement should not.

[Thrice1825]

why would it require more force to push on the pedal? sorry im alittle confused and would i do this after i flush the brakes and replace it with a different brake fluid? thanks

[fredo328]

I just replaced my front pads. When I purchased the stuff from Bavauto the service rep told me to be sure to lube up the caliper bolt (part #6) with caliper grease to keep it from sticking. Maybe you should try that before rebuilding.

[scottycs]

Actually it should be cleaned, but not lubed.

[Thrice1825]

ok great. I'll try that before i do a rebuild. thanks. any suggestions on what to clean it with?

[Wayne@PelicanParts]

Text from my book-in-progress (101 Projects). Hope this helps...

If your car is pulling to one side when braking, then there is a good chance that you might have a sticky caliper that needs rebuilding. The rebuilding process is actually a lot simpler than most people think. It basically involves removing the caliper, cleaning it, and then reinstalling all of the components with new seals. Very often, the most difficult part of the task is the process of actually removing the caliper from the car.
The first step is to jack up the car and remove the caliper. Refer to Project 56 for details on removing the caliper from around the brake disc. Refer to Project 55 for more details on disconnecting the brake line from the caliper.
Once you have the caliper free and clear from the car, take it over to your workbench, and begin the disassembly process.
First step is to remove the piston from the calipers. One method of removal, is to use compressed air to blow out the piston. Using a small screwdriver, remove the dust boot that surrounds the piston. Place a small block of wood in the center of the caliper to prevent the pistons from flying out of the caliper. Blow compressed air through the caliper bleeder hole to force the piston out of its chamber. Start slowly, and gradually increase pressure until the piston reaches the block of wood. Make sure that the piston doesn’t come all the way out of its chamber. After the piston is far enough out, you should be able to get a grip on it with your fingers. Be careful when working with the compressed air – as it is more powerful than it appears, and can make the pistons suddenly fly out of the caliper unexpectedly.
Using a rag to protect the sides of the piston, carefully remove them both from the caliper using either your hands, or a large pair of vise-grips. Make sure that you don’t touch the sides of the pistons with any metal tools, as you don’t want to scratch this surface.
If the piston is frozen, then more radical methods of removal may be necessary. Using a block of wood, pound the half of the caliper on the block of wood until the piston begins to fall out. If the piston starts to come out and then gets stuck, push it back in all the way and try again. Eventually, the piston should come out of the caliper half. Another method is to use the car’s brake system to release the pistons. Reconnect the caliper to the car and have an assistant pump the brakes to force out the piston.
Once the piston has been removed from the caliper, carefully clean both the inside and outside of the caliper using brake cleaner or another appropriate solvent. All of the passages should be blown out with compressed air, and it’s a good idea to let the whole assembly sit in some parts cleaner overnight. If the piston or the inside of the caliper is badly rusted or pitted, then the caliper should be replaced. A little bit of surface rust is ok – this should be polished off using a coarse cloth or some Scotch-Brite. Make sure that you thoroughly scrub out the entire inside of the caliper and the piston so that they are perfectly clean.
After the caliper and piston have been cleaned and are dry, coat the caliper and piston with silicone assembly lube. Don’t have this silicone assembly lube handy (it’s available from PelicanParts.com), then make sure you coat the entire assembly with clean brake fluid. Do not get any lube or brake fluid on the dust boot.
Insert the new piston seal into the inside of the caliper piston groove. It should fit smoothly in the groove, yet stick out only slightly. Make sure that you wet the seal with a little brake fluid. Now install the dust boot inside-out onto the piston, so that the edge of the boot is hanging out towards the area where the piston contacts the brake pad. [need to check this – and take photo] Then, insert the piston slightly into the caliper. It should slide in easily – make sure that it doesn’t get cocked. Wrap the dust boot around the outer edge of the caliper, and then push the piston into the caliper. As the piston reaches the internal o-ring, you will encounter some resistance. Make sure that the piston is pushed in and doesn’t become cocked as you insert it. If you have trouble inserting the piston into the caliper, you may want to softly tap it with a plastic hammer, or use a small piece of wood to compress the piston into it’s home position in the caliper housing.
Install the brake pads (Project 50), and remount the caliper back onto the car. Bleed the brake system (Project 49), and you should be good to go. Make sure that you carefully check the brakes on the car before you do any significant driving.

Picture 1: Rebuilding calipers is a lot easier than you would normally think. The basic principle involves tearing apart the caliper, cleaning it, and then reinstalling the pistons with new seals and clips. Professionally rebuilt calipers, like this one, are usually sandblasted and plated so that they return to their original gold color. Rebuilding your calipers may solve a lot of mysterious brake problems that you may have been experiencing. Because the process of rebuilding seems difficult, it’s usually the last project tackled when overhauling the brakes. Another option is to just purchase rebuilt calipers, and mount them on your car.

Picture 2: The left side of this photo shows the caliper piston being inserted into the housing. Insert the piston using a block of wood, and then wrap the dust boot around the outside of the caliper. On the right is shown the inner piston seal. This seal is what keeps brake fluid from leaking out past the cylinder. Make sure that you clean the entire inner cylinder for dirt, debris and corrosion. Be careful not to scratch the inside of the caliper cylinder while you are working on it, or you may have problems with the caliper leaking when you reassemble it.

[dabomb4ever]

Wayne, you are a genius, I bow before you. Great write ups!!! i helped a buddy pull his top end off becasue he warped his head, and your writeup was the best ive ever seen. Expect to sell many copies of your book. thanks

-Nick

[Wayne@PelicanParts]

Wayne, you are a genius, I bow before you. Great write ups!!! i helped a buddy pull his top end off becasue he warped his head, and your writeup was the best ive ever seen. Expect to sell many copies of your book. thanks

-Nick

Highly doubtful, but I will take the compliment anways. I'm sure my wife would have some good counter-arguments to the "genius" part. :)

-Wayne