brake problem
 

I resently changed my front brake calipers and the front right brake line and i bled them and they work but theyr still spongey and I've bled them alot so i cant figure out why they wont work right. the jeep will stop and the pads are almost brand new so i just dont know. my jeep is a 1993 jeep cherokee sport

It sounds like you still have air in the system? When you bled the brakes did you bleed all 4 wheels? I would start by bleeding all 4. Start with the passenger rear, drivers rear, passenger front then drivers front.

You still have air in the lines.

When I bleed brakes I take a 20 oz bottle, fill it half way with brake fluid and run a hose from the bleeder screw down into the bottle. Submerge the bottle end of the hose in the brake fluid.

Have a helper pump the brakes several times and then hold the pedal an inch off the floor. While they're holding the pedal just off the floor you open the bleeder screw and let the air out. When the bubbles stop flowing close the bleeder screw and repeat the process until you stop getting bubbles out of the line.

By having the hose in the brake fluid it guarantees that you won't suck air back in while the bleeder is open. It also prevents making a mess.

Do this with all 4 corners starting at the bleeder farthest away from the master cylinder.

Make sure the reservoir stays topped off and you don't over flow your bottle.

I usually have to do each corner 2-5 times each and make two complete laps around the vehicle.

The hardest part about this is listening to your helper ***** about their leg hurting from pumping the brakes 250 times. ;)

As long as you're going to be re-bleeding the system, I would recommend replacing the driver-side brake hose, as well. Replacing one side of an old system that needs to be symmetrical isn't a good idea and the hoses are only $12 from AutoZone.

Beyond that, I recommend the same as everyone else. Carefully bleed the entire system.

Other causes to consider.

1) Moisture or other contaminants in the fluid, the only way to know is to completely flush and replace the fluid, it takes about 2 pints to fill the lines and reservoir and the job is no more difficult than simple bleeding.

2) Leaking wheel cylinders (rear). Check for signs of fluid around the seals and on the drum backing plate. The cylinders are easily rebuilt ($8 each) or replaced ($20 each).

3) Leaking master cylinder seals. In the base of the master cylinder resides two aluminum pistons, a primary and secondary. Each has seals and o-rings. Rebuild kits are available for $15-$20 that include new seals and o-rings.

As others have mentioned, the most likely cause is air in the lines which can be remedied by bleeding them. If that fails to resolve the spongy pedal then check the other items.

Bleeders on top or bottom

This method also works if you don't have a helper. Plus if you are not in a really big hurry, once you pump the pedal a few times you can just let it siphon until you don't see any more bubbles then close the bleeder.

When I replaced my front brakes, I didn't flush the rear lines, and my brakes were very spongy, once I flushed the old fluid out of the rear lines(it was at a minimum of 7 years old, probably over 20), once it was flushed with new fluid they feel great.

theyr on top