laurel2000

I just replaced the driverside front caliber in my truck and I am having a hard time getting the air out of the system. Me and a friend bled the caliper numberous time as well as all the other wheels. At first there was quite a bit of air and now it is pretty much all fliud but the pedal still falls to the floor with the truck on. Any advice or tips for the 4 wheel abs?? Thanks.

nickg

You always bleed starting from the wheel farthest from the MC, Right Rear, left rear, right Front then Left Front. Adjust the rear brakes properly. and if you have no leaks (externally) and all the air is out, you can tell there is no air because the pedal will not feel like you are steping on a tennis ball, if the pedal feels hard but sinks to the floor you would have a bad Master Cyl
read this post
https://www.dieseltruckresource.com/...d.php?t=225923

drafalske

That's good info, but if you only remove one caliper then you only have to bleed the one you remove. Just watch out you don't run the reservoir dry. If you do then you gotta bleed the whole system.

D

infidel

Air in the system symptom is brakes that have to be pumped up to get hard but hold without creeping down.

If you used the pump the pedal method for bleeding the brakes you could have damaged the master cylinder seals causing an internal leak.
What happens is if you press the pedal down into new territory it doesn't usually travel in normal braking the seals get torn by the often rusty unused section of the cylinder.
Symptom is a pedal that slowly sinks to the floor with no external leaks.
Better to replace the master rather than rebuilding it on your own.
If I have to use the pump the pedal method I place a 2x4 under the pedal to keep stroke in the normal operating range.

Another problem you can run into especially with 4 wheel ABS is if you force the old caliper back with a clamp, screwdriver, etc to remove it without opening the bleeder screw. ABS units don't like backwards pressure and it can often damage them.
Often the brake fluid in the calipers is the dirtiest in the system and forcing it back poses it's own set of potential problems.

One more common problem is putting the caliper on the wrong side. The bleeder has to be on the top side of the caliper or you'll never get the air out.
The calipers on our Dodges have no problem fitting on the wrong side.

laurel2000

Thanks for the info guys, it is really apreciated. I will try again this afternoon to get it going. Also winter is coming close and since I have bought the truck I had to disconect the ABS motor due to it running constantly. I have heard alot of stories that it leads up to the control module, Any ideas. The speed sensor has been replaced, and the brakes have always worked good.

dozer12216

The next time - try this. When you are ready to compress the pads. Install a block of wood between drivers seat and pedal. MOve seat forward enough to turn brake lights on. Open the bleeder screw and force old fluid into a flat pan. Do not force fluid back into master cylinder and past the ABS module. Now you can replace caliper, wheel cylinder, brake line or whatever. After making repiars, remove block of wood and allow fluid to gravity bleed through appropiate bleed screw. It is easy enough to fail the MC or ABS by forcing junk fluid backwards. JMHO and several years of repairing.

laurel2000

Thanks guys, the problem was I was bleeding the front caliber from the line and not the nipple. I followed all your procedures and it worked like a champ. Now it time to get that motor to stop running constantly! Exciting uh!