Brakes hanging up/Sticking. Any ideas?

[Cppr Busa]

My 2002 7.3 has been having a problem with the brakes sticking on me. I drive for about 10 minutes and the brakes are cool and work fine. Then after about 15-20 minutes of driving the brakes start holding pressure until the point of smoke rolling off the brakes if I drive it long enough.

The things I have done so far is replace all 4 calipers, rotors and brake pads. I also swapped all the rubber lines to stainless steel braided lines. I have taken the calipers off each wheel lubed the pins and made sure the pads slip in and out nice.

I can pull the truck in the shop jack it up put it in neutral the wheels are locked up solid and won't move. If I crack a bleeder open everything spins free like it should. I tried it over again this time cracking the lines at the master cylinder and the pressure stayed applied.(then I cracked the bleeder on the caliper and it spun free again) So I'm guessing it's before the master cylinder and hydro booster.

Anyone have and experiences, ideas or guesses what I should look at next? Thanks for any and all help!

 

[sootie]

i would wonder if someone put the wrong fluid in the brake system at some point and it has caused all the rubber in the system to swell.


try a flush and see what happens.

 

[DHFF]

I had a buddy pour ATF in his brake reservoir because he was out of brake fluid in the field. It did this same thing basically before it blew all of the seals out. Id get it drained and see what's going on.

 

[Dantheman]

Sounds to me like a problem in the hydroboost.

 

[Cppr Busa]

Ok I'll work on getting all the lines flushed out good and make sure it has all fresh brake fluid in it. I appreciate all the feedback!

I'm using Valvoline synthetic dot 3 and 4 brake fluid. Do you think that could be the problem or is it good stuff?

If it were the hydro booster wouldn't it bleed off pressure when I cracked the lines at the master cylinder? I'm not afraid to buy a hydro booster and master cylinder just want to see what all you guys on here have to say first. Thanks again for all the help!

 

[Arisley]

Try cracking the bleeders at the ABS box. I think it is in the front on the driver side corner. Under the battery.

 

[Cppr Busa]

Try cracking the bleeders at the ABS box. I think it is in the front on the driver side corner. Under the battery.

Drove it again got the brakes hanging up. Broke the lines loose at the abs box and it freed everything up. So I went ahead and ordered a new abs box. Is there anything special to do when installing a new abs box?

 

[sbracing240]

Hey I have seen on some trucks the brake master cylinder and hydro boost hang up on each other from rust and corrosion. To check for this all you have to do is loosen the mounting nuts that hold master cylinder to hydro boost and slide it out of way and check with a light for rust between the two. If so just clean out and lube up with white lithium grease.

 

[Cppr Busa]

Hey I have seen on some trucks the brake master cylinder and hydro boost hang up on each other from rust and corrosion. To check for this all you have to do is loosen the mounting nuts that hold master cylinder to hydro boost and slide it out of way and check with a light for rust between the two. If so just clean out and lube up with white lithium grease.

Ok I will check that out! Thanks for the info!