Engine/Transmission (1998.5 - 2002) front brakes dragging, pre-loading???

[MxerChris]

more brake problems, replaced rotors, pads, bearings, drums, shoes, wheel cylinders, all rear springs and flexible rear brake hose, now finally got the rear brakes to work properly and right on que the front brakes starting dragging, when rolling up to a stop the truck will stop on its own, thought it was the rears and brought it in jacked up the rear and they were free, jacked up the front and they would not move after pulling the wheel off checked the calibers and pins all OK, put a c-clamp on the inner pad and could not force fluid back to the master cylinder to release the brakes, cracked the line at the master cylinder and they turned loose. it acts as if the brakes are slightly on (pre-loaded)????? Checked the brake pedal and rod for adjustment and doesnt seem to be a problem there, loosened the master cylinder a little and it allowed the pressure to release, OK now for the question why would the brakes get pre-loaded, is there an adjustment for the rod from the master cylinder to the brake pedal? Cant see how it could have changed but its as if the brakes are slightly on and wont release, could it be a faulty master cylinder? any help would be appreciated... .

 

[Wiredawg]

I didn't notice where you serviced the front calipers. There are some slides that need to be lubed periodically (at least when you replace pads). These tend to bind causing them to not properly release. Not sure if this is it, but all I can think of.



Let us know what you find,



Wiredawg.

 

[B.G. Smith]

Your problem is with the master cylinder, the piston is not returning far enough to allow the fluid to return when brakes are released. The fluid returning when you loosened the mounting bolts on the master cylinder indicates that the push rod is too long. I have a 99 manual but can't find anything about adjusting the length of the rod. bg

 

[MxerChris]

(Your problem is with the master cylinder, the piston is not returning far enough to allow the fluid to return when brakes are released. The fluid returning when you loosened the mounting bolts on the master cylinder indicates that the push rod is too long. )

Yea I'm thinking the same thing just cant think of how to adjust it either, maybe something wrong with master cylinder???

 

[Dieseldemon]

The rods come in diff lengths I did a conversion once from vacuum to hydroboost and had to cut about 3/16" off for it to release when you put the master cyl back if you have to push the rod into the master cyl it is to long cut enough off so there is no preload

 

[jhoughton]

Had the same problem on a gas Dodge truck before. The resevoir was too full and when the engine compatrment heated up the front brakes would drag and start to smell. Once the level was lowered, had no more problems. Also brake lines have been know to cause this problems too when they start to break down internally.

 

[DFerverda]

I just had a problem with the hydroboost, the new one had a rod to the master cylinder that was 1/4 inch too short, the brake peddle would return but was slow, about 8 seconds before it would shut off the brake lights, and the peddle would travel further down.
I put in the right rod,(from old boost) and that cured the problem.
If the brakes were ok before, i would say the master cylinder either is bad or has air trapped somewhere, or as stated above a hose is breaking down.
If the calipers are locked, open the rubber hose at the caliper, if it does not release, the problem is in the caliper

 

[MxerChris]

the reason I think it could be the master cylinder is both front wheels drag and release at the same time when I bleed off the line from the mc. it just seems odd to me because with everything that I did and replaced with the brakes I never touched the mc. seems odd to just start giving trouble.

 

[B.G. Smith]

Are you bleeding the preassure off at the master cylinder or at the proportioning valve?? bg

 

[Batphreak]

Just a problem like this I learned about a few years ago. Had a buddy with a '96 gasser 3/4-ton. He had front brakes that were chronically dragging for a few months, he replaced everything, even a couple new calipers and still had dragging brakes. Turned out his front brake lines (frame to caliper) had collapsed inside, they looked fine on the outside, and were acting like a check valve causing the calipers to drag. Replaced the brake lines and all was good. Just something you may want to check.

 

[MxerChris]

I've done it at both places with the same result it releases just enough pressure to let both front wheels move???? I'm so confused unless something has worn inside or related to the master cylinder.

 

[B.G. Smith]

The reason I asked that question is I thought maybe the proportioning valve had switched over and shut off the front brakes while you were bleeding the rears. Since you didn't do any work/replace the master cylinder and it releases when you loosen the mounting bolts the problem could be further back like in the hydra boost not returning to its original position or even some binding in the brake pedal keeping it from returning completely?????? Good luck. bg