Brake question

[Richard Koplin]

Okay all, here goes. My 1990 F350 Crewcab has had new drums, rotors, pads, and shoes installed. Bled the system at install. My right front brake seems to be dragging. I get a burning brake smell from it. I also have an issue with a soft brake pedal. So i am thinking that i need to replace the front brake calipers and the RABS.
Any input or tests would be appreciated.

 

[franklin2]

That can happen. Over the years the pistons slowly move out as the pads wear. They develop rust in behind them. When you use a c-clamp and push them back in so the new thicker pads fit, the piston runs over this rust and can start sticking. For extra insurance you can also change the rubber lines. They like to get a film of rust inside the line also, and when you are messing with it moving the caliper around to do the pads, this film of rust breaks loose inside the line and can clog it up. It will usually let the high pressure fluid through when applying the brakes, but the lower pressure as the brakes are released is not enough to break through the "rust dam" and they can drag.

 

[KZF250]

Battled the soft peddle on my shuttle bus...ended up needing to adjust the star in the drum quite a bit until the peddle came back. Messed with the Rabs and put a new Master in before adjusting the rears again but neither really helped. You do need to bleed the Rabs as you work your way forward.

 

[icanfixall]

As for front brakes issues my guess is the hoses are not allowing the fluid to return. Just replace both sides. My bet is they are original. when they fail the inside swells closed. Your foot applies enough pressure but then fluid can't return.
Now the spongy peddle. Usually the rear drums demand you adjust them manually. Best way to know if the rears are out of adjustment is to apply the parking brake. If it goes to the floor or near that. then the rears are needing adjustment. Sadly our self adjusters really don't work.

 

[79jasper]

Slide pins can do it also.....

Sent from my SM-G892A using Tapatalk

 

[Daryl4]

The calipers in these suckers tend to stick rather easy, mostly after work or when new/reman. I'd start there personally, they're held in place by spring clip bar things. Punch them out, lube them up, punch them back in, pretty easy and might solve a lot.

Does it pull to the left under breaking? If the right front is dragging and getting overheated then that can cause two things, a soft pedal as that break is overheated and it'll pull to the left under breaking as the right front isn't working and left front is stopping harder.

Rust behind the caliper piston would be VERY bad. DOT3 brake fluid is Hygroscopic, it absorbs water even from the air. If it's got enough water in it for internal parts to rust then it's VERY bad.

Other advice is good, I'd also suggest bypassing the RABS valve if you've done all else or are just not a fan of RABS.