Disk Brake Dragging One Side

I did the sidekick disk brake conversion awhile back and I can’t get the passenger side to stop dragging. I thought it would sort itself out and it never has. I’m a novice on all this but especially so on disk brakes...any idea where to start? Driver side is fine. I can turn the passenger wheel by hand, but it definitely drags.

I have a frame mount dual master cylinder set up from Herm for drum/drum (that’s what I ran for a long time) I have a proportioning valve in the rear to turn down the rear 11” drums. In the front I have a 2lb residual valve. I didn’t do anything to the valves in the master cylinder.

thanks for any direction!

 

My jeep knowledge isn't vast.
For cars I've converted to disc brakes in the past, I've heard you want to remove the residual valve for the disc side of the master cylinder.
It's only needed to keep the drums ready to activate, but can cause discs to drag.
I'd try removing that first.

 

Maybe there's some air in that caliper? Hope you figure it out!

 

I am assuming you put new brake hoses on when you did the conversation?

 

X2 on this. The factory master dual cylinder has drum brake residual valves behind the large brass nuts where the brake lines connect. You should pull the brass nut and remove the spring/diaphragm to disable the factory residual valve.

That doesn't explain why one side is worse than the other though. Old hoses can swell inside and act like a one-way valve that hold pressure in the caliper. It's also possible there's corrosion in the caliper bore causing the piston to stick. Even new parts can get surface rust on if they sit on the shelf too long. If it's a floating caliper, make sure it slides cleanly on the pins. If it doesn't, that can also cause drag.

 

Most likely possibilities, IMHO

 

I've seen a couple "remanned" calipers that start hanging up even a couple months into service. Some of these units haven't even come with new pistons. They just clean up the original one that has rust pits in non-vital areas.
I bought a pair for my mom's Cadillac CTS from RockAuto, and one had a new metal piston and the other reused an original plastic piston. Both of these started dragging within 6 months.
-Donny

 

Good tips. Thanks!

Yes, hoses are new and lines are just a few years old.
It was a reman unit from Rock Auto, and the caliper piston moves but isn't very smooth. I'll re-bleed it first...start throwing new parts at it.

I'll remove residual valve from the master while its somewhat easy to get to before I re-route my exhaust to that area.
Should I remove the one for the rear drum brakes too while I'm in there and have to bench blead the thing anyway, and plumb in a 10lb residual valve?

The wet braking was definitely better after the conversion, as was the darting under braking...but the overall stopping power seemed less than when I had 11" drums all around. Hopefully removing the residuals in the master will help that.

 

check the slides on the caliper.

 

Did you convert to power brakes at the same time you converted to discs or are they manual disk brakes? The challenge with discs is they need more line pressure to work then drum brakes. You can achieve this by either moving the pivot point on the brake pedal for better leverage, or using a power booster.

My bet is the one caliper's piston is hanging in its cavity, or the caliper is hanging on the slide bolts.

Mike

 

Don’t remove the factory residual valve to the rear drum brakes. That one you need.
I recently “rebuilt” a caliper on my old Porsche and it wasn’t difficult. The rubber parts are cheap.

 

The front disc brake reservoir is larger on the Disc/ Drum Master cylinder. You need that for proper disc caliper operation. Oh, like the others wrote,.........old rubber hoses & messed up slides will hang up a caliper , too