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CJ5 Front Disc swap; Now calipers way too tight

CJ5 Front Disc swap; Now calipers way too tight

cglax6

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VA
Vehicle(s)
'76 CJ5, 351w, Ford T18/D20, D44 (open), D30 (open), 2.5" BDS spring lift, 31x10.5x15 tires
All,
I really appreciate all the help so far. After driving my CJ5 around for a bit after replacing my front drums with disc brakes from Horsepower Sales, LLC, the calipers seem way too tight.

If I try and spin the tires if the front end is jacked up, it takes way too much effort to turn them.

After driving for a bit, I can smell the front brakes, and the front wheels are waaaaaay hot.

I didn't swap out the master cylinder because it looks like it's compatible for disc brakes...two reservoir system, and it has a proportioning valve mounted on the frame. I ordered a new MC and prop valve and they'll be in next week.

Just wondering if I have something else going on.

The brake pedal returns to where it should, and the pads don't look out of
whack.

Pic is of the current MC and booster for reference.

Any help is greatly appreciated!

Thanks.

IMG_20180728_111206.webp
 
If the drum brakes worked decent, then I'd bet your problem is the master cylinder. Drum brakes require slight constant pressure to keep the wheel cylinders from sucking in too far. This pressure will cause disc calipers to drag. You can remove the residual valve for the front, but your better option is to replace the master cylinder.

The drum/drum proportioning valve is also different from a drum/disc valve. I got much better braking after changing to a proper disc/drum master and prop valve than I did with the drum/drum master with residual valve removed and drum/drum prop valve.
 
:agree:

The front drum and front disc MC are different PN's.
You will also want to switch out the portioning valve.
Takes more psi for disc, than shoe type brakes.
LG
 
Kind of what I figured...which is why I went ahead and got the new MC and valve. I'm sure that'll fix the issue. When it comes in and I get it installed, I'll let ya'll know how it turns out.

Thanks again.
 
Make sure to bench bleed the MC and use only DOT3 fluid.
Good luck,
LG
 

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