Disc Brake Conversion - caliper problem

Just completing a disc brake conversion on my '66 cj5, and ran into a problem, which would appear that other people have had. This is what I am using; used mid 70's chevy 1/2 ton 4x4 caliper mounting bracket, reman. calipers, and '78 cj5 - 1 1/8" rotors. And this is what the problem was. After mounting the rotors, I could not get the loaded calipers to mount. The rotors were inset approx. 1/16" to far, which prevented the calipers from slipping on. I found several posts addressing this problem, with suggestions from using a thicker inner wheel bearing, to using a shim behind the inner wheel bearing. Both these resolutions would move the hub assembly out and in turn would make it difficult to install the snap ring on the end of the axle. After pulling my hair out and using language that I don't normally use in public situations, I went and closely inspected the caliper mounting bracket. What I found were burrs on the ears of the bracket were the caliper mounts and the openings appeared to be slightly tweeked in. I proceeded to file the burrs off and then "GENTLY" massaged the opening wider, using a digital caliper to make sure both openings were the same. This gave me most of the 1/16" needed. I now could get the calipers to mount, but they were tight. Next, I took approx. 0.010 off the inner brake pad. After remounting the calipers, I now have a proper fit. I hope this will help anyone else with a similar problem. If you have any further questions, feel free to email me.

hardtail84@hotmail.com

 

When I did my conversation I had a simaliar problem. One side fit fine the other didn't. Running the inner pad across the belt sander took take of the problem. Brakes have worked great ever since.

 

Im pretty sure that I've somewhere (may well have been the tech section) that the issue is buying loaded calipers. The pads that come with the calipers are designed for the thinner rotor and will need to be tweaked to work with the thicker rotors.
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Using the thicker inner bearing RACE and the National 8430s inner seals (assuming you are using drum brake spindles) completely alleviates this whole issue. Some people use a shim behind the inner race as well and that works fine.
I don't have the whole inner race # handy but the stock inner race ends in 10 and the thicker race ends in 11. The rest of the part # is the same.

I've done literally hundreds of these conversion using these parts and they have all come out just fine.

sanding the pads or grinding the mount is not fixing the problem, it's band-aiding it. That means everytime you do a brake job you are going to have to sand the inner pad instead of simply buying some pads and installing them.

Loaded or unloaded calipers have nothing to do with it. It has to do with properly spacing the rotor and bearing hub so the caliper has the travel it needs to be centered properly. Different aftermarket pads do sometimes have slightly different thicknesses, but that doesn't change the offset of the rotor, only determines how much you will have to remove from the inner pad when you do your next brake job if you don't have the rotor centered properly. Most companies that sell a disc brake conversion for a drum brake vehicle sell the kit with the proper race already installed in the bearing hub to make sure it fits properly.

By the way, unless your front axle uses the bendix joints there is no problem not using the snap ring. I've been running mine without them for 20 plus years with no issues.

 

X2 on everything Nick said. I've done a 27 and a 30 and both needed different inner races to center up. The 27 I could still get the snap ring on but the 30 was no go. Been running the 30 for 2 years on and off road in 2 and 4 at speeds up to 70+ mph w absolutely no issues.
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Part Numbers:
Inner Race LM501311 - Thicker
Outer Race LM501310 - Thinner
I had the same problem on mine. When I went to the thicker inner race it solved it completely!

 

A few questions for the file,

When You use the thicker inner race, you use the same bearing?

You then change the outer race to a thinner one, using the same bearing?

Steve

 

The 501311 is the conversion race to space the rotor outward for proper centering of the rotor and caliper. Used to replace the 501310 used in the D27 hub. The LM 501349 is the stock bearing # used with the D27. It's the wider bearing you need for the conversion. The 8430s is the seal you need to use with the conversion race. DO NOT drive it in all the way as it will hit the bearing as the conversion race spaces the hub out further. Only drive it in far enough to hold securely but still have clearance between the seal lip and inner bearing.

this was taken from my conversion thread, and it worked flawless.

 

here is a link for your reading pleasure

http://www.earlycj5.com/forums/showthread.php?t=71896&highlight=caliper+mount

 

The conversion race works with most Dana 25's and all Jeep Dana 30's with drum brake spindles as well.

 

I discovered a brand of brakes that fit in fine w/o any conversion to the axle. They are organic from "Wearever" part # WAD-52. I had tried other pads that I had to put on the milling machine to get to fit. These go in straight out of the box.