Need a couple of measurements, please!

ChuckW · Post by **ChuckW** » Thu Dec 19, 2019 2:11 pm

I am still dealing with the brakes on my 1952 M38. Does anyone have an ORIGINAL M38 brake shoe and can you measure the thickness of the web?

It would also be great if I could get a measurement of the thickness of an original brass eccentric washer, too.

Thanks!

Post by **wesk** » Thu Dec 19, 2019 7:21 pm

Discerning a rare original Willys M38 shoe and hardware from aftermarket parts can be a very large task!

Also a couple more measurement should be considered when trying to resolve excessive friction in movement of the shoe.

ChuckW · Post by **ChuckW** » Thu Dec 19, 2019 8:34 pm

I understand, Wes, thanks. Everything is original to this jeep EXCEPT the shoes. I have .002" difference between the eccentric washers and the brake shoe web.
With the two shoes folded all the way down to the point where the linings are completely clear of the backing plate, if the anchor pin nut is tightened down, the shoes won't move.
I feel certain that the thickness of the web on the aftermarket shoes is wrong, just thought I might be able to get a measurement to confirm.

Post by **wesk** » Fri Dec 20, 2019 1:39 am

I have .002" difference between the eccentric washers and the brake shoe web.

Which one is thicker? The bushing should be the thicker of the two.

Give it time, the answers will start flowing in with many different measurements.

ChuckW · Post by **ChuckW** » Fri Dec 20, 2019 10:07 am

The eccentric cam is .002" thicker than the brake shoe web. there are no consistent measurements on any of the parts. I have ordered a new set of shoes but now I wonder if I should also order a set of the cams, too. The cams should not be worn since they only move during the adjustment process. I will know more when the new shoes arrive. I can't believe I drove this thing for around 20 years like this! The brakes have never been very good but I just chalked it up to the 9" size!

Post by **wesk** » Fri Dec 20, 2019 10:57 am

The eccentric cam is .002" thicker than the brake shoe web.

As it should be but I would guess at least .004 to .005 to make sure the shoe web didn't get pinched when the pivot studs were tightened.

This is a topic that could benefit tremendously from a few factory blueprints.

I can't believe I drove this thing for around 20 years like this!

I have never purchased any one of my 1941 thru 1972 jeeps with properly functioning brakes!

Jeff_Lee · Post by **Jeff_Lee** » Sat Dec 21, 2019 6:00 pm

I have some Bendix 41486 shoe cores in my "brakes box". I removed these off a '51 M38 and I believe them to be originals or early OEM replacements. But in reality, who knows?

The eccentric area is a bit worn by the anchor bolts, so I did not want to measure there. I cleaned up the shoe and took the edge off the web in an area perpendicular to the "41486" number that showed no sign of wear.

The shoe web measures 0.1430"

Hope it helps, Jeff

ChuckW · Post by **ChuckW** » Sat Dec 21, 2019 7:59 pm

Thanks, I appreciate it. The shoes I pulled off all measured about .141". The brass eccentric washers measured between .140" to .138"
The new shoes I received today measured about .130" and they turn freely with the bottom retainer nuts tightened, so looks like the problem is solved.

RonD2 · Post by **RonD2** » Sat Dec 21, 2019 8:42 pm

Hi Chuck,
For those like me about to experience the same problem and weary of spending on aftermarket junk, it sure would be helpful if you could post us a link to where you found good shoes?

Thanks!

ChuckW · Post by **ChuckW** » Sat Dec 21, 2019 10:24 pm

I'm sure there are other people who have great parts and service, but I have been using Walck's for the past few years, especially for my CJ3B rebuild, and have been very satisfied with the quality of their parts and their service.
https://walcks4wd.com/?lpurl=http://wal ... oClObw_wcB

I will say that the old shoes that were on my M38 were purchased off e-bay probably 20 years ago from an unknown vendor and I am sure at that time I purchased the cheapest thing I could find....not always a wise idea!

Post by **wesk** » Sat Dec 21, 2019 11:03 pm

Chuck, Can you post the final measurements you were looking for that you found on your new shoes that fit and work well now? Are you using new eccentric bushings with the new shoes?

RonD2 · Post by **RonD2** » Sat Dec 21, 2019 11:11 pm

Thank you!

ChuckW · Post by **ChuckW** » Sun Dec 22, 2019 11:29 am

Chuck, Can you post the final measurements you were looking for that you found on your new shoes that fit and work well now? Are you using new eccentric bushings with the new shoes?

The web on the shoes that I pulled off all measured between .140" to .141". The eccentric bushings were between .138" to .140", the measurements were not very consistent. The thicker bushings must have been on the rear, as, although the shoes were tight, they WOULD move some. The fronts were very tight and could be moved only with much force. I don't think the springs could have retracted the shoes.

There was no signs of wear on the faces of the old bushings and they fit the holes on the new shoes good, so they were all reused.

The web on the new shoes that I received all measured right at .130". I carefully cleaned the preservative coating off of the shoe where the eccentric bushing goes and used a very small amount of white grease on the mating surfaces. With the shoes installed and the anchor bolt nuts tightened down, the shoes would now rotate freely on the eccentric bushing.

Thanks to all who provided input, this has been a bit of an eyeopener for me, I don't think I would have ever checked this. I would have probably left the anchor bolt nuts loose until the brake drum was on and the shoes adjusted, so there would have been no way to know. This all started when I pulled the RR drum to check for damage from a bent rim and noticed a very unusual wear pattern on the shoes. After pulling all 4 drums, I found that the rear axle shoes were worn only near the top of the shoes (plus they were on backwards!). Front axle shoes had no wear marks at all and, in fact, the drums were rusty on the wear surface! It all makes perfect sense now!
Merry Christmas, everyone!

WillysMotors · Post by **WillysMotors** » Wed Dec 25, 2019 2:42 pm

The Cam for the brake shoe anchor pin 637900 has a thickness spec of .1435 to .1485 and is Bendix number 41876

The shoe without lining is 637894, 906275 and has a thickness spec at the cam hole (which is coined) of .135 to .141 inches

ChuckW · Post by **ChuckW** » Wed Dec 25, 2019 9:58 pm

Thanks! Lots of leeway on those measurements, makes me think the tolerances were not held too close. The combination I have now seems to work OK, but I will be sure to measure from now on.