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I'm working a 1952 M38. So far it's 99% correct, and am getting it road ready. Is there a better tool to use to adjust the eccentrics on the brakes, than a 3/4 box end wrench? The Wrench seems too big to turn while holding the lobe of the Bottom eccentric. I thought there might be a specialty tool trimmed down to allow more room, or maybe somebody has a method that would help me out. Also, is there an actual tool to hold the lobe of the eccentric rather than pliers or a 1/4 end wrench?
Thanks

I found the same problems. Did you reuse your cams and eccentrics?

The 3/4" wrench is the correct size. If it is loose the adjusters are
worn. If everything is clean and reassembled you can use
an adjustable wrench for the inners to hold them.

If everything is tight and grimy you'll just round everything
off unless they already are.

You could try metric wrenches as they have some sizes just under
and over SAE sizes.

You can touch them up with a file and take off high spots and
return the flats to parallel to each other, but if they are worn
that much you should just replace them.

I thought there might be a specialty tool trimmed down to allow more room

The extent of special tools applicable to the M38 are covered in the three M38 specific manuals: TM 9-8012 Page 48, TM 9-1804A page 8 and TM 9-1804B page 13.

The civilian CJ manual SM-1002 lists Willys tool W213 for the narrow cam adjustment stems.

Some examples of this wrench are:





As for holding the jam nut still I would suggest you shop for a 6 point offset box end wrench and grind off enough meat so it will fit in the recessed well.


This example of a 6 point deep offset box is metric but if you look hard enough you can find a US inch the right size.

If your jam nuts aren't terribly worn or eroded then this tool will work well. They are called flare nut crows feet.



If you have very worn or rounded edges on your jam nuts sometimes this 6 point flare nut crows foot will fit in the well:

Thank you, The jam nuts are all in good shape as well as the eccentrics. Everything has been disassembled and cleaned. It was just at some points the eccentrics would turn while I was trying to tighten them. Thanks for the pictures and Ideas for the different tools. I'm not exposed to a lot of different type of tools and didn't know what was available out there.