M38A1CDN2 Brake Job and Hub Removal

Mike Baker · #1 07-08-11, 20:04

Two part question:

1) The maintenance manual says I have to remove the hubs to change out my brake shoes and wheel cylinders - is this true?

And if not, question "2" is what the best method of doing this is. My understanding is that it would be best for me to get a universal hub puller like the OTC 7394, along with a couple of extra legs, and pull the hub using all 5 lugs. However, that particular tool (and the extra legs) will cost me close to $300 in Canada. (Although if I had a US address I could get it for about half that, including shipping - despite the fact that our dollar is worth more). None of the local shops seem to have one I can rent, either.

Any guidance on this would be much appreciated.

Mike

Barry Churcher · #2 07-08-11, 20:21

Mike, surely someone around you has one of these pullers they will lend out. What about the mechanic that fixes your car? Partsource also has a tool rental service if there is one near you. You don't need to pull the rear hubs on a CDN3
model.
Barry

rob love · #3 07-08-11, 20:27

You can easily do the brakes without hub removal. But since your jeep likely has not had a full servicing in 25 years, you should pull the rear axles and repack the wheel bearing on each shaft. Also, replace the inner oil seals, and you may as well replace the outer dust seals. Failure of a wheel bearing will mean the axle will come out, shaft, hub, drum, and tire.

I do have a couple of those OTC hub pullers, and if I was home I would loan you one. Unfortunately I am not, and cannot say for certain when I will be. Do not use a puller that hooks around behind the edges of the hub...you will only bend the hub.

One option to removing the hub is to remove the drum and shoes, then undo the line to the wheel cylinder. You can then remove the 5 or 6 bolts that hold the brake backing plate onto the axle. At that point, the axle should be ready to come out...you may have to tap the hub a bit to get it to come out as you have to drag out the bearing race from inside the housing. Once out, the hub can be removed in a full size press. Then the whole works can be reassembled in the normal manner. On assembly, it is vital that you torque the hub nut extremely tight (I think the torque was around the 300 pound range, but check the manuals). Also, note that the axles should have a slight end play (around.004" IIRC). This is adjusted by removing or installing shims between the race and the backing plate.

Sorry to add this extra step to your brake job, but I am pretty sure when you see the condition of the bearings in there, you will be glad you did.

Mike Baker · #4 07-08-11, 21:55

Ha ha - that is what I feared. Well, no one ever told me this hobby would be cheap. Thank's for the info.

Mike

chris vickery · #5 08-08-11, 02:56

Mike, I ended up in this predicament myself.
My CDN3 had a CDN2 rear axle that needed brakes etc. Upon disassembly, I noted that the rear seals were also leaking. Time to do anoverhaul on the entire axle ass'y...
I tried to pull the hubs using the incorrect puller and let me tell you, my hubs ended up mangled. They are rusted right on, the military never used any anti seize.
I ended up recently purchasing the correct CDN3 differential and axle ass'y to make it right. I figured that if I was going to do a whole rebuild I might as well invest in the correct rear end anyways.
BTW, Partsource does not carry a puller anywhere near the size or type that you require. I would follow Robs advice to pull the axles bearing and all and have the hubs pressed off on an industrial shop press.

Mike Baker · #6 08-08-11, 03:08

After reading this morning's posts, I accepted the inevitable and ordered the hub puller and extra legs from Lordco (which thankfully offers a 30% military discount). This way if there is anyone else on the Island that needs it, I'll have it. (There are at least 3 other M38A1's here - one at the 11 Svc Bn museum, one at the AF museum in Comox, and another privately-owned one that is painted blue).

I have been trying to limit the amount of restoration I am doing on the truck right now, since I don't have a garage - just a carport (historically not much need for garages on Vancouver Island, just for shelter from the rain!). Just waiting for the inevitable posting to Ottawa so I can buy a house with a detached garage/shop where I can do a frame-off restoration without also getting a divorce.

Mike

Bob Carriere · #7 08-08-11, 03:27

Hi Mike

Whenever you get tranferred to Ottawa.....give the Hammond Barn guys a call....

Bob C.

rob love · #8 08-08-11, 15:21

Quote:

Originally Posted by chris vickery

I tried to pull the hubs using the incorrect puller and let me tell you, my hubs ended up mangled. They are rusted right on, the military never used any anti seize.

The military was not supposed to use antisieze on these. The DU (lube chart) did not call for it. The only thing you could use in that spot was lead paste as a last resort if the flange was loose on the axle and re-torquing did not help. If the lead paste did not fix it, then both the hub and shaft had to be replaced, as once bolted together, they were theoretically matched for life.