USMC M38A1 Undercoating

madmike · Post by **madmike** » Thu Dec 01, 2011 3:12 pm

The body shop where I took the tub for minor repairs convinced me that it should be sand blasted. I said okay but don't take off the undercoating. Everything underneath was fine. Well of course, you know the rest. The guy blasting did not get the message.

So now I have to redo that and I did not take pictures before I took the tub over to them. So my questions are:

Does the tub get the undercoating after being installed on the frame?

Does the undercoating get painted or left black?

Is the undercoating anything special?

Do me and my friends go over and kick some serious @#*?

53a1 · Post by **53a1** » Thu Dec 01, 2011 3:49 pm

I would be concerned with the condition of the metal after the sand blasting.

I would worry that one, they must have HAMMERED it with sand to remove the stuff or two, they charged you a bundle of money because of the extra time required to remove it. Bottom line, even if you did want it removed it should have been done before blasting.

My experience is that you have to be careful with the sand blasting because they usually have a bone head doing that job.

wilfreeman · Post by **wilfreeman** » Thu Dec 01, 2011 5:05 pm

Also, all of the concentrated blasting can lead to warping - that's what happened to my hood + they let the blaster eat through the front lip of it in one spot and I didnt know about the warping until I got it to the body shop.

Bretto · Post by **Bretto** » Thu Dec 01, 2011 6:59 pm

I know there are guys out there that know what they are doing regarding sandblasting but I guess I'm glad that I'm forced to be frugal and do things at home. Lots of elbow grease is being burned up in my garage.

vrod02 · Post by **vrod02** » Thu Dec 01, 2011 8:48 pm

I would'nt be concerned about warpage on the tub or frame that stuff comes of quick usually faster that multiple layers of paint, its had yrs of expansion to separate from bottom layer of paint.Its kind of like popcorn ceiling comes off in sheets,with proper technique. Does it affect worth of restoration? Not down with the 5's . was that a sound deading thing?The good news is you can now epoxy primer, then red oxide for finish color. Red oxide is key to desired color like gillespie on the 8's as well as the 5's
I

Bretto · Post by **Bretto** » Thu Dec 01, 2011 8:59 pm

8's and 5's? Huh?

vrod02 · Post by **vrod02** » Thu Dec 01, 2011 9:18 pm

sorry slang here in Mo. 8's short for 38's cj3a. 5's short for A1's. Cj5's

Post by **wesk** » Fri Dec 02, 2011 1:45 am

You can bet when those A1's were rolled through the USMC depot at Barstow the guy with the undercoating spray gun was not a very picky private!

Unless I planned on using it for a daily driver in Snow/Salt country or the salty beaches on the coast I would not undercoat it. I'd go with standard chassis satin black on the frame and whatever primary color on the tub.

evanso1975 · Post by **evanso1975** » Fri Dec 02, 2011 2:24 am

My experience is that you have to be careful with the sand blasting because they usually have a bone head doing that job.

The guy I took my frame & tub to for blasting also restores classic cars. Only a small set-up; just the guy & his father. Had a look at some of his work before I took the M38 bits there. I thought if he can blast a classic aluminium-bodied racing car, then the jeep tub should be no problem. And I was right, for once.

His price included etch primer too. Plus he was cheap.

It does pay to shop around, til you find someone that at least pretends to know what they're doing. And ask to see some of their work (even photos).

madmike · Post by **madmike** » Fri Dec 02, 2011 2:01 pm

Thanks for all the feedback. I want to undercoat it again because the guy did not remove all the undercoat (just most of it) and because it is a USMC unit that was undercoated, I believe, at the factory per the contract. Could be wrong there but it seems that all I have heard about these ordered in the early 60's was that they were undercoated.

I guess it must be standard type undercoating as no one weighed in on that. The body will be coming back next week and I hope to get it painted here before the rains come. Most of the other work is done.

Just did a rough tally on what I spent so far. I advise you not to do that unless you feel like beating up on yourself. It's an ugly number but I sure have had a good time researching this and interacting with everyone on the restoration. Thanks to all. Hope to roll it out at camp Delta (outside Lodi, Ca.) in April.

Mariposa Mike

Post by **wesk** » Fri Dec 02, 2011 11:42 pm

I haven't seen any evidence that they were factory undercoated. I know they were processed thru the USMC depots new and had the lift rings changed and etc.

Only contract special items I seem to see are the posi diffs and the basic fording system plumbing (not the deep water snorkle kits).

Remember if you want a factory resto they left there very bare bones. No accessories and very few stencils.

RICKG · Post by **RICKG** » Sat Dec 03, 2011 10:35 am

madmike wrote:Just did a rough tally on what I spent so far. I advise you not to do that unless you feel like beating up on yourself. Mariposa Mike

Affirmative on that, Mike-

53a1 · Post by **53a1** » Sat Dec 03, 2011 7:48 pm

You can bet when those A1's were rolled through the USMC depot at Barstow the guy with the undercoating spray gun was not a very picky private!

So true. The stuff was on everything that could be hit from the bottom of my Jeep. It's actually so much nicer now that I can now make out the different parts that make up my Jeep.

Not down with the 5's . was that a sound deading thing?

I pretty sure the m38 USMC had the undercoating as well. I would say it was probably used for corrosion control also.

Post by **wesk** » Sat Dec 03, 2011 8:16 pm

I wouldn't say corrosion control. Back then undercoating in the field was a quick cover-up that delayed the corrosion only a little and made repairs in those areas rediculously painful and time consuming.

wilfreeman · Post by **wilfreeman** » Wed Feb 15, 2017 6:53 pm

I'm going to bump this thread because it has the exact same title that I was going to give. I have spent the last 2 days under my USMC contract Jeep rebuilding the bellcrank/draglink and scraping, brushing and painting the frame, springs and axle.

First off, the USMC Kaiser M38a1 has a different/upgraded bellcrank with a metal cap on the bottom of it. The standard bellcrank rebuild kit WILL work on these upgraded parts, but the main bolt has to be re-used - the replacement bolt is too short. I had to use a torch to remove the sleeve from the bolt and installed the new sleeve on the old bolt. The standard rebuild kit resulted in a very tight bellcrank.

Second, you weren't kidding when you said a heavy coat of undercoating. And it is on EVERYTHING!

My question is: As Madmike asked, is the undercoating painted or left black? I brushed a heavy coat of OD on the frame, axle and springs - do I need to go back and paint it after I spray the undercoating on?