M38 tub installation steps

groundhog · Post by **groundhog** » Thu Apr 02, 2015 5:14 pm

I have been looking on-line for any good instructions on the best way to install a new repli-tub onto an M38. Another words, does the tub need to be level with the floor or with the frame, and does that tell me what size rubber mounts to put in, etc. I was surprised that I was not able to find very much. Even pics would be helpful. Thanks again, in advance.
Lakeview, Michigan

4x4M38 · Post by **4x4M38** » Thu Apr 02, 2015 5:50 pm

Ron,
I believe one of the downloadable manuals gives step by step
instructions for installing the tub.

4x4M38 · Post by **4x4M38** » Thu Apr 02, 2015 8:15 pm

Yep,
TM9-1804B

Starting on page 52, paragraph 45.

The manuals can be downloaded for free from the link at the top left side of the page under Navigation.

Post by **wesk** » Thu Apr 02, 2015 10:16 pm

You should not mount the new tub until you have the drivetrain installed along with the pedal stubs and steering shaft. Leave the tranny area covers and pedal/steering covers off until you are ready to make final tub adjustments.

The parts manual tells you the thickness of each rubber pad. ORD 9 SNL G-740

As mentioned above the TM 9-1804B tells you how to install it.

As a rule of thumb you start by aligning the rear edge of the tub with with the rear cross member. Then after inserting all the listed pads in the parts manual install the 4 rear bolts finger tight. You can start shimming as needed to center the pedals, steering and shift levers as close as possible.

Once you are satisfied with the tub position and before you do any final drilling and bolting be sure to assembled the fenders and grill and make sure their degree of adjustment capability will get them where they need to be. If they can't then you may need to give up on some tub adjustment accuracy to make sure the front sheet metal will fit nicely.

Now before you call it quits trial fit the hood.

groundhog · Post by **groundhog** » Fri Apr 03, 2015 5:10 am

Thanks so much for all of the help. I figured that this was one item that I needed to take my time on, and get it right. I will check these items out.
Lakeview, Michigan

oilleaker1 · Post by **oilleaker1** » Fri Apr 03, 2015 5:55 am

As others have mentioned, don't drill until you fit all the components. The height of the tub changes how the gaps look between the hood and fender tops. The grill on a M38 is a bit adjustable on the hinges. Then your pedals and steering column need to be checked for centering. I make my own rubber pads out of belting or truck mud flaps. They are usually 1/4 inch thick. You can add or subtract rubber to level and fit things on the mount locations. Take your time. Stand behind the Jeep and sight over the tailgate to the cowl and see if it has a twist, look at the gaps on the fenders and hood. The biggie is the fact that the fenders have two bolts through the center brace into the frame. Those don't move much. So, start there and work out. Some of the new bodies do not fit worth a darn and require modification to get them to fit. I have personally seen horror with MD Juan CJ2A bodies. The older production was just terrible. Folks like Midwest military make top notch repair floors and hat channels. I now avoid new bodies. John

Post by **wesk** » Fri Apr 03, 2015 8:21 am

I prefer metal shim stock for increasing the height of the tub at the mounting points. Keeping the original thickness rubber pads in their is better then increasing the thickness of the rubber at those point. The thicker rubber will age in a few years and as it ages it shrinks and that mounting point will become loose. The thicker the pile of rubber the greater the amount of shrinkage. The original rubber thickness was deemed adequate for it's designed purpose, to insulate the tub from the harmonics/vibration transmitted to it from the frame. If you use a machine shop to make the shims from 1/8" steel plate and have a dozen or so made in a small size that will mate with all the rubbers and predrill the bolt holes you will come away with enough shims at a fair price.

I have several illustrations on tub mounting in my photo album:
http://www.willysmjeeps.com/v2/modules. ... _album.php

oilleaker1 · Post by **oilleaker1** » Fri Apr 03, 2015 11:59 am

But Wes!---------------my teeth don't rattle as much!

Your idea sounds pretty good. John

Boze · Post by **Boze** » Fri Apr 03, 2015 12:53 pm

I installed an MD Juan tub on my '50 in 2004 and the fit for the starter pedal is off in two directions. This has caused me problems along with the lousy floor pan bolts, missing holes, lousy factory paint and no reinforcement on the rear corners. I should have patched my original tub. I know better now.

RickC · Post by **RickC** » Fri Apr 03, 2015 2:33 pm

I did the MD Juan tub. It takes a LOT of juggling shims and adjusting holes. I ended up using an original panel where the starter pedal mounts because
it was so far off. Unless the tubs have improved you'll need to trade off some stuff to get everything to eventually line up. I recall the hat channels weren't even close and the dashboard must have been made by someone that hadn't seen an M38. The gauge panel is bolted in place, no provision for the twist screws. Have pics in my album

WillysMotors · Post by **WillysMotors** » Fri Apr 03, 2015 4:16 pm

I'll be honest Ron, I wouldn't do this without having the old tub and the new one side by side to transfer holes, and if necessary, transfer 'patch' panels.

Trying to weld in a starter hole patch with the tub installed is not practical...

groundhog · Post by **groundhog** » Sun Apr 05, 2015 7:40 am

Unfortunately I don't have the original tub, and it was a pieced tub, one half being an M38 and one half being a CJ2-A. It was so far gone, and I decided that it wasn't practical to continue with a pieced tub mostly. I have temporarily installed the front fenders, grill and hood. The channels in the fenders that mount to the frame aren't lining up. It looks like my pto shifter opening is holding me up. Maybe enlarge front of hole. The grill may come into place with the fenders if I can get the tub moved right. I really appreciate all of the experienced tips and hints. It has been very helpful. And like you all have said, I am taking my time. Thanks

oilleaker1 · Post by **oilleaker1** » Sun Apr 05, 2015 7:59 am

I've read quite a few posts that bad mouth the passenger side front fender. They say the brace is spot welded 1.5 inches off, or the length of the tubs right side panel is off. Some have to move the brace from it's current position in order to get things to work. This means drilling out MD Juans spotwelds. All this on a brand new improved body? Keep your chin up. John

groundhog · Post by **groundhog** » Mon Apr 06, 2015 6:06 am

Thats about the size of it. Another words, keep smiling.

RickC · Post by **RickC** » Mon Apr 06, 2015 6:15 am

I used my original fenders. They actually fit pretty well.....