New body mounts, new problem...

[trz1000]

Just got done changing the body mounts on my 72 Jimmy 4x4. Four of the mounts have a sizable gap between the tub and the top mount, like 0.25" or more. Fortunately, I think anyway, it's the same two on each side. Starting at the core support if you number the mounts from 1 to 6 I'm seeing the gap on #'s 3 and 5 on both sides.

I used all new mounts (energy suspension poly) and hardware. There were shims that looked factory at the core support and the forward most cab floor mount which I re-used. I cleaned all mount perches as well as possible. I triple checked that I used the correct mounts in the correct locations. The stock mounts were in varying degrees of degradation. Some intact, some barely there.

I've only had the truck for a month. Bought it as a running project. P.O. did an ok job replacing inner and outer rockers as well as the lower section in front of the rear tire on the passenger side. The floor is real solid except for a small area by the kick panels on each side. Also the front floor supports need to be replaced on each side.

Here's the big red flag, someone prior to the P.O cut out the middle of the torsion boxes. Front and rear end caps are there and in real good shape as well as the vertical gusset that runs parallel to the drive train (about halfway between the rocker and frame). I think they cut them out to get at the floor support to replace it.

I don't think the tub is twisted as the top is on it and lines up ok. The fender door gaps are not 100% but that looks to be the result of the PO throwing it together fast after paint to sell it. Nothing appears to be anything but out of adjustment.

So, should I shim it and forget it or start getting nervous?


Thx,

[lks dcvn]

Since you don't know how the previous repairs were done [correctly vs incorrectly] then you have to go on what is there...

How do the doors open and close with the top on? Do the stick, catch, hang or do they shut like they should?

Have you had the top off since you have had it to test the doors then as well?

If the doors open and close fine with the top on - and all the correct body shims were put back where they were found then I would just add shims to the gaps at the areas you mention and call it a day.

The concern comes in when the top is off - if you take the top off and the doors have issues then - you will need to put a jack at each body mount location [usually the #3 one is the issue - right behind the doors - and jack [and shim] the body up/down until the doors shut correctly on each side.

Hope that helps - post up some pictures of your new ride.

[vtblazer]

IIRC, the poly mounts are thinner than the factory ones, could be the start of your issues right there.


FYI: Mount position's go.
Rad core support
1st position...etc to position #5 being the last one.

Welcome to the board, tons of reading to be had about body mounts, both factory & poly installs.

[SeventyOne]

Originally Posted by lks dcvn

The concern comes in when the top is off - if you take the top off and the doors have issues then - you will need to put a jack at each body mount location [usually the #3 one is the issue - right behind the doors - and jack [and shim] the body up/down until the doors shut correctly on each side.

Hope that helps - post up some pictures of your new ride.

So adding shims to that #3 spot kind of "bends" or "curves" the body to open the door gaps allowing them to close normally? - am I looking at it the right way?

[trz1000]

I have not had the top off yet, was waiting till I get the torsion boxes installed. Besides needing adjustment (bottom needs to be towards the truck a bit) the driver side door is fine. The passenger door hangs up a bit on the striker plate but I'm pretty sure it's an adjustment issue. The gaps are nice and straight on both sides.

All that said, good point about not knowing if the P.O. did everything right, looks good but famous last words right?

Yes, the poly mounts are thinner than the stock mounts. I didn't bother to measure the difference as I have no idea if the stock mounts retained their original dimensions but buy eyeballing it they looked maybe 1/8" shorter. However the core support and #1 position are thicker as are the stock mounts, #2 through #5 are all the same thickness. The difference in thickness seemed to be relatively the same comparing location to location.

Thanks for the info guys, I want to get everything as correct as I can before welding in the torsion boxes.

[vtblazer]

Originally Posted by SeventyOne

So adding shims to that #3 spot kind of "bends" or "curves" the body to open the door gaps allowing them to close normally? - am I looking at it the right way?

No...

Shimming the body won't open up the door space, if it does there are bigger issues looming.
Body mounts #1 & #2 can be used to correct for body-line adjustments though.

Keeping the door openings where they need to be is a function of all those multi layered pieces that so love to rust away on us.
*Outter rocker
*Inner rocker
*Torsion box
*Torsion rod
*'A' pillar (lower mainly)

If any of these stop working due to rust and/or get repaired incorrectly, the door opening measurements might be suspect.

I think if I were already at the spot trz1000 is at, I'd go ahead and torque things down and see where it all ends up.

Then decide a course of action from there if problems persist.

[vtblazer]

This might help get everybody on the same page as for mount location:

[turp mcspray]

If you have some gaps and torque it down, it WILL distort things and change your gaps. If you have access to a factory assembly manual, it has pics and explanations on where to shim to get specific changes on door gaps etc. If you don't have a manual, buy or borrow one. It will It will add a lot of clarity to this issue.
.

[vtblazer]

Originally Posted by turp mcspray

If you have some gaps and torque it down, it WILL distort things and change your gaps.

Exactly, with the old worn out mounts gone he can start fresh and produce the correct dimensions using shims.

As mentioned prior, position's #1 & #2 are the only two places to change and/or adjust the door area of the tub.

[lks dcvn]

My bad on the numbering - I always think of the radiator support as #1 - so I was actually speaking of the next one back from the floor pan bolt - at the rear of the front doors - which is actually mount #2 (as noted).

[trz1000]

Well first of all, thanks for the input. I did some measuring of the gaps and ordered some 3"x3" shims from McMaster-Carr. I'm on the road a lot so the Jimmys been neglected for a while. I was finally able to find the time to install the shims today. All of the mounts are now nice and tight. Now I need to get a set of torsion boxes and weld them in place. But before I do that I'm going to get the doors adjusted properly just to ensure that I don't have any major issues lingering about.

[lks dcvn]

Sounds good to me - now where are the pictures?

[SeventyOne]

This may have been mentioned earlier, but is the top on the truck? If not I would get that on, and everything lined up like you were mentioning before burning in those torsion boxes.