Body Mount / Hardtop adjustment

[Critter]

I have everything screwed up! I have a new urethane body mount kit installed and a double wall top that I just bought cause mine was shot. I am trying to shim the body a little to make the doors align and the top fit better but I am having some trouble. Basically it seems that the body has a low point in the middle of it. The top will not sit down on the bed rails especially right behind the doors. I feel like I need to raise the floorboard area, but I haven't been able to find a combination of shims that work.

OK, long story short, can anyone suggest which body bolts I should shim the most to help this? The one in the floorboard, the one right behind the seats, the one right behind that...?

By the way, my torsion boxes and windshield frame are in surprisingly good shape, but the floor pans are a little weak.

[FRENCHBLUE72]

You mean they all dont do that????

[Critter]

I have seen others that are A LOT better, there has to be a way to improve it...right?

[bouncytruck]

I haven't ever done the body mounts, but are there different ones for different areas? Can you lower the rear and forward most mounts?

I would try getting the top aligned and then shimming the body mounts. You might try loosening the body mounts all around and seeing if you can get the to bolted.

[jaros44sr]

Tough area your playing in!! Check to see if your hinges are in good shape, if there is no movement when you lift the back of the door, your OK. Is the gap in the door small at the top and big at the bottom? If it is you can shim up the bed crossmember, it's located on the stepup cross brace, there is another mount, about 12" to the rear that you will have to shim as well. About 1/2" spacer looks about right. Look for a good solid area to lift...

Are all the other body mounts the same size? Hieght? Hope you have a long reach on your floor jack, you're going to need it. Good Luck, J.

[lks dcvn]

I agree with what was said above - Blazer body mounts have different bolts, shims, pads, etc. for each area on the body...

Maybe they are in the wrong spots - just throwing an idea out there...

http://www.lmctruck.com/icatalog/cb/full.asp?page=34

[Critter]

Originally Posted by jaros44sr

Tough area your playing in!! Check to see if your hinges are in good shape, if there is no movement when you lift the back of the door, your OK. Is the gap in the door small at the top and big at the bottom? If it is you can shim up the bed crossmember, it's located on the stepup cross brace, there is another mount, about 12" to the rear that you will have to shim as well. About 1/2" spacer looks about right. Look for a good solid area to lift...

Are all the other body mounts the same size? Hieght? Hope you have a long reach on your floor jack, you're going to need it. Good Luck, J.

Yes, door is tight at top, too much gap at bottom. I tried shimming the 4 (2 left and 2 right) bolts that are farthest forward in the bed, but it seemed like it only made the condition worse.

The mounts are all in the correct position. I put them on about 6 months ago and reinstalled the factory shims in the same places they were originally at. The doors closed alright but I adjusted them a little. I didn’t have a decent top at that point to work with. Now that I have a good top, I am going back and working with the body mounts to get things right. It’s hard to say what the doors are doing beings that I adjusted them before (and I’m positive they were adjusted by the PO as well) so they aren’t a good reference point. I hope to get the top situated and then adjust the doors to match. Is that a bad idea?

Anyway, I removed all the old shims and the tub now sits on the new urethane mounts as it is intended to do. That helped things a lot and got me to where I am, but it seems that I need to lift all 8 (4 on each side) points in the bed area. Is it bad to do that and not shim the floor pan bolts at all? It just seems like it would put a lot of strain on the floor and torsion boxes. I guess they have a lot of twist in them though.

Thanks for the input guys.

[Jtrux]

Scrap it.

[jaros44sr]

[QUOTE=Critter;2527904]Yes, door is tight at top, too much gap at bottom. I tried shimming the 4 (2 left and 2 right) bolts that are farthest forward in the bed, but it seemed like it only made the condition worse.

Wierd, it shouldn't do that, how much shim have you installed at that location??

The mounts are all in the correct position. I put them on about 6 months ago and reinstalled the factory shims in the same places they were originally at. The doors closed alright but I adjusted them a little. I didn’t have a decent top at that point to work with. Now that I have a good top, I am going back and working with the body mounts to get things right. It’s hard to say what the doors are doing beings that I adjusted them before (and I’m positive they were adjusted by the PO as well) so they aren’t a good reference point. I hope to get the top situated and then adjust the doors to match. Is that a bad idea?

Sounds like a good plan, just don't try and pull the top down with bolts, I'm not sure what will crack first, your windshield or your top!!

Anyway, I removed all the old shims and the tub now sits on the new urethane mounts as it is intended to do. That helped things a lot and got me to where I am, but it seems that I need to lift all 8 (4 on each side) points in the bed area. Is it bad to do that and not shim the floor pan bolts at all? It just seems like it would put a lot of strain on the floor and torsion boxes. I guess they have a lot of twist in them though.

Do what ever it takes with in reason...I don't think you'll strain the metal, I'd be more worried about cracking your new top. Keep us informed so we can follow your progress. J.

[JimKshortstep4x4]

We used the Assembly Manual procedure for adjusting the door gaps on my son's 72 Blazer and it worked out. Here is a picture of the page out of the manual. Hopefully you can read it.

Jim

[JUSBLAZ]

Another consideration is torque specs. I don't have them, but I remember some of my body mount bolts were too tight after I replaced the bushings. Which did take some adjusting, along with the shims.

[jaros44sr]

Good point!!

[Critter]

Originally Posted by JimKshortstep4x4

We used the Assembly Manual procedure for adjusting the door gaps on my son's 72 Blazer and it worked out. Here is a picture of the page out of the manual. Hopefully you can read it.

Jim

Oh yeah, that's why I bought that big heavy book...

Originally Posted by JUSBLAZ

Another consideration is torque specs. I don't have them, but I remember some of my body mount bolts were too tight after I replaced the bushings. Which did take some adjusting, along with the shims.

True, but to be honest with you, I haven't been putting the nylon nuts back on the bolts every time I try a shim combination. I just lower the jack and let the body sit back on the mounts. Maybe thats part of the problem though.

I appreciate all the good info. I plan to tackle it again tomorrow and use some of this new found knowledge.

[pound41]

Start shimming the last mount in the cab area and maybe the first in the passenger area and check the other side as you go to see if that is being affected in the top/door closing. With no top on and old mounts your tub conformed to those specs based on the sagging of the floor. It is not uncommon to sometimes have to reshim when you put in new mounts and still have a good old floor/torsion boxes. Those shims were set for a new no miles/ no sag brand new steel floor etc. Quick example I once helped a carpenter friend install new doors in a 100yr old house. The molding was to intricate so only the doors were replaced. All the doors worked good. He said it was going to be a pain the A--. I said why. He said the doors and the frames have moved together over time. We were now installing Square doors in non square openings. The other thing I learned was the ripple effect. He would look at a door and say this reveal was this and that one is that I am going to put a screw here to pull this in and it will make this do this and that do that. At first it made no sense to me because I wasn't looking at how everything would be affected. Another example my blazer door rubbed the windshield frame when I bought it. The door worked good. The kick panel and floor had some rust. So I am now replacing the floors. Anyway I moved the windshield frame a 1/4 in forward. That move the kick panel and torsion in the box dow and back. This raised the the back part of the door and B pillar area about 1/2 inch. I know because the truck has pinn stripes that no longer lines up. But the body lines are good so the door b pillar was probably sagging and I didn't notice because the doors worked good. Also the other door now hits harder which I will adjust. That is the ripple effect Your sag could be vertical along the body or horizonal accross depending on floor/torsion boxes/ differing combinations Sorry for such a wordy post
Good luck

[red71cheyenne]

Dang. This just makes me realize I may have to do more shimming when I put the top on. Aaaaaahhhhhh......

Seriously, I had to pull the windshield frame on mine to get the doors aligned, then shimmed it to that. I'll wait to see what the top looks like once its on, but I'd almost be willing to leave it as is and just add rubber weather seal under the rails if thats all thats necessary to get it right. Let us know how you do yours. Jeff.

[Musclerodz]

You need to tighten the bolts every time. If the frame has a sag, the body will sag and it will never be correct. Get another set of plain nuts to check everything with. Nylon lock nuts are designed to be one time use. If the rubbers are all correct, and everything is locked down, shim the body whatever it takes to get it correct. The manual does not account for 40 years of abuse when it comes to shimming the body.

Mike