Help with shims and panel alignment

[C.I.Blazer]

Now that I got my 71 running and the bad door hinge fixed, I started thinking about diving into rust repair for my winter project. Before I did this I wanted to replace the body mounts (from Wes) so I had a good foundation to start with. The tops is on and, while the outer rockers have a lot of rust, the rocker (torsion) boxes are rusty but pretty solid.

Yesterday I got all the old bolts and rubber off and new bolts and top bushings in. I am not sure how to proceed with regards to shimming and how much of the door gaps and panel alignment are due to the shims versus door adjustment, versus front fender adjustment. Nothing on this truck was in good shape when I started so I am really starting from scratch.

When I pulled the old mounts off I had three of the square shims in position 1 (A-Pillar) on the drivers side and one in position 1 on the passenger side. I started with one shim in P1 and P2 on both sides. With this configuration, I could not close the passenger side door as the rear of it was jacked up too high. I moved the passenger P1 shim to the P2 location (now I had two here). The door will now close, but the gaps are off. Drivers side door opens and closes as well as it did before. It is pinching the fender, but it has always done this.

Soooo, my questions are:

1) How much shimming to I do at this stage? At what point to I try adjusting doors, fenders, etc. Or do I just kind of do them all together.

2) In the P2 position, one shim was too low and two made it too high. Should I buy a bunch of these shims from LMC to get more fine tuning in my shimming?

https://www.lmctruck.com/1967-72-che...lignment-shims

3) How tight do i tighten the nuts on all of these body mounts? How much do I want to squish the bushings?

4) Does anyone use washers under the head of the carriage bolts or do they just sit directly on the bed floor?

Sorry for the long-winded post. Did my best to search for answers but could not find anything. Appreciate the help.

[C.I.Blazer]

Pics of the drivers side.

[C.I.Blazer]

Pics of the passenger side.

[C.I.Blazer]

Sorry, I can't seem to get these rotated correctly. I have seen others have this issue with cell phone photos, but I have tried to open them and re-save them on my computer but they still do not work.

[simicrintz]

What phone are you using? If an Apple, I've found that rotating the phone 90 degrees when taking the pic helps.

[Thealien]

Tagging and to the top for you

[lks dcvn]

Driver pix fixed

[lks dcvn]

passenger pix fixed

[lks dcvn]

You are making good progress - let's start there. Once you dive in - you can only improve on what you started with.

Starting with the top on and replacing the body mounts is the absolute right process - w/o this - you would be in a tough spot to get things back to factory spec.

I've done this a few times so I'll explain my process (or at least my approach).

- Steps 1 & 2 are bolting the top on in factory holes and replacing the body mounts and bolts.

-Part of this process is taking note of where the shims are at each body mount position, which it sounds like you have.

-If the old bolts were hard to remove and the rubber mounts were toast - there is a high chance that they are factory originals. Mine have usually been welded to the floor as a special treat to me, which also sounds like it was part of the factory body mount install process.

- When I do this - I have not removed the doors as I like to shim until the doors open/close w/o sticking at the B-pillar. It sounds like you may have done this to replace a bad hinge. When I remove hinges, once they shut well, I usually drill a hole in them (through the a-pillar) as a guide for when I put them back on to help with alignment.

- the B-pillar (rear bedside is a fixed point) - I line up my doors and gaps to the b-pillar (latch) and then worry about the front sheet metal second.

- I have done this a few times and have never witnessed a smaller shim in the body mount replacement - it is usually the thick metal square shim. That doesn't mean you can't use whatever shim you want to get it lined up.

- When I have purchased the LMC body mount kit, It comes with a 'star washer' that goes between the bolt head and the cargo floor. It helps pull the carriage bolt down to the floor and prevent spinning of the head while being tightened. I have only seen them sold with the LMC kit. The rear-most body mount has a metal piece that matches the ridges in the cargo floor.

=================

Now looking at your pix (without hearing/seeing how the doors close) - I would line up your doors to open/shut cleanly at the b-pillar first. You may even consider taking off the front clip to focus on that as they will continue to rub. You don't know if the prior owner ever moved around the front metal so don't consider it a reference point.

You now have enough 'clean' data points to do this - top is on (OEM reference point) body mounts are solid (not sagging), door hinge replaced/repaired (not sagging), shim count at each body mount location to reference. With these the things left to tweak are the latch on the b-pillar and the hinge bolts for the door - way less things to adjust.

* Door gap tolerances from the factory were not perfect - so with that said*

Your door gaps on the driver side look pretty good and match the body line - I would move the door back toward the b-pillar if possible or move the fender forward toward the headlights to alleviate the rubbing.

The passenger side - close on the top, open at the bottom. Could be a few things
- door is hung incorrectly (appears higher in the back - so runs uphill to the bedside (also likely why it wouldn't shut when shimmed - it was already too high)
- weak metal in the pass side floor (floor mount, support under floor, a-pillar where door hinge bolts in)
- fender is hung incorrectly - appears to run uphill toward front of truck.

[DeadheadNM]

Here’s some info from the factory assembly manual: http://67-72chevytrucks.com/vboard/s...9&postcount=22

If you don’t have copies already, I strongly suggest getting copies of the factory assembly and the chassis manuals. Lots of good information therein.

[Thealien]

Where is a good place to purchase the big square body shims in different thicknesses?

[C.I.Blazer]

lksdcvn - Wow! Thanks for the great reply. That is incredibly helpful information for me and I am sure it will be for others in the future as well. Also, appreciate the help with the pics.

It sounds like I am on the right track which is great to hear. Doing something like this for the first time can be a bit daunting but the help on this forum has been phenomenal. A couple of comments then a couple of questions.

- Yes, the mounts must have all been original because they were pretty well destroyed. Also, all the bolt heads except one were welded to the bed.

- Yes, I did remove the drivers door previously to fix a bad hinge. The door would not shut at all unless I forced it down with a lot of pressure. After the repair, everything lined up much better and although the body lines are not exactly on. With the exception of the driver door pinching where it hits the front fender (as you can see in the pic), both doors function pretty well.

Questions:

- There is no extra metal piece in the rear-most body panel bolt. I can see that it was there but it has been removed. Do I need to fab something up to replace it? Is there a reason these where there on the rear-most bolts but none of the others? Is there more force here or something perhaps because it is near where the rear fender attaches to the frame?

- How tight do I tighten the nuts on all these mounts? How much do I want to compress the bushings?

Given what you have said I think I will:

- Call the shims good for now. I have only fixed one hinge that was cracked and bent where it attaches to the door. The other hinges are still saggy so I will get those rebuilt first.

- Remove the front clip and adjust my door position in relation to the B-Pillar.

- Once the door is lined up well, take some measurements then tackle by rocker, rocker box, and floor rust repair.

- rehang doors then re-install and adjust front fenders.

Any comments on my plan of action?

Again, thanks to everyone for the help. Deadhead, I do have the factory manual and did see that page. Just wasn't sure how to balance the shimming with the door and fender adjusting. As so man of you have encountered, it is hard to start with no reference point.

Appreciate all the help.

[notsolo]

The measurements in the shop manuals are in 10ths of an inch. be prepared to do some math. If you have a flat level surface you might try measure from a few different places to the floor and see if the Tub it is sitting level on the frame. Front clip spec's are probably for truck, but should measure the same.

[notsolo]

Couple more....Door opening in critical IMO.

[DeadheadNM]

For the body mount carriage nuts, the head should recess into the square hole in the floor pan so finger tighten the nuts then snug up with wrench. The off center LMC star washers will help especially if the hole is rounded out.

I swear I’ve seen the recommended ft lbs torque but can’t recall where. Maybe the chassis service manual? Does 35 lbs sound correct?

[notsolo]

Sizes no Torque spec's ........From GMC Pauls.............Ok I know its more info than you asked for but heres a cut & paste of the bolt info for Blazer / Jimmy / 1/2ton 2wd truck & 3/4ton 2wd 1/2&3/4ton 4X4 bolt lengths for Cab, Rad & Bed mounting
I figured as soon as I posted just 1 everyone would be asking for the others so I'm giving them all.
Radiator Support: 7/16"-13 x 3.375" carriage bolt
67-72 Blazer Body Mounting Hardware Sizes

Body Mount #1: 9/16"-12 x 6" hex head cap bolt

Body Mount #2: 3/8"- 16 x 10" Carriage bolt

Body Mount #3: 3/8"- 16 x 5.5" Carriage Bolt

Body Mount #4: 3/8"- 16 x 4.5" Carriage bolt

Body Mount #5: 3/8"- 16 x 5.5" Carriage bolt

3/4 ton, 1ton 2wd & All 4X4 Cab Mount Bolts
Front bolt 2- 9/16"-12 x 6" hex head cap bolt, 4- 9/16" large Diameter flat washers, 2- 9/16"-12 Nuts
Rear bolt 7/16"-14 X 8.5"

[notsolo]

1/2ton 2wd Cab Mount Bolts
1/2 ton 2wd Front Mount bolts- 9/16"-12 x 6" hex head cap bolt
1/2 ton Rear cab mount bolts, 7/16-14 x 6", hex head bolt


Core support bolts, 7/16-14 x 4", carriage head bolt
Sleeve Outside Dia. Inside Dia. Length

73-87 Bed Bolts
8- 1/2"-13 X 4 1/2" Carriage bolts

67-72 Door Hinge Bolts
3/8-24 X 1 1/4"

We also sell these as kits for those that just want to order theminstewad and for the guys buying Cab & Radiator support bushing kits from other suppliers and are finding they do not include new steel spacer sleeves we also have those invidually or in our kits except for the large rear spacer sleeve found on the rear mount of the 3/4&1ton 2wd & all 4X4 we do not have this one available.
Paul Jr @ GMCPauls

[C.I.Blazer]

Great info all. Hope this thread will be a good reference for others down the road as well.
Looks like I have a lot of measuring to do in my future.

Thealien, I did see that LMC had the square shims but only in one thickness. I may get a few of the other shims I listed above for any fine tuning I need to do.