Shimming a replacement frame

[Tony S.]

I'm helping a friend with his frame off restoration of a '65 convertible. His original frame couldn't be restored, so he bought a replacement frame. Is there a method for determining how many shims each mounting point will require before the body gets matched up with the replacement frame?

Any useful suggestions would be appreciated.
Thanks.
Tony

[Wayne W.]

Re: Shimming a replacement frame

I'm helping a friend with his frame off restoration of a '65 convertible. His original frame couldn't be restored, so he bought a replacement frame. Is there a method for determining how many shims each mounting point will require before the body gets matched up with the replacement frame?

Any useful suggestions would be appreciated.
Thanks.
Tony

No, but all you really have to do is set the body on. Then fill in the gaps, and shim so that when tightened, the door gaps fit and there is not any undue stress on any part of the body. You can slip shims in and out of any position on the frame without removing it.

[James W.]

Re: Shimming a replacement frame

Tony,

I think the information below will help you.

Regards,

James West
Omaha, NE.

Re: Mid Year Frame Shims (New Frame)Roger Legge <Send E-Mail> -- Friday, 7 December 2001, at 10:48 a.m.

Some time ago there was a Noland Adams tech answer in the back of Corvette Fever regarding a gentleman that bought a car with body off and no shims or shim counts. Noland's answer covers establishing shim count and how the shims affect door gaps, etc. I emailed the editor of Corvette Fever asking if it might be possible to pass this info on to other people via electronic means (an email list had several queries regarding shims). The reply was to paraphrase the info and give credit to the source. I have done so and would be happy to pass this on to anyone that may be interested.
Roger
#36313

Re: Mid Year Frame Shims (New Frame)Erv Schlepp <Send E-Mail> -- Friday, 7 December 2001, at 1:26 p.m.

My 1970 conv. requires readjustment of the body shims.I would appreciate it if you could pass this info on to me.
Thanks:
Erv

Re: Mid Year Frame Shims (New Frame)Roger Legge <Send E-Mail> -- Friday, 7 December 2001, at 2:19 p.m.

I was hesitant to just post here because it's a little long and I'm new to this board and didn't know if it would be OK. Here it is:
This information comes from the April, 2000 issue of Corvette Fever in the Resto Clinic section authored by Noland Adams. I have paraphrased the information and any spelling, grammar or technical errors are my own. The question that was answered by this info was from a gentleman that had purchased a '66 convertible. At the time of purchase, the body had been removed from the frame and the frame had been blasted and painted, any frame marks at the mounting points had not been noted and the shim counts had not been noted as well. In paraphrase form, here's the information about properly mounting and shimming the body.
There was a gauge used at the St. Louis assembly plant to measure variations in the frame. Color coded stripes were placed near each body mount to help figure out the final shim count for each body mount. These stripes were only a starting guideline. Due to inaccuracies in the gauge or variations in the body, shims were often added or subtracted as required. The gentleman with the above mentioned '66 simply lost his starting point.
The first thing to do is to identify the body mount locations. '64 and later convertibles have 10 body mounts, five per side. Coupes have four on each side, but the procedures are the same.
The front body mount (#1) is between the radiator support and the frame. The shims are welded in place at the factory and rarely need to be modified.
The second body mount (#2) is under the ends of the windshield. You reach this mount from under the hood - the left one is under the brake master cylinder, but a little more towards the rear and out side of the car.
The third mount (#3) is only for '64 to '75 convertibles and it's located under the sill plate.
The fourth mount (#4) is in the rear corner of the passenger compartment, hidden behind a metal rectangular cover in front of the rear tire.
The last mount (#5) is in the rear of the body and is the last mount to be shimmed and adjusted.
To mount the body to the frame, we are concerned with the adjustments to six body mounts. They are #2 left and right, #3 left and right and #4 left and right. Start with a minimum number of shims, which is either three or four at each mount. Hold them in place with masking tape and align them for the mounting holes. Lower the body onto the frame.
Install the body mount bolts, washers, shims, nuts, etc. on the six body mounts that surround the passenger compartment - left and right sides #2, #3 and #4. Correct placement for parts is shown in the Assembly Instruction Manual (AIM). AIM shows rough drawing and part numbers, but most body mount kits come with an instruction sheet.
Tighten the six body mount bolts to firm, just a little more than finger tight. Look closely at the shims at each of the six locations. The weight of the body should hold each stack of shims solidly in place. If any of the shims have spaces, remove the bolts and add shims as required. Replace the bolts and again firmly tighten all six bolts.
The bolts are slowly tightened until two things happen: the six bolts are evenly adjusted, but are all quite tight, and there are no gaps between the shims. These are the ideal body mounting conditions for the mounts around the passenger compartment.
The doors are installed next. Each door hinge has six bolts and there are a number of shims at each hinge, varying from none to six. Getting the doors adjusted can be rather difficult. There are two vertical gaps, one at the front of the door and one at the rear. The goal is to get both door gaps even. The front door gap is changed by adjusting the shims on the front mounts, #1 right and left, under the radiator support. Adding shims to mount #1 closes the front door gap at the top.
Each corner of the body is adjusted with more or fewer shims under the four corner body mounts. These are #1 left and right and #5 left and right. If the doors adjust properly, you're done. Some body work may be required for a perfect fit and you may have to adjust the doors a few more times.
If the body has to come off again for paint, the shims are already in place. You still need to adjust the doors after the body is placed back on the frame. Expect this whole procedure to take quite a bit of time.
Again, credit for this procedure should be given to Noland Adams. I just paraphrased it for this list.
Roger
#36313

[Tony S.]

Re: Shimming a replacement frame

Thanks for your help. I'll pass this on.
Best,
Tony

[Jack H.]

Re: Shimming a replacement frame

Another method is to set the frame on a flat, level surface (may have to use shims to achieve). Then, using a laser transit (they're pretty cheap now), sight from one mounting platform to the others & determine which is the tallest/highest.

That done, call that 'zero shim' and use it to sight back to the others and determine the number of shims at each pad required to bring it up to the same height as the master or zero shim pad. The point is, you're trying to achieve a flat, level, true plane for the body to sit on.

Now, there are experienced restorers out there who will consider this 'nonsense' and do the job by 'feel' and visual inspection vs. repetitive measurement. Don't discount this experience factor! From my experience these good ole boys come pretty darn close to the 'college boy' measurement approach....