Shims

[Bill M.]

I am in the process of cutting out and replacing rotten body bushings on rear of my 65 coupe. I suppose the amount of shimming was determined just before the body was mounted. How was the number needed determined ? I have ever read an article about shimming. This car has 3 on each sides. Thanks

[Mark F.]

Re: Shims

I am in the process of cutting out and replacing rotten body bushings on rear of my 65 coupe. I suppose the amount of shimming was determined just before the body was mounted. How was the number needed determined ? I have ever read an article about shimming. This car has 3 on each sides. Thanks

Hi Bill,

The shim count and markings took place at the 2^ndth station (2^nd-to-last) on the Chassis Line (CL)
Body Drop was 3 stations later.

I think this is the fixture in question...
FUD Fixture_001.jpg
This is all Per John Hinckley's C2 Assembly Process Presentation (available in the Database of Restoration Documents [DoRD] Sticky Post) as follows:

	Frame Upside-Down Line (FUD):observe plunger readings and mark shim count on frame side rail, rivet upper and lower ball joints to front control arms, sub-assemble jounce bumpers to lower control arms, assemble rebound bumpers and press upper control arm shaft splined bolts to frame, install upper and lower control arms to frame, leaving upper control arm shaft attachment loose.
FUD-14	Frame turnover device transfers assembled frame to Chassis Line chain-on-edge conveyor in right-side-up position.

	Chassis Line (CL):
CL-24	Install #1-2-3-4 body mount spacers/cushions with shims per frame markings and tape to frame brackets.
CL-25	Spray chassis blackout paint on the outboard side of both mufflers.
	Body Drop (BD):
BD-1	Apply compression fixture to both tailpipes and throw over-center lever to pull mufflers together so they clear quarter panels, place shift lever in neutral.
BD-2	Drop body on frame using alignment pins at radiator support mount and at #4 body mount; drive all body mount bolts and remove tailpipe compression fixture. Vehicle remains elevated on Chassis conveyor.

[John D.]

Re: Shims

Here's a pic of the shim fixture used in St Louis- credit to Mr. Hanson the originator.

frame shim check fixture.jpg

[Mark F.]

Re: Shims

Here's a pic of the shim fixture used in St Louis- credit to Mr. Hanson the originator.

Thanks, John,

I think the fixture I show is the one used to establish the chalk marks for how many shims are needed.

The shims themselves are not installed until another 35 or so stations down the chassis line...dunno if a compression fixture is needed to do that, but the one you show sure is a big Mama, eh ?

[Bill M.]

Re: Shims

Mark John thanks. So it looks like the bodies were all alike and the frames deviated from frame to frame. Sorry for late response busy day

[Gary B.]

Re: Shims

Mark John thanks. So it looks like the bodies were all alike and the frames deviated from frame to frame. Sorry for late response busy day

Bill,

That is the theory. I originally thought it would be the opposite. But after reading about the shimming process you know the variability has to be in the frames. Not surprising given how they are made by welding, which can create unpredictable, large twisting and bending forces.

Gary

[Bill M.]

Re: Shims

Thanks Gary !! Any body notice Mr Hanson has a cigarette in his mouth. Man I miss the days of the American factory.

[Mark F.]

Re: Shims

Mark John thanks. So it looks like the bodies were all alike and the frames deviated from frame to frame. Sorry for late response busy day

Bill, That is the theory. I originally thought it would be the opposite. But after reading about the shimming process you know the variability has to be in the frames. Not surprising given how they are made by welding, which can create unpredictable, large twisting and bending forces. Gary

Hi Bill and Gary,

Here's my guesses and I'm thinking this is a binomial equation with the following variables and their relative % weightings affecting the shimming required:

1. X = Frame deviations at mount points caused by differences in frame rails and other parts supplied before frame welding

[Bill M.]

Re: Shims

Thanks all,I never smoked myself but I do love the smell of welding rod.