Early 63 Trailing arm bolts / washers

[John H.]

Re: Early 63 Trailing arm bolts / washers

You would think GM would use a grade eight bolt at this location.

Tim -

That bolt is tightly clamped in the classic double-shear configuration with a rubber bushing to absorb shock loadings, so Grade 5 is adequate for the application.

[Michael G.]

Re: Early 63 Trailing arm bolts / washers

Can someone tell me if this is the original shim for a Nov 62 car in this application?

Thanks

[Alan D.]

Re: Early 63 Trailing arm bolts / washers

It's not, the 63/64 had two round holes at each end. Take a look at the LI cat, part number 51-29A Just noticed LI says the slotted shims (as shown above) were used from 64 on, that's incorrect at least on a March 1964 car and supported by the AIM Sec 4, sheet B3.00.
Just another error in repro land which may get you a point hit.

[Harry S.]

Re: Early 63 Trailing arm bolts / washers

Can someone tell me if this is the original shim for a Nov 62 car in this application?

Thanks

I believe it is. I just put a set of these in my April 63 car.

[Edward J.]

Re: Early 63 Trailing arm bolts / washers

It's not, the 63/64 had two round holes at each end. Take a look at the LI cat, part number 51-29A Just noticed LI says the slotted shims (as shown above) were used from 64 on, that's incorrect at least on a March 1964 car and supported by the AIM Sec 4, sheet B3.00.
Just another error in repro land which may get you a point hit.

Alan, I think I read in the judging manuel that the slotted shim were on some of the 63's and at some sometime during the year the were changed to the round holes at either end????

[Kim C.]

Re: Early 63 Trailing arm bolts / washers

fyi LIC has changed the bolts to the 4-1/4 . (#51-33A)

[Alan D.]

Re: Early 63 Trailing arm bolts / washers

Ed, those 63's have to be hell to restore correctly due to running changes, give all you owners lots of credit.

My AIM shows part numbers of 3846595,6,7,8 for the shims with a drawing release date of 6-4-63, however it was redrawn & revised on ?-10-63 under ECR 56795 (? is due to missing copy data in AIM)

Perhaps somebody has dated data to give a better time frame or a 63AIM in better shape. So all I can really say is that a two hole was used on a March 1964 car, amusing every time I think I know I don't!

[Tracy C.]

Re: Early 63 Trailing arm bolts / washers

....

I've attached a pic of the LI bolt installed with just the lock washer, no flat washers. As you can see, only the chamfer on the end of the bolt is sticking through the nut in the installed condition. GM doesn't, and never did, design attachments without at least one extra thread on the back side of the nut.

....

Michael...you will want to install the bolts such that the nuts are inboard. The AIM shows it like you have it installed, but you will not be able to remove the bolts to adjust alignment shims once the body is on the frame. They will hit the tubs behind the seats when you try to extract them.

tc

[Michael G.]

Re: Early 63 Trailing arm bolts / washers

Thanks, Kim, glad to know Long Island is responsive. I'm sure they'll send me some replacements

I think those shims are original to my car, but I just wanted to make sure they are what the judges are looking for, before I re-plate them.

Tracy, since I'm reusing the slotted shims, I wouldn't think I'd have to remove the bolt to add or subtract shims (probably add, after they fall out...)

Thanks,

[Tracy C.]

Re: Early 63 Trailing arm bolts / washers

Sorry Mike, I forgot about the change over. My late 63 has unslotted shims that are a huge PIA.

[Michael H.]

Re: Early 63 Trailing arm bolts / washers

Can someone tell me if this is the original shim for a Nov 62 car in this application?

Thanks

Michael,

Yes, the slotted shim with the weird shape is the correct shim for all early 63's. I think the change to the 3846595 rectangular shaped shim with holes instead of a slot occured at least half way through 63 production.

The original part numbers were 3819810-811-812.

The rectangular shims with holes for late 63 and probably all of 64 are 3846595-596-597-598.

[Edward J.]

Re: Early 63 Trailing arm bolts / washers

Michael,

Yes, the slotted shim with the weird shape is the correct shim for all early 63's. I think the change to the 3846595 rectangular shaped shim with holes instead of a slot occured at least half way through 63 production.

The original part numbers were 3819810-811-812.

The rectangular shims with holes for late 63 and probably all of 64 are 3846595-596-597-598.

Mike, My March 14 car had the slotted shims.

[Michael G.]

Re: Early 63 Trailing arm bolts / washers

My shims look like they may have been zinc plated at one time (I'd say they are "rust plated" now). Is zinc normal for these parts?

Thanks,