1967-1969 rear spring single leaf cushion pads

[camaro cat]

I managed to secure a set of rear spring single leaf cushion pads from a member over here the SuperCar site. 2 sets of part #3792585 & 3791381 in the original GM box. I, for some reason, had never even tried to source these but when I saw them up for sale, I thought I better buy those. I'm glad I did as I learned something I never knew before. Both the top and the bottom pads each have "Forward to Increase" & "Forward to Decrease" molded into the rubber on opposite ends, along with an accompanying "+" or "-". If I stack the 2 appropriate halves as they would be installed, it is obvious that the line of meeting slopes up or down slightly from one end to the other. One has to make sure that the 2 halves are properly orientated to each other at installation or the gap at the ends will either be too tight or too wide. Can someone tell me how to determine which way is correct for a car? I will also report that it looks like when you went to purchase these, you ordered a complete set of 2 halves for each side to do the entire car and so since it was a combination of 2 part #'s, the order itself was its own part # under "1 #3921060 G.R. 7.545 Cushion Unit" I also posted this on CRG.

Thank you for any and all help

Loren

[enio45]

Do you have a pic of the side profile?

I had/have a set that had a slight wedge look to them and i believe they were for single leaf - leaf springs.

I reread your post - so yours are for mono leaf?

[camaro cat]

Here are photos of the side view and end views with correct alignment and incorrect alignment. I was incorrect in stating that the side view changed with incorrect matchups compared to correct. The alignment stays the same regardless of alignment. But the end views change quite a bit. When correctly aligned with "Forward to Increase" being matched up on the same ends. That results in the end gap matching up the same on both ends. However, when mismatched, the end gap is narrow on one and wide on the other.

Is the purpose of this alignment option to adjust the pinion angle to the drive shaft? Doesn't seem like anything they would have used on the assembly line though as too time-consuming.

There also is a #3920213 on the bottom half piece. Could that be the Pontiac part number for use on the 1967-1969 Firebird? I also assume this piece was used on the 1968-1974 Nova's with low horsepower drivetrains. That brings the question of when did Chevy quit using the mono leaf spring on Nova's. I assume they still used them in 1970.

Loren

[TerryD]

I was looking through service bulletins for something else when I came across this one. Good explanation of the usage of p/n 3921060 G.R. 7.545 Cushion Unit.

[Too Many Projects]

Well, that's interesting . Those replacement pads must be super rare, if they were only made for correcting the "shudder".
I don't know if you should use those on a car built after Feb, 1967, as it may change the pinion angle too much.

My Car is 02C, so should have the corrected pinion angle rear axle.

[TerryD]

It seems that the shudder could but not necessarily be encountered on all Camaro V8 automatics built prior to Feb ‘67 and only addressed if there was a customer complaint.
I wonder if the condition was prominent enough that a high number of cars were repaired under this service bulletin and if guys with original drivetrain V8 automatics are addressing it during restoration of their pre-Feb cars.