Rear suspension questions

[Vincent D.]

I finished rebuilding/restoring my rear suspension and I have a few questions to insure I've put everything back together the proper way as this is my first corvette.

1. I researched the discussion posts on rear strut rod bracket orientaion and assume I have it installed properly since former posts say it can only be installed one way. The reason I ask this is that it looked symmetrical me and looking at the finished installation the strut rods at the attaching points on each end appear to be a slight bit racked or twisted, ie, they don't seem to sit square or parallel at the mounting locations. I still have the car on jack stands and I'm thinking that they may sit better when the car has weight on it. I set the camber bolts as they were before removal.
2. The "correct" trailing arm pivots bolts I purchased from Corvette Central appear to be too long. I had to add an adddional flat and lock washer on one side and a lock washer on the other to get the cotter pin hole to line up. Has anyone experieced this? The judging and AIM show just flat washers on end end of the pivot bolts. I installed the same thichness of new shims on the inner sides that were previosly installed and the shimmed the outter space till vey snug ( the outter space required lees shims). I don't understand why this is happening. These arms were obtained from Bairs by Gary R, who rebuilt them for me along with the diff. I don't have the origanal bolts to compare them to as they had to be cut out.
3. The front bolt on the lower diff. mounting bracket, the one with the cotter pin is too short; with the lock washer tighten up to tork I can't get the cotter pin inserted...it needs to be tighten further and won't go any further. I could file the slot in the castlelated nut a bit but don't think this is a good thing to do. I hate to drop everything again to get this bolt ouT Any suggestions?
4. Can I tork the camber bolts and the control arm pivots bolts now with the car on jack stands since I'm gennerally putting it back the way it was? I would tork them with the whells/rotorss supported at ride height, the AIM says otherwise. I'm aware that the 4 spring bolts get torked when loaded.Thanks,
Vin

[Wayne M.]

Re: Rear suspension questions

2. The "correct" trailing arm pivots bolts I purchased from Corvette Central appear to be too long. I had to add an adddional flat and lock washer on one side and a lock washer on the other to get the cotter pin hole to line up. Has anyone experieced this? ..... I don't have the origanal bolts to compare them to as they had to be cut out.

3. The front bolt on the lower diff. mounting bracket, the one with the cotter pin is too short; with the lock washer tighten up to tork I can't get the cotter pin inserted...it needs to be tighten further and won't go any further. ....

Vin --- about the trailing arm pivot bolts and the front bolt on the diff carrier, they are the same bolt # 3846867 [at least in the '65 AIM]. I have a pair of originals off a '64 [assuming same part #] and measured them at 4_1/2" from under head bolt along shank to pilot tip. I suppose yours are now installed, so difficult to measure.

[Michael W.]

Re: Rear suspension questions

Question #1 the strut rods will not be aligned in any axis while the suspension is at full extension- don't worry about it, perfectly normal.

Question #4- wait until the car is at normal ride height before tightening any bolt or nut that retains a rubber bushing.

[Gary R.]

Re: Rear suspension questions

Vin,
The differential front bracket bolts and the T/A pivot bolts look the same but the lengths are different, could you have mixed up?

[Joe L.]

Re: Rear suspension questions

Vin --- about the trailing arm pivot bolts and the front bolt on the diff carrier, they are the same bolt # 3846867 [at least in the '65 AIM]. I have a pair of originals off a '64 [assuming same part #] and measured them at 4_1/2" from under head bolt along shank to pilot tip. I suppose yours are now installed, so difficult to measure.

Wayne------


The GM #3846867 bolt was discontinued in August, 1977 and replaced by GM #458984. The GM #458984 bolt is 4-9/16" in length.

[Vincent D.]

Re: Rear suspension questions

Thanks all for the responses.
I checked the 66 AIM and it has the same bolt, number 3846867, for both applications. I measured the original diff bracket bolt and its 4-1/2"; I also measured, as best I could, the new bolt and it appears to be the same length, 4-1/2" so I guess I'll leave it as is and maybe just put a very shallow saw cut in the notch that lines up when its fully torked as the hole for the cotter pin is off just about half the thichness of the pin. Either that or try to elongarte the hole a bit with the bolt installed. I think this woud be a better solution since it won't be compromizing the integrity as much.
I'm certain I didn't mix the bolts up as they were ordered new and were clearly tagged.
My main concern was the strut rod bracket being oriented in the right direction. Since no one responded to that I'm assuming I have it installed properly with the straight leg of the U shaped channed facing the rear of the car.

Thanks again,
Vin

[Wayne M.]

Re: Rear suspension questions

....My main concern was the strut rod bracket being oriented in the right direction. Since no one responded to that I'm assuming I have it installed properly with the straight leg of the U shaped channel facing the rear of the car ....

Vin -- yes, again. This way, the 4 holes in the bracket line up perfectly with the tapped holes in the bottom of the differential carrier. The forward passenger side hole is moved slightly inward [to the centerline of the car] (versus the other 3) to avoid installing backwards.

[Wayne M.]

Re: Rear suspension questions

Thanks all for the responses.
I checked the 66 AIM and it has the same bolt, number 3846867, for both applications. I measured the original diff bracket bolt and its 4-1/2"; I also measured, as best I could, the new bolt and it appears to be the same length, 4-1/2" so I guess I'll leave it as is and maybe just put a very shallow saw cut in the notch that lines up when its fully torked as the hole for the cotter pin is off just about half the thichness of the pin. Either that or try to elongarte the hole a bit with the bolt installed. I think this woud be a better solution since it won't be compromizing the integrity as much.
I'm certain I didn't mix the bolts up as they were ordered new and were clearly tagged. ....

Vin -- here's my original '64 bolts, [#3846867 assumed] to compare where your cotter pin hole is located, threaded length, and the geometry of the castle nut slots. On the left, I've aligned the bottom of the nut slot with the bottom of the hole in the bolt. I show both washers, even though one goes under bolt head.

[Joe L.]

Re: Rear suspension questions

Vin -- here's my original '64 bolts, [#3846867 assumed] to compare where your cotter pin hole is located, threaded length, and the geometry of the castle nut slots. On the left, I've aligned the bottom of the nut slot with the bottom of the hole in the bolt. I show both washers, even though one goes under bolt head.

Wayne and Vin------


It's also very important that the slotted nut be of the correct, original configuration. There are many different styles of slotted nuts and castle nuts.

Also, I have NEVER seen a case in which when the proper torque for the bolt was reached without alignment of the hole and slot it was impossible to tighten the nut further to align the cotter pin hole on the bolt with a slot on the nut. NEVER.

[Vincent D.]

Re: Rear suspension questions

All I can say is that mine didn't line up....it was about a half the thickness of the cotter pin off. I could feel the longer leg of the pin engaging the hole; I used a large straight pin to check the alignment so I knew I was close or inline. So today I drilled it a slight bit larger and inserted the pin...that's that...done. Thanks for your responses and sorry for making a big deal out of this. So much for what appears to be the 'short' bolt.
Any ideas why the trailing arm pivot bolts were longer then they should be? I had to add washers to get the hole to line up like I mentioned in my original post. I'm guessing the side walls may have been forced inwards altough I don't see how as they're in pretty good/subtantial solid shape. The original nuts did have one flat washer and the proper cotter pin inserted in what appeared to be the right location...I know because I sawsalled them off. I have them bolted up with the extra washers and the cotter pin installed and hope to get the car on the road this weekend. Also bleed the brakes today (had the incorrect calipers and purchased correct ones form CSSB) and now everthings done except for reinstalling the spring. I'm reinstalling the 10 leaf spring for now as per one of my other posts since I spent a good amount of time balasting it until I realized there were 10 leafs. So much for the very original car I was sold; everythings a surprise! My intent was when changing/restoring/etc I would do it NCRS correct...its been quite an effort so far.

Thanks again,
Vin

[Vincent D.]

Re: Rear suspension questions

I just had to add this today. As I mentioned, I was going to install the rear leaf spring today and did. Almost everything went well except...one of the cotter pin holes on the control arm bolts was not drilled all the way thru; it was about a 1/16" deep...can you believe that. An easy fix so not a big deal. I attribute all these pain in the neck issues to the quality or careless of/in workmanship today. Reproduction parts, even when they say they're correct are not equvalent to originals. Just have to mount the rear tires and the car's ready to go after about 4 months.

Vin