Brutus

I was just trying to clean up the left rear shock mount (have the whole rear end out) when I noticed how different it was to the right hand one. It appears to be offset...I'd prefer not to say bent for the moment.
Actually it's more the strut part of the mount that appears to be crooked.
Is this meant to be or am I up for a new one?


[Modified by Brutus, 12:26 PM 11/24/2001]

xrated

Brutus if u mean the bottom part where the shock bolt too. Then is it meant to be offset. If u look at the mounts from left to right one is bent up and one is bent down. When i first saw mine i pooped myself then a knowledgeable guy told me that are meant to be that way.
If im talking about the wrong part entirely disregard my rambling.

Chuck Gongloff

The rear shock mounts should be "mirror images" of eachother as you hold them in your hand. If they're not, something's bent. Hope this helps. Chuck

PatsLs1vette

ya know mine are exactly like xrated said too ones down on drivers side and pass. is up.i guess thats something else to change.would that make it lean to the drivers side alittle bit.

Chuck Gongloff

The mounts are symmetrical...mirror images of eachother. How they're installed is another question. As the spindle supports wear and the shock mounts wear, the "D" eggs out. Also the "gnurls" on the shock mounts wear. As you tighten things..."clockwise", it would make common sense that the drivers side would be twisted downward, and the passengers side upward, because this is the force you would use to tighten the nuts. The solution is to "match" them when you install them, or replace the spindle supports and/or shock mounts if they're worn. Chuck

Re-read my post, and it sounded "nasty". Didn't mean it that way :) It's just that as you tighten the bolts, the torque that you put on the nuts lowers the drivers side and raises the passengers side. I'll usually hold the passengers side "down" and tighten it that way. Chuck


[Modified by Chuck Gongloff, 2:00 PM 11/24/2001]

Brutus

Chuck...I have both mounts right here in front of me and by holding them side by side it definitely appears that the castings are dissimilar. Though the r/h strut mount appears to be at a different angle it's still perpendicular to the mount face.
I'll check again, but from watching Van Steel's suspension video yesterday I'm sure they mentioned not to get the mounts mixed up because they were different.
The plot thickens.

Xracer

Mine look like they can only go in one way. Other wisse the shock would be on the wrong side of the T-arm. :confused:

Brutus

The difference with mine is that you could put the right hand mount into the left side and it would sit exactly the same as it does in the right, but the left hand one would place the r/h shock mount lower than it is with it's proper mount.
This seems to be all due to an apparent casting difference in the l/h strut mount position. It's definitely not bent. If it's a casting fault then there must be lots of cars in the same situation.

Rowdy Rat

There were actually two different "types" of rear shock mounts used by the factory. Part numbers 3820929 and 3820930 were used in base suspension applications, the other set, 3829265 and 3829266 were used with heavy duty type suspensions (F41, FE7, etc.). All of these mounts had the part number cast into the body of the mount and were plated (most likely zinc) to prevent corrosion. The base suspension mount hasn't been serviced for many years, but the heavy duty suspension mount continues to be serviced by GM (although I understand the part number is now stamped in somehow rather than cast). My understanding is that non-GM mounts that are currently available do not have any part number at all.

You might want to check the part numbers on your mounts which will identify both the manufacturer (GM or not) as well as which suspension application (base or heavy duty) before making any comparisons. I understand that the heavy duty mounts were made differently to provide clearance for the larger shock absorbers that were included in heavy duty suspension option, but I don't know offhand what that difference was. I do have one set of each type of mount... I'll see if I can't dig them out to see if there is anything obvious.

Regards,

Brutus

Thanks for the info Stan. It appears that I have the second numbered ones you mentioned as the numbers cast into them are identical. The only thing is tho that I have a 9 leaf spring which doesn't go with that suspension set up as far as I'm aware anyhow.
At least hopefully we've established that there is a difference in these mounts and not one of them damaged or bent as first suspected.
There was one thing else I noticed in the Van Steel video where they mentioned the the upper shock bolt has the spring washer under the bolt head and not behind the nut. Again something to do with shock to body clearances.
Just when we thought we knew what we're doing too........Wonders will never cease.

Chuck Gongloff

Hi Brutus. Have my rear out too. Am holding my "65-66" cast shock mounts in my hand. They are mirror images, the only difference is that the "D" flat on the threaded bolt that goes through the camber rod is 180 degrees different between the left and right. There are no bends anywhere on either piece. The "D" flat allows the shock mount to be inserted through the spindle support correctly only through one side, and not the other. Regarding the upper shock bolt, the washer does go under the head of the bolt. There is a thin "jamb" nut used behind, not a standard thickness nut. Hope this helps. I'm sort of confused at the difference between both sides of your car. Something just doesn't sound right. :) Chuck

paso

The D is the key I have seen the wrong one installed so that the D is just jammed in the spindle hole so there is no More D after taking it out. Can you see the D in yours Brutus? One Spindle on my 77 was like that, bubba"s brother rounded out the hole when they hammered it In.

Brutus

Paso and Chuck....With both mounts held side by side and with the strut mounting pins held parallel to each other, it's the shock mounts that show the difference. The L/H one is approximately 3/8"shorter. This then seems to follow that there is a definite design difference in these mounts to shift the L/H shock into a different angle at least from the R/H one. When comparing the back 'face' of the mount bodies, there is a very obvious difference in their shapes. The L/H mount body shows an almost flat surface by comparison to the R/H one which has a very marked angle to it's casting. Almost 45 deg.
The "Ds" on both strut mount pins are exactly where they should be in relation to each one's relative mounting position.
I'd have to say then Chuck that there's a very obvious difference between the C2 and C3 mounts from what we've both discovered through this discussion. I'm amazed that it's never been discovered or brought up before this.

paso

I have both out, and 3820929 is the left mount 3820930 is the right I tend to agree with Chuck they look exactly the same EXCEPT the D is at 6oclock on one and 12 oclock on the other Figuritly speaking. Is it possible yours is just bent? :)

Chuck Gongloff

I still say something isn't right, Brutus. The mounts I have out of the car now are from my C3, a 69 roadster. I crawled under my C2, a 63 roadster, and both the left and right mounts appear the same. There is absolutely no difference in the configuration of the left and right mounts, other than the "D" slot on either car. Could you post a picture? I cannot think of any reason why one would want to change the shock angle on one side of the car. I've torn a lot of these cars apart over the years and have never seen any differences. :) I still believe that you have either a modified or bent piece. Chuck

PatsLs1vette

so if they are bent would it make it lean ?(the body)my drivers side is defintely sloping down.


[Modified by pats406nitrovette, 8:26 PM 11/25/2001]

Brutus

I'll try to get a pic taken and posted when I can, but as Keith (Rowdy Rat) said earlier...there are two different sets of mounts and my numbers match the second set not the same as Paso's which were the first numbered set he mentioned.
Until I can post a pic of these I can't actually show you what I'm referring to, but neither of these mounts is bent. The difference is most definitely in the casting.
I'm satisfied of this to the point that I won't be replacing either one of them. As I get closer to putting this conglomeration back together again I'll keep tabs on what the final outcome is and hopefully get some pics of what this all means.

Chuck Gongloff

Hi Brutus. Took 3 pix of the rear shock mounts that are out of my 69 now. These are the second type described by Stan. Each has the cast number "3829265-66" This number is embossed, not stamped. These are most definitively replacements on my car, as my car also has the standard suspension only. When you look at the pix, you'll see that both side are symmetrical---mirror images. The only difference is the "D" slot which allows each to slide into only one spindle support. Paso has the other style with the earlier number, and by reading his posts, his are symmetrical also. Let us know what you have. Chuck