Paul Borowski

Since a few post have come up about this, it made me think... I wonder how many people maybe driving their C2,C3 cars around with this not done properly. People talk about taking their cars to shops for "alignments" and all, but I can't just believe these guys can properly "set this up" right.
When I did my '68's last year, I made a tool with washers, all thread and nuts to "spread" or open up the frame pocket where the pivot bolt is. It to me, almost seems that this trailing arm bushing needs to be "crushed" or at least tight enough(which to me is super tight)so that inner bushing does'nt "spin" or rotate. It seems if this is not tight enough and you can literally pull the shims out, I can't see how it's getting tightened enough. Another thing, when I got new "pivot bolts", the castle nut was "brass". Now, most of you know how soft brass is and GM did'nt use it, I can see these "stripping" very easy-especially, when trying to pull the frame pocket together!!! If some people have their arm actually pivoting on that bolt, that can't be right??? I actually stripped two of those "brass" castle nuts tring to "get the inner bushing NOT to pivot or spin. What have you other guys done that have done this and your thoughts,too. :confused:

PRNDL

i sure wish I knew what you were talking about. Maybe you could give me a lesson at the next NCRS meet. MJ

daily_driver

rubber yes... pressed.

poly.... NO!

just slip it on..

dont even have to take the trailing arm off completey for poly..

just slide it outta the pocket on a jack..

:lol:

Monty

Paul,

I see what you're saying, you want the bushing to pivot, rather than the inner sleeve pivot on the bolt. It would have to be tight to clamp or lock the sleeve onto the bolt.

When I rebuilt my rear suspension a couple of years ago, I looked for stainless steel pivot bolts and nuts, and found that no one offered them. I didn't really trust hardware store quality stainless bolts for such a critical fastener, so I used ARP stainless steel bolts with ARP nyloc stainless nuts. I've had them on for over 2 years now and they are still tight. You've been around here for a long time too, you might remember that I was giving away these bolts and nuts, since I had buy a whole package from ARP and had several sets of extras. I sent about half a dozen sets out.

Frank75

Paul,

I agree with your premise that you want the inner bushing immobile with respect to the bolt. If I recall correctly, those are 7/16" bolts torqued down to 50 lb-ft. Depending on what you assume for friction, it's in the range of 5-6000 lbf. pulling those frame sides together. As long as the pocket is packed as full as possible with shims, I would think the frame would close in on the bushing.

I remember being concerned about this when I changed mine (I used poly), but VB&P called for fitting shims so that the inner sleeve is just "proud" a bit i.e. so it would be held in place rigidly. Not sure about rubber - it should be part of the design.

WATTAC

First the inner sleeve and retainers (washers) are held in place by the shims and the frame. The shims are suppose to be wedged in hard, in fact the procedure says to set the alignment using one side of the arm, pressing firmly to ensure correct alignment, then fill the other side completely and "fully", no motion or space. If the bushings have been correctly installed the inner sleeves are butted together inside the pivot and should hold firm against any pressure. (If they are loose to begin with then start all over again. ) Then when the nut is tightened down the extra pressure holds the retainers and inner sleeve in place inside the frame. The outer sleeves are pressed into the trailing arms, if they're loose, replace one or both parts, something's worn out. And the rubber spacer is compressed when the bushing is installed, so it firm too. In '68 and some '69s the shims only have holes, not slots, so the pivot bolt goes through the shim, it's impossible for the shims to come out. On later models the shims are slotted but a cotter pin was added that goes through the frame and the shims and holds them in place. The earlier models are a real PITA to align because the shims must be kept aligned so the bolt can go through them and the frame too. That's why Chevy changed over to the slotted shims.

As a final note if you're a "puriest" the nut (not brass) on the pivot should only be tighten with the car sitting on it wheels, just like the front suspension and the shocks. So says the Chevy manual. This reduces the stress on the suspension bushings. And of course always install the cotter pin in the pivot nut/bolt. You NEVER want this nut and bolt to come apart.

Andy

Dalannex

I had the same thoughts as Paul when I did the ones on my 81'. I used a large prybar to pry the t-arm over once the first side was full, then stuffed the other side. Then when I tightened them down, I kept close tabs on the play of the shims so that I knew they were getting snugged right to the bushing.