Replace Rear Suspension Rubber Pieces

[Michael C.]

First, let me say that this car will not be judged. At this time I'm just trying to make it safe and possibly eliminate
some of the issues related to deteriorated rubber cushions, bushings, grommets and/or washers. All of these items are
original, so you can imagine their condition.

Any tips/warnings for replacing the leaf spring cushions on my 69? Currently the car is on four jack stands as I wait for
the arrival of new calipers, rotors and other brake related items.

Would it be effective/safe to use a floor jack to gently relieve the tension of the spring at the trailing arm in order to
remove the cushion bolt? How can I be sure to get the bolt properly adjusted during reassembly. The castle nuts are still
on the car, so if the hole in the bolt aligns with a slot in the nut, is this adequate adjustment?

I've read on this forum about the difficulty of replacing the cushion retainers, so I'm not sure I'll tackle them. I've sent a PM to Gary Beaupre asking for his past Restorer article on this topic.

Similar questions regarding the strut bushings. I imagine I'll have to get the camber reset after replacing the bushings,
but is there anything I should or shouldn't do during disassembly/reassembly to get things in the ballpark for a safe trip to the
alignment shop later?

Thanks folks,
Mike

[Larry M.]

Re: Replace Rear Suspension Rubber Pieces

Michael:

If your car has deteriorated rear bushings, etc. I would strongly recommend that you also service the trailing arms at this time and also consider new liners for your leaf spring.

You do not want to install new rotors on the back and not service the trailing arms. Any uncorrected rotor runout can cause air pumping and other brake issues. The rotors are normally riveted to the trailing arm spindle and any alignment and runout corrected as part of the trailing arm rebuild.

Consider Bairs or Gary Ramadei from this forum for trailing arm rebuild. Do it once and then forget it for another 25 years.

You can use a good high-quality floor jack to safely unload the rear spring.........one side at a time. But you want a jack that has some weight to it or is on some cardboard so that the rear spring will not cause the jack to suddenly push/roll inward when you are unloading the spring.

The long spring bolt with the castle nut and cotter pin can simply be unbolted after the jack is under the spring and the spring is raised so there is no longer any tension on this bolt. You will see this when it happens. When re-installing, you simply tighten up the bolt until you run out of threads and then align the castle nut and install the cotter pin. This ASSUMES an original type bolt with only 1 inch or so of threads and original length.

Rather than install new bushing in my old strut rods, I chose to buy new reproduction ones with new bushings from LICS. They are identical to originals. Installing new bushings in old strut rods can require some special tooling as well as new bushings........but this is your choice. My old rods were bent a bit as well, so this made the decision easier for me.

When you go back with new, do not tighten any bolts more than finger tight until you have the car back on all four wheels. The only exception is the long rear spring bolt with the castle nut and cotter pin. If you do not heed this advice, you stand an excellent chance of breaking components or getting the bushings in an un-natural and stress/twisted condition......which can affect ride height and cause the bushing to fail early.

Larry

[Jeffrey S.]

Re: Replace Rear Suspension Rubber Pieces

Mike,
When using a floor jack to unload the spring, put a c-clamp on the spring just inboard from where you plan to place the floor jack on the spring. This will prevent the jack from slipping inboard as you lift the spring. This is detailed in the service manual.
Jeff

[Joe L.]

Re: Replace Rear Suspension Rubber Pieces

First, let me say that this car will not be judged. At this time I'm just trying to make it safe and possibly eliminate
some of the issues related to deteriorated rubber cushions, bushings, grommets and/or washers. All of these items are
original, so you can imagine their condition.

Any tips/warnings for replacing the leaf spring cushions on my 69? Currently the car is on four jack stands as I wait for
the arrival of new calipers, rotors and other brake related items.

Would it be effective/safe to use a floor jack to gently relieve the tension of the spring at the trailing arm in order to
remove the cushion bolt? How can I be sure to get the bolt properly adjusted during reassembly. The castle nuts are still
on the car, so if the hole in the bolt aligns with a slot in the nut, is this adequate adjustment?

I've read on this forum about the difficulty of replacing the cushion retainers, so I'm not sure I'll tackle them. I've sent a PM to Gary Beaupre asking for his past Restorer article on this topic.

Similar questions regarding the strut bushings. I imagine I'll have to get the camber reset after replacing the bushings,
but is there anything I should or shouldn't do during disassembly/reassembly to get things in the ballpark for a safe trip to the
alignment shop later?

Thanks folks,
Mike

Mike------


Instructions for all this work are well-covered in the factory service manual, including photographs and diagrams.

[Michael C.]

[Duke W.]

Re: Replace Rear Suspension Rubber Pieces

The easiest way to replace the rear spring link cushions is with the car sitting on the ground. Use a small floor jack with a wood block between the jack puck and spring as far outboard as possible while still allowing room to work and install a big C-clamp to secure the jack as suggested. Then jack up the spring enough to release the bolt tension plus about another half inch. Since the new cushions are not compressed you may have to jack the spring more to get the nut started.

Prior to the above suggest you remove the cotter pin and verify that the nut will turn. If not soak it in some liquid wrench type product.

The '63 AIM says to turn the nut down just enough to fully expose the cotter pin hole and install the pin.

BTW, the cushions are still available from GM and Joe L posted the part number recently. I've heard the aftermarket cushions crush and crack soon. Hopefully the GM cushions are better.

As suggested, before starting any maintenance or repair job always review the information in the service manual and AIM.

Duke