biggd

Everyone claims to have a better mouse trap but until it has the longevity to support its claims of superiority then it's just new product without a track record. Buyer beware, it's all about the $$$$$$$$. That's why these forums are a valuable information tool. Everyone has a story, good or bad.

Vogie

I can contribute this: Do not try to use polyurethane trailing arm bushings with the Guldstrand screw type rear toe adjusters. Instead of adjusting the rear toe, the metal sleeve inside the bushing just moves allowing the front of the trailing arm to move at will. I will have to go back to stock bushings or fab some kind of thrust washer for each side of the bushing.

65air_coupe

I put in a complete GT kit from VBP with poly control and sway bar bushings and was never happy with the ride. Front and rear bars are off and stock front bar back in place and next I'll be changing the control arm bushings back to rubber. Keeping the front and rears springs and shocks though, consider them a good upgrade.

henry63

My 63 had poly bushings installed when I bought it. Trailing arm bushings crumbled like OP's but front upper control arm bushings evidently rotated on the shaft and with pressure on the washers holding them in loosened the bolts.

shft22

Yeah I honestly was not expecting to have to touch the bushings again, so I gues I will be going back to rubber. How hard is it to fit rubber bushings to the trailing arms, I was reading the poly can be done without taking the arms out of the car but no the rubber, why is this? Can they be pressed with a small press? I am traveling now but will look at the book when I've back home.

Mike Ward

This is common too.

TCracingCA

First I don't think that poly bushings should ever be used in the trailing arms. Prior to going with the multi link rear suspension, I was looking at Global West's ball sphericals which I don't think are being sold any longer for Corvettes (not enough customers). These are similar to a new product just released by a C6 aftermarket guy that I saw in one of the more recent Vette mags.
The Guldstrand rear toe adjusters aren't meant to run with the poly nor the rubber. They are designed to use with the metal spherical bearings. I would say that the idea trying to get them to work with a different than designed bushing is interesting. The things to be careful of is that the sleeve isn't one that is supposed to be flared. The material is soft and the washers would compress the poly and the sleeve. The washer should be of a thicker material. Thus you have an interesting little engineering project on your hands.
Thus my observation is that you simply don't like the shims to align and neither did I. Interesting!

JohnZ

The OEM trailing arm pivot bushings have to be pressed together until the outer shells meet in the middle, then the center sleeve must be installed while the bushings are compressed, retainer washers installed, then the end of the inner sleeve is flared while the bushings are still compressed. If this isn't done correctly, the bushings will be loose in the arm. The procedure is covered in detail in the Chassis Service Manual, with photos and a cross-section of the assembled bushings, retainers, and flared sleeve.

Vogie

Your points are well taken.

I have trimmed the adjusters approximately 3/16 (which made the bearing surface larger) and made washers out of 1/8 bar stock the same diameter as the bushing, but I'm still not happy with the lateral adjustment. With these adjusters, a lot of pressure on the sides of the trailing arm bushings is not required since they are not subject to loosen or fall out. I believe the total width of the polyurethane bushing is greater than the stock unit. I am looking at stock bushings or thinner washers made out of better material

I have a set of Dick's spherical trailing arm bushings that were installed in a set of his trailing arms. Getting the inner sleeve flared properly is a bigger headache because the sleeves are cut so short and there is no compression. There is no margin for error. It is a good setup, but the problem is getting lubrication to the bearings. One needs to put a grease fitting in the forward end of the trailing arm that will conduct grease into the bearing assembly.

Just my observations so far.

Matt Gruber

Me too. on my 72, with "seals it" rubber seals to keep dirt out.
BUT i used polyU in the TA in 1995. Handles great so far, but i'll be watching for.....
.
EDIT I took a look!
I used 2 red(not sure of source) polyu end link bushings and they look like crap,
BUT the other 6, VPB BLACK look NEW, from 9-94. So i'm optimistic that VBP was using a different supplier in 94 that made better POLYU since they look great 18 years later.

shft22

thank You John, as soon as I get home I will look in the Manual for the instructions, funny thing is rebuilding the T-Arms has been the only part I have ever sent out to be done. I cant remember were I send them except it was some one in Florida, Palm Beach are I think...

Matt Gruber

I checked my 72s' A-arm bushings.
20 yrs ago i replaced CRACKED RUBBER OEM with new STOCK OEM. NO THEY DIDN'T last AGAIN.
CRACKED AGAIN after only 20 yrs. NO, they won't last OEM either!
This is why new cars sell well, old cars fall apart

TCracingCA

The first is the rear bearings. I was already planning to go multi-link, but at one time I was playing with the same thing as you. My memory goes back over 15 years, but I put the metal spherical units back there and drilled the top of the arm for a fitting and used to inject grease, but it made a bloody mess coming out of the bearing during operation and getting all over everything. Also with those Guldstrand units you couldn't keep grease in them. They are race pieces and I found they were impractical for the street usage. Thus I tried a few other things which were weird ideas with mixed results.

Then I bought a set of Van Steel deep offset arms to learn that the bushing sold for that unit are undersized from the stock size. Thus talked to the engineer of Van Steel at Carlisles about a number of things and now they sell the arms in stock bushing size. Thus until I got motivated. I put some poly units in temporarily and used washers instead of shim since I cut access to pull the entire bolt out.

The best that I was looking at were the mono ball units mentioned where there is a sleeve with a ball built in that slips into another sleeve with the ball sleeve held in with C clips. Also the lube stays in, so you have full rotation, but I never got that far in buying them and trying them with the adjuster bolt set up. My adjuster bolt that I bought was gun drilled with a zerk on top to inject grease.

The bottom line is that you sound like a good engineering guy and I think you will make it work. I think alot of guys just get used to the toe steer wandering caused by a single point attachment and the inherent slop. Alot of guys loose the alignment shims shortly down the road because of this, so the smart ones end of slotting and pinning those and I have seen a few get there alignment and put a bolt and nut thru them. Also some of the polly bushing for this location have a straight sleeve which doesn't require flaring. Since you seem to have the units needing to be flared, my first inclination prior to my editing everything was semi relevent.

I have to get back to work. With the attention to detail, I am sure you will get your ride handling in the upper 90% bracket of all others.

PS the stock rubber in my opinion is better than all of these poly unit, unfortunately you need some higher end tools to service your arms. I now have heim joints (spherical bearing units) on two trailing arms, problem solved but far more expensive.

TCracingCA

To answer directly to the thread, I would use a durometer to test for the quality of poly bushing. Some and I won't mention brands are crap. They are just basically plastic put in a mold.

The ideal would be to take a material such as Delrin and machine to spec some bushings. I have done so in a few locations such as for the donut disks for the rear spring on one of my cars. The other car has a female heim secured thru the uprights with a bolt passing thru the spring secured on both side of the spring. Thus the movement of the spring directly moves the upright eliminating any slop movement there.

W Guy

I can add another negative experience with Poly-U but it doesn't pertain directly to Corvettes (or suspension).
A '62 Passenger car has the disadvantage of having a 2 piece driveshaft (due to the X frame) with a center carrier bearing that's mounted in a metal ring with a molded rubber "vibration isolator" around the bearing. The problem with it is that when torque is applied to the driveshalf, the bearing wants to move off center. The rubber absorbs that, but constant launching results in the bearing deflection actually bending the metal ring and/or wearing out the rubber so it is then loose or distorted. The result is a constant vibration.
The answer supposedly was a center carrier support that had a molded poly-u isolator instead of the rubber. It worked fine for a while, but age was the culprit. It had no movement on the ID or the OD to wear it out. The poly simply dried out, cracked and fell apart in a few short years.
No more of that stuff on my cars!

Verne

Dejavet

John, I did allot of upgrades to my 65 convertible a few years back. Added 50+ horses, Tremic 5 speed, steering upgrade and some suspension upgrades. At that time I put polly bushings in the A arms as well as a few other places. After the car was on the road I noticed that the front end would rise significantly when I accelerate. I thought it was the new Bilsten shocks, so I put the old shocks back on and it did the same. I have worked this problem for a very long time now and I am beginning to believe it is the polly bushings. Your comments about how the OEM rubber works makes me suspect the polly even more. Do you think this could be caused by the polly?

Charlie

TCracingCA

I have them on one of my cars and they are great! You do have to make sure that the exhaust is shielded where it runs close to the arm bushings. Global West is a fairly serious outfit. They recommended only running their pieces if you gusset the arms (box them) and you cotter pin the shaft bolts to prevent them from walking out.

Matt Gruber

same thing with fuel hose
FLAPS sells crap that leaks in 5 years.
i order Goodyear hose by the roll. on car since '99, looks new.
there is no product that can't be made cheaper and worse.
My '94 polyU looks new after 18 years (except for that red crap from a swap meet)

TheSaint

After reading this i will not use any parts of my Total Poly kit

The only bushings i have used is for the front sway bar and they will stay there until i need to change them again

Glad that i ordered rubber bushings for the strut rods

Matt Gruber

How could u put crap rubber in the struts when they sell heim joint struts?
Chinese rubber won't last 2 years.