I have a 1965 C2 Convertible that I am doing a restomod on. The body and engine are off the frame so I began looking at the suspension components. I have bushing rebuild kit (poly) for the front end, but when looking at the rear I found that one of the strut rods is bent and all the bushings are dry rotted and need to be changed, and one of the camber cam bolts is stripped.

In looking through past threads on how to replace the bushings I discovered that there are adjustable strut rod kits available. Seems to me like a better way to go. The recommendations called for getting a set that has Heim joints rather than poly bushings. Also the recommendations are not to get ones with zerk fittings. The only rods that I can find through several recommended vendors have the Heim joint rods that are for competition cars and are not recommended for street use as the ride would be too stiff. All the other adjustable rods have poly bushings and Vett Brakes and Products has a set with poly bushings that has zerks so the bushings can be greased. Vett Brakes and Products also has an adjustable strut rod set that does not have the zerk for greasing, but “Rod-end are forged (stronger than welded), and the polyurethane bushings are graphite impregnated for silent operation and long life”.

I would appreciate hearing from those who may have installed the competition grade strut rods that have the Heim joints, and use them on the street to see if they are really too stiff for street use. My car is going to be used only for street driving.

What is the downside for getting the struts that have poly and zerks for greasing the bushings?

I would also appreciate hearing from those who have used the ones from VBP that have the zerks and anyone who has used the ones that have no zerks but are impregnated with graphite.

Thank you for your advice, Mark.

 

I'll give you my opinion. Poly bushings are a bad idea in any but a very few locations. Contrary to advertising BS, they do not last longer than rubber, significantly less in locations where the point is required to move in more than one axis and specifically the strut rod ends you are considering. The trailing arm bushings are another prime example.

An adjustable strut is not better than stock, it's just different in how camber is set.

Stock rubber bushings last 40-50 years. What's wrong with that?

 

Plus...more points of adjustments, "4 per side" to worry about vs ONE PER SIDE...

 

My 63 has had the heim jointed adjustable rods for um...40 years or so. In that time, I have replaced them once due to wear. The advantage is they are adjustable, and they stay adjusted. If you actually drive your car (not a trailer queen) then the stock rubber will wear out. The OEM struts have a cam adjustment within a rubber grommet. If and when you hit a big bump, the cam will rotate within the rubber grommet and go to full negative camber. That will not happen with the heim jointed rod ends. They are NOT "too stiff" for street usage, and in fact there is no suspension stiffness added nor subtracted, they ONLY set your rear camber, Stiffness (or lack of it) is determined by springs and shocks in conjunction with the attaching hardware (poly, rubber, etc). Try them and I predict you will feel no difference, however you will not have to adjust your rear suspension settings as often. I think you will like them, but if hot, you can always change back! As mentioned above, do not use poly for a street car.

 

Plus and negatives of their own products.

The heims do pick up a slight handling advantage in that those types of ends rotate and the idea is to keep tire footprint down regardless of where your camber, castor or even toe is going based on suspension travel capability, what the road is causing, or whatever settings we all decide on. Now if the part that the ends are attached to are restricted or hampered from movement elsewhere by an attachment that can't take advantage to allow the rotating (like the arm attachments at the frame connection), then they may not provide anything better than the stock type pieces and then just benefit you as a convenient adjustment device and then you are operating on the simple principle of deflection!!! You get deflection with rubber and poly, which you hope will squish in the dirction you need predictably-- "no"!

Why are they considered for competition only (due to the heims), because it is all solid and way less forgiving than rubber and poly, on a rough road or hitting a pot hole, you could sheer the joint off. And then you are in a world of hurt. Ideally on a race track, those are smooth and not causing heim joint to deal with any severe road issues. Therefore what makes me comfortable operating with heims on the actual roads (only larger stronger, very high quality ones that are expensive-- and you don't buy those from Guldstrand or Vette Brakes etc.). Now with all of those manufacturers, they are adequate is how I will put it, and you could get years and years of street usage out of their products, but it would depend on the success of your driving ability to pay attention and not hit potholes and such at speeds over 100 mph on the road, or ultimately your road manners tooling around within a tolerance of the street limits (give or take a margin of pushing their posted recommendations!

Ps if the suspension sellers state- "not recommended for the street", then they are worried about a heim sheering and the liability and safety of operating with them in the street enviroment. I think there have only been two complete heim suspension limited production cars ever built, and one is a very special Ferrari and I would have to remember if it was a very special model by Porsche, i think so!

So didn't quite finish! I had to run to the bathroom!!!!! It must have been the EL DIABLO Combination plate that I ate late yesterday!

But then we get into spring rates and I am one of those heavy spring guys and advocates, but when operating on a heim suspension and heavy springs-- if i hit a road irregularity, I just want to hit it and for it to not upset the balance of the car (no bouncing, no rolling or swaying etc.. -- just one big hit THUMP!!!!!! So I just go thumping down the road, and it can be tiring and painful in the backside! Maybe should wear a kidney belt! Passengers be warned, you may not like the ride quality! So now we are talking why soft spring rates are preferred! It will sure make things better on the street, softer in general allowing movements easier and suspension travel, so a heim would be less prone to snap (so then the Corvette tuner's units would probably without a significant road issue------------ hold up)!

 

I've used just about everything that's been made. Here are some basic rules.

Poly bushings are junk. Yes they do wear out faster than the stock rubber bushings. I know that for certain.



There is nothing wrong with the stock strut rods if you drive on the street. In fact they would be the best for a street car.

Heim joints art the best if you want to play with camber setting all the time. That means you need to take tire temperatures and keep adjusting. Those of us who run at the track love to do that sort of thing. Usually it's for no good purpose.

The only downside to using heim joints is dirt. I clean my heim joints all the time so I have no problems. I've never used heim joints on the street but we feel good when we're doing it.

Zerk fittings and grease can be a problem. Dirt and grease can become an incredibly efficient grinding paste. I try to avoid great around suspension parts.

Here's an article I did about heim joints last year.

Richard Newton

 

I buy from Coleman alot and have theirs, not that their covers are better or worse! But here is a couple of different types that are available, and they help for putting these types of units onto the street to keep them clean.

The downfall is if your suspension bracket is very precision fitted, then care should be taken to fit these and some shaving or file work to fit might be needed. If you put one of these covers on each side, the heim is wider by the thickness of these covers, so wanting that heim tight (no mounting slop) and no forced compression on the mount, then you should essentially blueprint the fit. I run rotational spacers to give the heims ability to have full rotation and travel where alot of the kits from our beloved suspension Sellers want to trap that by big a$$ washers! Therefore putting your heims sandwiched by washers makes for just a fancy dancy adjustable rod with heims that do very little for you!

Newton, these should help so you aren't cleaning them all of the time!



And here is examples of stuff- the first cone shaped things are similar to the Coleman spacers that snug on the heim bolt thru facings and then you put your washers sandwiching. Then they have other stuff for alignment and the last picture just shows some washers and you can visually see that those when tightened down would lock the heim in on the top one and then with spacers the bottom showing how you get rotation. It is unfortunate but most of our beloved Corvette suspension experts, just sell stuff not designed by them, and they aren't up on some of the finer tuning products like with what I just posted. And it isn't a cost thing, because the covers and spacers aren't that costly, maybe if you went thru the entire car, adds a few hundred! Plus because my heims can rotate, it does help so they don't sheer!

 

Ps but what do i know, I am just an old Canyon racer where roads are rough and we are traveling faster than our intelligence!

 

I installed the above about 2 yrs. ago, after my OEM style wore out. The ride and handling were not noticebly affected. I had the camber set at shop, made registration marks on the struts, and nothing has moved since install. The heim joints have zerk fittings for lubrication if, and when needed. I've put about 6K miles on them and have no complaints-lib

 

When you have to replace the heims, and you will because the grease attracts abrasive dirt which will wear them out, buy non-greasable, teflon lined heims. They last much, much longer.

 

Thank you all for your input....I got quite an education. The pictures of the poly ends on the adjustable shocks really told the story. I read the article on HEIMs that rfn026 wrote and now I know what HEIM joints are. I think I am going to get the adjustable HD adjustable struts from VPB. They have spherical rod ends which from what I understand are HEIMs. We will see what happens.

Thank you again for your assistance

Mark

 

I've been running the adjustable strut rods from VBP in my 68 for about 15 years. I changed out the original strut rods after while taking a Sunday ride I hit a harsh dip in the road and the cam spun around and allowed the driver side rear wheel to come so far out of adjustment I had to limp home. I call my local supplier to order a new strut and told him the rod was bent. He said it was common for alignment shops to do that to bring them into adjustment when it was necessary to gain more adjustment than the cams allowed. I didn't like the fact that the cam came loose so I upgraded. I've never had a problem with them since and I really like the high tech look of the adjustable struts. BTW guys who run 4 bar rears have far more adjustments and I don't hear any of them complaining.

Don

 

It was even more common for gas station jockeys to raise them on a typical 2-column lift with a cradle for a solid rear axle, and the axle cradle bent BOTH strut rods; the midyear Corvette was the only American car (besides the Corvair) with independent rear suspension, and most gas jockeys had never seen one.

The only time I ever saw a strut rod camber bolt come loose is when it didn't have the two little hardened cap washers installed on the ends of the inner sleeve.

 

OK....I've read all this....and I'm ready to order new rear strut rods....
Am I CORRECT in saying that if I'm not racing, then I should just stick w/ the
HD adjustable strut rods, like original, only without the cams, and with RUBBER bushings? I WAS ready to order the Heim end units....now I'm NOT SURE!!

 

Since you are doing a restomod, you might want to explore using the C3 camber bracket that the inner end of the strut rods bolt up to. The General changed the design to accommodate the wider tires in the later Corvettes. They are supposed to keep more of the tread on the pavement with wider tires.


Gerry

 

AND the Pontiac Tempest