Rear Suspension Strut Rods

[William G.]

Greetings,

I'm trying to get answers to a few issues (questions) on my newly acquired '66 coupe before it arrives from its last home. A former owner (apparently) had the rear suspension "aligned" and when it came time to set the camber (what, one degree negative?) it couldn't be achieved because the spindle and bearings were worn to the point where something like 2-3 degrees negative camber was present. So.......as I imagine all (or most) of us have seen the shop elected to bend the strut rods to "shorten" them and thus reduce some of that negative camber. The first repair I'm going to do is have those spindles and bearings replaced. But then can those strut rods be straightened and reused or should I replace them. One source I've seen has a price of about $100 for new ones (the pair, with shipping) and I believe these include bushings. If the originals could be straightened for, say, $20 each I might prefer that solution. What say ye (the experts)? Any downside to straightening--say weakening?

Thanks for the help,
Bill

[Michael W.]

Re: Rear Suspension Strut Rods

Might be worth pulling the strut rods off to examine/replace the rubber bushings. Worn examples can cause the condition you've mentioned.

The rods can be straightened quite easily, do it prior to installing the new bushings.

[Wayne M.]

Re: Rear Suspension Strut Rods

After straightening the rods, if you still have excessive negative camber, with cams adjusted to max, suspect worn ends on the differential output yokes, as well their contact surface on the differential pinion shaft.

[William G.]

Re: Rear Suspension Strut Rods

When visiting the car at the former owner's home I grabbed each rear wheel at the 6 and 12 o'clok position and rocked the wheel in and out and the excess play is quite noticeable and is in the spindle and bearings. I couldn't see any at the differential yokes. So........I'll have the spindles and bearings replaced, the strut rods heated and straightened and install new bushings, and then see how the alignment checks. Hopefully that will resolve the issue. If not, then as Wayne says there likely is play in the yokes.....we'll see how my luck holds. Thanks, Michael (and Wayne), I'll have my strut rods straightened as noted above. This is a five star Bowtie car and I'm not going to replace anything that can be saved.
Bill

[Alan D.]

Re: Rear Suspension Strut Rods

Remember that the new Strut Rod bushings will not look like originals even the GM service replacements, so before you remove them check them.

[Stan E.]

Re: Rear Suspension Strut Rods

Stick with the orig. rods. Repo's are smaller dia.

[William G.]

Re: Rear Suspension Strut Rods

Thanks Stan--now I'm SURE I will!!

Bill

[Michael W.]

Re: Rear Suspension Strut Rods

Stick with the orig. rods. Repo's are smaller dia.

And service replacements have larger dia. bushings, so repairing the originals is the right thing to do.

[Larry M.]

Re: Rear Suspension Strut Rods

Reproductions with the correct head diameter and shaft diameter are available from Long Island Corvette Supply (LICS). They are identical or almost identical to originals. Not certain you can tell them apart.

Bair's also has correct head diameter and shaft diameter reproductions made in the USA......but the head is welded to the shaft versus one piece forged as original. This welding is detectable.

Both are excellent replacements. I recently installed the LICS pieces on my 1967.

Larry

[Joe L.]

Re: Rear Suspension Strut Rods

When visiting the car at the former owner's home I grabbed each rear wheel at the 6 and 12 o'clok position and rocked the wheel in and out and the excess play is quite noticeable and is in the spindle and bearings. I couldn't see any at the differential yokes. So........I'll have the spindles and bearings replaced, the strut rods heated and straightened and install new bushings, and then see how the alignment checks. Hopefully that will resolve the issue. If not, then as Wayne says there likely is play in the yokes.....we'll see how my luck holds. Thanks, Michael (and Wayne), I'll have my strut rods straightened as noted above. This is a five star Bowtie car and I'm not going to replace anything that can be saved.
Bill

Bill------


Usually, the rods can be straightened but it can be and should be done cold. I've straightened these rods and ended up with a rod that was undetectable as ever being bent. Might there be some compromise to the strength of the straightened rod? There might be but I don't think it's significant.

Usually, the reason that the rods were bent was to "make up for" the consequence of worn bushings. Replacing the bushings was all that really needed to be done, but it was easier (and cheaper) just to bend the rods to effectively shorten them.

[Brian G.]

Re: Rear Suspension Strut Rods

I've also heard that on some older garage lifts there's a bar or bracket that would line up with the rods and bend them when the car was raised.

[Paul J.]

Re: Rear Suspension Strut Rods

[quote=Joe Lucia (12484);497499]Bill------


Might there be some compromise to the strength of the straightened rod? There might be but I don't think it's significant.

Maybe, but I doubt it. Cold working changes the crystalline structure and increases the yield strength. As long as the metal is not fatigued, it should be stronger. It has to do with the sub-granular characteristics of the material and the Hall-Petch effect, and a bunch of other things that I've forgotten since my materials classes 34 years ago.

Paul

[John H.]

Re: Rear Suspension Strut Rods

I've also heard that on some older garage lifts there's a bar or bracket that would line up with the rods and bend them when the car was raised.

Yup! The older 2-post in-ground hoists (like I had in my Shell station in 1960) used a rear saddle arrangement that picked up under the rear axle tubes on both sides of the diff (no independent rear suspensions on domestic cars in those days). In later years, if an un-trained attendant lifted a midyear Corvette on one of those hoists, the rear saddle picked it up by the strut rods, and bent them (instant positive camber).

I think more strut rods were bent accidentally from using an old hoist than from frustrated alignment techs; it takes WORK to bend a strut rod that's on the car.