Rear end "sway" at highway speed

[Gary R.]

Re: Rear end "sway" at highway speed

Replace the bushings,use rubber. If you have more then 050" true endplay in the yoke(s) I would consider replacing them. .500"-.625", if correct,indicates the yoke wore to the snap ring or the ring fell off, that is way too much and should be addressed now.
I would get the 1/2 shafts out and then really check the endplay. If the yoke comes out of the diff more then .187( 3/16) then the ring is off. Replacing just the yokes is something I would think over. If the end is ground down then you have a lot of powered metal in with the gear oil, makes a nice lapping compound. I find a lot of the C2 yokes and early C3's are still good many times. The play may be from worn or improper posi setup or cross shaft wear, both requiring attention and really dialing in the posi will make a big difference in both operation and life.
I can link you to my threads on rebuilding a diff and custom building them if you like,just PM me.

[Gene M.]

Re: Rear end "sway" at highway speed

Yokahama radial tires......!? it just sounds like the car trying to shake them off it's rims. Just sounds wrong having jap tires on a Corvette.

[Timothy B.]

Re: Rear end "sway" at highway speed

Roger,

To add to what Gary say's , there is a excellent article in the restorer not to long ago from Duke Williams that addresses this exact same issue.

It's good to understand how the relationship between yoke side play and proper differential side gear backlash all works together.

[Bill M.]

Re: Rear end "sway" at highway speed

The sway issue appeared to come and go while I was driving in a staight line at a constant speed on the highway, not during turning. For most of my highway drive everything seemed fine. The problem only came up for short periods - roughly 20 to 30 seconds at a time, and only a few times during the drive.
Thanks again for all your help,
Roger (50141)

This sounds like a wheel bearing is seizing to me. The bearing is briefly locking up and the inner race is spinning on the spindle. That higher friction causes increased drag on one wheel and that is what you describe as sway. The friction heat then tightens the inner race on the spindle, and the bearing goes back to working "right".

[Roger P.]

Re: Rear end "sway" at highway speed

Gary and Tim,
Sounds like we're getting to the bottom line cause of my issue. Thanks again for your advice. I will research the Restorer with Duke's article, and will PM Gary for the links to his threads. The mechanic works for my brother, so I will be able to provide your information to assist him during the repair. He's a very good mechanic and values the advice I receive from NCRS members. Once the yoke endplay has been repaired and the bushings replaced, I will get a front and rear end alignment, and should be set to enjoy sway-free cruising during our perfect winter weather here in South Florida .

Gene,
I always try to purchase American-made products to support my country. However, I also like to buy the best available products for the money I spend. Keep in mind that many products are now made in U.S. plants by American workers even though their mother company or name doesn't sound American. My Yokohama whitewall tires look great, drive great, were reasonably priced, and received excellent consumer & expert reviews - and they were manufactured in the U.S.A.! Duke recommends Pirelli tires and, from what I understand, they are made in the U.S., too. With that said, I appreciate your point about the name not sounding right. I never see the name of the tires because, like a beautiful lady, who's examining her shoes anyway? Her good looks and sexy curves keeps my attention way above the ground !

Happy cruising,
Roger (50141)

[Gary R.]

Re: Rear end "sway" at highway speed

Here this will save you some time searching

http://www.digitalcorvettes.com/forums/showthread.php?t=77316

http://www.digitalcorvettes.com/forums/showthread.php?t=77377

[Roger P.]

Re: Rear end "sway" at highway speed

Gentlemen,
I hope you all enjoyed a Happy Thanksgiving! My mechanic tore down the rear suspension today - just about everything other than the trailing arms. The yoke endplay issue was that the retaining clip fell off and was wedged in the bottom of the case. The yoke and the gears look perfect, so he will replace both clips and yoke seals and the differential should be ready for action once again. One strut rod is slightly bent, the other is larger in diameter, and the bushings have seen better days. We decided to replace both strut rods with new ones to resolve those issues. As planned, the leaf spring bushings will be replaced with new rubber bushings, and the rear shocks will be replaced with Monroe gas shocks. The hidden item that was discovered upon tear-down is the trailing arm bushings. They look so-so, and being that everything else is dismantled, they are staring us in the face asking to be changed. Of course, it you tackle the trailing arms, why not the wheel bearings? Well, as I have read in the archives, and per conversations with a few helpful members (of which I am very grateful), trailing arm restoration is a beast of a project that has to be done by someone with experience - typically outsourced to get a quality job. I really don't want to empty the vault, and the mechanic feels that the wheel bearings are fine. He would like to remove the trailing arms and only replace the bushings at this time. I agree with his decision, but wanted to know if anyone has a different opinion based on my description of what had been uncovered. Otherwise, the frame and other components are rust-free and look very good!

Thank you,
Roger (50141)

[Dick W.]

Re: Rear end "sway" at highway speed

Roger, I think that at this point, you would be penny wise and dollar foolish not to rebuild the trailing arms. Most vendors that offer this service include the front bushings in the rebuild. If nothing else, it will give you peace of mind while driving your car

[Jean C.]

Re: Rear end "sway" at highway speed

Roger, re ur posting this evening about your trailing arms and the plan to replace only the bushings. It I had the trailing arms out and was replacing trailing arm bushings, struts, spring components, shocks, etc, etc, I would go ahead and replace the bearings, particulary if you are planning on driving the car long distances. I had a bearing go out on my '64 and although it did not result in the catastrophic failure that Jerry experienced, I would rather have had it give up closer to home (I was in Maryland) rather than on a road trip. JMHO.
Best regards,

[Gerard F.]

Re: Rear end "sway" at highway speed

Roger,

I agree with Dick, for peace of mind you ought to have the trailing arms and bearings R&Rd.

How does your mechanic know that the bearings are good. On my 67, the rear wheel bearings are "lubed for life". But on a 67, "life" mean't only 50,000 miles or 5 years by my owners manual. On a 65, probably less. I pushed mine to 65 K and 41 years before they failed.

So you can fix everything else, but then you will always worry about those wheel bearings.

Also the trailing arm front bushing takes a heavy duty press tool to put that bushing in. I had a mechanic change mine with one of those gypo bolts with a beveled nut before my incident. I think it was part of the problem.

So if you can't afford to send them out now, have your mechanic fix everything else, but don't plan on driving it much. Then when you have a place to store the car for a couple or three weeks and have the $, then you can take the trailing arms off and send them out for full refurb. It is really not hard to take them off and put them back on.

Just my two cents.

Probably see you in Florida in January.

[Gary R.]

Re: Rear end "sway" at highway speed

Here is the T/A thread I wrote a few years back. It may help.

http://www.digitalcorvettes.com/forums/showthread.php?t=77000

[Roger P.]

Re: Rear end "sway" at highway speed

Time for a quick update: The differential is back together, painted, and ready to be reinstalled. The new strut rods and leaf spring bushings are also ready to be installed. I changed my mind and will purchase ACDelco shocks in lieu of the Monroe shocks based on what I have read in the archives. The big decision that I had to make was the trailing arms. Other than the worn bushings, the T/A's look to be in very good condition and the wheel bearings appear to be OK as there are no signs of any problems. However, based on the advice of several members, I decided to outsource the T/A's to have them rebuilt with new bushings, bearings, rotors, hardware, etc. With that done, I will have a completely rebuilt rear suspension that should last for many years. This is certainly a proactive move; an "insurance policy" that will give me peace-of-mind not having to worry about future wheel bearing issues. It has become clear to me that Corvette T/A's are complex components that have to be assembled properly by an experienced shop to avoid potential problems. Many thanks to everyone who has offered their opinions & advice; and extra appreciation to John and Gary for their expertise via phone calls & PM's. As always, you guys are all great! I'll keep you posted of the final results when the car is back on the road - hopefully in the next couple of weeks.

Roger (50141)

[Joe R.]

Re: Rear end "sway" at highway speed

Roger,

Who did you decide to send your trailing arms to?

Joe

[Roger P.]

Re: Rear end "sway" at highway speed

Roger,

Who did you decide to send your trailing arms to?

Joe

Joe,
I decided to go with Van Steel in Clearwater, Florida. They have a good reputation, my brother's shop has used them before, and they are located on the west coast of Florida (we are in South Florida). Their location saves me some money on shipping, and will also save me about a week of down time as FedEx Ground only takes one day each way in-state (vs. 3-4 days with the vendors further north). To cover "Murphy's Law", I paid a small additional FedEx fee to insure the two packages for a total of $ 1,200.00 (they only insure up to $ 100.00 without the extra fee). I'm anxious to get back on the road again, but also feel bad keeping one of my brother's lifts tied up for so long . He's OK with it, though - he said the Vette makes the shop look very cool .

Roger (50141)

[Roger P.]

Re: Rear end "sway" at highway speed

Happy Holidays to everyone ! Well, I just wanted to let you all know that my rear suspension restoration project is finally finished, and I was back on the road for a Christmas day drive in sunny South Florida . The ride was improved with a smoother, tighter feel in the rear. The trailing arms were rebuilt by Van Steel... they did a nice job, but they took much longer than originally discussed. When it was all said and done, in addition to the trailing arms (including new spindles, rotors, bushings, and bearings), I replaced both strut rods, leaf spring bushings, shocks, and repaired the excessive differential yoke endplay (only the clip fell off and was wedged in the bottom of the unit). On Christmas Eve Day, I brought the car in for a 4-wheel alignment. My brother's discounted cost was $ 225.00 which seems a little high, but two guys spent almost 3 hours -- they told me I got a great deal . Tomorrow, I will head back to my brother's shop so they can check the torque on all the components and install the spare tire carrier. The rear stance of the car is about 1" to 1 1/4" higher than spec., but I understand from previous posts that the rear will settle as the new rubber spring bushings compress over time. If necessary, I can always change to longer bolts in the future to lower the rear of the car. This project gave me an opportunity to learn more about my car -- it was great to see that my frame and T/A's were in excellent, rust-free condition; including the trailing arm pockets. You wouldn't believe how much 40+ year old road dirt collects in those pockets! Again, I want to thank everyone who helped me with their guidance and opinions along the way . Take a look at the attached photos of the rear suspension when the project was nearly complete. Hoping for fewer and cheaper projects in 2010...

Have a Happy & Healthy New Year,
Roger (50141)