Vader953

ok guys, I need some input. This has happened since I bought it. It's in great shape, but it wanders at high speeds only (interstate). I completely rebuilt the front end, all new bushings, tie rods, idler arm, etc. Didn't help a bit. I know my rear end might need a rebuild too. The alignment shop said the rear is a "little" out. The bushings look ok, but not great. Could this be the culprit? Or the steering box? It is original too.

It happens worse when I change lanes and the road angle changes, and when I hit bumps, it wanders pretty bad. But somehow if I stay straight for a while and don't change lanes the wander will work itself out and go straight for a while. Wierd, huh?

I have heard of serveral 78 owners say that they had this same problem and they never could get it fixed. PLEASE HELP!

LAvetteman

I find all of these things affect hwy wandering:

Worn front suspension.
Worn rear suspension.
Worn steering box.
Worn idler arm.
And the thing that affected my 71 the most, too large of tires on the front. I was running 255/60's all around and the hwy wonder was dangerously terrible. Switched to 215/60's on the front, no more wondering

mvftw

My '78 also wanders, it has the original front & rear ends except for shocks & links. I just bought new 255's all around (had them on before). I hope it's Not the tires, if so, I'll live with it.

Dwayne 76

Just a thought, but could it be the wheels are not balanced? The car working its way out of the wondering COULD be harmonics, but I don't think so, just figured I'd mention it anyhow. Improperly inflated tires; too much one side not enough the other etc. Wish I could help.

BigBadRed

How old are the tires? I have had that issue twice, once on a 88 vert and another on a 95 z28. Especially on rain grooves, the car wanted to follow the groves. Both had obviously worn tires. Replaced the rubber and the problem went away.

--marc

norvalwilhelm

My car had the same problem even after totally rebuilding the front end. I then rebuilt the steering box, same problem so I went back into the steering box and replaced the pitman bushings. That really helped.
Then I went for a very aggressive alignment. 5 degrees caster, -.75 camber and 1/8th toe in. I also run 265 x 50 x 15 front tires.
I have absolutely no wander when passing and even at 100 mph it is a one finger deal on the steering wheel.
I have worked alot on bump steer so going through severe dips has no effect either.
It takes work on the old vetts but it is duable.

rexx78

How's the rag joint?

mvftw

Second time the Pitman arm was mentioned...did you replace the pitman arm when you rebuilt the front end?

Vader953

I know it's not the tires, they are inflated and balanced correctly. When I steer in the garage, I can't notice any play in the rag joint, so I think it's fine. I don't remember replacing the pitman arm. What and where is that?

So far I thinks it's the steering box being worn out or the rear end.

BTW, 255's came stock on my car in 78 (first year as an option). I know the size of tires is fine.

Any other ideas fellas?

Thanks a ton!

dath

The pitman arm is the little arm that's attached to the ouput side of the steering box. I'm not much more help as I'm going through the same pains as you. I think my problem is the steering box and I have a rebuilt unit, but I don't have an engine in the car right now, so there's no way to tell for sure:D


[Modified by dath, 2:03 PM 7/30/2003]

Milest

It might be the rear trailing arm bushings. If they are worn then the rear end will flex and try to steer the car, mainly during acceleration. I replaced mine on my 72 and it made a big difference.

hunt4cleanair

Hate to brag but just returned from a 1300 road trip to Hershey PA from Myrtle Beach in 33,500 mile 78 with new tires and it performed flawlessly. I set the cruise at 70 on the interstates and drove...at times had to push to 80 but never noticed the first hint of wandering. Over past few years have rebuilt the power steering control valve, brakes, check all four corners for alignment (learning they are out), suspension solid blah blah blah.

BTW...anyone got a set of F51 shocks laying around unused?

78Vette-SA

I had a little more wander then I liked after completing a complete rebuild a few years ago. What worked for me was tightening the lash on the steering box a little (loosen the nut on the top of the box, use a screwdriver and turn to teh right a 1/4 turn at a time and test - you don't want to go too far and it should have a tiny bit of play in it). That took the play out of the wheel and gave more control.

It also makes a difference if I run the tires with lower pressure. I like them around 28-30 for a comfortable ride and I also have regular shocks on the car (Monroe Sensatracs). For a tighter ride with even les wander I sometimes put the Gas shocks on and pump up the tires a bit.

:auto:

Disco_Mike

Good question!
great responsed thanks
mine wanders really bad on old asphalt roads too.
most of the suspension is still factory. Next spring Im scheduled to get the rear wheel bearings replace. Then Ill go from there.

Packy76

Replaced rag joint and problem went away, and even better replaced my 15 year old Cooper Cobra tires w/BF Goodridges T/A ..GREAT RIDE!