I just had my entire rear diff replaced and new shocks all around however whenever I hit a bump my car completely looses control. What could this be? I have not replaced the front suspension. If I were to what would be the general consensus for a "grand touring" kind of suspension?

 

VB&P

Get the "Grand Touring" kit.
Comes with all the doo-dad's to give you what (it sounds like) you need.

 

THE very FIRST thing to do is a complete analysis of the entire car by a vette shop who knows what is what....these sharks are SO old now, the issues of rust and decay are all over the map as to what to expect, or ignore....

WAY too many areas to consider....

frame, bird cage, bushings, ball joints, rear suspension, steering, tires, brakes, bearings...the list is endless....

without some specific information on your car or at least some critical pix of certain areas to go by, its impossible to give accurate advice....

 

I actually did, chuck over at corvettes of westchester examined the entire thing and replaced the braking system, rear differential, and transmission along with the bearings. the tires are brand new but they are a tad smal, all shocks were replaced. He said the front didnt look bad. But man, when I hit a bump the car loses control.

 

There is a place in Montgomery that could probably help you out called The Corvette Shop run by forum member paulywannafly, but I think it might be too far of a drive considering how you car is handling. You could always get in touch with Paul, explain the problem, and see if he can recommend someone closer to you.



Rick B.

 

I could deffinetly get there. I've been a few hundred miles with her in the last few days but living on back roads its not easy to keep in control. I'll contact him and see what I can arrange.

 

My guess would be alignment.
My 79 had same symptoms prior to and after rebuilding the rear suspension, the final alignment fixed the handling perfectly.

Find a shop that knows Vette alignments and let them look over the suspension and check the alignment.

Also- how are your side yokes? Excess end play can cause the rear wheels to move in and out causing handling issues. Ask me how I know.

 

they're brand new replaced them as well.

 

When you say "completely loses control", how literal are you being?
Does it just feel a little loose, or does it really get scary?
If it is the latter, I hve seen the welds that connect the front crossmember to the frame on more than one C3 break.
It will get scary when that happens. Sometimes you dont even have to hit a bump.

 

well my car sways from side to side a bit when I'm driving. it could deffinetly be a faulty allignment. it loses enough control that if i were to hold the wheel loosely i would be flipped in a ditch. I didn't notice anything when she was up on the lift a week ago though.

 

Did it do this before you had the work done or just after?

 

hadnt driven the car prior. It was undrivable due to the rear differential.

 

I'm still going with alignment.
My 79 would jump sideways when I hit a bump or changed lanes and then get very swirvy. It felt very loose and uncontrollable at any speed over about 50mph.
I rebuilt rear suspension, replaced springs, replaced side yokes, removed rear sway bar, replaced front hydralic steering, replaced idler arm, it was still squirrely at highway speed even after all the parts where replaced with new. Alignment fixed it perfectly. My front toe and camber was off.
Prior to alignment, I had to have 2 hands on the wheel at all times and be very aware of what was in front of me. After the alignment, 70mph with no hands on the wheel over potholes and straight as an arrow.

 

I think it's your rear trailing arm bushings.

You could also try A & R Corvettes in Patterson - not too far from you.

 

That was my first thought. Also could be the rear spring is hosed.

 

I had a very similar probrem and it turned out the be the steering box. You would drive down the road then all of a sudden the car would swerve to the right and you would have to adjust the steering wheel to the left to straighten it out. Then a few miles later the car would swerve to the left and you would have to correct to the right again.

It hard to say what it is on your car. You have a car you have never driven and now you are chasing down issues.

Most likely it is something rubber that has or is failing like, strut rod bushings, trailing arm busings, front A-arm bushings or bad ball joints, bad steering box. Or your alignment is off. Or a combination of things.

Don't forget your car is 30 years old. I'm sure there are a few parts that are no longer within tolerance.

 

All the above plus one more thing.....IF you have larger rims and modern tires.....any shortcomings in the older designs like our sharks become much more apparent.....It has proven itself to be that way over the 15 years I have had this car....
when I got it I replaced everything in the frame/suspension/diffy/arms bearings, that moved...miss NOTHING....

car drove fine, for a older car....that constant tending of the wheel is something that goes with older cars....tires mainly back before steel radials...hardly seen anymore for some decades now....

then there are larger rims/tires lower profiles which act to accentuate the negatives about our older steering type...mainly that the control valve on the p/steering is on the end of the pitman arm and easily subject to road feedback then that looseness is magnified some 16x by the ratio of the box....

NOW when putting in a modern rack/pinion OR from what I hear a later Jeep box conversion, the ratio is changed to 12-1 in the box.....much quicker handling, and because of the design the input/assist valve is on the input shaft not the output like a old truck....so instead of a inch+ of play in the wheel you have damn nearly none.....really noticeable with modern tires, maybe less so with 15" tires....but I have had 17" on there since getting the car in '95.....