TealZR1

I own a 1991 ZR1 which vibrates slightly at higher speeds - generally above 55 mph. Feels like it's coming through the seat/bottom. I now have at a driveline shop and they think it may be associated with bad ujoint(s). They are putting up on lift shortly and running it to see which ones are bad. My understanding there are 8 ujoints?
My question, rather than replacing all ujoints if only one is bad (troubleshooting) - are there any particular ujoint(s) that go bad first to replace? Thanks!

antfarmer2

Mine just needed the half shaft joints. But good time to do them all.

vader86

Half shaft joints go first, but if you are having heavy vibrations through the steering wheel, you may want to have a good look at the balljoints too.

TealZR1

Thanks to all that responded to my original post. Quick question again:
Well we may replace the half shaft u joints first BUT would bad half shaft ujoint(s) cause vibration at both the steering wheel and from underneath? Thanks

antfarmer2

Helll you might have just lost a wheel weight. Pick it up and feel for it.

A Peter C4

Road force balance fixed my 94 coupe after 4 wheel alignment.Computer tire balance would not stop vibration at 65+.Now all is well.

xrav22

Its strange I have been trying to get rid of vibrations at 80 mph, I just got new tires ,alignment, and was replacing my shocks found left front was locked. Have not been out on highway yet but seems like it could be anything, I have replaced all ujoints.

JrRifleCoach

Locked? Musta handled like a truck.

Have you driven it yet?

JrRifleCoach

Ujoints will shake your butt.
Ball joints, tie rod ends, tie rod ends at the steering rack and tire balance will shake the steering wheel.

Now that you're doing some maintenance, check those rear wheel bearings before everything goes back together. It'd be a shame to pull that rear end apart again for a wheel bearing.

antfarmer2

Don't forget the Teflon washers.

95wht6spd

dt#2

I agree on the u joints. I am getting a vibration at highway speeds too. This just started last year on mine. I also got a leak at the pinion seal as well even after a complete rebuild by the local speed shop. I am runing Yukon Gears (3.55) and they are noisey as hell. I am getting ready to change the rear to a D44 rebuilt with Dana gears and new u joints so we will see what is up.

TealZR1

Since I started this thread. Conclusion was the Tire Monitor Module broke loose from the wheel and was churning violently. Rides much better but will check into a speed balance and possible wheel balance this weekend here into Atlanta where it will be almost 70 degrees for Caffeine and Octane!

JrRifleCoach

You gotta be shitting me.....

TealZR1

I sheet you not! Here is a pic. Funny, the warning light never came on either. Thanks for all's help!

Dt86

Just need a little glue and it'll be good as new.

xrav22

Just wanted to reply I have driven on the freeway but not at no traffic speeds. I noticed with the bad left front shock the hood looked like it was vibrating. So I guess the shock that would not expand was kind of bouncing along. Got to be better now.

Crossed Flags Fan

Wow, who knew?!?!
BTW and file in the back of your memory bank many (and I mean many) years ago I had a front end balance issue in another make that stumped lots of people for months. Turned out the gas station I was filling up the tires with never drained moisture from their tire pressure pump.
You guessed it, the tires were filling up with water and causing a tire balance issue which understandably got crazy when the temp went below freezing....!