Vibration from rear-pic inside..
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 3
From: Austria
Vibration ..solved!!!
hi all
my car discovered some rear vibrations on higher speeds, above 70mph
Vibration did not change with clutch in-out, speed up, speed down, trans in neutral or in gear..was only dependent from speed
balancing and rotating tires front to rear didnt change anything, finally i decide to change u-joints
...and i found this..(pic below)
my Question, can this type of wear cause this vibration? didnt have had a chance for a test drive yet, but your opinions would be very welcome
thank you
my car discovered some rear vibrations on higher speeds, above 70mph
Vibration did not change with clutch in-out, speed up, speed down, trans in neutral or in gear..was only dependent from speed
balancing and rotating tires front to rear didnt change anything, finally i decide to change u-joints
...and i found this..(pic below)
my Question, can this type of wear cause this vibration? didnt have had a chance for a test drive yet, but your opinions would be very welcome
thank you
Last edited by corvette90; Aug 16, 2013 at 02:26 PM.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Your pic is too small for my old eyes to be able to really tell but any time a u joint has the kind of wear ridges in it like that it means there is enough material worn away to cause excess clearance. It does not take much of an offset to cause a vibration, especially at the speeds you described.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 3
From: Austria
Your pic is too small for my old eyes to be able to really tell but any time a u joint has the kind of wear ridges in it like that it means there is enough material worn away to cause excess clearance. It does not take much of an offset to cause a vibration, especially at the speeds you described.
anyway, thank you for your statement, confirms my thoughts
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
I got your pm but accidently deleted it. If the dark ridges on the u joint are grooves worn into the steel, it needs replacing. If it is just dark grease then you probably have another issue causing the vibes.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 3
From: Austria
the dark ridges are feelable with the fingernail, the other u joint has severe scuffing, there are some spots where the hardened surface is worn through, about .02" deep in the material...
greetings
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Yep, they're done for, you did not say if the pics were of the ones in the driveshaft or the halfshafts but if it were me, I would change all 6 of them. It's not that bad of a job but it is one you only want to do once every few years.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 3
From: Austria
it still vibrates....
was on highway today, vibrations started again, always at around 80mph and get worse with speeding up...
things done so far..
Rotated tires (front-rear)
Changed all 6 u-joints
driveshaft was balanced..
slip yoke is new
tailshaft bearing is new
tires were balanced..
shocks are new..
im getting out if ideas, next thing is to change the driveshaft to a custom made one..
my driveshaft have been professionally balanced, but i know, that it have a bit of runout, GM driveshafts are not famous for beeing very high grade...
im also run 3.73 gears which give me around 4000rpm on the driveshaft with 80mph..maybe thats simply too much for a stock drivehaft?
any other opinions out there?
thank you
things done so far..
Rotated tires (front-rear)
Changed all 6 u-joints
driveshaft was balanced..
slip yoke is new
tailshaft bearing is new
tires were balanced..
shocks are new..
im getting out if ideas, next thing is to change the driveshaft to a custom made one..
my driveshaft have been professionally balanced, but i know, that it have a bit of runout, GM driveshafts are not famous for beeing very high grade...
im also run 3.73 gears which give me around 4000rpm on the driveshaft with 80mph..maybe thats simply too much for a stock drivehaft?
any other opinions out there?
thank you
Last edited by corvette90; Jul 18, 2013 at 08:06 AM.
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Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
was on highway today, vibrations started again, always at around 80mph and get worse with speeding up...
things done so far..
Rotated tires (front-rear)
Changed all 6 u-joints
driveshaft was balanced..
slip yoke is new
tailshaft bearing is new
tires were balanced..
shocks are new..
im getting out if ideas, next thing is to change the driveshaft to a custom made one..
my driveshaft have been professionally balanced, but i know, that it have a bit of runout, GM driveshafts are not famous for beeing very high grade...
im also run 3.73 gears which give me around 4000rpm on the driveshaft with 80mph..maybe thats simply too much for a stock drivehaft?
any other opinions out there?
thank you
things done so far..
Rotated tires (front-rear)
Changed all 6 u-joints
driveshaft was balanced..
slip yoke is new
tailshaft bearing is new
tires were balanced..
shocks are new..
im getting out if ideas, next thing is to change the driveshaft to a custom made one..
my driveshaft have been professionally balanced, but i know, that it have a bit of runout, GM driveshafts are not famous for beeing very high grade...
im also run 3.73 gears which give me around 4000rpm on the driveshaft with 80mph..maybe thats simply too much for a stock drivehaft?
any other opinions out there?
thank you
I would also raise the car & spin the wheels & watch for a very slight bit of runout from a bent rim. Just keep in mind, it is going to be slight so watch real close. Did you have the driveshaft balanced or was it a PO that had it done? If it was done before you owned the car then I would venture to say it was a problem the PO was trying to cure also.
Can you borrow another driveshaft from someone? If you can't find any runout on the shaft or the wheels then I guess a 4 wheel alignment would be a good idea but I'm not sure being out of alignment would cause a vibration.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 3
From: Austria
hi Midnight85 (and all others)
i had the driveshaft balanced, with balance sheet and everything...
will check for wheel runout also..
i doubt that misalignment will give vibrations, normally just bad driving manners...and the car was aligned , not too long ago..
anyways, i will kepp you updated...
i had the driveshaft balanced, with balance sheet and everything...
will check for wheel runout also..
i doubt that misalignment will give vibrations, normally just bad driving manners...and the car was aligned , not too long ago..
anyways, i will kepp you updated...
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
I agree with Midnight 85
Wheel alignment is your next step, note have had reputable mechanics balance the wheels and encountered horrible vibrations went back and had them balanced again ...same. Tried another tire retailer and it was perfect not even the slightest vibration.
There are some places that can balance the wheels on the car..
Also check your rear suspension bushes, make sure there is no movement.
Warped disc rotors can give a vibration however that is usually felt thru the brake pedal when braking.
Good luck, nothing worse than a rattle or vibration
Wheel alignment is your next step, note have had reputable mechanics balance the wheels and encountered horrible vibrations went back and had them balanced again ...same. Tried another tire retailer and it was perfect not even the slightest vibration.
There are some places that can balance the wheels on the car..
Also check your rear suspension bushes, make sure there is no movement.
Warped disc rotors can give a vibration however that is usually felt thru the brake pedal when braking.
Good luck, nothing worse than a rattle or vibration
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
[QUOTE=gerardvg; Wheel alignment is your next step, note have had reputable mechanics balance the wheels and encountered horrible vibrations went back and had them balanced again ...same. Tried another tire retailer and it was perfect not even the slightest vibration.[/QUOTE]
This is what you must keep in mind, just because work was done, does not mean it was done right. Good luck.
This is what you must keep in mind, just because work was done, does not mean it was done right. Good luck.
Racer
Joined: Aug 2012
Posts: 279
Likes: 2
From: Las Vegas Nevada
I just replaced the u-joints in my rear because I've had the same problem as the OP. Vibration at +70mph and hard accleration. I had the same ridges/marks in the joints aswell and found that one of my dogbone nuts wasn't secured all the way down, causing the poly bushing stick out enough to rub on my rear shock. Definitely solved something there, but where are the c-beam bolts and what else should I look at to tighten? I still have my 85's rear end on stands so this is a perfect time to check everything.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
There are two vertical bolts through the center section and the C beam at the differential and the same through the tailshaft of the trans. Maybe someone has some pics of them they can post.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
The two holes you can see just behind the driveshaft yoke is the location of the c beam bolts, there are loose nuts on top so you will have to put a wrench up there to hold the nut while tightening. Once you find these you will know what to look for on the trans.
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Racer
Joined: Aug 2012
Posts: 279
Likes: 2
From: Las Vegas Nevada
Finished replacing the u-joints earlier. Filled them with marine grease and took it for a slow spin. Drove around town and back home without any vibration and very smooth driving... much better throttle response to the wheels. Also no vibration at +70mph. Still have a ping... need to look into this.