Author Topic: 66 vibration (Read 5376 times)

bootlegger · « **on:** April 03, 2012, 08:24:24 PM »

I took my 66 coupe for a run today. when I got to 110 on the freeway it started vibrating. It wasnt violent sort of like a rumbling. If you slowed it went away.
I didnt feel like a tyre out of balance.
When I got home I checked the air pressures and then jacked up the rear end.
I rotated the wheels and at one particular point in the rotation the wheel almost became impossible to turn. At this same point the suspension seem to lift and then drop over this hump and turn again until it returned to that point.
I also noticed a bit of play in the tailshaft yoke where it enters the gear box.
Its pretty unerving when it happens. I didnt try and drive faster to see if it would drive out.
Any ideas? Could it be the half shafts or the tailshaft?

Dave 0413766501

Reklaw · « **Reply #1 on:** April 03, 2012, 09:16:12 PM »

Dave, if you jack up the rear of the car, the suspension hangs down and the halfshaft universals will foul. That's normal. If you can have someone else try to rotate a wheel and you lay underneath and watch the universals, you'll see what I mean. What about if you grab the top & bottom of each rear wheel and check for movement, how much is there? Do the same for sideways movement. Is there any noise from the rear end when you're going slow and turning?
Bob

bootlegger · « **Reply #2 on:** April 03, 2012, 09:35:20 PM »

Bob thanks for that. I thought there would be an explanation re the tight spot. There is no noise coming from the diff when I turn etc but there is a bit of backlash.
When this vibration comes on there seems to be a noise then.
I did wobble the wheel when they were up in the air and didnt notice any movement. Maybe it is a wheel balance problem.
I took the car up Macquarie pass from Albion park the Moss Vale a few weeks ago.
I gave it a real hiding. Maybe something is bent

Scott · « **Reply #3 on:** April 04, 2012, 08:31:44 AM »

It could be a uni joint somewhere in the system. When was the last time they were changed?

bfit · « **Reply #4 on:** April 04, 2012, 11:45:29 AM »

Yes if you have a uni starting to go that will give you that vibration problem
Also
How old are the tires they may be starting to separate between the layers
have a look a see if you can see any bulging in the tread it happened to me and the vibration was very bad over 70 MPH
Bfit

bootlegger · « **Reply #5 on:** April 04, 2012, 01:40:22 PM »

The tyres are old and I did look for bulging. They looked fine. I have bought a set of stock rims for the car but have been putting off buying tyres as There is still heaps of tread on the ralleys.
Which unis are you talking about the Tailshaft or the half shafts.
The half shafts are easy to get to the tailshaft looks like a night mare to get out.

bootlegger · « **Reply #6 on:** April 04, 2012, 01:44:05 PM »

Quote from: Scott link=topic=9128.msg1045942386#msg1045942386

It could be a uni joint somewhere in the system. When was the last time they were changed?

Ive never changed them but the guy I bought it off said he did the half shafts. Ive had the car almost five years but I didnt ask him when he did it. The car underneath looks like its never been apart.
I just put all new brake calipers.Ive put a heap of miles on her since I bought it. I think its time do give the car a birthday.

bfit · « **Reply #7 on:** April 04, 2012, 03:33:33 PM »

remember where park brake is when you lift the rear of the car.
chock front wheels first
if you can lift the car
at the rear remove the wheels
and give all the universals a good look at see if you can get any play at all in them
check the input bearing on the pinion shaft for play
It would be a good idea to take the drive shaft out and have a look at the universals

to get a vibration you will have something running at reasonable rpm
and prop shaft runs at least three time faster that the half shaft run
while you are at it check the front mounts of the diff

Bfit

do you get any vibration with the gear box in neutral and engine at 4500 RPM

77CVT · « **Reply #8 on:** April 04, 2012, 04:14:53 PM »

If taking the tailshaft out you may as well replace the uni's. Just like most cars you have to undo the rear uni first and slide it out.

Remember that auto fluid may run out the rear when removing.

Not fun but not hard.

bfit · « **Reply #9 on:** April 04, 2012, 04:33:13 PM »

I have only had the drive shaft out of BB cars
and they have had u bolts retainers bother ends
of the shaft.
Bfit

bootlegger · « **Reply #10 on:** April 04, 2012, 08:46:02 PM »

Thanks for that guys. Ill renew everything in the rear end. All the rubbers etc are worn anyway.
Might as well do the front end while Im at it.

77CVT · « **Reply #11 on:** April 05, 2012, 08:02:18 AM »

Rear diff mounts cop a hiding too, so while you are there....

Trouble is there is usually a lot of road gunk around there, so a 20 min job takes 6 hours cause if you are like me you want to clean and paint it. :rolleyes:

bfit · « **Reply #12 on:** April 05, 2012, 08:17:11 AM »

bootlegger
Any work on the drive line if nothing else you will know exactly what condition it is in.
Give you confidence if you are venturing any distance from you home.

I recently had a noise in the rear of a vette i had just got registered
so replaced all the universals
noise was still there
replaced the rear diff mounting rubbers
noise still there
I ordered new bearing and offset trailing arms
and rubbers
While waiting for parts to arrive
I took some advice that i was given and changed the diff oil
noise done
the noise was so load and maniacal
I did not believe the diff oil was the problem
Bfit

bootlegger · « **Reply #13 on:** April 06, 2012, 06:33:09 PM »

well the diff oil is easy to change. Is it just limited slip diff oil or something special?

bfit · « **Reply #14 on:** April 06, 2012, 07:21:15 PM »

Lim slip 90
The wrong oil plays havoc with the clutches in he diff
Bfit

bootlegger · « **Reply #15 on:** April 07, 2012, 09:05:59 PM »

Thanks