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Locating the Source of a Vibration

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ripvwsss Dennis B
Forest, Virginia, USA   USA
I am in the process of trying to isolate the source of a pretty bad vibration that occurs between about 55 and 65 MPH. I have read many of the previous posts here on the subject. I have installed new outer tie rod ends, tightened everything in the steering column and rack, had the wheels balanced and aligned, and rotated the tires. I still have the problem. I am now installing new front shocks and checking the front wheel bearings. If that doesn't do it, I will move on the rear end. I do tend to feel the vibration in the seat and gear shift. I have read that it is possible for the drive shaft, universal joints. axels, etc. can cause the problem.

My question is - if I raise the rear wheels off the ground on jack stands and then run the engine/wheels up to the speed of the vibration, should the vibration still be there when the car in not on the ground and under load?

Thanks,

Dennis
'76 TR6

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Marksg1 Avatar
Marksg1 Mark Greenbaum
Evanston, IL, USA   USA
1976 Triumph TR6 "Nigel"
Dennis, I don’t know the answer to your question but I would really think teice about running your car on jack stands, too dangerous. You’ll get some good advice if you can describe where you feel it coming from; front end, rear, chasis, do you feel it in the steering wheel, on accelleration, etc.



I love the smell of hydrocarbons in the morning.

POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
I think I'd have a close look at four axle 'U' joints. They are asked to do a lot back there. And no, I would not lay under a car in gear car running up to 60 MPH either. Get it up safely on stands and just grab an axle. Try to twist it back and forth and look for play. Drive shaft too actually.

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dicta dick Taylor
Downey, Callifornia, USA   USA
In reply to # 1494804 by ripvwsss I am in the process of trying to isolate the source of a pretty bad vibration that occurs between about 55 and 65 MPH. I have read many of the previous posts here on the subject. I have installed new outer tie rod ends, tightened everything in the steering column and rack, had the wheels balanced and aligned, and rotated the tires. I still have the problem. I am now installing new front shocks and checking the front wheel bearings. If that doesn't do it, I will move on the rear end. I do tend to feel the vibration in the seat and gear shift. I have read that it is possible for the drive shaft, universal joints. axels, etc. can cause the problem.

My question is - if I raise the rear wheels off the ground on jack stands and then run the engine/wheels up to the speed of the vibration, should the vibration still be there when the car in not on the ground and under load?

Thanks,

Dennis
'76 TR6

Dennis --- Vibration felt in the gear shift area usually comes from a bad propshaft U-joint. Take a good light with you and rotate the propshaft back and forth to see if there's lost motion (or hints of rust) at both the front and rear 'joint.

Dick

M. Pied Lourd Pied Lourd
Ontario, Canada   CAN
Driveshaft balanced?

Cheers
Tush

Casey808 Avatar
Casey808 Casey S
Honolulu, Hawaii, USA   USA
1969 Triumph TR6 "Adèle"
In reply to # 1494874 by dicta Dennis --- Vibration felt in the gear shift area usually comes from a bad propshaft U-joint. Take a good light with you and rotate the propshaft back and forth to see if there's lost motion (or hints of rust) at both the front and rear 'joint.

Dick

In concurrence with Dick's advice, the basic rule of thumb is when propeller shaft vibration is felt during acceleration then suspect the gearbox drive flange U-Joint, conversely shaft vibration occurring during deceleration is indicative to the final drive flange U-Joint.

If you haven't already, try pumping some grease in your propeller shaft and driveshaft U-Joints to see if this alleviates your vibration. Otherwise if worn propeller shaft U-Joint replacement is necessitated, prior to disassembly remember to mark the relationship of both the gearbox and final drive flanges to the U-Joint flanges to reinstall the prop shaft the same way it came out. drinking smiley

Keep 'em on the road. Cheers!

South San Frncisco, california, USA   USA
with IRS... think twice about running the machine on jackstands,
you can't do it with jacks to frame and IRS hanging.. you have to support trailing arms...
maybe you just hunt down the source by pulling driveline and replacing the Ujoints
one after the other, but do in one session...
even pause and have drive shaft balanced...you need shop for that...(they are disappearing fast
in San Fran...)
I did do this with my MGA, run the car on jackstands... and had there been
an accident, car would have slipped off at 100MPH indicated and destroyed house...
dint happen... but there was the risk, less so since not IRS...
TR6 not happy with their suspension hanging... junk in the wind so to speak...
I shut up now
wes

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j007 Avatar
j007 Joseph M
Madison, Ohio, USA   USA
Dennis, I have a similar problem with my TR6, my vibrations are between 45-50mph, I replaced my propeller shaft U joints and had it balanced, replace U joints on both output shafts, installed new trailing arm bushing, new bushing for the diff and rebuilt diff, reinforced diff mounts, new rear springs , adjustable trailing arm brackets and rebuilt lever shocks. Wheels balanced and checked for run out. All of those items needed addressed, vibration a little better but still there. This winter I am pulling my engine and trans, need work done on it, at that time I know I need to address the front end, bushing, shocks and springs. Once you figure your issue out please post your results, as mentioned above I would start with the propeller shaft U joint. Good luck!



Joe
73 Triumph TR6

rjc157 Avatar
rjc157 ralph c
pearl river, new york, USA   USA
I would do easy things first do the wheel bearings and see what happens .I know driving these cars past 65 can be hairy but does it do it past 65 can you get it up to 70 does the vibration go away .Taking out the driveshaft out is no easy task anyway jack up the rear and turn the wheels and see if you hear any clicking maybe a bad u joint in the axels a easier fix than the driveshaft let us know

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dsixnero Avatar
dsixnero Dan Colanero
Westville, New Jersey, USA   USA
Dennis, the fact that it happens at certain speeds would indicate wheels.Does it go away after 65 mph? Alloy wheels got rid of my vibration.The tire guy told me the oem wheels were hard to balance. Dan

Stampy Avatar
Stampy Silver Member Scott Stamp
Victoria, BC, Canada   CAN
I highly recommend checking the rear hub flanges.

I had a vibration and grinding coming from the running gear that sounded like the front end. Put it up on a hoist and there it was, only the shaft nut holding the wheel on.

Must have broken sometime after i put new rear bearings in.

Scott

ripvwsss Dennis B
Forest, Virginia, USA   USA
Update:

I just finished installing the new front shocks. I also checked and repacked the grease on the front wheel bearings. They looked to be in really good condition. I did find that that the right front spindle nut needed to be tightened one notch in order to eliminate a little top to bottom play. The good news is that the overall feel in the front end is really good now after all of the work there. There is no vibration or play at all in the steering wheel.

The bad news is that the heavy vibration between about 55-65 MPH hasn't gone away. It nearly goes away above that speed until I chicken out. It doesn't seem to change based on whether I am accelerating or decelerating through that range. So I am moving on to start working on the rear. I plan to check on all the universal joints and replace the shocks and springs. I am hoping it doesn't turn out to be the drive shaft. I understand that it is pretty involved to remove.

One question. A main reason that I plan to replace the springs is that the left rear sits about 3/4" lower than the right and there is more than normal negative camber on that side. Is it possible that the sag and negative camber could be part of the problem?

Thanks,

Dennis

dicta dick Taylor
Downey, Callifornia, USA   USA
In reply to # 1495339 by ripvwsss Update:

I just finished installing the new front shocks. I also checked and repacked the grease on the front wheel bearings. They looked to be in really good condition. I did find that that the right front spindle nut needed to be tightened one notch in order to eliminate a little top to bottom play. The good news is that the overall feel in the front end is really good now after all of the work there. There is no vibration or play at all in the steering wheel.

The bad news is that the heavy vibration between about 55-65 MPH hasn't gone away. It nearly goes away above that speed until I chicken out. It doesn't seem to change based on whether I am accelerating or decelerating through that range. So I am moving on to start working on the rear. I plan to check on all the universal joints and replace the shocks and springs. I am hoping it doesn't turn out to be the drive shaft. I understand that it is pretty involved to remove.

One question. A main reason that I plan to replace the springs is that the left rear sits about 3/4" lower than the right and there is more than normal negative camber on that side. Is it possible that the sag and negative camber could be part of the problem?

Thanks,

Dennis

Not likely that the sagging spring causes the vibration, but good to level the car if only for appearance sake.
Removing the propshaft isn't too difficult, but it's a fussy job if exhaust pipes need removed to get to it. I remember having to jack up the tail of the gearbox a tad and taking out the shaft thru the front.
As others said, it could be a tire imbalance, so look for cupping in the tread as an indication.

Dick

rjc157 Avatar
rjc157 ralph c
pearl river, new york, USA   USA
Springs really don't cost that much Richard Good sells spacers if you go that route .The vibration I think has to come from the wheels see if they can be balanced with the trim rings on good luck

rjc157 Avatar
rjc157 ralph c
pearl river, new york, USA   USA
I would also take a look at the rack and pinion mounts the rubber rots out my whole unit moved when I turned the wheel I put in RG aluminum mounts now it's solid as a rock

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