Vibrations - driving me mad !

Vibrations - driving me mad !

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gifdy

Original Poster:

2,073 posts

248 months

Wednesday 6th April 2022
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I need some help to track down a pretty bad vibration in my LR Discovery. The symptoms are:

- kicks in around 65-70mph and gets gradually worse. Doesn't clear at higher speeds
- mainly felt through steering wheel but also in seat - feels central but can't be sure
- related to road speed, independant of engine speed
- starts 5-10min after water gets to temperature ( oil warming up ? )
- severity varies, although it's getting more consistent.

I've tried swapping tyres around, replacing each with the spare. No difference.
Just to be sure, I've just had the front two rebalanced. They said they were out but it made no difference afterwards.

My friendly LR mechanic thinks it's a wheel out of true which he says may not show up when they are balanced on a machine. I'm not convinced...swapping the wheels with the spare should have eliminated it. He checked the propshaft and wheel bearings and says they are ok.

Any other ideas ? It's driving me bonkers and I have a trip to Skye this weekend !


Smint

1,996 posts

42 months

Wednesday 6th April 2022
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It can be illuminating getting someone to drive your car whilst you follow in another car and observe from all angles.

Assuming that reveals nothing, don't forget the brakes, sticking calipers can cause odd vibrations etc.
You've checked the obvious ie transmission fluid levels, props greased.

gifdy

Original Poster:

2,073 posts

248 months

Wednesday 6th April 2022
quotequote all
Yeah, that's a good idea. I can get my wife to drive.

I had the transmission fluid changed...but no improvement. Mechanic checked the prop and said it was ok, but this is my current suspicion. If it was a bearing I'm sure he would have spotted it but can they lose their balance ?

InitialDave

12,243 posts

126 months

Wednesday 6th April 2022
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Old live axle Disco? Make sure the front hockey stick bushes on the axle end are good, along with all the other bushes and joints.

Could be a mild version of "death wobble", which in simple terms is caused by issues with suspension geometry setting up a feedback loop between the forces through the tyre contact patch and the steering axis intersection. More common on lifted suspension stuff with reduced castor angle and trail.

Have had it in a leggy one, and it presents pretty much as you describe.

gifdy

Original Poster:

2,073 posts

248 months

Thursday 7th April 2022
quotequote all
No, it's a Discovery 4. Some of the suspension bushes on the rear look a bit tired though. Not perished but they've seen better days.