Heavy vibrations at 40mph

Hi all,

My defender started producing this really heavy vibration around 35 until 45mph.
So I went online and ordered some new rear ujs as I thought that would be it.
Fitted them and went for a drive and its still there albeit not as bad now.

Just unsure what my next steps should be?

Many thanks

Front prop?

Surely getting under it a wiggling stuff is a better diagnosis than thought?
It could show up as a diff bearing issue.

J

marjon said:

Front prop?

Surely getting under it a wiggling stuff is a better diagnosis than thought?
It could show up as a diff bearing issue.

J

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Well I did go underneath and it didnt seem that bad on either prop but for the low cost of some new ujs I did it anyway. Maybe I was missing something when I gave them a wiggle?

Take off front prop and drive without it in diff lock. Vibration gone then there's the issue.

The ujs can be partially seized/ notchy so no play but removing prop the uj should move freely

Vibrations or death wobble ?
My 90 would shake violently at around that speed and if I hit a pot hoke

No noticeable play in panhard rod bushes but once I changed them the problem stopped

tottot said:

Take off front prop and drive without it in diff lock. Vibration gone then there's the issue.

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without the front prop wouldn't all the power still be trying to be sent to the front, power always takes path of least resistance? so i'd just be sat there not moving?

steve2286w said:

The ujs can be partially seized/ notchy so no play but removing prop the uj should move freely

Click to expand...

yeah I think the best bet will be to drop the prop and give it a feel.

chrisstdt said:

Vibrations or death wobble ?
My 90 would shake violently at around that speed and if I hit a pot hoke

No noticeable play in panhard rod bushes but once I changed them the problem stopped

Click to expand...

cant imagine its death wobble as its not something you feel through the wheel, more so ur arse!

CocaineOnTheCob said:

without the front prop wouldn't all the power still be trying to be sent to the front, power always takes path of least resistance? so i'd just be sat there not moving?

Click to expand...

You would have to put it in difflock

I would also add to check your tyres for lumps, perishing or mis-shape.

You would know if it was death wobble, it feels like the whole thing is disintegrating around you

Steering wheel used to shake like mad on mine

Just start with the easy things like removing prop and checking / swapping wheels

I've seen some props where the uj was all but ready to fall off and they didn't vibrate

Badly balanced wheels tend to show between 50-60 mph and after that they all but balance themselves

Prop joints that are nearly seized get hotter/tighter as one speeds up, result vibration.
TIP. Point an IR temp reader at UJ's after a run, you will soon note a seizer.

Thanks everyone for the advice, went back underneath today and compared the two props. Not sure how I missed it but after feeling how tight the new rear is I realised I missed a huge amount of play in the front.

How I missed that before I truly dont have a clue

Missed it probably because it was firm in just one position. It moved to another position or spat the little rollers out and then you found it.