Vibration at 50mph

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Glyn D

Glyn D

Active Member
Posts
134
Location
North wales
I know this has been asked before but I've read through the other threads and tried lots of the advice. Figured it was about time I started a new thread...

When going at approx 50mph, I get steering judder in my Defender 90 300tdi

This lot is brand new:
  • All four wheels and tyres
  • Front and rear propshaft
  • Swivel housings
  • Front stub axles
  • Front drive flanges
  • Front half shafts
  • CV joints
  • Front wheel, CV and swivel bearings
  • Track rod and ball joints
  • Drag link and ball joints
  • Steering damper bushes
Changing all of this has made it a much better ride and removed a lot of the clunks and rattles but the steering judder remains.

If I let off the throttle it seems to stop.
Importantly, removing the front prop and putting the diff lock on completely eliminates the judder.

Originally, after following the Haynes manual and this video:

I had the male end of the prop attached to the front diff. Also, after reading through posts about advancing one end of the prop because the front diff is at an angle, I had the two prop ends 45 degrees out of phase.
I tried 45 degrees in both directions but it made no difference, so I then tried it with them in phase but I still got the steering judder.

After more reading I found that the Haynes manual is wrong and the male end of the front prop should in fact attach to the transfer box. With the prop now the right way around, I've tried it 45 degrees and 22.5 degrees out of phase.

I seem to get the least amount of judder with the two ends of the prop perfectly in phase but I'm not able to eliminate it completely; at 50mph I still get steering judder which vibrates through the whole car.

As I was reading this back it made me realise that changing the phasing does seem to influence the judder which makes me think it is prop related. With the male end attached to the transfer box I will need to try 22.5 and 45 degrees in the opposite direction just so I can rule them out.

In the meantime, is there's anything else it could be?
 
I am assuming as you have removed the prop and are playing the phasing the prop itself is in good condition both the UJ's and the slider itself. I know it is a basic check and I don't want to come over as patronising, but the reason I ask, is vibration at 50 is exactly the same point I get it when a UJ is beginning to fail.
 
If your original prop is only the UJ's I would perosonally think about spending 25 notes changing the UJs and trying that instead.

Cheers
 
Glyn D said:
If I let off the throttle it seems to stop.
Importantly, removing the front prop and putting the diff lock on completely eliminates the judder.
Click to expand...
These two statements do appear to be the new prop being out of balance.
It is so easy to keep spending money and just buy another prop, if it is possible for you to borrow a known good prop to try fist could save money,
 
I had similar judder and replaced much the same. Mine turned out to be the panhard rod bushes. I presume the axle was wobbling side to side causing the steering wobble....
 
tottot said:
But it is fine without the prop.Has it got a lift?
Click to expand...

Very true.

The prop off, wobble goes, does point the finger at the prop, but if it will be expensive to sort the prop, you could have a wheel checked in 15 minutes for 10 pounds.

All i know is that I have just spend 2 very busy weeks trying to solve a massive judder at 50mph. Changed bushes, wheel bearings, UJ's and i thought it would never be the wheel balance as it was.
 
NiallRussell said:
Very true.

The prop off, wobble goes, does point the finger at the prop, but if it will be expensive to sort the prop, you could have a wheel checked in 15 minutes for 10 pounds.

All i know is that I have just spend 2 very busy weeks trying to solve a massive judder at 50mph. Changed bushes, wheel bearings, UJ's and i thought it would never be the wheel balance as it was.
Click to expand...

But did you disconnect the prop and drive it without it fitted?

Cheers
 
yes I did - was chasing a noise as well and seeing if it went away. I don't remember the wobble going away, true - so you're probably right that it's pointing to the prop.
 
Thanks for all the replies guys and sorry for the delayed response.

NiallRussell said:
Balance your wheels. I was chasing my tail for ages until i did this.
Click to expand...
Wheels and tyres are all brand new (newly balanced too). With the car up on axle stands, engine running and putting it into gear, there was really bad wobble on all of the original wheels but I found no play in the bearings. Looks like they were were all buckled, especially the front wheel on the driver's side.

tottot said:
But it is fine without the prop.Has it got a lift?
Click to expand...
I'm not sure. The springs and shocks aren't original so it is possible. I did put a wide angle prop on just in case. Would a wide angle prop make this wobble if it wasn't fitted to a lifted vehicle? What's the best way to know for certain if it's been lifted? Measure the loaded springs? (New tyres have a larger diameter than the originals).

I am making some progress with it though: With the male end of the prop at the transfer box, I went ahead and rotated it 45 degrees in the opposite direction. This has reduced the vibration massively, but it's still not perfect. I plan to go back a spline (to 22.5 degrees) and then I've covered all angles.

One of my neighbours is building a series 3. He stopped by the other day whilst I was under the car. He says he has a disco prop which might fit. Do you guys have any thoughts on that?

He also gave me a bunch of Defender poly bushes. No panhard bushes, but if I'm replacing bushes anyway, I doubt it would add much to the job to include the panhard rod.
 
Wide angle on standard hight should have no effect.Measure by comparing your loaded spring hight with a known to be standard landy the same as yours.
A prop substitute would be a good idea.There is a chance your prop may not be balanced right.
 
It could be a problem with your front diff. I had similar juddering and my rear diff pin was sheared. Having the rear prop off I had no judder...but when it was connected it was unbearable
 
I found this comment on another forum "Height on a standard 90 between top and bottom spring mount should be about 265mm". Not sure what year/model this relates to but it's a starting point at least.
 
Spring height on the front of mine is 264mm, so pretty much standard.

Back to the topic: I don't think trying the 2nd-hand disco prop will be of much use. If it still rattles then it could be the disco prop at fault so that won't tell me anything. If it fixes the rattle then it will tell me that I need to replace the prop, at which point I'll have to go ahead and buy a new prop so that I can return the disco one. I might as well just go ahead and buy a new prop.

Before I do that though, I'll have one last go at changing the phasing and then I have tried every possible angle.
 
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