90 vibrates

[grant1985]

Hi all my 90 vibrates throughout when i get to 40mph and will stay there, also my front prop shaft has play in a rotational fashion, ie i can grab it and turn alot which is causing a nasty clunk when i pull away and change gears. need advice to get it sorted. thanks

 

[grant1985]

Anyone

 

[pos]

Hello,

Vibration is more than usually caused by wear in the universal joints on your front and rear prop shafts. The best way to check them for play is to park your 90 on a flat surface with the gearbox in neutral and the handbrake off. Have someone sat inside ready to apply the brakes just in case your 90 starts to move, whilst you clamber underneath. Grab the prop shaft at either side of the universal joints and give the thing a really goos shove about and turn from left to right. If there is play in the joints then you have your answer. Some times the universal joints don't necessarily have to move much to cause a lot of vibration.

Another possibility is that the balance weight has dropped off one of the prop shafts (usually the rear). If you examine the length of the shafts, you should find a small metal patch stuck to the surface. Manufacturers stick these in place to balance the shaft when it is rotating. If it's not there, the weight of the shaft is offset and it will vibrate like hell.

You should also check your prop shafts to ensure that the arrows are aligned (have a look through Buster's guides for more information).

-Tom

 

[bluehaze]

Agreed, as Tom suggests start with the UJs.

 

[grant1985]

Thats interesting and very helpfull will go check that out in a minute would what you said above cause my frknt prop shaft to turn alot at the flanges as when im pulling away etc i get hell of.a nasty clunk and am hoping the ujs would make the shaft turn at the flanges :-(

 

[pos]

Thats interesting and very helpfull will go check that out in a minute would what you said above cause my frknt prop shaft to turn alot at the flanges as when im pulling away etc i get hell of.a nasty clunk and am hoping the ujs would make the shaft turn at the flanges :-(

There is a limited amount of 'free play' or sloppy rotation that you will get with worn UJ's. If you watch the drive flange at the transfer box and axle differentials whilst you rotate the prop shaft back and forth you should be able to determine whether or not the free play is being caused by worn UJ's or by general slack in the front and rear axle differentials or the transfer box. My guess would be a mixture of both. It is pretty normal to have a bit of free rotation at the diff too. The clunk is more than likely free play at the transfer box side of things either thorough a worn UJ at the transfer box side of the front or rear prop shaft or through a little slack in the transfer box its self.

-Tom

 

[grant1985]

I checked all ujs and removed front and rear props today and all is fine, i think the play ie slack is in the transfer box or the front diff but im unsure how to check as both prop shaft flanges have about the same amount of play in the transfer and the front diff, the rear prop shaft is nice and snug. just dnt know where to start now

 

[Farrar]

I've got a vibration at about 30mph. Could this be the propshaft or something different.I've recently had my rear propshaft off and thought it only went on one way.

 

[jamesmartin]

only if you split prop at slide and refitted with yokes out of line

 

[Farrar]

only if you split prop at slide and refitted with yokes out of line

Should rear ujs be in line or ofset

 

[wickford90]

Should rear ujs be in line or ofset

have been told they should have marks on to align, but could not for the life of me find them on mine.

 

[jamesmartin]

inline like a open ended spanner if ujs were removed

 

[Farrar]

inline like a open ended spanner if ujs were removed

I'll check mine tomorrow and come back to you. Fronts are offset so why is rear in line

 

[Farrar]

Propshaft removed and aligned with arrows. Problem solved. Thanks for useful information. Something else I've learnt.

 

[grant1985]

Where are the arrows on my propshaft

 

[COA]

Hi - I had a vibration at 40mph and changed the UJ's on the front prop - well actually I ended up changing the whole front prop because when I tried to replace the UJs I found it really hard to get the new bearing cup into one of the yolks and had to use so much force that the neddle bearings always became dislodged. I decided that 100 quid for a new prop was just an easier solution in this instance! I think the UJs have been changed so many times that the old yokes are just knackered.

The new prop made the vibration go away. The new fuel pump fitting at the same time makes the 90 feel like a stabbed rat!

 

[Farrar]

Where are the arrows on my propshaft

Mine were on transfer box sliding end. Had an arrow on prop and line on uj. Had to clean it to find them. Hope this helps as I think a lot of people don't know about this

 

[grant1985]

Refering to coa replie. Did your vibrations start at 40 and not disappear till you went below or was yours different. And farrar im going to check your suggestion tomorrow and hopefully in a way they wont be inline lol. will be back on here tomoro to let you know how it goes.

 

[norfolkmick]

also check that the UJ'S are lined up ie on the slider the are meant to be inline when i got my 90 i had a vibration problem and thats what it was, took it to bits turned it 90 degrees and its sorted.

 

[COA]

Refering to coa replie. Did your vibrations start at 40 and not disappear till you went below or was yours different. And farrar im going to check your suggestion tomorrow and hopefully in a way they wont be inline lol. will be back on here tomoro to let you know how it goes.

Yep, the vibration started at or around 40 and only went away if I went below 40 or took my foot of the gas. The MOT had given me an advisory for worn UJ bearings a few months back and I knew it needed doing so I assumed that was the cause and wanted to replace them anyway. The new prop has taken the vibration away and I changed nothing else.