Prop shaft balancing

[baldkev]

I failed today..... my L200 needed a new propshaft centre bearing, so i bought a new one from mitsubishi ( the aftermarket ones often dont last well )

Anyway, i took it off, split the u.j, took the yoke off, pulled the bearing and then reassembled. When i drove it a few hours later, it had a vibration under load i spun the rear diff plate 180° and a quick test drive showed the vibration, so i unbolted it all again, rotated the u.j and reassembled, thinking it could have been the 2 halfs of the prop were incorrectly positioned... still shaking.

I'm now fairly sure the it must be the yoke connection to the prop that has thrown the balance off, but how to align it correctly without doing that procedure on every spline combination??? Agggghhhhhhh!!!! I should have marked it, but hindsight is a wonderful thing.

Any clever ideas?
Thank you, kev

 

[Spectric]

Look up Hooks joints they are not "constant velocity" and have angular velocity changes with rotation.

To get constant velocity from input to output the joints have to be aligned so as one is accelerating the other is deaccelerating and so cancel out.

https://sdp-si.com/catalogs/D757-Couplings-Universal-Joints3.php

 

[baldkev]

Thanks roy, but in terms of nailing the position of the yoke on the splines to get the prop balanced again.....
Currently im thinking i might take the shaft off, and just have the yoke and prop bolted in, with bearing, and see if i can detect any wobble.... if so i might be able to figure it out without having to rebuild and strip the prop for each spline position until i get it right ( if that makes sense )

 

[Fergie 307]

I am afraid you have hit the nail on the head with the comment that you should have marked them! Only things I can suggest is that some manufacturers, Mercedes for example, do have marks put on the shaft when it's balanced originally. Can be hard to spot, and have no idea if Mitsubishi even do this. You could also see if there are any witness marks on the components which may help. If there are balance tabs on the shafts, they are often in a similar position in both halves, that might be worth looking at. Alternatively you are back to remounting it repeatedly until it's correct, or taking the whole thing off and getting it 're balanced, if you can find anyone who can do it. I used to use a specialist prop shaft firm in Luton but they closed years ago. A search for prop shaft reconditioners or similar might find something. Or maybe contact someone who repairs trucks, they will probably know someone.

 

[Just4Fun]

30 years ago - Jeesus, 40 years ago - I balanced the prop on my Triumph GT6 Using a technique I read about in Practical Mechanics or some such magazine. It was a bit fiddly, involving rotating 2 jubilee clips clamped on the back end of the prop. It did work though. Unfortunately I don't remember the procedure, but maybe google knows.

 

[Jameshow]

30 years ago - Jeesus, 40 years ago - I balanced the prop on my Triumph GT6 Using a technique I read about in Practical Mechanics or some such magazine. It was a bit fiddly, involving rotating 2 jubilee clips clamped on the back end of the prop. It did work though. Unfortunately I don't remember the procedure, but maybe google knows.

Like wheel weights to balance any out of balance weight. You could stuff a bit of lead flashing under the jubilee clips to add a bit of weight!!

 

[baldkev]

Thanks all for the comments.... i got lucky in the end, I was talking to a neighbour who is a marine engineer. He googled it ( which i had tried ) and found a bit of info suggesting the yokes should be inline to balance the prop. I then realised i had been pretty dumb, because the rear half was still fully intact, so i looked and the yokes on the rear were inline! He solved it for me and saved me a lot of grief, but if i could have just sat back and looked at it for 10 minutes, i should have worked it out

Then the fun started.

I took the prop off again, seperated the u.j and one set of bearings were trashed. I had a spare ( new ) which turned out to be the wrong size, despite me using my numberplate to confirm fitment. I went to a local motor factors and they had to order me one in..... which was also the wrong size because the guy put in the wrong product code on the order but..... they could get one before 4pm!
That didnt happen.
I stole mrs balds motor and drove to another motor factors that did have one, although not close to me.
20 minutes after i got back home, it was all done and working fine.

Hopefully someone will get some use from this info in a future search
MARK YOUR BITS BEFORE STRIPPING!!! Ok, that sounds weird

 

[clogs]

or use ur iPhone's camera.......use mine all the time now......
even for stupid stuff.......

or use a center pop for making while everything is still conected origionally.....

glad ur fixed up......

 

[Fergie 307]

Tipex