[Mgs] Drive shaft balanced

[Charley & Peggy Robinson]

Fine post Paul, especially the link.  BTW, you sure live in an 
interesting place.

O.T. :  A shame about the O. Bird statue vandalism.  How did that come out?

CR
On 9/9/2012 9:17 AM, PaulHunt73 wrote:
> New driveshafts are balanced off car on a machine so should be capable 
> of being fitted to any car and run true, but it does depend on the 
> trueness of the shafts in the gearbox and diff of course.  It's easy 
> to check the UJs yourself, grasp the shaft and flange and try and turn 
> them in opposite directions and see if you get any play, also for 
> sideways play along the length of each arm of the 'spider.
>
> The Workshop Manual makes great play about marking the flanges if you 
> remove a prop-shaft from a car in order to replace it in the original 
> position.  A nice to have, but irrelevant as far as balance goes 
> because of the off-car balancing that was done on it in the first 
> place. What isn't mentioned, but is vital, is to mark the all four *UJ 
> yokes* before dismantling, get those back wrong and balance will be 
> compromised.  This will ensure that the UJs at each end have the 
> correct orientation relative to one another, which is something else 
> mentioned in the manuals.  However Haynes (my edition at least) shows 
> the incorrect exploded orientation but the correct assembled 
> orientation.  The Leyland Workshop Manual (again my edition) shows it 
> correct in both cases.  You can check this, which will show if the 
> sliding joint has been reassembled incorrectly, but either shaft yoke 
> could still be 180 degrees out with each other, and either flange yoke 
> could also be 180 degrees out with its partner.  There is some 
> evidence that the each half of the sliding joint should have arrows to 
> ensure correct reassembly, but not all prop-shafts seem to have the 
> marks, and they can be very indistinct, see 
> http://www.mgb-stuff.org.uk/propshafttext.htm#yokes
>
> Even with that you can still get the flange yokes 180 degrees out 
> unless you mark them first.  If the UJ came to you with the car then a 
> PO may have dismantled it and got it wrong, it might be worth 
> comparing the cost of testing/rebalancing against the cost of a 
> replacement shaft (and hope *that* has been balanced correctly ...).
>
> Note that prop-shaft vibration would normally be evident at a given 
> road speed in various gears, not just one gear.
>
> PaulH.
>
> ----- Original Message -----
>> After some tests at several revs of the engine and speed I finally 
>> found, that some vibrations between the speed of 50 and 70 m/h are 
>> caused by I think an unbalanced driveshaft between the gearbox and 
>> the differential gear.
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