Technical Main shaft not centered after replacing gearbox main seal

[Luke W]

Hi All,
I just replaced the rear main gearbox seal in my 1969 500L and after putting it all back together I realized the shaft is not centered in the housing. I did not do any other work to the gearbox so I am not how this might of happened. I am wondering if it will sort it self out once it runs or if there is an issue I need to address before I reinstall it.
Thanks in advance for any advice on this,
Luke

 

[Goldnrust]

The collar that holds the bushing and seal around the input shaft can be removed from the gearbox.

I suspect this collar being out of alignment is the issue, rather than the main shaft itself being out of line.

In the case of my gearbox, the O-ring seal on the collar had got pinched on installation and was holding it off the gearbox at an angle.

You should be able to remove the collar without opening the gearbox, just remove the clutch release bearing and there’s a single bolt behind it, the collar is a reasonably tight fit but should pull out with some effort!

Picture of the part I’m describing along with the pinched O-ring that was causing my misalignment attached.

 

[Bleeding Knuckles]

Hi Luke, As far as I can remember from when I rebuilt my gearbox the thrust bearing will move to one side by vertu of the forks it is attached to. When you have the splines of the shaft located into the flywheel the thrust bearing will locate into the centre of the clutch pressure plate and will sit there happily, make sure you apply a small amount of grease to allow the thrust bearing to slide along the shaft during it's action.
Ian.

 

[Luke W]

The collar that holds the bushing and seal around the input shaft can be removed from the gearbox.

I suspect this collar being out of alignment is the issue, rather than the main shaft itself being out of line.

In the case of my gearbox, the O-ring seal on the collar had got pinched on installation and was holding it off the gearbox at an angle.

You should be able to remove the collar without opening the gearbox, just remove the clutch release bearing and there’s a single bolt behind it, the collar is a reasonably tight fit but should pull out with some effort!

Picture of the part I’m describing along with the pinched O-ring that was causing my misalignment attached.

Hi Goldnrust,
I had removed the collar and replaced the main seal and replaced the bushing. I checked and the collar is snug to the bell housing and I don't see any gaps at all so I don't think it is a pinched o-ring. I don't recall if it was off center before I switched out the seal, but it could have been.
Thanks for the reply,
Luke