W211 2.7 Cdi Rear axle shaft nut size?

[james2747]

Hello
The larger metric sockets I have are 6 sided hexagons.
I need to remove the axle shaft nut on a 2004 W211 2.7 Cdi, to sort out a leaking differential seal but it looks like I need a conventional multi-hex socket for the best fit.
Does anyone know what size of socket I need to buy as I'm told nut is on tight so need a good fitting socket.

 

[Uncle Benz]

Yes, you need what is commonly referred to as a "triple square" socket, 30mm if memory serves. (32mm if memory unreliable)

The nut is only half the battle, the splined end of the shaft is often tight in the hub.

 

[james2747]

Yes, you need what is commonly referred to as a "triple square" socket, 30mm if memory serves. (32mm if memory unreliable)

The nut is only half the battle, the splined end of the shaft is often tight in the hub.

Thanks Uncle Benz
It looks like the nut is designed for single use only so I've ordered a new one and will then go and find the exact socket to fit as you are not sure if its 30mm or 32mm.
I don't like the sound of 'tight in the hub' … I do have pullers but not ones that can exert massive force.
Think I may just end up topping up the diff 3 or 4 times a year as the whole job of replacing the oil seal sounds quite daunting.

 

[Uncle Benz]

If you are only changing the diff output seal, you can undo the arms on the knuckle and pull the inner joint out of the diff without undoing the hub nut. Might be easier. I'd only attempt to get the shaft out of the hub if the abs reluctor ring had gone, or the wheel bearing needed replacing.

 

[james2747]

If you are only changing the diff output seal, you can undo the arms on the knuckle and pull the inner joint out of the diff without undoing the hub nut. Might be easier. I'd only attempt to get the shaft out of the hub if the abs reluctor ring had gone, or the wheel bearing needed replacing.

Thanks Uncle Benz
Doing the job without needing to remove drive shaft from the hub would definitely be better.
I looked at the Mercedes workshop manual to prepare me for the job and they say, "remove shaft from hub" … they also show a special tool / drill jig for drilling out the end of the drive shaft and tapping a thread in to it, which I assume is to enable it to be drawn back in to the hub … so I have no desire to do that.
Will follow your advice and remove shaft/hub all in one by separating any control or link arms.
Thanks again for your advice.