Advice on rear pinion seal replacement

[WGB]

I would rather leave it alone but there is a definite small weep from my pinion seal so it will have to be replaced while the rear end is out.

I am aware that the pinion pre-load is critical and will buy/make a tool to measure it but would appreciate others experiences and advice as I have a relatively quiet diff with a functioning LSD and would like to keep it that way.

It may also be necessary to hand it over to an "expert" but diff experts are few and far between.

Bill

[Big_Richard]

when i did mine it was noisy as hell for quite some time, but it turns out that i didn't have the flange nut torqued correctly. After doing that the diff has become silent again. (TJ just did it with my torque wrench) The nut was very loose in comparison to where it needed to be.

Maybe i got lucky who knows, but proceed with caution. I would most certainly obtain the special tool and follow the advice of the service manual. Otherwise if in any doubt hand it over to a specialist along with the manual.

[TJ 450]

The special tool looks brilliant, and I'm watching this thread with much interest.

With the diff, as MT is aware, the one in my 6.9 needs a rebuild at some stage... In fact, by the sound of things, I think it may well be noisier than his. I'm led to believe that Klaus, Nathan's mechanic, knows how to rebuild them to factory specs. Maybe Nathan will chime in on this and confirm.

Tim

[Big_Richard]

with the rear seats installed in my car now, the diff can no longer be heard.

The noisiest thing is the m100 - which i think along with yours TJ needs the static valve adjustment done as it sort of sounds like a quiet sewing machine.

[TJ 450]

As I remember from the 450, the clearance adjustment and check of the lifters really makes a difference. The lifters get clogged with old, sludgey oil too.

Tim

[WGB]

I will plough the Internet tonight looking for " Torque measuring tool for friction torque at rear axle drive 30-600 Ncm" M-B part no 001 589 42 21 00 or equivalent but I have  1/4" drive torque wrench that can read that low so it might already be in hand.

Bill

[goldacre]

Hi Bill, if you get stuck contact Doug at Automac transmissions in Myaree, he does all the Merc repairs there and has done so for over 30 years and owned a 280SEL at one stage so is in the 'know'.

(08) 9330 5105
Fax: (08) 9330 3939
Address
77 McCoy St, Myaree WA 6154, Australia

G

[WGB]

Thanks for the reply Julian.

I will see if I can accurately measure the pinion preload "drag" with my 1/4 inch drive torque wrench and if I can I will do it myself.

Bill

[goldacre]

I will see if I can accurately measure the pinion preload "drag" with my 1/4 inch drive torque wrench and if I can I will do it myself.

I honorably admire your DIYer drive and ability Bill, well done! 

Good luck!

G

[koan]

I will see if I can accurately measure the pinion preload "drag" with my 1/4 inch drive torque wrench and if I can I will do it myself.

The "professional" way is to mark the nut and flange before undoing then after the new seal is installed tighten the nut till the marks line up.

Would the "drag" of a new seal compared to a worn, leaking seal affect the torque measurements?

Might be worth marking things in case of unforeseen problems.

koan

[s class]

Thanks for the reply Julian.

I will see if I can accurately measure the pinion preload "drag" with my 1/4 inch drive torque wrench and if I can I will do it myself.

Bill

Bill, my 1/4 torque wrench goes from 100Ncm to 2000Ncm (in 5Ncm increments), and this is precisely how I set up steering boxes. 

[WGB]

I will see if I can accurately measure the pinion preload "drag" with my 1/4 inch drive torque wrench and if I can I will do it myself.

The "professional" way is to mark the nut and flange before undoing then after the new seal is installed tighten the nut till the marks line up.

Would the "drag" of a new seal compared to a worn, leaking seal affect the torque measurements?

Might be worth marking things in case of unforeseen problems.

koan

Sounds like an excellent idea Koan if you use the same nut but the workshop manual says to replace the nut. I'll keep an open mind on that.

Thanks for the reply Julian.

I will see if I can accurately measure the pinion preload "drag" with my 1/4 inch drive torque wrench and if I can I will do it myself.

Bill

Bill, my 1/4 torque wrench goes from 100Ncm to 2000Ncm (in 5Ncm increments), and this is precisely how I set up steering boxes. 

Yes I think that is the way to go but I like Koan's idea if I can re-use the nut - it depends on what sort of nut I find and whether it can be staked twice if that is the type it is.

It sounds like there are ?two ?four types of pinion shaft and three types of nut with only one type being still stocked.

Bill

[s class]

These nuts that get staked usually cater for two applications - usually they have two stake points with only 1 being used, or 4 stake points with 2 being used.