Final drive oil change

[Davey]

FD Oil

I had my final drive replaced under warranty at 4500 miles last month because of the excessive play.

1600 miles later I get a whining noise when decelerating and with the bike leaned over for cornering.

I checked the oil last night in case the new unit had not been filled. The oil was black - is this the normal colour?

It`s going to have to go back in methinks?

 

[sjwb]

Whilst it is fair to say that oil will not last forever, it is equally fair to say that it will last the duty cycle of the bike. By that I mean whatever parameter has been set by the manufacturer. For the motor industry durability cycles are broadly based on 150k miles or ten years, either being within the scope of modern oils.
Should seals fail and allow ingress of water, then equally oil would leak out, again not the fault of the lubricant.
The FDU is the most hostile environment, with the shear stress on the oil far in excess of that of the gearbox.
Having for some time, read of the antics of some of our contributors, I stand by my original assessment - some things are best left alone.
Apropos, Ford, Chrysler in the 70's had filled for life transmissions and currently MB and ZF transmissions are filled for life, indeed the Benz has no fill facility at all.

 

[Aurelius]

I find it hard to believe that 250ml of gear oil will last forever - contamination could still happen either from internal sources or water leaking past the seals. And oil does wear out - admittedly the FD is probably not a very hostile environment but it's probably similar to the gearbox.

I find it hard to believe as well, but apparently cars have had sealed final drives for many years without any problems. When my old Volvo went in for servicing, I asked the mechanic if it wouldn't be prudent, given its high mileage, (200,000+ miles on the clock) to change the final drive fluid. No reason to, he replied. By way of proof, he extracted a small amount of final drive oil and showed it to me. It still looked like new oil.

 

[motobiker]

I've done it

And I'm sure I posted about it before, but if you don't search for exactly the correct word or phrase you don't get everything.

Anyway, here goes, in brief as I'm late for work

1 - Remove rear wheel

2 - Remove rear ABS sensor. You don't need to remove the brake disc to do this, just rotate the disc until you can get at the sensor through one of the gaps. Undo the little bolt and then the sensor pulls out. Make sure the O ring is in good condition.

3 - Support the final drive with a ratchet strap (a bungee won't be strong enough, it is heavy) through the rear spindle and around the frame.

4 - Remove the paralever arm rear bolt, and allow the strap to take the weight of the FD. As the FD tilts backwards, the rubber "Sydney Opera House" seal should pop away from the end of the swinging arm. Be careful not to rip this seal.

5 - Remove the drain plug at the rear of the FD, and loosen the strap enough so the FD tilts 90 degrees backwards, draining the oil into whatever container you have ready.

6 - While you're at it, check the condition of the drive shaft splines that mesh with the final drive. I gave mine a bit of a lube with molybdenum sulphide grease, although I think the correct substance to use is some sort of molybdenum based white paste.

7 - Also take the opportunity to clean everything, don't use solvents but wipe any dirt from the end faces of the swinging arm, the driveshaft and the opera house.

8 - Apply a small amount of silicone sealant to the sealing faces of the opera house, and then mount the OH onto the FD.

9 - lift the FD back into position, using the ratchet strap to take the weight. Gently wiggle the drive shaft end back into the FD, this can take a bit of doing but don't force it. Ensure the opera house is properly located into the swinging arm, and replace the paralever bolt.

10 - replace drain plug (if you haven't already) and add 250ml of the oil of your choice through the ABS sensor hole.

11 - Replace ABS sensor, and rear wheel.

I think that's about it, did I miss anything?

Is there any good reason for this work to be so goddamn complicated?
Seems a hell of a lot of work just to change the oil....

 

[Pukmeister]

I've just changed the oil in my FD and about to do the gearbox oil. The smell of the black filth that came out is unbelievable, it has stank the house out.

I took some pics which I will post up later. I'm using some Comma Masterlube fully synth 75W-90 gear oil (API GL5 Spec) which is the same spec as the recommended Castrol SAF-XO.

On doing a web search for the Castrol spec it is recommended for HGV axles and differentials as well as BMW vehicles without limited slip diffs. Maybe if anyone wants to get the officially recommended stuff they could get it from a local truck depot or HGV repairers. As you only need 0.23 litres I bet they'd give it to you for free if you provided the container !!

Heres the spec for Castrol SAF-XO:

TYPICAL CHARACTERISTICS

SAE Viscosity Rating 75W/90

Relative Density @ 20º C 0.855

Viscosity @ 40º C cSt 103.7

Viscosity @ 100º C cSt 15.7

Viscosity Index 162

Flash Point (COC) ºC 220

Pour Point ºC -51


P.S. Mouse, you forgot to add about removing the rear brake caliper and tying it up out of the way before unhinging the rear FD bevel unit. I would advise anyone interested in doing this maintenance to buy a new O ring seal for the oil drain plug before you commence as mine is a bit chomped and will be replaced once the dealers re-open tomorrow and I can get one. Also get a can of disk brake cleaner handy so you can degrease your rear disk as you will inevitably get some oil on it doing the FD oil change.

 

[Fanum]

Whilst it is fair to say that oil will not last forever, it is equally fair to say that it will last the duty cycle of the bike. By that I mean whatever parameter has been set by the manufacturer. For the motor industry durability cycles are broadly based on 150k miles or ten years, either being within the scope of modern oils.
Should seals fail and allow ingress of water, then equally oil would leak out, again not the fault of the lubricant.
The FDU is the most hostile environment, with the shear stress on the oil far in excess of that of the gearbox.
Having for some time, read of the antics of some of our contributors, I stand by my original assessment - some things are best left alone.
Apropos, Ford, Chrysler in the 70's had filled for life transmissions and currently MB and ZF transmissions are filled for life, indeed the Benz has no fill facility at all.

But read what Mouse actually said...the second time he did it, there was evidence of water emulsification in the oil.........

It may well be that for 'normal' 1200gs'ers, the FD oil change isn't necessary, but some like Mouse and Clive do a lot of wet stuff and from what M said, it IS necessary.

The widely reported smell part worries me as well......oil does not normally smell that bad....to get a strong smell like that, it's either breaking down or has become contaminated.....and in general, strong smells = strong chemicals.

Ok, the parts are steel, but there are seals and even steel will be affected by many strong chemicals in the long term.

Just a thought

 

[sjwb]

For the record, I first changed my FD oil at about 6000 miles, and it was dark black and smelt of wee. However the FD still failed at about 15,000 miles. I changed the oil in the new FD after a "deep fording" experience, after about another 8,000 miles (I think, I should note this stuff down) in case it had been contaminated with water, but it looked fine. I think in the future I'll change it when I change the gearbox oil (every 12,000).

Fanum,
If this is what you mean, I don't see any reference to emulsification. The 1200 FDU is, unlike the 1150, a sealed unit - ie no breather.
The smell is no indication of anything other that that which is typical of sulphur, which is not found in engine lubricants. As you are aware, Extreme Pressure oils are typified by said smell.
Quite what your last sentence means I am not sure.

 

[bonox]

100.000 mile oil change on cars will be here soon

very unlikely until we get perfect cylinder and valve guide sealing. Water and other interesting combustion byproducts enter the oil and cause acids that like to eat things. Gearboxes and FD's shouldn't have this problem which is why their replacement (if specified) is ALWAYS longer than the engine change period.

Electric motor gearboxes could very well be 100,000, but you'll need a battery change long before that comes, and many electric motors do not require gearboxes.

 

[Pukmeister]

I suspect the smell has more to do with anerobic bacteria than sulphur, due to the FD unit being totally enclosed without a breather. All that heating up and cooling down can't be helpful either. Like Mouse, I am glad I have done the oil change on my final drive, though the strap to hold the unit seems a bit pointless. If you find it heavy, you ain't the kind of engineer that should be doing their own spanner work.

 

[Mouse]

Just to clarify, I never found evidence of water in the FD oil, despite my various fording experiences. Which is a good thing, as it means you don't have to worry too much about the oil after dunking the bike, unlike on an 1150.

Also, a friend with a Pan European told me that when he changed the FD oil on that bike, it too smelt really nasty. So it doesn't seem to be unique to BMW, I think gear oil probably just goes nasty under certain conditions.

 

[Ken H.]

Is there any good reason for this work to be so goddamn complicated?
Seems a hell of a lot of work just to change the oil....

Seeing as your doing something that doesn't have to be done. No.