Final Drive

[GLS4004]

2002 1150 RT 55k miles.

I have had the final drive rebuilt twice due to oil leaks. Last time was 10k ago, leaking out of the boot once again. I use Mobil1 100 Syn.

Love the bike, need the leak stopped, any suggestions other than a different final drive?

CM

[sjbmw]

The only suggestion I can think of is to not use synthetic. Try dino sludge.

[R1150Rclean]

I use Redline shockproof gear oil (http://www.redlineoil.com/Products.aspx?pcid=8), the stuff is so thick I could not see how it could leak. But the first time I used it I had to add ~400 mL (after a Valvoline semisyn 80-90 oil drain) after repeatedly turning the rear wheel to distribute the oil and then waiting for the oil to settle. When I changed the Redline after a year only 200 mL drained out, so the rest was stuck to the gear/bearings which is why it is so good at protecting the final drive.

[TicTac50]

I use Redline shockproof gear oil (http://www.redlineoil.com/Products.aspx?pcid=8), the stuff is so thick I could not see how it could leak. But the first time I used it I had to add ~400 mL (after a Valvoline semisyn 80-90 oil drain) after repeatedly turning the rear wheel to distribute the oil and then waiting for the oil to settle. When I changed the Redline after a year only 200 mL drained out, so the rest was stuck to the gear/bearings which is why it is so good at protecting the final drive.

I did not know that FD takes more than 250ml of oil.

[CycleRob]

Here is what the FD from Boxer's now gone OilHead looked like after a 50 mile trip to my garage, plus time to drain it's very warm RedLine oil and disassembly. It was taken apart because the big bearing failed, but after ~8oK miles (128,750 km). Both bearings were replaced. The first pic is especially revealing in that the drip-drop drain rate was 10+ seconds between them. The film remains.
Click Thumbnail. Click big pic for full size for printout.


I used Mobil-1 gear oil in my OilHead and that big bearing also "wore out", giving rear wheel free play. Here's the FD after overnight draining the Mobil-1 gear oil plus some others FYI:


The RedLine gear oil is really-really good stuff, but apparently neither Mobil-1 or RedLine full synthetic gear oils won't prevent the almost common FD bearing failures.

EDIT: To change photo host from PhotoBucket to the faster, less intrusive Postimage.org and add more FYI pics.
.

[R1150Rclean]

I wonder how often the Redline and Mobil 1 were changed in the two FDs. You can also add molybdenum to any oil, would that work better?, though I thought Redline had molybdenum in it. You can get Guard Dog moly to add to oil http://guarddogmolylubricants.com/gd421.shtml

[sweatmark]

I wonder how often the Redline and Mobil 1 were changed in the two FDs. You can also add molybdenum to any oil, would that work better?, though I thought Redline had molybdenum in it. You can get Guard Dog moly to add to oil http://guarddogmolylubricants.com/gd421.shtml

The inherent problem with R1150** final drives has to do with assembly process and poor BMW quality control; it has nothing to do with lubrication. Just as in automobile differentials, the crown/pinion gears/bearings must be preloaded correctly. Bearing failure in the R1150** final drives is due to incorrect preloading.

[GLS4004]

How does the oil get in the boot and seeps out? Would that be the pinion seal if is dry if the rest of the FD is clean and oil tight?

[grwrockster]

GLS4004,

I believe that any oil in the UJ boot ahead of the FD is more likely (or at least just as likely) to have come from a minor weep from the gearbox output oil seal and tracked down the driveshaft.

As long as oil levels in FD & Gearbox stay good and aren't losing lots of lube, then I'd do the usual regular level checks and not worry about a weep getting a bit of oil in the gaiter/boot over the UJ myself.

But that's just me - if people really can't live with any trace of oil loss then that's entirely up to the individual I reckon. I've decided that I'm only splitting my FD or going near the innards of my gearbox if a bearing or other mechanical bit needs attention.

[Arbreacames]

It is difficult to avoid leaks of the FD because there are several paths that the oil can take. (See paths A, B, C, D, E in the figure below).
Many mechanics assume that the leak is due to a bad seal "joint 4", which causes leak path C. However, other leak paths could be more common. To prevent these other leaks, the shop manual specifies some a thread sealant and a flexible joint compound.

The seal replacement is a DIY operation. The hardest part for me was to remove the threaded ring that holds the joint. It can be done with an axle locknut socket (free rental at AdvanceAutoparts), but it takes a lot of force and I am kind of wimpy.
Also, the FD needs to be held down somehow. It "should" be done like below. I held it onto a vise grip by two lugnuts and prevented the FD from spinning around by bolting onto it a long metal bar.
If anybody attempts to do this repair, I could provide some more details from memory. Also, the dummies at ChicagoBMW sent me four identical seals, so I would be glad to send you one free.

For those of you who read French, or who only look at pictures, here is an excellent web site by a great mechanical engineer: http://isatis.no-ip.org/K1/Joint_ent_pont/p4.html