small leak from final drive....

[fair1535]

2006 1200 gsa 55k

Noticed a small leak from final drive housing ( appeared to be coming from behind large plastic cover, suspect faulty seal)

Purchased new seal from dealer.

Prior to replacing remembered reading somewhere that hot weather could cause weeping from seal. So prior to replacing seal decided to drain and renew fd fluid. What came out was dark brown, no evidence of metal on speed sensor or drain bolt, good start. No play in rear wheel. 220ml came out. 180 ml put back. 40 miles later, no leak. Happy teddy. Would appear that spell of hot weather must have had some impact on seal together with the 220ml.

Recently spoke with previous owner who explained that he had the original fd upgraded, something to do with the failing bronze bearing on early models.

Thought I would share this experience for what its worth.

Only issue with her now is an annoying small oil leak coming from behind the black plastic alternator belt cover, lowest fixing bolt.
Any ideas? Big/Small job?

Cheers
Steve

 

[KMD]

Are you able to elaborate on the failing bronze bearing issue you mentioned? I have a same year GS with only 10k miles and I don't know of this problem. If it's common then I may take some preventative measures.

 

[Bendy toy]

I always use 200 to 220ml of oil in the FD and have only had oil seal problems when the wheel bearing failed as they are prone to do on these bikes. The bike had done 50K miles.

The rear wheel side play had been more than ideal (but ok for MOTs) for a few thousand miles before it eventually started to leak. I sent the FD to MikeyBoy for rebuild. He said all bearings were at end of life.

The small leak from behind the alternator cover is likely to be the seal behind the alternator drive shaft.. Remove the plastic cover and remove the alternator belt. With the bike on its wheels and a helper holding it on brakes in gear you should be able to get a socket onto the drive pulley retaining nut and remove the nut and pulley. Use the self tapping screw method to remove the old seal.

BMW sell a special tool for fitting the new seal. I used PVC tape wound from the engine end of the shaft to cover any edges that could damage or flip the seal lip.

 

[fair1535]

I didnt go into detail regarding the upgrade other than to confirm that he had it done. He mentioned it was something to do with the bronze bearing failing on the early models. Im sure someone with greater knowledge than I will be able to expand on the topic for you.

Cheers
Steve

 

[fair1535]

Thanks for the pointer regarding the leak Bendy, will ake a look at that.

Steve

 

[Bendy toy]

On second thoughts, the alternator pulley oil seal doesn't need the tape wrapping faff-about. Just grease the seal and be careful the lip doesn't flip over as you fit it over the step on the shaft.

 

[Illya Kuryakin]

Its the output seal £11.90. to you sir or 3 week wait to a shit like me!

 

[fair1535]

Quick update re leak.

Whipped timing cover off and discovred it was the sealing ring to alternator balancing shaft, £7 from Rainbow for the seal, also removed and discarded the foam insert before reassembling, 1/2 hour job leak cured, happy teddy.

 

[Hoff]

A recent post from Mikeyboy suggested that 180mL was not enough on the newer FD. His thought was 200mL (if I remember correctly).
As he is the master of these FD`s I now put 200mL into the FD, by the way I had mine rebuilt by Mike this year and what a fantastic job and service he gave.
As usual it is your decision what you!!
Cheers
Paul

Sorry just seen the post was about the earlier FD but my thoughts on the newer one anyway.

 

[Bendy toy]

BMW had problems on a few FDs with leaks. The standard warranty fix was to replace the whole FD - not low cost. rather than sort out the real cause, BMW mandated that the FD is fine with less oil. Certainly its fine for the warranty period but I believe the relatively short wear life of FDs is down to marginal lubrication.

I always use 200ml on oil changes and have never had it overflow or blow the seals.

If in doubt, ask Mike who's rebuilt more worn FDs than Ive had hot dinners.