Rear drive unit meltdown!

[milleplod]

As I'm off through France to Spain at the end of the month, I thought it prudent to get the rear drive unit checked out - my 1200ST has done 30k miles now, and forums are awash with tales of issues as the miles rack up, some units failing at much lower mileages too. Anyway, I booked myself in at Overland and Classic near Melton Mowbray, and went today to see Mike, a bit of a guru with rear drives.

Its a good job I went! After a brew, Mike dropped the drive unit down and started his examination - there was very obvious play in the pinion bearing, plus other associated issues - suffice to say, I might not have got to Spain and could very well have found myself broken down and at the tender mercies of the French!

Mike had the parts in stock, and set-to the job straight away - I called my Mrs for a lift home! I think the bike will be ready for collection tomorrow - pretty good service all round, I thought. Oh, the bill came to £540 all-in - bit of a stinger, but better than the cost of a new one!

Pete

[kfrogzx7]

Where exactly did the bearing play show up Pete ?
I've got mine stripped down now for the mother of all services, everything seems to feel very tight smooth and the oil was perfectly clean.
Mines done 43k now btw.

[milleplod]

Evening Simon.

The play is in the bearing that the arrowed shaft in the pic goes through -

rear_drive_25.jpg (185.55 KiB) Viewed 13198 times

I could easily see the side-to-side movement, not much, but of course there shouldn't be any at all! When I picked the bike up today, Mike showed me the bearing - the case-hardening on it had almost been worn through, you could see the metal particles as silvery-grey swirls in the drive's oil...I only changed it a few hundred miles back!

Pete

[Justcruising]

Thanks for sharing! What oil specifically, had you run in it to-date & what was the service regime/history to-date.

[milleplod]

The ST had around 6k miles on it when I bought it just over 6 years ago, it now has 30k ish showing. Each year, I've drained the oil and refilled with 180/190ml of 75w90 fully synthetic gear oil, so I'd like to think its been fairly well looked after.

Pete

[popsky]

Did you get any feeling of “roughness” from the final drive, only ask as when I test rode a 12s (many years ago) from CW, it had 9.5k on it and there was a definite feeling which I can only describe as being like a bad tight spot on a chain driven bike, I took out a much newer GS that day to see if this normal but all was good so didn’t do a deal on that 12.

[milleplod]

No, no roughness felt in there at all - even Mike, on his initial examination before he dropped the unit, said it felt fine.....so, my hopes were raised, and then cruelly dashed, all in the space of 5 minutes!

Pete

[kfrogzx7]

Thanks for that info Pete, I'm in the workshop all day today hoping to finish my servicing, I'll give the bevel an extra careful examination.

[Neil178]

Is this a ST issue or all boxers? I’m not aware of this ....... worried now!

[Al]

All boxers, do a search, had my 1100s repaired at around 35k, my GS is about that at the moment. The guy who is fixing Petes is one of the best, lots of recommendations on all the BMW owners sites.

Al.

[milleplod]

I hate to say it, but its all of them - I think Humbug/Steve on here had a problem on his S, although that might have been the driveshaft, not the rear drive itself. Over on UKGSer, there's more than a few owners had the same problem as mine. Mike ('mikeyboy' on UKGSer) at Overland and Classic, has done loads of them, 30k-ish miles seems to be the point at which problems arise, but it can be earlier. Mike recommends dropping the drive every year to have a look at the bearing in the pic, and to check the u/j at each end of the shaft too.

Pete

[Justcruising]

Can’t comment about early models, ie. airheads. But as a generalisation, mainly Oilhead/hexhead’s. Although quite robust, the FD is a fairly stressed component that needs to be closely monitored for early signs of higher service needs.
Maintaining scheduled oil changes, correct oil spec, monitoring for any bearing play or oil leaks and material in the oil at change time is a necessary minimum.

[Humbug]

It is an issue on them all. My 12S had to have the rear drive rebuilt by Mike at about 70,000 miles for the same reason as Pete's, play in the bearings. I seem to have been a little unlucky as I've had both the shaft destroy itself and the rear drive rebuild. Shaft for a 12S is £545 just for the part, like hens teeth as an exchange and not the same as any other of the BM's apparently!

[nab 301]

Is this a ST issue or all boxers? I’m not aware of this ....... worried now!

My 11S got noisy after 90 k miles a few years ago and it appears to be the same bearing as milleplod , but luckily I had acquired a spare unit and just replaced it . I haven't got around to repairing it yet...

[Neil178]

“La La La, I’m not listening ...”
The 1200S as well? Everyday is a school day .
I didn’t realise that this can be an issue. My bikes are still lowish miles so I’m not going to lose sleep over it just yet. I am thinking about doing a looong trip next year, until I run out of money, the bike gets knackered or I find Nirvana. So I will certainly get it checked out before I set off.
I remember something in the USA about guys fitting some fancy bronze set up and swearing now great they were. Except they fell apart before long!