Final drive refurb.....

Discussion in 'Technical Discussion' started by austin, Apr 28, 2017.

  1. austin

    austin Well-Known Member Forum Supporter

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    The reputation precedes, other owners say fix before it's fecked, the slight weep of oil, and the ocassional roughness, and that little nag on your mind that says it can't last forever. Yup, I have bitten the bullet and going to get the FD reburbed at Mikeyboy's Overland and Classic place. Cost will be £450 ish - more if the shaft itself needs attention. Compared to the cost of 3-4 chain and sprocket sets over the same mileage there's not much in it I guess but it's a lot in one go. Got to be done though.

    When drained the FD oil usually comes out polluted with water - either condensation or it sucks it through a seal as it cools. Anyway, bound to have caused corrosion in there. The main seal has had a slight weep for ages but that had grown into a drip every thousand or so now. And every now and then I get a rumbly graunchy feel even though the Tarmac is good and smooth. Hopefully all good afterwards for 100,000 or more. :).

    Just thought I would mention it.
     
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  2. Hamster

    Hamster Active Member

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    Good news ( apart from the cost haha ), and what price do you
    Put on peace of mind.
     
  3. austin

    austin Well-Known Member Forum Supporter

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    I have also decided to get the swing arm bushes and bearings replaced while he is in there. A couple of bolts are loctited on at 140Nm. That's effing tight, esp for just a Torx 50 socket and I know I will feck it up if I try to either loosen them or retighten them that tight. Should be just an or so of labour on top plus the parts.
     
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  4. austin

    austin Well-Known Member Forum Supporter

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    I eventually got the bike down there today and Mikeyboy has already stripped it down - all off back to the gearbox. He reports that the pinion seal was shot and all bearings inside the drive are worn and need replacing. The failed seal probably explains why the oil was always affected by water ingress and the water ingress probably explains the worn bearings. One of the UJs on the propshaft is stiff, so probably on the way out and bearings in the para lever also worn. Finally a boot on the front suspension is split so no doubt some corrosion in there too. Swing arm bearings to be replaced while he is in there. I think the bill will be big :(
     
  5. Raymo

    Raymo Member Forum Supporter

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    But that's it sorted for some serious mile munching, and better than spilling its innards in some strange and distant land :)
     
  6. austin

    austin Well-Known Member Forum Supporter

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    and that Raymo is exactly why I have had it done. There have been enough warning signs and it felt like it was only a matter of time. Mind BMW were supposed to have sorted issues with the FD and para lever in the later models like mine. But water ingress is a sign all is not well.
     
  7. Lowflyer

    Lowflyer Well-Known Member Forum Supporter

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    Gulp !!!

    Dare I ask, how many miles before you noticed something wasn't quite right ?

    I check mine periodically ( and the final drive as well :D) and so far so good.
    Might be planning another biggish trip this year, should I be worried ?

    Yours sincerely

    M Proops
     
  8. austin

    austin Well-Known Member Forum Supporter

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    You can do basic checks to look for slack in bearings and bushes just as you would for wheel bearings or swing arm bearings. Also put it in gear and see how much lash there is in the system by moving the back wheel against the drive.

    I had some lash - about 1/8th of a turn of the wheel which seemed a lot (and at times I was sure I could feel it when going from throttle on to off) and a bit of play like a wheel bearing was knacked. The main problem though was that every time I changed the FD oil it came out milky coffee coloured right from the first time i changed the oil at 24,000. Water was getting in so something was not right. I changed the breather on the top as it was split (yours may not have a breather John) and the boot between the shaft and FD as that also seemed to be damaged. Neither made any difference. I also had a slight weep of oil from the FD from the main seal. It had been like that for ages but was turning into a drip. The rear speedo sensor also kept playing up with an error message on the GS911 saying "implausible signal" again suggesting all not good inside the FD. Finally every now and then the whole back end had a rough feeling, like a bearing was running rough or dry. I mostly just figured it was all going to bang one day and it would be even more expensive if it happened away from these shores.

    I asked Mikeyboy to check all the other bearings in the FD, paralever, suspension and swing arm as a precaution rather than anything really untoward and as it was mostly stripped down anyway for the FD. I am hoping for good things when I pick it up on Friday. Apart from the FD refurb that needs some specialist equipment most of the rest is a DIY job, its just that a few of the bolts are tightened to 140Nm with thread lock and need a lot heat to get undone when new, let alone after 6 years and corrosion associated with 67,000 miles of ignoring them. I just knew I would strip a bolt of torx head and turn a difficult job into a nightmare. Even Mikeyboy says he often has trouble.

    There are a couple of other places that do FD refurbs but Mikeyboy is the main man for these things. Not the cheapest it seems though. His workshop though reflects a methodical approach. Everything mostly clean and tidy and ordered, tools put away, and many jobs and projects in progress with dismantled bits neatly stored.
     
  9. Philwhiskeydrinker

    Philwhiskeydrinker Well-Known Member

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    A big bill for sure Austin but for the trips that you do, it's far better than being stuck in the arse end of nowhere and an even biggerer bill, not to mention a potentially spoilt trip.
     
  10. austin

    austin Well-Known Member Forum Supporter

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    That's me back with the bike today. Feck, travelling on a wet Friday afternoon is an ordeal. 6 hours to do 150 miles on major A roads and the M6 is shite.

    Anyway Mikeyboy showed me the box of bits that came out the FD and swing arm : mostly quite rusty with worn faces and rough bearings although none of it on the cusp of disaster. He did say it that corrosion and wear meant it was when it would have gone not if. The para lever and swing arm bearings were in a rather poor state - worn dry and rusty although there was no play. Same for the crown pin at the front, although I had had a knock from there for a while.

    It definitely feels better to ride, with a certain harshness/rough feeling in the drive gone and backlash on shutting the throttle gone. It was a fecking lot of money, mostly on exorbitant BMW parts and 6 hrs labour but glad it's been done. Peace of mind is priceless.
     
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  11. Alba

    Alba Active Member

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    Must be worth it if you drove 6hrs to get to Mikeyboy's. You've got me thinking...
     
  12. Philwhiskeydrinker

    Philwhiskeydrinker Well-Known Member

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    So, how much is a fecking lot of money then?
    It'll be sorted until past 100k now surely?
     
  13. DaveS

    DaveS Administrator Staff Member Forum Supporter

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    Just chopped my 20 month old GSA in for a new one.. Just had the 12k service and the dealer reported slight play in the FD! So decided to buy a new one. :D
     
  14. Flyfifer

    Flyfifer New Member

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    So is "slight play" not a warranty claim at only 12k miles ?
     
  15. DaveS

    DaveS Administrator Staff Member Forum Supporter

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    Yeh probably but a new bike sorts that. It's their problem now!
     
  16. austin

    austin Well-Known Member Forum Supporter

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    Final Drive refurb parts £387 + 4 hours labour.
    Prop shaft refurb 1.5 hours plus £80 parts
    Remove FD and Strip the bike back to the gearbox and refurb everything = 4 hours labour and ??? parts (cant identify the parts separately on the invoice must be part of the £387)
    Front tele-lever ball joint replaced: 1hour plus parts £82.
    Oils etc £20.
    VAT 20%
    (hourly rate is £45 / hour)

    Total just over £1200. Gulp:eek:. When I had phoned Mikeyboy to book it in he had said expect £1000 or more depending on what needed doing. In the end everything I thought needed looking at needed doing so right at the top end of the estimate, plus the VAT. I should be able to at least double the mileage on the bike now before any of this needs attention again which would take it to around 150,000miles. The rear subframe is in need of a good coat of paint, as are some of the engine casings otherwise all seems good.

    (the £450 I stated in my first post is how much it costs to refurb the earlier FDs - the ones that go all the time. Later models, i.e. mine, have improved and bigger bearings and slightly different internals. Parts and labour is more as more complex).
     
  17. Lowflyer

    Lowflyer Well-Known Member Forum Supporter

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    Holy shoot Austin,

    Guess the bikes a keeper now then, eh :D

    Thanks for all the info





    I think :eek::p
     
  18. nick949

    nick949 Active Member Forum Supporter

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    Sorry to hear about the expensive woes. On the bright side, you're all set for new adventures now. Go. Make me jealous again. :ride:

    Nick
     

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