R1200GS Adv oil leak - seal and Siebenrock
Weekend 2 - Day 3
Another bright early start. Getting the gearbox off was proving to be very difficult. The top left and bottom right would not come away after the bolts were out. I tried all manner of maneuvers including trying heat with a hairdryer, but it would not shift. I did not want to get drastic in case of damaging the housing. I went to see my local BMW store to ask the service guy for advice.
Fortunately one of the mechanics was handy and his words were 'heat, and more heat'. Not entirely convinced, but with this as the only option left, I went and bought a heat gun, applied heat to the stuck areas, and some gentle pressure with a crowbar and off she popped. Crowbar applied against clutch housing and front of gearbox. A heat gun is a hairdryer on double dose steroids.
Once I get the gearbox off it is quickly apparent that the gearbox input shaft seal is the source of the oil with oil seeping around the seal.
Pulled the clutch plates off and sure enough the friction disc was melting onto the clutch plates. See the black smear marks round the pressure plates?, that's clutch meat. The clutch plates were very smooth, no scoring at all after I cleaned off the melted friction disc material. This was looking good that I would not get clutch chatter requiring another couple of weekends to redo the whole clutch.
The old melted friction disc, still with plenty of 'life' in it :(
Spent half the morning cleaning everything, the engine sump area, gearbox, engine output shaft and clutch area.
I was a bit nervous getting the gearbox input shaft seal out, did not want to do damage. Drilling the old seal caused a bit of concern, I seemed to be drilling metal, and I did not expect metal. After a few stops and starts I satisfied myself it was drilling the seal correctly and finally broke through with a sudden jolt.. oops!. Fortunately no damage done. Same for the second hole. Fu#k!! Need to get a brand new drill bit next time!. Insert screws into seal, grab with pliers and gently tap on the pliers, alternating screws, to slowly extract the seal.. WooHooo!!. Out she pops, and no scratches on the aluminium.
No protection required on the input shaft while sliding the seal on, the seal cleared it by a good couple of thou' all round.
I had pre-measured the old seal depth at between 5.1mm and 5.4mm. I made up a drift tool
to insert the new seal with a plastic plumbing joiner bit. Seal finally seated at 5.2mm measured.
If the drift tool looks a little lumpy, solution is to turn the tool and tap all round the seal so it all sits at the deepest point of the drift. This plastic was a bitch to cut straight.
Next to rebuild the clutch assembly with the Siebenrock disc.
This is were the gearbox studs came in handy. For centering the friction disc, I slid the gearbox onto the studs I made, input shaft into the friction disk to centre it, then tightened a couple of the bolts on the clutch housing cover to hold the friction disk in place, removed the gearbox, and tightened and torqued all the bolts to 12NM. Engine locking device not required. RepROM states clutch housing is balanced at manufacture.. I take RepROMs word.
Re-apply the gearbox and tighten bolts to 19NM. Attached starter motor, cables, connectors and starter motor cover
A good place to stop for the day, time to go cycling to loosen up my aching body again.
Start putting all the bits back on, come to put the two halves together while managing the dastardly drive shaft, but rear frame will not line up to the front frame. There is something stopping it connecting and I cannot figure it out. I now realise it was the drive shaft where I did not appreciate it had to pop over the circlip, also I am not sure it hadn't fallen off the the other end during removal.
Wife now wants to drag me out to a surprise (to me!) lunch with friends. I cannot escape this one. I miss the best part of the day for getting the bike back together.
After lunch and the bike is not going to go back together. With darkening sky and no desire to rush this important part of the job and do damage, I pull the bike apart again ready for another day. The drive shaft sticks solid on the gearbox output shaft. Bollocks. I have to pull the shaft halfway out before it finally lets go of the gearbox shaft. Well now I will have to strip the drive shaft end .. next weekend! WHERE DOES THE TIME GO!!??
Seek advice from ADVRider
on work required for sorting the drive shaft. Thanks people!