What Lies Behind....

...when you finally managed to extract the Gearbox Output Shaft Inner Seal...before inserting into this cavity a new non-Magura copy Clutch Slave Cylinder :-





Scratches ? Wot scratches ??

And if one is supposed to drill a drain hole as near tot he seal ( when it's inserted ) as possible, how does one source a 20cm long 2.5mm drill bit because the swing arm and lower lip of the gearbox casting are in the way of your portable drill's chuck ?

You drill the hole in the slave, not the gearbox... But instead of the hole you can just cut a little channel into the gasket, at the bottom of course.

Well done for getting it out. Can you see if any of the fluid made its way all along the push rod to the clutch?


Sent from my SM-N910F using Tapatalk

Wow, that looks very nice! Did you polish the insides? Mine was alot more corroded.

I'm not sure if the slave poiston really moves so far into that polished bore? When you look at the slave body, it's not as long as the bore is deep...

So if you think those scratches will affect the sealing of the gearbox oil, is it possible you could fit 2 seals butted up to each other? I think one of the gurus would have to answer that.

It will totally flummox the person who changes it next if ever it needed doing. But it might solve a problem for you!

I would definitely go to the trouble of putting a slot into the gasket because it would give you a heads up quite quickly if the seal wasn't quite making it.


Sent from my SM-N910F using Tapatalk

In fact I managed to source a 160mm long drill bit in 2mm size, so I reckon I might be able to drill the recommended weep hole upwards into the cavity close to the new viton seal, operating the portable drill from below the lip at the bottom of the gearbox casting.

Most gurus seem to advocate that hole in the gearbox casting in that 'forward' position, as a solution to any weep that might enter into the cavity from a compromised slave cylinder bearing, and migrate along the pushrod onto the friction plate - ugh....

Thankfully mine seemed not to have done so, judging by the depth of the tiny puddle of foul-smelling gunk in the bottom of the cavity, and the fact that the pushrod was dry, or just slightly moist with what I hope was a smear of the original assembly grease. Also, the little felt anti-rattle sleeve in its detent slot along the rod ( not a grease barrier as is erroneously assumed ) was perfectly dry.

And mentioning pushrods.

At the start of this nightmare experience of replacing the cavity seal more than 2 weeks ago,when I first removed what turned out to be the damaged slave cylinder, I pulled out the pushrod which was in this seemingly fully-home position :-



Now after replacing the seal ( don't get me started ) I can only insert the pushrod to this extent :-



When the rod is lightly tapped, it seems invisibly of course to be locating into the hole in the end of the crankshaft and I can't imagine that the clutch pack has come out of original alignment just by withdrawing the rod a fortnight ago.

When tapped a bit harder, the rod seems to slightly bounce agasinst the tapper, as if its shoulder is against the diaphragm spring plate, but I worry. Even though it also rotates when the plugs are removed and the rear drive is slowly turned in 6th gear.

Mechanic son advises that there's no way on earth that anyone, including Charles Atlas, could push in the rod by hand, so as to compress the diaphragm spring plate in there just like the hydraulic actuation does, so hopefully the pushrod is correctly fitted.

Fingers firmly knotted...

AL in still-sweltering Andalucía.

Al, Nothing can come out of alignment. All parts of the clutch pack are bolted in place and the clutch disk is held by the transmission. You can check this by removing the starter and looking in from there. The rod doesn’t connect to the end of the crankshaft, rather it contacts the clutch pack.

I just did this job two weeks ago. To me the photos are shot from a different angle and it looks like the shaft is out the same distance. There will be a medium effort spring force to overcome when you reinstall the clutch slave but you should be able to push the slave all the way home by hand, and insert the bolts while you hold it. If you can things are fine. If you can’t push the Slavs home by hand then you’ll need to re-evaluate.

The photo below from dirtrider shows the diaphragm spring that the push rod seats into.

Thanks ever so much for the reassurance, Roger.
Yes, I was unduly concerned, following the nightmare of doing the awful job of old-seal extraction. The new viton seal went in a dream using the long spark-plug socket with a smear of Staburags NBU30-PTM special grease on the leading edge of the lip in the cavity where the seal sits.
I also used a blob of it on the engine-end of the pushrod and on the pushrod's shouldered part where it rubs against the diaphragm-spring plate's centre hole when the clutch lever is pulled.

Extract from Chris Harris's masterful clutch tutorial video showing just this relevant bit :-


AL in Andalucía