Rebuilding clutch slave... again

[Skivvy]

Going through the 89 so I can drive it home and get it inspected.

Took the clutch master cyl and slave off the bike and brought them home. Just found the steel clutch slave piston is completely rusted inside where the seal goes. Supposedly this was just rebuilt by the previous owner at a bike shop. If they didn't remove the rust it was a pretty lame rebuild. Wondering if all the sanding is going to leave the bare metal finish to rust again?

Perhaps a new one from Yamaha (while they are still available) is the way to go. Took 20 some years to get this bad, maybe a new one will last another twenty. 

Stripped the screw head on the master cylinder cover. Couldn't find the impact driver and tried to finesse it. Grrr.

Probably should helicoil the threads on both master cylinders and replace with stainless screws anyway. Just one more thing to r&r before I can ride it...

[ribbert]

Old brake fluid gets water in it. Once you have changed the fluid it should be fine.

[RichBaker]

Randy has them.......  http://www.rpmracingca.com/proddetail.asp?prod=Clutch%3Aslavecyl&cat=26   Probably less $$ than Yamaha.

[Skivvy]

So the screw threads were not frozen, just the head. Hmmm never anticipated that.

Once the head was removed with a countersink the screw came right out. Didn't want to try and drill out a steel screw stuck in aluminum anyway.

So now I'm wondering how to get the very last bit of air out of the clutch line? Right now the trans shifts so bad I dearly hope its not damaged from the abuse/neglect of previous owners. Please let it be air in the line...

[grannyknot]

Skivvy, a trick I learned from this forum to get the last little air bubbles out of the line is.
get a large syringe from a farm supply store, connect it to the bleed screw on the clutch slave unit with plastic hose, fill the syringe with fresh Dot 4 and back bleed the system. Air bubbles naturally want to rise anyway.
While your squeezing the syringe slowly pull in the clutch lever a few times to dislodge  any bubbles that are hiding in the M/C. I don't bleed any other way now.

[ELIMINATOR]

What worked for me when I couldn't get all the air out. I pumped the piston a fair way out, while it was off the bike. Then with my thumbs, pushed it all the way back in. I nearly jumped when I saw out of the corner of my eye, this small fountain appear at the master cylinder.