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- Austin, Texas
I have decided to put a hydraulic clutch on the Super RustBucket. I have literally spent hours and hours -- like an entire day -- researching this. I've read every single relevant thread on this and other forums, but maybe I'm missing some information gems hidden in member's build threads. I'm open to and am soliciting any help and suggestions.
The basis for my install is information by member osteoderm in his build thread:
and info provided by member ippytattoo in a few different threads, including this one:
in which he used to offer an Aprilia "kit," including modification of the left case cover.
However, these threads are over 8 years old, and all of the pics are missing from osteoderm's thread, plus he's been mia for over 7 years, so I think it's time for an update.
Here is ippytattoo's hydraulic clutch in mock-up stage. Basically, the mod is pretty simple: you bolt an Aprilia slave cylinder where the worm gear used to be, you make a longer push rod, and that's pretty much it.
Today I bought the knock-off Aprilia slave cylinder in the first picture above. So, it'll be a few days before it arrives and I can begin.
Here's another ippytattoo install in mock-up stage. Note the bleeder screw which is incorporated in the banjo bolt.
Here's another Aprilia install by short-time member Opus5150. When I first looked at this, I didn't see the bleeder screw. I though the hose went directly into the cylinder with a straight hose end, instead of the 90-degree banjo bolt fitting actually used.
Which brings me to my first question: is the bleeder screw even necessary???
In mrriggs' most excellent hydraulic clutch thread:
I despise brake fluid so this was designed as a "mineral oil" system. You will hear all kinds of opinions on what fluid is best; baby oil, ATF, fork oil, power steering fluid, or even [gasp] mineral oil brake fluid. I like fork oil because it's easy to get, has good lubricating properties and seal conditioners. I'm using the thinnest stuff I could find, RedLine "Like Water".
I agree, brake fluid sucks. Which brings me to my second question:
Why not use this stuff? Without a bleeder screw? Just fill the Aprilia slave cylinder up with fluid using a syringe, then start a gravity siphon using mineral oil in the hydraulic hose, and screw the hose into the slave as the mineral oil dribbles out. No air gets in, and the dribbled out mess is just mineral oil, so easy clean up.
I know I'm kinda getting ahead of myself, but when the time comes, is there any reason this would be a bad idea?
EDIT: Just wanted to add for the record that the Aprilia slave cylinder has a 30mm bore. Thought that might be useful for mathemagicians who are trying to figure out push rod travel, or to compare to other slave cylinder options.