Jonathan Dyer

iTrader: (5)

I'm hoping to get some advice from personal experience. I've got 2 available clutch master cylinders: a 3/4" from Ram and the 1" from Mcleod. Everyone seems to love the Mcleod but posters in those threads are typically using a slave and clutch fork. My concern is that the larger-than-stock bore of the Mcleod will over stroke the release bearing.

I'd be grateful for comments from anyone else has this type of setup.

Thanks,
Jon

JSD MOD 24/03/09

Sonix

iTrader: (1)

Been there, done that!


I have a 3/4" in my car. I'm using the howe hydraulic TO bearing.
My howe bearing recommends a 3/4" MC, with something like 1" of throw. Do the math and that's how much fluid it requires. (no more than 1.25" stroke or it can damage the TO bearing, and less than .75" and you may not get it out of gear..)
I couldn't get enough stroke with my pedal linkage assembly, so I did the math, and bought a 1" instead.
I tried that, and the linkage still couldn't work out right, so I went back to the 3/4" and dinked around with the linkage until it worked. (I made a bell crank linkage).

The TO bearing doesn't really care what MC you're using, just needs the right amount of fluid. If you use a short stroke linkage, and a large MC, it'll be a stiff pedal with a small amount of play basically. A long stroke and small bore will be a long pedal engagement time. Man ways to skin a cat. Just take the recommendations from the TO bearing manufacturer and give it the right amount of fluid.

Jonathan Dyer

iTrader: (5)

Thanks for the reply. By short and long stroke linkages you mean the rod that attaches the cylinder to the pedal? To my mind the adjustability built into that rod would only affect pedal height and not the amount of stroke. So is there some way to modify what's inside?? Sorry if I'm being dense here.

Also, I've seen a reference to a bell crank linkage in another post (perhaps one of yours?) but I'm not sure what you mean. Could you elaborate please.

Thanks,
Jon

Sonix

iTrader: (1)

Right, with the stock setup you have roughly 1" of stroke.
If you were to bolt your master cylinder to the firewall, and connect the rod that goes from the pedal, directly to the master cylinder that's what you'd have.
However I had no room to put the master cylinder in that location. I bolted mine about 14" out from the firewall. So I needed to extend it.

What I did was use a bell crank linkage.

I took two pieces of angle iron, and used them to sandwhich a piece of 3/16" plate. the angle iron pieces are bolted to the frame rails, and are about 3/16" apart. The plate is bolted between the angle iron, using a nylock nut. Ie. it's not tight, so the plate can swivel. I drilled holes in the plate. The plate is about 6" tall.

The master cylinder has an extension rod going to this bell crank plate. The master cylinder extension is bolted to the plate about 3" up from the pivot bolt.

So if I put the pedal rod into a hole 2" up, then 1" of travel on the pedal, will increase to 3/2, or about 50% more, to the master cylinder (or about 1.5")

So in reality it's about 2.5 and 3.1" up respectively... Something along those lines.

I might have pictures of this somewhere, but I can draw an ms paint picture if needed...

Jonathan Dyer

iTrader: (5)

Wow, sounds like you could be in one of those "moment in history" adds about Canadian ingenuity! Seriously though, thanks for taking the time to reply. I've read it over a couple of times and I think I've got a pretty clear picture in my mind now.
Thanks again,
Jon