Hydraulic Clutch master/slave cylinder size question

I'm getting a '62 Suburban with a hydraulic master cylinder/slave. One of the two of them leaks a little bit--dude says sometimes you have to top the master off, and sometimes it needs to be double-clutched. This probably accounts for the worn synchros he told me the trans has--clutch isn't fully disengaging before shifts are made.

Before driving it 900 miles home on the back roads, I thought I'd swap out the slave. Parts store (a good one) says they show two in the book: 1-inch bore, and 1 1/16-inch bore. I don't know which one the truck has, so here's my thinking:
Go with the smaller bore slave cylinder, because if the master is the small bore, I'm good to go. If the master is the BIG bore, then I'm thinking the small bore slave will work, because a big bore master is going to push more fluid and therefore the slave will work fine. I'm thinking small master/large slave wouldn't work out as well because the small master isn't going to move the same volume as the slave.

I know the bores should be matched, but I can't do that from 900 miles away.
I haven't ever messed with a hydraulic clutch, so any thoughts would be appreciated.

-Brad

 

get both , return the one you don't use

 

Brilliant!

 

I would just pull the old one off and mesaure the bore that way you get the right one. Or even just crawl under and pull back the boot you should be able to get the mesaurement you need.

 

Yeah, except the truck is 900 miles away. I'm sending it ahead, along with some tools, radiator hoses, etc.

I thought about buying both and returning one. The smaller one is $50, the bigger bore is $75. $125 is a little more out-of-pocket than I'd like right now, as I've got other things I need to buy to make sure the trip is uneventful. Like a radiator. And rear tires. And full fluid change. Air cleaner. Seat belts. Plane tickets, food and hotel for one night.

I've got a new 4spd OD trans to put behind it once I get it home (Translated: sometime in the next 4-6 months), so it doesn't have to be perfect, just get by reliably.

So knowing that, will the smaller bore slave do the job? Which is the better short-term band-aid?
-Brad

 

My thoughts are to get the bigger one (given your situation) - the bigger bore will displace MORE fluid volume per push and just might be the hot ticket if everything else is marginal. If your "old" cylinder is actually GOOD and was BIGGER then you now made the situation worse by putting in a cylinder that displaces LESS.

That's my take for what it's worth.