1961 hydraulic clutch problems

[gmcbigbl]

Just got my new (to me) 1961 Apache. Its pretty much rust free except for lower fenders and hood which is the later one for 1962 to 1966 trucks.
It has a hydraulic clutch problem, that I can't quite figure out yet. Initially checked dual master cylinder and was MT. Added brake fluid
and did bleed the actuator (slave cylinder), and checked all around for any leaks and didn't find any.
If I try to put the tranny into gear while running, it just grinds away and won't go into gear. If I pump the clutch pedal several times (I guess to build
up pressure) it will go into gear and shift. After a minute or less clutch won't shift anymore and depressing it does nothing-truck keeps
going and stopping with the foot brake kills engine, because tranny is stuck in first and can't remove it. Pumping clutch pedal does help
for a shift or two. but loses pressure fast??? Clutch grabs flywheel very low on pedal(about 2" from floor) and seems to fade away quickly.
Sounds like a leak somewhere, but I can't find any and brake reservoir remains full?
Any suggestions would be a great help.

[jonzcustomshop]

if it sat for any great length of time the master cylinder is probably bad...
my 60 series 66 has the hydraulic setup, and after I put on a new m/c ($$$) it worked great again...
when I got it the farmer had let it sit for about 5 years...

[markeb01]

Beautiful truck! If you're not losing fluid, its probably just leaking internally. I would rebuild or replace both the slave and master cylinders since both may be old and tired.

[Wrenchbender Ret]

Put kits in the master cyl. & slave cyl. They are easy to do & not expensive. You can buy a hone at the Chinese tool store. Then bleed them. Bleeding is easy on these as the master cyl sits way up above the slave cyl. It will work good after that. The cups get a lot more wear in this system then brake systems as they make a full stroke each time compared to brakes that just apply pressure.

[gmcbigbl]

Finally found the leak - very small off the master cylinder under dash. It was dripping very close to firewall on inside and going behind the rubber floor mat.
I got a new master cylinder when bought the truck so just have to figure out on how to install. Looks easy enough, butttttttttt I guess I'll find out.

[speed_freak5150]

They are easy to install. I did it when I had my '61. Wish I still old that old POS. The only reason I got rid of it was because I could not find a heater core for it and the original was to rotted out to have repaired.

[markeb01]

Glad you found the problem. Looking back over the pictures, that is a very clean looking truck. Also noticed what appears to be a pretty cool Martin & Schwartz model 80 gas pump too!

[pinefieldfarm]

What wheel size/tire size do you have there?