Clutch Hyrualics....................

[bobsy]

Hello folks,
I have a 1964 series IIA, 88. It sat in my barn for the last 10 years. I know...... Shameful.
After all the snow we had this winter in Virginia I thought it might be a good idea to have an operational four-wheel-drive.
In the course of replacing the hydraulics, wheel cylinders brake, clutch, master and slave, I have run into a little problem.
The truck was fully operational when I parked it, everything worked. Now when I try to bleed the clutch
system I can't get the air out. I cracked the line at the master cylinder and then bled the slave cylinder
in typical fashion. It pumps up with a good pedal, open the bleeder and release some air.
All pretty normal except after about 15 seconds to pedal is an inch from the floor.
I don't have a flex line between the master and slave so it is hard to tell which is at fault.
I just got a new flex to install later. The only other unusual thing I noticed is that the rod
going into the slave has been modified, I think probably lengthened. So after all this my question is:
Would that affect the slave cylinder? Is it necessary to bench bleed the master, tipping it
to get the air bubbles to the top?

Sorry for the long post any input is much appreciated.

Bob

[SafeAirOne]

Well, the catch-all answer is that obviously, there is some leakage taking place somewhere in this very basic system. Depending on where you shop, you can replace your entire clutch hydraulic system for under a hundred bucks. Rebuild kits are always hit-or-miss, depending on the condition of the cylinders that have been sitting there, corroding away for the last decade.


Replace the entire system and problem solved for at least another 20 years!

[bobsy]

Hey Mark,

Thanks for the reply.....maybe I was unclear. Everything hydraulic is new, not rebuilt... that's why I'm stymied.

[I Leak Oil]

First off, get the flex line installed. The movement between the engine/transmission (which is what the slave is attached to) and the bulkhead (which is what the master is attached to) may cause the hard line to leak. You didn't say if you've started it since the clutch rebuild but if so this could be the source of the leak. Once the flex line is installed you can clamp it off to see if you're still getting the same symptoms. If so you can narrow it down to the master, if not, take a look at the slave.

What do you mean by after 15 seconds it's an inch from the floor? The pedal drops by itself or there is no pressure until it's one inch from the floor?

If it's an air issue there's really only 3 major sources of leakage. The master, the slave and the connections to them. As Mark said, this is a really simple system and having that flex hose will give you a good way of narrowing down where to look.

[SafeAirOne]

Hey Mark,

Thanks for the reply.....maybe I was unclear. Everything hydraulic is new, not rebuilt... that's why I'm stymied.


Doh! You DID say that. Well, I can only speak about the SIII clutch system. I initially thought to pinch off the rubber section to see if you get a hard, steady pedal, like Jason said, but alas there is none.

My SIII clutch system which, hydraulically speaking, is the same as yours, required no bench bleeding of the MC. In fact, by opening the bleeder port on the slave and keeping the reservoir topped off for a few minutes, the system is essentially self-bleeding.

Note that I've had a brand new, dubious-quality clutch slave go bad in a few weeks, just because it was a cheap, knock-off part.(I no longer do business with that parts supplier and have had no troubles since).

[bobsy]

Thanks gentlemen....I'll fix up the flex tomorrow and let you know the results. Probably a bad master or slave given the simplicity of the system.

Cheers,
Bob