Clutch Bleed Blues- '67 40 (1 Viewer)

[bb67tlc]

I'm fighting what seems like a simple war- bleed the new clutch master and slave- and losing. I bled the master first- looping back into reservoir- then tried different techniques to finish- traditional pumping and cracking nipple, gravity- until bubbles stopped. Then when I push the pedal, the slave rod extends and then, while still holding the pedal, it retracts. I can also very slowly apply the pedal and the rod won't extend. There are no leaks, so seems clear there's air trapped somewhere. Gone through a fair amount of fluid.

The units are 'new' but they were sitting in their boxes with the truck for perhaps 8-10 years. I pulled the 'plunger' out of the slave and the rubber looks and feels good. Before we tore everything down, I had installed the master and drove for a while with no problems, so I feel that piece is good. Is it my technique or perhaps the slave?

Other than that (and a ground fault in the heater circuit), we're getting there!

 

[ZackR]

Never tried this on a 40 series but I've had good luck bleeding the clutch from the "bottom up" before on other vehicles. Attach a clear hose to a syringe, fill with fluid, push until all air is gone, connect to bleeder on slave cylinder, then open the bleeder and push new fluid through. Just make sure you have enough space in the reservoir for the fluid to come through. Oh and close the bleeder when done before removing.

This method forces all of the bubbles upward and out of the system.

 

[bb67tlc]

Thanks Zack- that's one method I hadn't tried.

 

[oregon fj]

You can try the reverse bleeding bit, but the part about the rod extending and then retracting without pedal movement sounds like the master cylinder is bypassing - pressure leaking past the piston rubber back into the reservoir. I don't think there's air in it.

 

[bb67tlc]

Yeah, that seemed really weird. Just odd that the MC was new and I had installed it before the teardown- worked fine then. Gremlins. Probably same ones that are in my left turn signal.

 

[bikersmurf]

You can try the reverse bleeding bit, but the part about the rod extending and then retracting without pedal movement sounds like the master cylinder is bypassing - pressure leaking past the piston rubber back into the reservoir. I don't think there's air in it.

X2

I was going to hit like... but although I believe you’re right, there is nothing to like about a failure in a new part.