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I was bleeding the hydraulics and found that the lever for the rear diff lock will not move. I opened the bleeder valve, thinking the lever should then move, but it did not. The fluid that came out was fairly clean, and I hooked up a vacuum bleeder which pulled out all of the old fluid until it ran with clear fluid (no bubbles). I have engaged the rear diff lock in the past without any problems. The front diff lock and 4x4 engagement bled normally. Any idea what idea what may be going on and how to fix this?

Thanks,

John Cotner
Falmouth, VA
(703) 632-5802
1971 710M

Do not pull hard on the leaver it can break off. I have had mine stick, when it did the piston in the driving cylinder had stuck in the cylinder. A small amount of lever jiggling freed it up, I got lucky. You may need to disassemble the dash cover to gain an angle to the cylinder and use a wood or brass rod to attempt to free the piston with light tapping. When mine stuck Jim L. also mentioned that sometimes the actuating rod that attaches to the leaver can sometimes fall out of position if the piston doesn’t return as quickly as it should.

As Edzz says, do not force it...it will break and a new one is about $50...you really want to know how I know?

Sometimes just letting it sit for awhile will allow the pressure to ease up and it will move.
By the time I got the new lever it had eased off and the new one made everything OK.

It is really not that difficult disassemble the arrangement but it is sort of tight in there to get it all back into position.
While you are there check the rubber connections for cracks, might as well get it all back to prime condition.

Happy trails

You may want to check the plunger rod that goes into the rubber boot. Sometimes if it is adjusted a little short and can come out of its socket and lodge against the edge of the cylinder, thus jamming the lever from moving. If you can see it to check it out and get your fingers in there wiggle the lever and see if you can move the plunger rod back to center. If you can just readjust the lever stroke.

Miles

I wiggled, wobbled, tapped, and pleaded with the actuating rod, but it is still stuck fast. I also tried to prop the rod up and actuate the lever, but that didn't work either. I took off the dash panel, and will try pulling the boot and taking a closer look at the rod tonight. Do you think light tapping of the body of the master cylinder will make a difference, or should I focus on the rod?

The rebuild kits for these actuators are pretty cheap. I would remove the front plate for the lever assembly, check for mechanical bind, and if clear, remove the bolt from the rear of that actuator. Try moving the lever. if its still locked up, remove all of the rear nuts from each actuator and remove the assembly. Plan on rebuilding or at least investigating further. They are a very simple mechanism and a novice "engineer" should be able to get them back in no time.

If the actuator moves freely after releasing the rear bolt, you have something stuck in the line.

The lever seems to move freely on the pivot, and will push upward (pulling the piston out). And fluid flows from the bleeder at the differential. I'll try unbolting the actuator. Any reason I can't drive it while waiting for the rebuild kit? The rear end isn't locked.

No reason not to drive it.