Re: 86 4kq diff locks

["Avram Dorfman" <dorfman@est.org>]

I have some experience with this. My 87 4kcsq center diff has the same
problem. Apparently there's a vacuum servo somewhere that actuates the diff
lock, and mine has gone bad. I haven't looked at the servo myself yet, but
the mechanic said that the diaphragm had a hole in it.

the diff lock itself is just a little rod going through the diff case that
you can push in by hand to lock it (if you're under the car of course). It
stays locked until you pull it out though (no auto-unlock based on speed,
etc), so it doesn't really help you much unless you live in a permanent
snow-on-the-road location.

My mechanic wanted something like $250 to fix it, $125 for the servo, and
$125 for labor. I don't believe that it should cost that much, I was
planning on looking it up in a Bentley manual, checking a dealer for a price
on the part, and doing it myself.

Please let me know if this helps, and what you find. I don't have a Bentley
for my car yet - I'm particularly interested to know what it says about
these vacuum servos - where they are and what it takes to replace them.

-Avram