Rebuilding locker masters

Diffs, axles, lockers, transmissions, portals, that kind of thing.
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MTPinz
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Rebuilding locker masters

Post by MTPinz »

Going in deep!

My 710 came with a broken rear locker selector and the piston seized in it's master cylinder so I decided to rebuild all three at the same time.
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The manual says that the piston and cylinders are a matched tolerance set so I'm keeping everything separate. I'll mic them out once everything is cleaned up just for personal reference.
It also mentioned not to hone the bores? How about just some light scuffing with some fine Scotch Brite or something?

Any BTDT tricks for getting the new seal on the piston? Just lube it and stretch it over?

Richie
MTPinz
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Re: Rebuilding locker masters

Post by MTPinz »

Well that was easier than I thought it was going to be. I rebuilt all three master cylinders for the lockers, fixed the lever assembly with the 'upgraded' bolt addition, and took care of the rusting mounting box. I went ahead and cleaned the reservoir and replaced the rubber T's coming off it for good measure too.
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With how rusty this rig is in places, I was very surprised that when I went to bleed it none of the bleeders on the slaves stripped. I couldn't believe my luck! I replaced them with bright shiny new ones anyways.
On to the next item on the list...the fuel system!
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VinceAtReal4x4s
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Re: Rebuilding locker masters

Post by VinceAtReal4x4s »

Nice. Which brake fluid did you use to refill?
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MTPinz
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Re: Rebuilding locker masters

Post by MTPinz »

Nothing special, just Prestone DOT3
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Tank
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Re: Rebuilding locker masters

Post by Tank »

MTPinz (or anyone who has done this) -

How did you disassemble the locker masters? I have them removed and the c-clips out, however the plunger/spring/valves are stuck in the recessed position. The piston rods only make contact at the very end of their throw.

Does the c-clip retain an inner sleeve in? There appears to be an inner sleeve, but it won’t budge with light motivation.

Do I need to press them from the output / special bottom valve?

I took the locker master tray out to do some rust busting. When I had it back together, I went to bleed them and none of them would bleed with pressure and/or vacuum. All three are seized up and I’m scratching my head. They have some corrosion in places, but they all worked prior to me taking them out.

I don’t want to screw them up any more than I may have already. Any tips or ideas would be greatly appreciated!

Chris
Chris Rehwaldt
1973 Pinzgauer 710K
Jim LaGuardia
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Re: Rebuilding locker masters

Post by Jim LaGuardia »

First and foremost, you cannot pressure bleed the locker masters or slaves. It is a 2 man job. It is easier to explain over the phone, but I'll try to summarize.
With the locker tray out try to actuate each lever, you can spray some penetrate on the back of the pistons and let soak for 20min. Next remove effected masters from frame, remove in order: retainer, washer, nylon end(twist and pull) sometimes this alone will free the stuck piston. If not, put a piece of wood down and slam the locker master piston end onto the wood. Kinetic energy usually work. try not to push piston out from other end as it will destroy the spring .
You can also try a heat gun to expand the housing.
Bench bleed before re-installing , it will make bleeding system easier.
Cheers, Jim LaGuardia
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