ARB locker broken piston

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Nov 29, 2003
Some of you may be interested in this locker repair and that ARB does stand behind their products no matter how old or abused....

Couple years back the rear locker had a leak - it was at the seal assembly where the copper tubing was brazed it cracked there - I took it out and it was an easy fix.

Fast forward to last year - at the start of the Rubithon the rear locker leaking again (of all the trails to have no rear locker) - thought it could be the same issue.

I took the diff out a few weeks ago and tested it on the ground - I could hear air leaking inside not the "O" rings this time.... had to put it back in to drive it.

I emailed ARB - they sent me a new bonding seal thinking it was leaking there - but once I had it apart, I could see the piston was cracked. So I called Marc Bowers at ARB right then, and while on the phone I sent him a photo - he said yeah this can happen when the locker gets engaged while a wheel is spinning and the gear can snap back and brake the piston. What else can he say? Marc overnighted the piston... at their cost and it was there the next morning

I took the rest of the locker apart and replaced the piston, bonding seal - and for good measure while I had it out a new seal assembly and the infamous "O" rings too, along with new cap bolts and lock rings.

Moral of the story; Not always the "O" rings - and Its always good to dig into your own repairs so you know how things work...

The locker is simple once you have it apart - and it goes right back together easily with limited tools.

1) Broken piston

2) Top cracked where it hits the bonding seal inside

3) The locker guts all apart
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1) these 8mm 12 point bolts suck to remove...

2) boiling up the ring gear to expand it a bit to fit on the locker shoulder - good thin for teflon that my pizza pan.

3) Torqued all the bolts to spec and its now ready to ground test and slide it back in.

4) Tested perfectly on the ground and in the truck - and the ride is smooth - end of story!
Wow, a head gasket repair AND the ARB locker repair back to back!

I'm not worthy, master......

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