I'm chasing down a vacuum issue with my ESOF hubs. Last spring I rebuilt the front axle - axle u-joints, upper/lower bj's, all the related hub seals. When I bought the new rotors and brake pads from Rock Auto I also order the ESOF hub o-ring kit, that also had the new SSTL snap rings.

Right after I installed all this everything worked fine, then things got touch and go. Now nothing, only when I manually lock the hubs.

I know Rich has gotten mighty use out of a Mity-Vac, so I bought one. I checked the vacuum at the reservoir...pump shuts off at just over 15" vacuum. Checked the PVH solenoid for the proper signal....yep, 15" then 6". Located the hub vacuum feed line off the solenoid and attempted to build some vacuum. No dice, nothing notta. Plugged the feed line one end, obtained vacuum at the other...line checks good. I have DieselSite braided SSTL line to the knuckle. Applied vacuum to both the driver's and passenger sides. Nothing.

Now here where my question lies. When I purchased the hublock o-ring kit from Rock, it came as a Dorman piece. I figure how hard can it be? It's an o-ring and circular clip.

I think either the o-ring is undersized, Woods n Things on is page says it's a -152 (.103 cross section) o-ring. But I wonder if the SSTL clip is also small in diameter...which could affect the seal.

Can somebody bust out a micrometer and measure the diameter of the hublock retainer for me? Like a dum*ss, I tossed the OEM ones. Diesel O-rings sells a kit, but I can source the o-rings locally. But if the clip is under-sized on mine, then I will order from Diesel O-rings.

Hopefully that solves the problem, if it isn't, then it's either the yellow hub o-ring or the $50/ea axle shaft vacuum seal. And I truly won't be a happy camper.

 

I'm going through the same problem now. Good Luck! Hope to get into to mine tomorrow. I try to post up some numbers.