How I rebuilt my rotary hydraulic kneeling valve. Issues I ran into and how I got the stubborn knob off!!

[RRaulston]

 

[RRaulston]

Just to add a few things. I didn't test for leaks by activating the kneeling circuit. Mine leaked quite a lot by just activating the cab and tire lifts. So, I checked it in the way I used it. Also concerning the index wafer. I think the wafer may be the same as the 3-position selector knob. I believe I once had the wafer in a 3 click position upon assembly and then the 2-position spot. Hard to explain but when you turn your knob and it indexes 3 times for a raise/lower 2 position circuit, you may need to flip it. Cheers!!

 

[BERZERKER888]

Just to add a few things. I didn't test for leaks by activating the kneeling circuit. Mine leaked quite a lot by just activating the cab and tire lifts. So, I checked it in the way I used it. Also concerning the index wafer. I think the wafer may be the same as the 3-position selector knob. I believe I once had the wafer in a 3 click position upon assembly and then the 2-position spot. Hard to explain but when you turn your knob and it indexes 3 times for a raise/lower 2 position circuit, you may need to flip it. Cheers!!

I rebuilt all rotary valves using a Harbor Freight Blue O ring kit…been over 1 year.. zero leaks……

 

[coachgeo]

@RRaulston - maybe you can get the white Ring from Power Packer who makes these units. Was honestly shocked CAT even had a clue where to look.

otherwise you might could try super glue sprinkled with baking soda to fix the ring? shape it as needed with Drimel tool orr? ?

 

[87cr250r]

The white ring is simply a backup ring. It prevents extrusion of the o-ring under pressure. They follow the same size format as the o-ring. You can cross reference the Cat part number to get the dash size of the o-ring.

McMaster-Carr Page:
https://www.mcmaster.com/backup-rings

If this system is using standard hydraulic oil or ATF you'll want to run 90 durometer buna-n or nitrile o-rings.

 

[RRaulston]

The white ring is simply a backup ring. It prevents extrusion of the o-ring under pressure. They follow the same size format as the o-ring. You can cross reference the Cat part number to get the dash size of the o-ring.

McMaster-Carr Page:
https://www.mcmaster.com/backup-rings

If this system is using standard hydraulic oil or ATF you'll want to run 90 durometer buna-n or nitrile o-rings.

WOW! Great information!!

 

[RRaulston]

This is the device CAT used to size the O-rings. It was pretty nifty!!

 

[marchplumber]

This is the device CAT used to size the O-rings. It was pretty nifty!!View attachment 884874

Ive seen something similar, but it wasn't at a "CAT" dealer!

LOL

 

[coachgeo]

Ive seen something similar, but it wasn't at a "CAT" dealer!

LOL

least you didn't admit it was at your house.

 

[87cr250r]

I have the same tool. It definitely takes some talent to use effectively. You must be able to rule out metric sizes. Metric isn't that common in valves and such but I suggest a good caliper to take measurements.