What size o-ring for 520 h hydraulic cylinder hose? I just rebuilt the cylinder and want to replace the o-rings

[Huntingtown520hc 6]

What size o-ring for the cylinder hoses for 520hc 1989? I would appreciate any help someone could provide.. thanks 

[pfrederi 17,866]

I am pretty sure by the 520 series WH had adopted SAE ORB# 6 fittings.  If so the #6 use dash #906 ( 9/16 18 tpi thread)

Edited July 11, 2021 by pfrederi

[peter lena 8,720]

@Huntingtown520hc, use a silicone grease , like dielectric grease on those o ring areas , not a lot , but it will help the ring seal and seat, instead of twisting in its place, pete

 

 

 

 

 

 

 

 

 

 

 

 

@huntingtown520hc

[Jeff-C175 7,203]

30 minutes ago, peter lena said:

silicone grease

 

You'll only need a tiny amount so go to box store and pick up a small container of the stuff they sell in the plumbing aisle for use on faucets.

 

I wouldn't trust their o-rings though.  I would go to one of the hydraulic suppliers and get good quality.  Viton material is good stuff.

Edited July 11, 2021 by Jeff-C175

[Huntingtown520hc 6]

Thanks. The rebuild appears to be leak free

[Huntingtown520hc 6]

Ok I spoke too soon looks like I need to rebuild the hydro control valve …. Do we think o ring 22 and 23 are still number 6 …

 how pain full is this going to be I just put my snow cab on….

 

[Huntingtown520hc 6]

Sorry 23 and 24

[Jeff-C175 7,203]

4 hours ago, Huntingtown520hc said:

Sorry 23 and 24

 

You mean -6 ?  As I recall, there are two different sizes on there but it has been years since I did mine and my memory ain't good!

 

Let's see what the parts book says... Mine's a 175, not a 520, and it appears that I scribbled some notes that two of them are -6 and two of them are -5 so maybe you oughta get some of each.

 

Didn't you replace them when you rebuilt the valve?  Or did you rebuild it?  I'm confused...

 

Edited December 19, 2021 by Jeff-C175

[lynnmor 7,353]

The cab will be a real pain, I would remove the components on the left front.  If you have the four hoses running to the valve like the diagram, you can replace the two o-rings inside the valve without loosening the hoses.  If you have two steel lines running to the valve, then that is a big job.

What I did on my four hose setup was remove the battery and the console plates for access, then removed the lever and the two mounting bolts using the access holes in the battery support.   I was able to remove the screw in the back of the valve by tilting it and using a very long screwdriver. Yes, it is a bit like brain surgery,but with a flashlight and mirror you will see exactly what needs done. Once the screw is out, the spool can be pulled out.