3000 series hydraulic valve rebuild??

[thunderbirl]

I just bought a 3225 with 60" mower, 45" snowthrower, 3 pt hitch and 42" hydraulic tiller.

I've traced the source of a hydraulic leak to the hydraulic control valves. The middle of the three valve stack leaks at the top. Before I pay $145 for one of these, I decided to take it apart. The piston is held in place by an inner c-clip at the bottom. When I slid the assembly out, I found that the upper o-ring isn't really making any contact with the wall (the lower one is).

Does anyone know the size of or source for this o-ring?

Does anyone know how to "size" the o-ring? (I have a set of calipers!)

I'd love to fix this for $0.60!

Many thanks for any help.

Steve MacLeod
Rochester, NY

[peavs]

I used the universal metric and standard kits of o-rings available at Harbor Freight to rebuild mine. I think I used a metric one because it fit tighter in the bore. Mine still leak a little bit but better than when I got it.

I have not tried this (yet) but you might try this valve rebuild kit 759-3512. It's from a Super. The valves are not the exact same but if you go to a cub parts site, it looks very close.

P.S. I see that this the set from Messick's on eBay. You got a great deal! I have this too (blade and hyd. angle no blower). That tiller runs nice.

[thunderbirl]

The answers are:

Two o-rings on the spool. Both 11 mm ID, 16 mm OD, 2.5 mm thickness (kind of hard to find!) and not a drop where it shouldn't ought to be!

My stack had a single o-ring on each hydraulic line (not two like in the parts diagram) and they were 5/16" ID, 7/16" OD, 1/16" thickness.

For the big money: Spent 10 hours of labor and $5 on parts doing it this way vs. 12 hours labor and $135 on parts by replacing the whole valve section vs. a huge bill from the dealer.

[Gary in NJ]

Recalling an old thread here.

Steve, I have a leak (once again) in one or more of my lift valves. Luckily, last time it was just the hydro-line fittings. This time, since I'll have it all apart, I'll do the spool o-ring as well.

Regarding the hydro lines, from memory, I recall having two different size o-rings and the parts diagram confirms this. The parts diagram calls for an an inner O-ring on the line of .301ID x .070 dia and an outer on the line (.327 x .433 x .05.

Does the single 5/16 x 7/16 x 1/16 work in this application?

[Slim]

Gary;

Did you ever get an answer on this, or did you find out the "hard" way?

I rebuilt the hydro gear on mine last year (broken gearrotor) made a few posts about this, and now this year the hydraulic valve is leaking. Looking to fix it all this year.

Thanks,

[thunderbirl]

The original design really isn't two o-rings. The outer "ring" is a contoured back up ring (which really isn't an o-ring at all). The back-up ring has one side as a concave surface (positioned facing the o-ring) for receiving the o-ring and prevents it from being extruded out.

Here's a picture or a contoured backup ring (lower right): contoured back-up ring

When placed under high pressure (like lifting a heavy object or when running the tractor into a fixed object), some hydraulic fluid pushes on the o-rings. If you have the backup ring, the primary o-ring is cradled in the contour and any excess pressure may seep past the edge of the o-ring. If you don't have the back-up ring, the o-ring will be extruded out through any gap between the metal bits.

In the end the parts are a pain to find - which is why I tried other things. However, they are not expensive and well worth using. I use my tractor quite hard and have had no failures since.

hope this helps!

[Slim]

Thanks, Steve. The link is helpful. I'm going to get into it tonight.

[Gary in NJ]

I ended up using two 5/16 x 7/16 x 1/16 o-rings on each line. I ordered BUNA70 (Acrylonitrile-Butadine Copolymers) rings from oringsusa.com. All leaks are gone.

[Slim]

OK -- Now I'm stumped. See mine appears to be dry at the lines connecting into the valve, but is leaking at the top of the valve, where the arm pushes the "valve rod" (yes, that's my word) down to actuate.

See Picture.



Gary, if you are saying you put two o-rings on each line (hose, hardline, etc) that connected, I'll do that in a heartbeat.

Mine is leaking at the top.

Thunderbirl, do I need two rings, one a contoured backup ring and one an o-ring at the top-most recess?

Thanks for all the help.

[thunderbirl]

Originally Posted by thunderbirl

The answers are:

Two o-rings on the spool. Both 11 mm ID, 16 mm OD, 2.5 mm thickness

Mine had a single o-ring on each end of the "spool" - no back-up ring arrangements here.

The back-up rings are where the hydraulic lines go into the block these spools mount in. On those lines, the o-ring goes into the block and the back-up ring on the "outside". To do this, slip the back-up ring onto the line first (contoured sufface facing "inward"), then the o-ring and then insert the line into the block.

Hope that helps!

[Slim]

awesome. I owe you
thanks.

[Gary in NJ]

You've been asking about spool o-rings?

They are 11mm ID x 16mm OD x 2.5mm. Get the BUNA70 rings; part number 19354 from oringsusa.com

If you remove the flange (by removing the screw) from the bottom, it will keep you from nicking the lower ring as you roll it past the grooves - which are SHARP. Use assembly lube as you reassemble the unit.

[Slim]

Yes, yes. I've been asking about spool rings. I just didn't know it. I'm adding to the vernacular, though. Spools, backup rings --- all sorts of stuff I didn't know before.

I am going to replace all the rings on the lines while I have it out / apart, etc.

Thanks.

[thunderbirl]

Originally Posted by Gary in NJ

If you remove the flange (by removing the screw) from the bottom, it will keep you from nicking the lower ring as you roll it past the grooves - which are SHARP. Use assembly lube as you reassemble the unit.

Gary,

I broke that screw off on the first one I tried on mine. It seems to have been lock-tighted (if that's a word) and snapped off. I repaired it on my lathe, but wow! I didn't bother even trying the others!

I went over the top for both seals and had no problems. However, you're right that the grooves are VERY sharp.

[Gary in NJ]

Originally Posted by thunderbirl

Gary,

I broke that screw off on the first one I tried on mine. It seems to have been lock-tighted (if that's a word) and snapped off. I repaired it on my lathe, but wow! I didn't bother even trying the others!

I went over the top for both seals and had no problems. However, you're right that the grooves are VERY sharp.

I loosened 2 out of 3. One wouldn't budge so I know what you mean. I wouldn't try to stretch the o-ring over the flange, but one needs to be very careful rolling the ring over the valve. Perhaps rolling some Saranwrap over the valve first would be the safe way to go.