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3000 series hydraulic valve rebuild??

68K views 143 replies 34 participants last post by  Jon4x409 
#1 ·
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
 
#2 ·
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!:thThumbsU I have this too (blade and hyd. angle no blower). That tiller runs nice.:fing32:
 
#3 ·
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! :bannana:

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.
 
#10 ·
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!
 
#4 ·
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?
 
#5 ·
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,
 
#6 ·
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!
 
#9 ·
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.
 
#12 ·
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.
 
#14 ·
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.
 
#13 ·
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.
 
#17 ·
Has anyone located an actual contoured backup ring that will fit the line, or am I just as well off using a 5/16 x 7/16 x 1/16 as Gary has successfully done?

Also, somewhere in this forum I once read the correct o-ring size for the quick disconnect fittings. Do any of you recall the size? I believe it is the same size as the spool, but I cannot find the tread.

Cheers,

Doug
 
#21 ·
-0492 is the back-up, -3021 is the main.

Buy MANY of both as you might find that you are replacing them from time to time and it's nice to have them on-hand. Anytime you remove a line on the tractor, the o-rings should not be reused.

I have a bag-full of each o-ring.
 
#22 ·
Just placed my order with o-rings usa. I ordered extras. Wasn't sure on the size for the backup-ring, so I guessed. The size I guessed on was out of stock anyway, so I cancelled that item from my order to get it going faster.

By this point, I'm getting confused who turned me on to oringsusa.com, but Gary, did you buy your stock from MTD/Cub or did you buy from oringsusa? If so, do you have the P/N for the backup ring?

The P/N of what I cancelled was MS27595-011.

I wish I could just roll down the street and pick these up -- I'll be happy when they get here and I can get back to work.
 
#24 ·
Just placed my order with o-rings usa. Wasn't sure on the size for the backup-ring, so I guessed.
I may have a reasonably priced source for all o-rings discussed in this tread, including backup rings with the intended contour.

I placed the order this morning (Saturday), and will report back with details as they come in.

Don't mean to leave anyone hanging, but I also don't want to send anyone on a snipe hunt either.

Doug
 
#26 ·
OK,

Took FOR-EVER to get the o-rings from oringsusa.com, but I got them today.

Put the spool valve back together tonight and reinstalled. Fired it up and...........NO LEAKS! Woooot!

Since the backuprings were backordered, I just followed the advice in this thread and used two 5/16 x 7/16 x 1/16 o-rings BUNA70's per Gary's instruction on each line. The 11mm x 16mm x 2.5mm were just the ticket for the spool. Much tighter on re-assembly and it's no longer pouring out the top of the spool valve. Thanks much to both thunderbirl and Gary.

While I was waiting for the orings to arrive, I placed and received two seperate orders from Messick's! Ok, so I'm local and in zone1 for shipping, but still.

First order was new flange bearings for the fwd/rev pedal linkage. This is the second time these have been replaced (last time by dealer). Man, what a difference to have reverse again without pulling up on the fwd pedal. If anyone wants the diagram / PN's I'll put it up.

Second order was airfilter/pre-cleaner, fuel filter, plugs, oil filter, and a hydro filter. Tinkered around and did the spring tune up waiting for the o-rings to get here. All I have to do is drain the hydro and change the fluid filter now that I know it's buttoned-up.

Of course I screwed up and had everything back together, got on it, started it, took the parking brake off and **STALL**. "****". Before the motor was done rotating, I knew I had forgotten to re-plug-in the emer cutoff under the seat. What a PITA, since my tractor is old, rusty and "modified". :) Taking the seat off used to be a 5 minute ordeal. It's worse now. LOL


I took it for a spin moments ago, headlights burning. Using my xray vision, I could see my neighbors shaking their heads and saying, "there goes that 'neck again -- spring is here, we will know no peace"

Hope to get the deck stripped down and a quick sand and paint before the grass gets too high. For now, I'm good though --- I really need to drag the aerator around for a few beers this weekend.

Thanks for all the help.
 
#29 ·
I also ended up getting 3GCH7 back up rings. Mine came from Grainger.

Hooked it all up last night with new o-rings and these backups. Be sure that the contour goes toward the o-ring and that the flat side of the back up ring is against the ridge on the hydraulic line. Everything went together very nicely.

For the record - every line has a new o-ring and a new contour ring.

Today I mounted my aerator on the rear lift and jumped up and down on it. No issues. That's a very dynamic load of about 275 lbs.

Maybe this will be the start of the first year that I get through without blowing out the hydraulics!
 
#31 ·
Gary or slim, do you know where I can get the spring that sits at the bottom of the valve? I have a spare valve. One valve doesn't work in one direction. The other valve doesn't return to the middle after actuating it up or down. You have to manually put the valve handle in the middle to stop flow. Im fairly certain it's the spring. I have no idea why the other valve works in only one direction.
 
#32 ·
The lever not returning to it's neutral position is not a result of poor spring pressure. It is an indication of either contamination on the surface of the spool and/or cylinder or worn spool o-rings.

I would simply clean the surface (do not alter the contours, just clean it) of the spool shaft and cylinder bore and replace the two o-rings. That will restore the valve.

I've also seen levers hang because they needed a slight adjustment in how they protruded through the fender. Make sure that the levers aren't binding when you reassemble.
 
#34 ·
I think we have info about the o-rings on the spools and the oring and backup ring on the attaching lines. We know the spool is sharp and can cut the orings, so be careful. We know that the screws in the bottom of the valves may unscrew - or may not!

I don't think we know the size of the spring at the bottom of the spool. This spring provides the return motion to recenter the spool.

I don't think we have proven experience with the o-rings between the blocks. I know I haven't taken mine apart.

Outside of this thread, I've read suggestions to replace the nylon flange bearings at the top of the block.

Only other advise ihave is to keep track of the arrow that is etched/engraved on the top of each spool. The spools will spin arround and can be inserted with the arrow pointing to the front or back of the tractor. If you change the direction of the arrow, then what was down becomes up. Don't ask how I know this....:dunno:
 
#35 ·
I don't think we have proven experience with the o-rings between the blocks. I know I haven't taken mine apart.
I've replaced those. They are the same rings used on the lines. My last rebuild was a winner, no leaks in 3 seasons. In that rebuild I replaced every o-ring and cleaned the heck out of the spools.
 
#36 ·
Why am I not surprised at who HAS done this!!

Thanks Gary!:thThumbsU
 
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