Recently bought a 4430 from a scalper ...should of known better...anyhow both scvs leaked continuously with hoses hooked up. Cleaned out all the paint the scalper sprayed into the barrels, put new orings in the barrels and have the external leaks fixed I think. Problem now is the right box will not hold any pressure. Trying to use this tractor on a grain drill and need it to hold constant for down pressure. Could this have anything to do with the one way valve under the left side? The tractor has a small hose setup on the right scv which my dad thought was for one way cylinders? If the scv needs rebuilt do you Tim S work on boxes if I could ship it to you? Thanks.