Hydraulic valve 420C

[LMB]

I have a problem with the valve on my 420. It was leaking through the check valves very bad. it also was leaking from the seals on the spools but not as much. The hydraulic work perfectly otherwise, the blade would always stay in position where I would put it. I could leave it up and it would not leak down no matter how long I left it.

Now no matter what I do the blade is now always dropping even when running. It is making it hard to use the machine because the blade is always diggin deeper and deeper and I constantly have to manually float the blade in the position I want. If I shut of the engine the blade will fall in a matter of a minute or less.

I have taken the valve off and checked every thing multiple times now. I have a manule and do not see where I am going wrong, does any one have aby ideas for me?

The blade is a rebuilt/home made 62. It has two cylinders but they attach in slightly different places on the blade than a 62. It no longer angles either, but for hydraulic information it is the standard 62, one vlave shown in the manual. It is mounted on the crawler fender.

If no one has any ideas on how I can fix myself, is there someone who rebuilds these things? I live in central MN if that helps.
Is it hard to locate a good used valve if I need to go that route? How much do used ones sell for?

Also I love the new site. I quit lookin a couple of years ago because of all the spam I received and the popups from the old board. I will spend more time here again.

I have many questions for you guys to answer, but I am at the end of my rope on this one.

Thank you,
Lou

[Lavoy]

Did you replace all of the seals, o-rings and such?
lavoy

[LMB]

Yes I did

[Lavoy]

If the blade held before, and all of a sudden started dropping, I would say that it is the cups in the cylinder, not the valve.
If the valve is leaking after putting in all new parts, my guess is that an o-ring got cut or rolled, or one of the gaskets sucked in. IF the valve was not leaking before, it can be made to not leak again, it has to be a simple fix.
Lavoy