520HC Hydro Control Valve Help

[stevebo-(Moderator) 8,531]

Guys,

The control valve in my 520 is leaking and not as strong as it should be. Under a load it is humming. I believe it is the bypass. Can anyone tell me how tight the set should be on this? I took the dash panel off and on the right side of hte valve there is an acron unt and once removed there is a set screw with an allenhead. It was backed out several turns. I believe what is happening is the bypass is too loose. Does anyone know how much it should be backed out from fully shut? Any help would be great. Oh yeah, it is a 1988 520HC. Thanks- steve bo

[stevebo-(Moderator) 8,531]

I checked the manual and all it says is to replace it in the original position in which it was removed :thumbs:

[Operator 7]

Unless someone else has the exact setting here is what I would try.

Turn in set screw then back it out a couple turns. Then try lifting, you want the valve to squeek just a little when it hits top. And not to lower engine R's If it lowers the R's turn screw out just a couple more turns. then try it again. Just keep trying untill the engine maintains the same R's.

This is what I would do, doesn't mean it is right or wrong. But I mess with these on

a lot of equipment.

Randy

[stevebo-(Moderator) 8,531]

Randy,

That is good info. I will let you know how I make out. I am swapping out the 16hp with a 20hp so it is a true 520. This way a couple of the local guys won't give me any more lip about me having a 516 with 520 decals .... Go ahead guys chime in.. :thumbs:

[nylyon-(Admin) 7,880]

Steve, do you have a picture of the control valve? I may have one lying around here.

[nylyon-(Admin) 7,880]

Hard to tell but does it look like this one:

I have the correct valve on the 160 now and this one is off.

[baerpath 517]

Steve if you don't make out I have a 520 HC

l'll probably take it apart, Bought it for the front axle and body parts I have a complete lift from a 417H out If you need let me know

Duane

[TT-(Moderator) 1,162]

"Flying by the seat of your pants" can get expensive when you're fooling with relief valve settings and system pressures in a hydraulic system.

If you don't believe that, download the Eaton 1100 manual from Toro (492-4205) and read for yourselves.

Here's an excerpt:

1. Connect gauge system to front lift cylinder hose.

Gauge can be connected to place hydraulic lift

cylinder either in or out of circuit, as desired.

2. With engine running, hold lift control valve in

"Down" direction. Normal pressure reading is

700

[stevebo-(Moderator) 8,531]

TT,

I read the same thing and that is why I am trying to figure this out before I mess it up. I am good at certain things then the others I ask for help. How the heck and I going to get "factory assistance"??

Karl,

Joe's outdoor has the one I am looking for under 520 hydrolic control valve. It looks different from the pic you have but Terry is right it is a Victor single.

Duane,

Is yours a Victor?

My issue is that I did not mark the setting prior to moving it Thanks guys-

[TT-(Moderator) 1,162]

How the heck and I going to get "factory assistance"??

In this case, the factory assistance comes in the form of the service manual. I'm sure you can scare up a 0-1500 (minimum) psi gauge and plumb it in to the cylinder line like stated in the manual, Stevebo.

This might not be a justifiable purchase for someone who owns one tractor and will never lay a wrench on it, but you tinker with a lot of these and will probably benefit from it again in the future.

[nylyon-(Admin) 7,880]

Mine looks just like that one, but it has a handle on it. The tag reads Dukes Power Fluid, but it is identical to the one Joes has down to the lettering on the side. It works and has no leaks. Your call, you can have it tomorrow if you'd like.

[stevebo-(Moderator) 8,531]

pm will be sent

[stevebo-(Moderator) 8,531]

Guys-

Karl is not only giving me his extra valve but actually delivering it to my house That is the kind of people we have here !! I am sure I will be able to repay the favor as I have a few extra parts laying around.

[truckin88 104]

stevebo where is it leaking at? all the connections in the 520 hydro system have O ring seals, they do go bad.

[stevebo-(Moderator) 8,531]

Will,

I am not sure I can only tell you that the lines are tight and the control valve is the highest point on the hydro system and it is leaking from that point. it could be the plunger shaft too. It is so hard to get at I figure once I take it out I either need to rebuild or replace.

[truckin88 104]

replace the hose fitting O rings at the same time worth the 20 cents or whatever each for no headache

[stevebo-(Moderator) 8,531]

i will !! thanks will

[baerpath 517]

Sounds like Karl's got ya covered on this one If you need anything just holler

Duane

[nylyon-(Admin) 7,880]

Steve, box delivered. It should work just fine, there were no leaks on the valve when it was on the 160.

[Operator 7]

Stevebo how did this ever turn out?

Randy

[stevebo-(Moderator) 8,531]

I put the one on that karl dropped off and replaced all the orings and tested the pressure and it works great !!! Thanks again karl. Drop that deck off when you want and I will get it taken care of.

[JoeMonag 1]

Steve, do you know if your friend Tom has an e-mail address, I am talking to him about his 520-H withthe 16hp Onan. Could you forward my address to him please and ask him to send me his e-mail address if he has one? My e-mail is JoeMonag@aol.com

Good luck with your 520-H, Tom told me you are a real Wheel Horse purist.

Joe in Norton, MA