[Dan O.]

Friends,
I am trying to learn a little about the vacuum that take place in the hydraulic storage tank. There is a relief valve on the top (I think that is what it is) and sometimes activity with the loader control valve will cause fluid to come out, run down the side of the trans and get everywhere. I cannot always cause it to happen by rapidly dropping the boom. So I investigated the tank fluid levels very closely to see if I am overfilling. I tried variations like lowering the 3 point and raising the 3 points thinking that may have an affect on the tank level. Is there a chance the relief valve does operate well, or should I try putting in a tube to a secondary capture tank? I am not sure what to expect in normal operation.

The problem existed with the OEM control valve (6 gal. per min.) and I replaced it with a brand hydraulic (10 gal. per min.) which should have exasperated the situation but causes about the same disruption occasionally. Had to replace original because of wear and leaking.

 

[BigT]

Hi Dan, welcome to the tractor forum.

I think the "relief valve" you refer to is possibly an air vent? Check me out on that. Remove it and see if you can blow thru it.

When you lower the loader, return fluid to the reservoir at high velocity sometimes splashes out the vent with air being displaced. Possibly happens with a load in the bucket, forcing it to come down faster?

I like your idea of installing an overflow tube and small tank to catch the fluid. Your tank must have an air vent. Your reservoir has to "breathe".

Alternatively, you could install an orifice in the return line to slow down the return fluid velocity. This will slow down your loader lowering rate, which may not be desirable.

 

[Dan O.]

BigT - thanks for the reply. Yes I did mean something like an air vent but did not know what to call it. I like your idea about the orifice on the return, especially if it had the added benefit of slowing the boom response down a little bit because it is jumpy since changing to the new hydraulic control valve. The new valve has a higher flow than my old one. I will definitely look into this type of solution.

Good day