Pressure in the hydraulic tank

[SylvainG]

So yesterday after using the box grader for several hours, I've reattached the backhoe to the tractor. I was first unable to connect the hydraulic lines for two reasons. First one was fluid in the backhoe warmed up from morning to afternoon. Had to drop one of the stabilizer to remove the pressure. Second, and is the one that I question with, was the pressure in the tank prevented me from connecting the return line. Had to slowly open up the tank's fill cap to release the pressure. Is this normal? When the backhoe was off the tractor, my remote valve (that supply the backhoe when in its 'release' position - it's a log splitter valve) was centered so hydraulic fluid was automatically returning to tank.

Thanks

 

[oldnslo]

I believe most tractors have the transmission reservoir vented to atmosphere to prevent damage to shaft seals. If this was my tractor I would be checking to verify if transmission reservoir is supposed to be vent and then locate that vent.

 

[SylvainG]

I just checked my user and service manual (LK30) and couldn't find anything with 'vent' in them

 

[PILOON]

I just checked my user and service manual (LK30) and couldn't find anything with 'vent' in them

Printed or not, some venting is a must for any reservoir.

However in hydraulic lines buildup is common so depressing the connecting tip will relieve accumulated pressure, for the other side poking the inner connection accomplishes the same effect, that or a gentle attempt to couple usually relieves the pent up pressure.
A 'blip' of hydraulic oil is considered normal.

 

[WranglerX]

Yes, "tank" needs to vent.... May be some sort of vent hidden (not readily visible) on top of "tank" or maybe in tank filler cap and just plugged....

Dale

 

[Doc G]

Hmmm... is yours a hydro drive machine? In my gear drive tractor, I noticed that some pressure builds up in the hydraulic tank. Enough that when I added a rear remote once, a burst of fluid came out when I removed a cover plate. I have no idea where the vent is, if there even is one. Have you ever taken the fill cap off and noticed pressure in the tank before this incident?

 

[SylvainG]

It's a gear tractor, not HST. I don't think I've noticed it before but it was the first time changing implement after using it.

I've contacted the dealer in case he knows where the vent is on that 10 years old tractor and I'll look for it myself later this week when I'm back at the cottage. I don't think there is a vent on the cap. I'll look more closely.

Thanks all.

 

[SylvainG]

I think I've found it in the part diagrams. #29 is described as "TUBE, BREATHER" in the "HYDRAULIC CYLINDER GROUP". If that's it, it's behind the fill cap so should be easy to spot.

Edit: Actually, that's the BACK of the tractor. I don't have that filler cap (#27) there but the return port for the backhoe. I've seen that #29 thing and I thought it was a hose holder lol. I'll see if it's plugged.

My filler cap is in another diagram (TRANSMISSION CASE GROUP), part #9. That picture above sits over that big #1 part below.

 

[3Ts]

I have a vent on my tractor just like the one in the drawing, my dealer warned me that mud daubers will fill it up and cause problems. It's one of the things I check regularly on the tractor.

 

[buck12]

On my previous tractor, Mahindra 2615, the vent somehow got clogged. I ran a wire through the vent and no more issues.