Hyd. Safety Valve One and Done?!

TraktorFreunde · May 25, 2018

All, the question:
Just wondering if the safety relief valve is a one time use item. As in, though it has a spring, once it opens, is that it? Need to replace it? Or should it just open/close as needed?
I will be opening the side cover to inspect, but, like I said, was just wondering. Back story below.....

The situation:
Last year I bought an 8N with a 6' flail mower. Never used the mower. I replaced the valve, top cover gasket, cylinder(was scored bad enough) and piston (new rubber oring style), because the 3pt wouldn't stay up when you depressed the clutch, or the tractor was turned off. It's worked great since then
I recently had to move the mower (sold it) and now, my 3pt is back to not staying up. I'm assuming the mower was just way too heavy and the valve busted. I can't think of any other reason, unless the o-ring on the piston blew out. It still raises up and down, but won't hold. Plus I can feel like a pulsing when its working.

Like I said, I'll be doing some diagnosing, just wondering about the valve, as it seems the most likely culprit right off the bat.

Thanks!

TheOldHokie · May 25, 2018

(quoted from post at 08:32:44 05/25/18) All, the question:
Just wondering if the safety relief valve is a one time use item. As in, though it has a spring, once it opens, is that it? Need to replace it? Or should it just open/close as needed?
I will be opening the side cover to inspect, but, like I said, was just wondering. Back story below.....

The situation:
Last year I bought an 8N with a 6' flail mower. Never used the mower. I replaced the valve, top cover gasket, cylinder(was scored bad enough) and piston (new rubber oring style), because the 3pt wouldn't stay up when you depressed the clutch, or the tractor was turned off. It's worked great since then
I recently had to move the mower (sold it) and now, my 3pt is back to not staying up. I'm assuming the mower was just way too heavy and the valve busted. I can't think of any other reason, unless the o-ring on the piston blew out. It still raises up and down, but won't hold. Plus I can feel like a pulsing when its working.

Like I said, I'll be doing some diagnosing, just wondering about the valve, as it seems the most likely culprit right off the bat.

Thanks!

It is a poppet valve that opens and closes as needed and can cycle many, many times.

TOH

TraktorFreunde · May 25, 2018

(quoted from post at 06:06:20 05/25/18)

It is a poppet valve that opens and closes as needed and can cycle many, many times.

TOH

Ugh, that sucks. So either it failed or I've got bigger problems.

I figured the mower probably didn't weight more than 600lbs, but perhaps that wasn't the case and was far heavier.

Could something overweight blow the o-ring or cause major damage? Isn't that why the valve is there? To prevent something major from happening?

Well, either way, looks like I'll be enjoying some tractor maintenance this weekend.

R Geiger · May 25, 2018

When you installed the o ring on the piston, did you get the back up ring in the correct position?

TraktorFreunde · May 25, 2018

(quoted from post at 08:02:24 05/25/18) When you installed the o ring on the piston, did you get the back up ring in the correct position?

Yes, I researched things before putting it on (videos and what not), so I'm confident that is on correctly.

I'm sure I'll see if there is a leak from the cylinder or the oil churning if it's one of the common culprits.

I just don't get why something would happen of the like, due to the weight of the thing (the only factor in play before this happened).

I've picked up at least 300 pounds before this, and things held fine before this happened.

My only hope is that it's not something with the pump itself, as I don't feel like dealing with that right now. It still lifts so I don't think it's that.

Of course, I will update here my findings.

carlntexas · May 25, 2018

I would suspect the relief valve don't think China uses the right numbers to set those. I replace mine and it worked great until I tried to pick up a welder with a boom pole. I bought a replacement and it blew out ordered one that looked like the original and it blew out. I finally screwed the first one down as tight as I could and used it. It will pick the front end up off the ground now and hold. I still need to replace it but don't know where to get one that works. I can replace one now through the left side cover in less than 15 minutes

TraktorFreunde · May 26, 2018

So I popped open the right plate and didn't see anything obvious. Doesn't look like the valve is bad (no churning) and no leaks from the cylinder (which I've seen and thus replaced). The color of the fluid is a little suspect, but it does sit outside (in a temp garage), so maybe there's a little water in it, besides just getting dirty with use (filled it last November).
I took a video, but it doesn't look like I can post here and I'm sure it's too big anyway. I did take some snapshots though and my only other observation is more near the front of the hydraulic chamber. In the video I caught some oil dripping down. Is this normal or should there be absolutely nothing above the pump? Could it be the top cover gasket or that smaller gasket for the cylinder is bad? I replaced both when I had it open to replace the cylinder.

[/img]

TraktorFreunde · May 27, 2018

Any thoughts out there?

Thanks

TheOldHokie · May 27, 2018

(quoted from post at 10:55:59 05/27/18) Any thoughts out there?

Thanks

Oil from above is a leak of some sort and likely the source of your lift problems. I'd say whatever you fixed didn't stay fixed.

TOH

TraktorFreunde · May 27, 2018

Thanks Hokie
I just really wanted to verify that there should be absolutely nothing from the top. I never looked when I fixed everything (as everything worked the way I wanted). Guess it's a gasket I'll probably be replacing. Any chance it's better to make a gasket from some better material, rather than sticking to the paper ones?

Thanks again.

carlntexas · May 27, 2018

I had the thin top cover gasket blow out on the outside. I cut a washer out of some thicker gasket material to go around the pipe hole and it fixed it. Did you use all three gaskets on the cylinder when you replaced it,if not that could cause a leak. Also just because you don't see any turbulence around the relief valve doesn't mean it's not leaking. I had a bad one and couldn't tell until I stuck my hand in there and felt the oil squirting. You don't want your hand in there with the pump running I have live hydraulics on mine. I'm just really leary about relief valve after getting three bad ones.

TraktorFreunde · May 27, 2018

(quoted from post at 09:42:26 05/27/18) I had the thin top cover gasket blow out on the outside. I cut a washer out of some thicker gasket material to go around the pipe hole and it fixed it. Did you use all three gaskets on the cylinder when you replaced it,if not that could cause a leak. Also just because you don't see any turbulence around the relief valve doesn't mean it's not leaking. I had a bad one and couldn't tell until I stuck my hand in there and felt the oil squirting. You don't want your hand in there with the pump running I have live hydraulics on mine. I'm just really leary about relief valve after getting three bad ones.

Yeah I got them all. Like I said, thing was totally fine working great until I lifted the flail mower. I may get another valve, just in case.....

carlntexas · May 27, 2018

(quoted from post at 12:58:57 05/27/18)

(quoted from post at 09:42:26 05/27/18) I had the thin top cover gasket blow out on the outside. I cut a washer out of some thicker gasket material to go around the pipe hole and it fixed it. Did you use all three gaskets on the cylinder when you replaced it,if not that could cause a leak. Also just because you don't see any turbulence around the relief valve doesn't mean it's not leaking. I had a bad one and couldn't tell until I stuck my hand in there and felt the oil squirting. You don't want your hand in there with the pump running I have live hydraulics on mine. I'm just really leary about relief valve after getting three bad ones.

Click to expand...

Yeah I got them all. Like I said, thing was totally fine working great until I lifted the flail mower. I may get another valve, just in case.....

f you take the top cover off you can see if it blew out around the pipe hole. Those gaskets should be made with a thicker material around the hole,which is the only pressure point. Good luck on the relief valve I haven't gotten a good one yet.

Hobo,NC · May 27, 2018

I was going thru some old photos and remembered your post this is my safety relief valve tester... John Smith post his so I had to make one for myself. I need to make another this one leaks to bad to be useful.... Its of no help but good old news of a nice tool...

carlntexas · May 27, 2018

China steals all of our patents hope they copy that and actually test some relief valves.

TraktorFreunde · Jul 4, 2018

Though it's been a while, I wanted to give an update. I finally got around to pulling the top cover and it was indeed the gasket. There was a tear right at the oil pipe hole. Put a new gasket in (from yesterday's tractors, I don't know where the other came from) and now it's back to normal. This gasket seems better quality, so I hope it holds up.....

JMOR · Jul 4, 2018

(quoted from post at 15:14:03 07/04/18) Though it's been a while, I wanted to give an update. I finally got around to pulling the top cover and it was indeed the gasket. There was a tear right at the oil pipe hole. Put a new gasket in (from yesterday's tractors, I don't know where the other came from) and now it's back to normal. This gasket seems better quality, so I hope it holds up.....

hanks for reporting your findings. Turns out that it was a "pressure relief", just not the one most were suspecting.

TraktorFreunde · Jul 13, 2018

Quick question, without starting a new thread:

After replacing the lift cover gasket, things were good for a few runs, but suddenly the hydraulics just dropped and wouldn't go back up. I checked things through the inspection point and oil is squirting a plenty on top. No turbulence such as from the pressure relief. With the implement off (about 300 lbs), the arms will raise and holds, so I know it's generally operating OK.

The only thing I can think of is that a different gasket blew or the new gasket blew. When I put the cover back on, some oil got on the gasket. So the question is, can some oil on the gasket, especially by the oil tube, break it down enough that after a couple weeks it's ruined?

I would think yes, but i'm more used to cork or rubber gaskets, rather than paper and maybe it doesn't really matter too much.....maybe it was just a quality issue or it's another gasket.. Any thoughts?

Thanks

JMOR · Jul 13, 2018

(quoted from post at 21:44:34 07/13/18) Quick question, without starting a new thread:

After replacing the lift cover gasket, things were good for a few runs, but suddenly the hydraulics just dropped and wouldn't go back up. I checked things through the inspection point and oil is squirting a plenty on top. No turbulence such as from the pressure relief. With the implement off (about 300 lbs), the arms will raise and holds, so I know it's generally operating OK.

The only thing I can think of is that a different gasket blew or the new gasket blew. When I put the cover back on, some oil got on the gasket. So the question is, can some oil on the gasket, especially by the oil tube, break it down enough that after a couple weeks it's ruined?

I would think yes, but i'm more used to cork or rubber gaskets, rather than paper and maybe it doesn't really matter too much.....maybe it was just a quality issue or it's another gasket.. Any thoughts?

Thanks

ost likely the two mating surfaces in that area are not flat & true.

TraktorFreunde · Jul 14, 2018

[/quote]

What would be the suggestion then? some goop?
Besides of course making sure the surface is clean, flat, etc....
I also made sure that the bolts were torqued correctly.....

JMOR · Jul 14, 2018

(quoted from post at 02:04:40 07/14/18)

ost likely the two mating surfaces in that area are not flat & true.[/quote]
I have personally used just the paper gasket and once with a slightly damaged gasket (too far from a good new gasket) I used Permatex Aviation & still holding.

Hyd. Safety Valve One and Done?!

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