Tractor squeals under load after getting warm

[Ken Pike]

Is there some type of pressure relief valve in the system? I have a '48 Ford 8N & even it's antiquated hydraulic system has a relief valve that apparently squeals a bit when it operates.

 

[Soundguy]

for sure... and it's been discussed back in the thread..

soundguy

 

[hlukeh]

Hello Jim, Bill, Duff,

Thanks a lot for all the replies! Shortly after I asked about my hyd problems I became very busy and had to leave the country for work. Now that I'm back I'll have some time to look at this again.

I should really be paying you guys for your time. A couple of you are obviously very experienced, and your input is worth a lot.

Bill, when I changed the oil it looked clean. I appreciate the discussion about safety. It makes anyone reading this thread in the future (including me) aware of the potential dangers when diagnosing their hydraulic problems.

I've used both my hand and an infrared thermometer to try to pinpoint the source of the squeal, but it hasn't been that obvious. There are a couple places where the temperature is slightly hotter, but nothing over 110deg. F. I've got a guy coming over this week who sounds like he knows quite a bit about hydraulics and small tractors, but I'm not sure how much he knows about hydrostatics. We'll see if he can determine if it's a valve or other mechanical wear.

Thanks Jim for the diagram and for the detailed analysis. When the tractor is off, sitting on a flat surface, should there be high pressure in any of the hydraulics (I assume that if I left the loader up there would be pressure build up, but other than that I wouldn't think there would be any)? If I were to determine with my IR thermometer that a relief valve is the culprit and I decide to pull it, should I be worried about hyd fluid spurting out at high pressure, or should it just ooze out when the tractor is off?

Luke

 

[jinman]

Thanks Jim for the diagram and for the detailed analysis. When the tractor is off, sitting on a flat surface, should there be high pressure in any of the hydraulics (I assume that if I left the loader up there would be pressure build up, but other than that I wouldn't think there would be any)? If I were to determine with my IR thermometer that a relief valve is the culprit and I decide to pull it, should I be worried about hyd fluid spurting out at high pressure, or should it just ooze out when the tractor is off?

Luke

Luke, I'm not sure how you intend to use a thermometer to determine pressure, but it will tell you if there is something creating a hot spot. If pressure relief valves are opening and staying open, they will heat up, but I don't think you will be able to "see" that with the thermometer.

If the tractor is off, you won't have to worry about any pressure except if it is in the sun, external lines can heat up and have pressure that will immediately drop as they are disconnected, sometimes with a small squirt of fluid. What you do have to worry about is disconnecting a line below the level of the reservoir or trapped fluid in a line or filter and have it drain out on the floor or ground. It's not a safety issue, but certainly a spill issue. If you remove a relief valve, you will certainly have some fluid leak out. How much fluid is something I would not know.

Glad you are back home. I'll have to revisit all of this thread to refresh my memory of your problem. I don't remember as well as I used to.

 

[edsan]

I have the same problem, did you get yours fixed, mine squeals after 20 minutes and I get a vibration from the hydrostatic pedal, also I get a chatter when I try to raise the bucket, and the tractor will not move until I shut it off for a couple of minutes
Could you please get back to me.
Ed

 

[jlrsn]

edsan,
I've seen Pressure Relief Valves with a weak spring squeal and cause a chatter with rapidly fluctuating hydraulic pressure. I'd also bleed your Hydraulic System of any possible air. Someone else can jump in with their experience.
Good luck,
Jim

 

[dynasim]

I'd bet your sucking air into the inlet line.

Chris

 

[edsan]

Thank You Jirsn I will check that out.
Ed

 

[edsan]

Hi everyone My real problem is the tractor will not move after getting hot and the hydrostatic pedal gives a high pitch noise vibration when I step on it. does anyone know of this problem and what the fix is.
Ed

 

[edsan]

Hi hlukeh
I have the same problem with my 1520 4wdr. did you find the problem, could you get back to me Please.
edsan