445 Hydraulic Pump Relief Valve Leak

JRMoline · May 10, 2019

Last fall I developed a serious leak out of the relief valve plug on the hydraulic pump of my 1958 445 Moline. I expected a broken valve spring or something in the valve seat so I pulled the plug and got a heavy flow of fluid so I replaced it. Now that it's warmed up, I'm tempted to remove the pump and disassemble it but I don't want to cause my self a bigger problem.

So can anyone tell me if I can unbolt the pump and remove it without a problem? How much of the hydraulic fluid do I need to drain to prevent a spill? Is it unwise for a shade tree mechanic to disassemble the pump? There's really no one in my area that services these old workhorses. Any advice would be appreciated.

molinegb · May 10, 2019

Two bolts and line and pump comes off. It is plumbed internally.

JRMoline · May 10, 2019

(quoted from post at 11:28:50 05/10/19) Two bolts and line and pump comes off. It is plumbed internally.

Good news, thanks.

T.R.K. · May 10, 2019

And I think all the oil from the reservoir above will come out through one of those holes, as it is a direct feed from the reservoir.

MMDEL · May 11, 2019

Don't remove the pump to check something leaking externally at the relief valve. You won't gain anything other than you don;t need to stand on your head to see what the problem is since the relief valve is on the bottom of the pump. And you can't cause it to leak to see what is going on if the pump isn't operating. Clean everything off real good then start the tractor, hold one of the remote levers against the stop and watch where the leak originates.
MMDEL

JRMoline · May 11, 2019

(quoted from post at 10:59:05 05/11/19) Don't remove the pump to check something leaking externally at the relief valve. You won't gain anything other than you don;t need to stand on your head to see what the problem is since the relief valve is on the bottom of the pump. And you can't cause it to leak to see what is going on if the pump isn't operating. Clean everything off real good then start the tractor, hold one of the remote levers against the stop and watch where the leak originates.
MMDEL

Okay, thanks. I will try that first before I tear anything apart. My recollection is that it was leaking from the relief valve itself and not somewhere else on the pump body but I can double check. I suppose I could check the pump housing bolts to make sure nothing has vibrated loose as well.

445 Hydraulic Pump Relief Valve Leak

JRMoline

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molinegb

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JRMoline

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T.R.K.

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MMDEL

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JRMoline

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