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3388 IH pfc pump queation


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Hi all I have a question regarding the pfc pump on a 3388.  The tractor has been running great until last night.  Was bush hogging and went to raise the wings to go through a gate.  Wings raised half way then dropped back down.  Also cannot raise the three point arms, but I can pull them up by hand then they fall down.  I changed all filters still nothing.  I just pulled the pfc pump from the tractor this morning.  All of the splines and gear look fine and the large gear turns easily by hand.  So first question when I split the pump from compensator block what am I looking for to be wrong?   Second I have seen conversion kits to go to a gear style pump.  Would this be a good move for me?   Thanks in advance for your knowledge and help!!

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So I found my problem.  The large gear that drives the pump has sheared the shaft going into the pump.  So now the question.  Do I buy a reman piston pump or do I buy a gear pump conversion.  I do not use anything with a hydraulic motor.  

ED99CCF8-EC0A-41D2-A8AB-4AB15EAAF159.jpeg

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going back to the gear pump is a joke the piston pump is much better those pumps are simple to work on I've rebuilt dozens with excellent results if all you want lower performance flow the gear pump will be ok they are reliable but you'll sacrifice other things flow and closed center hydraulics and the flow control and motor valve function plus alot more expense converting it over to the old gear pump

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1 hour ago, jtmurphy1 said:

Hi all I have a question regarding the pfc pump on a 3388.  The tractor has been running great until last night.  Was bush hogging and went to raise the wings to go through a gate.  Wings raised half way then dropped back down.  Also cannot raise the three point arms, but I can pull them up by hand then they fall down.  I changed all filters still nothing.  I just pulled the pfc pump from the tractor this morning.  All of the splines and gear look fine and the large gear turns easily by hand.  So first question when I split the pump from compensator block what am I looking for to be wrong?   Second I have seen conversion kits to go to a gear style pump.  Would this be a good move for me?   Thanks in advance for your knowledge and help!!

PTO work makes them shafts break I've seen it first hand chopping corn the internal pto shaft flexes and exerts to much side pressure

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2 hours ago, ksfarmdude said:

going back to the gear pump is a joke the piston pump is much better those pumps are simple to work on I've rebuilt dozens with excellent results if all you want lower performance flow the gear pump will be ok they are reliable but you'll sacrifice other things flow and closed center hydraulics and the flow control and motor valve function plus alot more expense converting it over to the old gear pump

Did you buy rebuilt pumps or rebuild them yourself?   If so where did you find the parts?   Thanks ksfarmerdude!

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2 hours ago, jtmurphy1 said:

So I found my problem.  The large gear that drives the pump has sheared the shaft going into the pump.  So now the question.  Do I buy a reman piston pump or do I buy a gear pump conversion.  I do not use anything with a hydraulic motor.  

ED99CCF8-EC0A-41D2-A8AB-4AB15EAAF159.jpeg

 Hy-capacity will sell you the shaft, it’s not that hard to change it! 

 But before you buy a new shaft you should take the pump apart and see if it’s seized. 

 I’ve had two of those pumps break the shafts because the pumps seized due to contaminated oil, it happens in the cooler weather because the bypass screen has a valve in it that will close only when the oil is warm. The oil got contaminated from the brake discs, the plates between them warped and was running the brakes in the on position which caused them to wear and fill the hydraulic oil with particles from the brake discs. 

 I converted two of my tractors so far and the next ones that have hydraulic pump problems will be converted too, I installed 17 GPM pumps and they work better than those piston pumps which in my opinion were good but they weren’t designed for those tractors. Piston pumps need a charge pump to feed the oil to them. 

 Whatever you decide to do, good luck!    I’ve never had much luck with those pumps!

 

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12 hours ago, jtmurphy1 said:

Did you buy rebuilt pumps or rebuild them yourself?   If so where did you find the parts?   Thanks ksfarmerdude!

I would get them at dealers that swapped other tractors out to gear pumps that they removed and i have a connection thru the company that manufactured them pumps for IH the pumps were salvage value basically and all the replacement parts were very reasonable mostly broken shafts gears with teeth gone an occasional cracked housing I'd always keep  one ready to go just in case but after we quit using our 1086 on anything pto the pump never quit again but the pumps are easy to work on if your very clean and careful I know most guys don't like them and hate dealing with breakdowns they cause and gear pumps are more reliable I just never went that route good luck

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12 hours ago, Qc.Can.IH man said:

 Hy-capacity will sell you the shaft, it’s not that hard to change it! 

 But before you buy a new shaft you should take the pump apart and see if it’s seized. 

 I’ve had two of those pumps break the shafts because the pumps seized due to contaminated oil, it happens in the cooler weather because the bypass screen has a valve in it that will close only when the oil is warm. The oil got contaminated from the brake discs, the plates between them warped and was running the brakes in the on position which caused them to wear and fill the hydraulic oil with particles from the brake discs. 

 I converted two of my tractors so far and the next ones that have hydraulic pump problems will be converted too, I installed 17 GPM pumps and they work better than those piston pumps which in my opinion were good but they weren’t designed for those tractors. Piston pumps need a charge pump to feed the oil to them. 

 Whatever you decide to do, good luck!    I’ve never had much luck with those pumps!

 

there was a filter by-pass bulletin on those tractors years ago that did away with the thermostatic bypass filter screen so the pump wouldn't cavitate in cold weather they replaced it with the common spring by-pass screen like all the older tractors had

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those pumps wouldn't be much of a problem if they would have had a charge pump in my opinion.

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1 hour ago, ksfarmdude said:

there was a filter by-pass bulletin on those tractors years ago that did away with the thermostatic bypass filter screen so the pump wouldn't cavitate in cold weather they replaced it with the common spring by-pass screen like all the older tractors had

 How many of those screens do you think were actually changed?

 I have five tractors with those pumps in them and I have never seen one with an updated screen.

 What I do with those thermostatic screens is jam a nut to hold the valve shut all the time, I use a five eights or three-quarter inch nut

 The conversion kits come with the updated screen. 

6 minutes ago, Brian stortenbecker said:

those pumps wouldn't be much of a problem if they would have had a charge pump in my opinion.

 Exactly!!  Those pumps were just added on to an existing hydraulic system!

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1 hour ago, snoshoe said:

What ever way you go. I would certainly reshim the front pto bearing.

that still won't stop shaft deflection and that's the problem causing shaft breakage on these pumps

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20 hours ago, wheatking said:

inside the compensator block theres a bunch of o rings nothing to much could go wrong in there, how was the O ring on the cover that the pump bolts to? they can bypass pressure if the o ring is no good 

the compensator valve block has a dart valve that can break or stick it also is where you adjust the system standby pressure when the pump isn't in stroke

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10 hours ago, ksfarmdude said:

there was a filter by-pass bulletin on those tractors years ago that did away with the thermostatic bypass filter screen so the pump wouldn't cavitate in cold weather they replaced it with the common spring by-pass screen like all the older tractors had

Do you have a copy of the service bulletin?

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On 9/22/2019 at 5:33 PM, 2+2love said:

Do you have a copy of the service bulletin?

No that's been years ago I seen it maybe a oldtimer has a copy we first learned about the bulletin and change over to the old style by-pass because we'd  top dress wheat in very cold weather and the pump would make loud hmming noises and sound like air in the system it got so bad it cracked the motor valve accumulator line that bolts onto the left side of the rockshaft housing after we changed by-pass screens to let oil pass thru faster it stopped that problem from then on

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