Hydraulic Pump Seals - My turn to cry

[jinman]

Well, my hydraulic pump is back in my tractor and working quite well. The total charge for the seal kit and replacement was $188. That's not too bad in my book. Of course, I needed to buy some o-ring seals and such, so the total cost of the repair was around $200. That's a whole lot better than the price of a new pump.:thumbsup:

Below, I've included an illustration of the piping. Notice item #9, the high pressure line between the pump and the diverter valve. At the diverter valve end are an o-ring (item 30) and a thimble shaped screen (item 27). The screen was partially clogged with brown fibrous looking trash (2nd image). I cleaned the screen and put in a new o-ring, then used grease as "glue" to hold everthing in place during installation. The 3rd image shows a bad cellphone image looking up at the bottom of the pump with one bolt installed. The last image shows the pipe going into the diverter valve. Note the large suction line above the smaller high pressure line. I don't know if it is just me or what, but the line to the diverter valve has only two small bolts and an o-ring to hold back 2500 psi of hydraulic pressure. It's amazing that it doesn't leak.

When I got all finished and the pump checked out, I reinstalled my loader. I was all excited and then my heart sank when I noticed one of my loader quick connects was leaking. A quick inspection turned up a quick connect o-ring with a chunk missing out of it.:smiley_aafz: So off to my NH dealer I went and bought another o-ring (actually a couple to have a spare). It seems it's always something when you own equipment or a house. These things can nickel and dime you to death. I'll cross my fingers and hope there are no more failures for awhile.

EDIT: I had a picture out of sequence. I added the final picture of the tube to the diverter at the end of the series.

 

[dcyrilc]

Well, my hydraulic pump is back in my tractor and working quite well. The total charge for the seal kit and replacement was $188. That's not too bad in my book. Of course, I needed to buy some o-ring seals and such, so the total cost of the repair was around $200. That's a whole lot better than the price of a new pump.:thumbsup:

Below, I've included an illustration of the piping. Notice item #9, the high pressure line between the pump and the diverter valve. At the diverter valve end are an o-ring (item 37) and a thimble shaped screen (item 27). The screen was partially clogged with brown fibrous looking trash (2nd image). I cleaned the screen and put in a new o-ring, then used grease as "glue" to hold everthing in place during installation. The 3rd image shows a bad cellphone image looking up at the bottom of the pump with one bolt installed. The last image shows the pipe going into the diverter valve. Note the large suction line above the smaller high pressure line. I don't know if it is just me or what, but the line to the diverter valve has only two small bolts and an o-ring to hold back 2500 psi of hydraulic pressure. It's amazing that it doesn't leak.

When I got all finished and the pump checked out, I reinstalled my loader. I was all excited and then my heart sank when I noticed one of my loader quick connects was leaking. A quick inspection turned up a quick connect o-ring with a chunk missing out of it.:smiley_aafz: So off to my NH dealer I went and bought another o-ring (actually a couple to have a spare). It seems it's always something when you own equipment or a house. These things can nickel and dime you to death. I'll cross my fingers and hope there are no more failures for awhile.

Good job on the repair. I hope mine goes as well. Last fall I had a hydraulic line over the engine blow. Low pressure held on with a hose clamp. It dumped about 7 gallons of fluid over the top of the engine. The alternator died within a week and the starter just smoked last week. Both are in being rebuilt right now. The shop confirmed oil in them as the cause of failure. The alternator is no big deal, but it's going to be interesting trying to get the starter back in as there is vertually no access to the lower bolt to put it in and get the threads started. I used a magnet to keep from loosing it when I removed the starter.

 

[Elviscaretaker]

It seems it's always something when you own equipment or a house. These things can nickel and dime you to death. I'll cross my fingers and hope there are no more failures for awhile. .[/QUOTE]

Amen to that
Thanks for the pics! Do you think that little filter(screen) may be on all of the NH pumps? I might just pull that line off and take a look. Can't be good if crap starts plugging it.
Good luck with nothing else going wrong :laughing:.

 

[jinman]

Amen to that
Thanks for the pics! Do you think that little filter(screen) may be on all of the NH pumps? I might just pull that line off and take a look. Can't be good if crap starts plugging it.
Good luck with nothing else going wrong :laughing:.

In my opinion, the chance of that little screen being plugged up enough to cause you a problem is not nearly as likely as something being messed up in the process of removing the high pressure tube. Let me be completely honest. I pinched one o-ring and had a leak. I had to remove the pipe and replace the o-ring. The 2nd time I used my head and held the o-ring in place with grease. Getting to the four bolts under the pump takes a unversal adapter and short socket on a 3/8" rachet and a good open-end/box-end wrench. If I was not sure there was a problem, I'd never remove the pipe. I sure would not recommend just doing it for a regular inspection. If you had a clog and could not find the source, it might be worth a look-see. Otherwise, I'd recommend leaving it alone.

 

[Wacky]

Chalk this up to another learning experience for me, as I expect to call upon you experts when I run across an issue like this one! Great thread guys:thumbsup:.

 

[wdchyd]

Chalk this up to another learning experience for me, as I expect to call upon you experts when I run across an issue like this one! Great thread guys:thumbsup:.

Great Thread especially when everything turns out right.....Knowledge Is Power..!!.......:thumbsup:

 

[JC-jetro]

Jim,

So what failed inside the pump after postmortem analysis?

JC,

 

[Elviscaretaker]

In my opinion, the chance of that little screen being plugged up enough to cause you a problem is not nearly as likely as something being messed up in the process of removing the high pressure tube. Let me be completely honest. I pinched one o-ring and had a leak. I had to remove the pipe and replace the o-ring. The 2nd time I used my head and held the o-ring in place with grease. Getting to the four bolts under the pump takes a unversal adapter and short socket on a 3/8" rachet and a good open-end/box-end wrench. If I was not sure there was a problem, I'd never remove the pipe. I sure would not recommend just doing it for a regular inspection. If you had a clog and could not find the source, it might be worth a look-see. Otherwise, I'd recommend leaving it alone.

I'll follow your advice! Thanks.:thumbsup:

 

[jinman]

Jim,

So what failed inside the pump after postmortem analysis?

JC,

The inner high pressure seal blew out and the outer shaft seal followed because it is not designed for high pressure. It's function is more to keep engine oil out of the pump than to hold hydraulic pressure inside. With both seals blown, the engine was slowly filling up with hydraulic fluid.

The service manager told me that the first one of these they did, they just replaced the obvious outer seal. He said when they installed it back into the tractor, it instantly failed again and they learned that you should always replace both seals for a reliable fix.

 

[dfkrug]

The inner high pressure seal blew out and the outer shaft seal followed because it is not designed for high pressure.

Glad you got it fixed, Jim.

Any reason you did not open up the pump and replace the seals yourself?

Anyway, I hope you can pave the way for your grandson to become quite
handy; not many kids have good mentors these days....

(WDCHYD: I hope lots of folks see your post about what can happen
when you increase those implement pump pressures. A new pump is prob
north of $600.)