leaky hydraulic pump - can I replace front seal

[oldnslo]

This company advertises that they can identify Cessna pumps.

Cessna Gear Pump Identification

 

[buffdan]

wow, you guys are great.

I emailed knight hawk supply.. see what they have to say.

J.J.
You think this could be a replacement pump? Of course adapting..

Dan

 

[J_J]

It depends on what you need for GPM's,

Some people can look at the gears width/diameter and tell the GPM

You can use engine HP to see how much HP you can drive a hyd pump.

What is the engine HP.

For instance, to obtain 20 GPM's at 3000 psi, you will need about 41 HP.

 

[buffdan]

I got a reply back from knighthawk: "this pump was made for the OEM only"
No parts idea from them.

The engine is a Wisconsin THD, 18HP 3600 rpm.
The pump is direct drive off the engine.

I think my trencher is a TF500, Task Force 500 from Davis/Case.

I saw some posting for a TF300, which indicated "pump should be about 19 GPM @ 1800 PSI "
TF300 is similar, but I believe maybe a bit smaller..

I'll have to poke around some more.

I guess my plan will be to line up a "just in case replacement", and see about seal.

This also has a davis d100a backhoe attached to it ..
Its quite a versatile machine..
So I'd like to get it up to speed, so to speak.. '

Thanks for all the help.. Very much appreciated

 

[Egon]

Many cases a seal starts leaking due to other internal problems like play in the shaft.

 

[wdchyd]

True, 50% of the time it's not just a seal needed

Worse case scenario, if you had to replace the pump you could always add an adjustable variable flow divider just after a new standard pump.....that way you could tune your system to get same basic results as the priority flow rear cover on your existing pump

Best would to try to fix the original pump though

 

[alex16701]

Dan

I believe those are Cessna / Eaton numbers. Eaton purchased Cessna years ago and this product could be considered obsolete. Like wdchyd said. Yes you can typically replace the shaft seal. Concern would be why is it leaking? Just wore out from age, shaft damaged, excessive wear on gear wear plates allowing excessive leakage which over pressurizes the seal, etc..

so is there another pump i can replace this one with

 

[oldnslo]

Alex
I did not go back through this post to see what information you have provided but yes suspect you could obtain a pump that would mount in same location with similar displacement. The big unknown would be port style, size and location vs existing unit.

You will need to know pump mount flange style, input shaft, displacement and direction of rotation.

 

[ROUSTABOUT]

Just take old seal out carefully. Numbers on seal itself are what you need. I never ever use a seal puller. It destroys the seal. Seals have a spring that goes around the rubber that holds it tight on the shaft. Spring may be gone. That would be a simple fix. Also any bearing that has wear or slack, numbers are on bearings and races too. You shouldn't need any hard parts, only wear items. Like I said, be careful with removal and take apart like you will have to use the same parts when you put it back together. That way you will save the numbers to order new replacements. If you can't take something apart without destroying it, my confidence in you putting it back together properly ain't gonna be there.

 

[Egon]

Might be best to follow your plan to run as is and then sell If it’s possible to keep it running.
If you do touch the pump make sure you can get a replacement pump that will fit Before any work is done.