D series pump rebuild

[Firebug 267]

soooo when I bought my 74 d200 the old man told me the pump was getting weak. Me being the skeptic that I am figured it probable needs a good fluid change and shift lever adjustment. I hate to admit, while those did help, the old man was right. The pump is getting weak. I have another off my parts tractor but I'm unsure if it's internal condition. Does anyone know who rebuilds those or if a rebuild kit is available. The tractor is supposed to be going to the local trade school soon for a rebuild/ restore and figured that would be the perfect time to get the pump rebuilt but I'm not sure where to source the rebuild kit from. I talked to a local hydraulic shop and he said he isn't to familiar with that sunstrand pump, his labor rate was 150 per hour and he said he would have more than 6-8 hours into it. I figured there has to be a cheaper option while not sacrificing the quality of work. Any help would be great. Btw I'm in ravenna (akron) Ohio if that helps. 

[daveoman1966 3,762]

I live near Meadville PA...not too far from Akron.  These Hyd PUMPS are not difficult to rebuild as I have done a dozen or more of them.  However, if you intend to rebuild the pump, you'd be well-advised to also rebuild the Hyd MOTOR assembly and the circulating fluid is common to them.  I say that because the internal components are nearly identical and usually suffer from the same 45 years of use/abuse.  In other words, the power loss MAY not be just from the pump...but from the motor also.most difficult part is getting the PUMP removed from the tractor....can be a PITA.  The MOTOR is much easier to get to, but still more than a nuisance.

If you know what a wrench is and how to use it,  you can manage this rebuild.  It is rather time-consuming and tedious, but don't let that be intimidating.

Here are a few pics of what MAY be expected.....       

 

Edited August 28, 2017 by daveoman1966

[Firebug 267]

So my guess is the fluid bypasses around the score marks. Are the plates replaceable?

[daveoman1966 3,762]

When dirt gets into the system, tiny particles scratch the BRASS surfaces and then oil pressure is lost as the oil escapes thru the scored surfaces.  Use graduated steps from 200  to 400 to 800 grit paper to resurface the BRASS surfaces, but not to a mirror finish.   Put a drop or two of oil on the sandpaper first and use the ole' wax on...wax off' method or a surface plate (thick glass is ok).  Use the same procedure on ALL mating surfaces that have scratches / scores, including steel surfaces.  If any two parts rub together or spin against each other, resurface them.  Keep a can of carb cleaner at the ready and, after resurfacing each part, spray generously to clean it. Try to keep the pistons in original cylinders and resurface them one-by-one.         

Does you pump leak at all.....would be a good time to install new seals if it does.  

Take EXTRA CARE to mark the orientation of the CHARGE PUMP HOUSING.  Note the pin in this pic: 

Another matter is to THOROUGHLY clean out all of the valves on the MOTOR assembly.  Be sure to keep them oriented correctly as well.

[Firebug 267]

It sounds pretty involved but I'm sure once I've done it that it isn't as bad as it looks

[daveoman1966 3,762]

It is time consuming to do it right...  Just take your time and keep work area clean as possible.  Flush ALL parts in kerosene before refit, and use some PRE-LUBE oil (the red oil) as used in engine rebuilds.  

Dirt is your worst enemy...keep everything white-towel clean for reassembly.

I can probably help you out better if we chat in off-site emails  My direct email is:

daveoman@windstream.net

I have hundreds of pics of these parts, buit don't want to clutter up Red Square with all of them.  I can send them in emails to you though. 

 

[Firebug 267]

What about deep scoring, do those polish out the same as light scratches?

Sounds great. My direct email is sagaser1213@hotmail.com. 

[daveoman1966 3,762]

Sometimes ya' just can't get them perfect....  but do the best possible.