If we go back in again I will break out the 1k grit - thanks again!

By the way, where can you get new slipper springs?

 

Putting the rotor in backwards is a common problem. -hehe

I would not worry about sanding the interior surfaces with 1,000 or any other grit sandpaper. I like to keep abrasive particles as far away from hydraulic parts as possible.

The noise usually comes from fluid bypassing from the high pressure side back to the inlet side thru grooves or scratches in the valve plate. The valve plates are ground at the factory and hardened. Remanufacturers can not grind them properly and then hard coat them so they do not do it. There are usually shallow indentations around the ports that will change dimensions if reground lowering the efficiency of the pump. A fresh ground non-hardened surface will wear rapidly.

The relief valve pressure may need to be lowered slightly to keep the engine from being loaded down so much but it is fairly normal to notice a load. Was the relief valve reassembled properly?

Has the steering had other adjustments made like to the sector gear? If the gear has been mis-adjusted you will notice binding as the steering is turned. This can be dangerous and must be repaired. Other steering linkages can bind also.

 

The slipper springs only hold the slippers or vanes against the wall for startup. I doubt if they can be sourced individually. If they are bad the pump is probably trash.

 

I would think it would be standard procedure after micro polishing to wash the parts to remove any grit. Far as springs that's the reason to have a spare "parts pump" which was scored up and left for trash can. Assemble in a clean room where you can locate them should they (they will) shoot out before all are installed and slippers wired into the rotor.
The pressure relief valve is swaged in at the factory, no need to destroy it to remove just flush and check for full free movement. Relief spring pressure shouldn't change, this isn't like valve springs going weak. As far as lapping scored side plates they are hard and you'll never wear thru that, hell you'll only be able to bright polish the plates and wear out sand paper for days. If they are that bad it's time to look into another pump. There is no reason to lap the pump body as it doesn't wear with the end plates so rotor and slipper side clearances stay the same. With the springs missing you missed the joy of assembly besides at idle rpm's you can loose pump pressure hence manual steering like over demanding what the pump puts out at idle. If the Thompson Pump Company didn't think there was a need for the springs why are they there?
.....=o&o>.....

 

Well, now the DANG reservoir is leaking around the pressure output fitting! My hyd buddy put an o-ring on the fitting before the can went on, and I don't think we have anything between the can and the first nut, so OFF it comes again and I am SOOO tempted to discharge a can of FOAM STUFF all over this pump and encapsulate it!!!

 

Beemer, I think you misunderstand something. The springs are necessary but only for initial startup. After that hydraulic pressure holds the slippers against the cam ring. The springs alone could never do that. Inserting the rotor backwards did not apply hydraulic pressure to the slippers properly and they only had spring pressure which is why he had no output.

As far as sanding the pump, -it is entirely unnecessary and introduces the possibility of introducing abrasive particles so it should be avoided.

Remanufacturers should regrind the end plates etc to return a pump to full factory specs and remove the scratches and grooves that are always there. Unfortunately they can't because it changes some fine feature dimensions and they seldom have the equipment to properly surface harden the parts afterward which is why they do not do that. It is also why the reman pumps often make as much noise as the pump that is being replaced. The valve plates usually have been scored by abrasive particles which is what usually makes the "whine" noise in pumps. Bearings also go bad but they make a different noise.

BTW- I am a fluid power instructor and have had many years of experience with hydraulics.

 

That means instructions given by GM's aircraft division which is Allison for their 501-D13 Turoprop engines (C-130's),Pratt and Whitney have been wrong
and I've been wrong for over 27 years on fuel controls, hydraulic pumps and gear reduction boxes? This is smoothing minor scratches not scars from dirt or metal contamination. Only if it's a bushing or other soft metal that can imbed grit from sanding, grinding, polishing and burnishing is not allowed. Same rule applies to king pin bushing that are honed not reamed but thats another story.
wrong thread.
.....=o&o>.....

 

Please realize doing something in an industrial setting is different than doing it in a "home shop" environment. There is a difference, and home shops frequently do not have all of the facilities or knowledge we have in an industrial setting. That is why I temper the instructions with the setting. In a home shop setting people are more likely to destroy parts by obliterating metering edges or by using contaminated abrasives than anything else. In hydraulic applications the greatest majority by far of the scratches are below the surface and do not represent raised material. Any raised material is long gone. Of course if someone mishandles a part such as dropping it or allowing the high precision parts to bang around into other tools etc those imperfections must be removed.

 

Dropped parts? My friend a high school swim coach rebuild his 300 six that siezed up after running 10 minutes. He dropped a piston on cement but still installed it. Said piston fit tight in the bore, with his thinking it would be ok.
At the paint store years ago a employee cleaned the inside of a 352 by filling block with 10 gallons lacquer thinner and let it soak 24 hours. Front and rear mains leaked big time as well the fuel pump failed.
Sounds like Tim the tool man is at it again.
With a fresh sheet of sand paper, glass surface and a little solvent anyone can hand lap a part successfully, give more credit to fellow mechanics out there.
.....=o&o>.....

 

Sorry, I have seen more accidents than successes by any number of well meaning individuals so I try not to recommend practices that have a high "Oooops" factor.

 

I like your "Oooops factor".
Back in 68 in high school I was given a 64 Rambler American 440H (no hemi) without a trans. Installed a T96 with OD that was stock but would break with my driving habits, I started young at testing the limits. Located a standard T86, opened the rear of the case for the OD unit, welded relocated the mounting holes for trans to bell housing bolt pattern. All along the machine and auto shop teachers told me it wouldn't work your wasting your time. With the head milled .085", two two barrel carbs and cam it stayed together many years after I sold it. Not only I don't take no for an answer I also want to know why, stubborn German.
.....=o&o>.....

 

The "Oooops" unfortunately has too often come from my personal experience... -Been there done that seen that TOO many times!

I watched a guy ruin a $2000 servo valve one day and I couldn't say "DON'T" fast enuf.

 

On a different shift at the engine test stand a 18 cylinder 2800 Pratt went over speed because low pitch, blower in high boost and throttle set 100% from a disgruntle employee. The only word for that motor was carnage.
At United a JT9D came apart due to a socket thrown into the intake as the socket had and employees name on it an he had enemies, were talking $800K rebuilds in the 70's. Never mark your tools with your name or employee number or forget traction bars in the silver plate tank.
.....=o&o>.....

 

Morning, guys;

For what it is worth, the most worn out part of my pump was the shaft bearing, which was missing chunks of aluminum up and down the inside. Cool thing was it still had the script FORD on the outside of the bearing - original part! With the new bearing and the parts put in right side up, the pump is much quieter, and tonight it didn't seem to have as much stiffness in turns. Although I think I turned the steering wheel a bit slower, which should have helped. Tomorrow I make a gasket to go between the nut and the reservoir can - suggested material?

Thanks for all your combined inputs and knowledge!

 

My drawings show the nut goes on the outside of the can with the O-ring inside.

Beemer may be able to look at one of his tho.