WD45 hydraulic pump

To adj the pressure, remove the 4 -1/4 in bolts on front of pump holding plate on. There will be two valves exposed. Tap quick and lightly on the one closest to pumping plungers. It should bounce out farenough to get ahold of. Pull it out easy to keep every thing togather. There will be shims between spring and plunger. Add shims to increase pressure.

Just take your time and pay attention to detail.It's not as intimidating as you think and you really can't mess up much.I'd say keeping track of the direction and order of the control vavles and sleeves would be the most critical if you remove them.Mack's advise had you leaving them in and alone.If it's pumping good they are are not your problem as far as pressure goes.Sometimes they can get tiny bits of FM in them that don't let them shift position which controls pump flow rate.Let's say you tear it all apart and don't have a clue how to put back.Put all the pieces in a box and take it to someone who knows these old units and they can whip it back together in short order.It ain't really that high tech. 

I do have the section outlining the repair of that pump, I can send you copy if needed.

Please do Chris!! It never hurts to see another manual. My Email is RjRenko@aol.com. Thanks very much Chris. Ryan

Ryan,  Don't be intimidated by working on the hyd pump.  Just keep all the parts in order as they are removed.  Keep the parts in clean diesel oil so they will not enlarge.  Be sure to clean the pump.  As said above it does not take much to foul up action. 

All the plumbing comes off the hold valve.Remote and both lift arm cylinders so if your transport valve is not turned in tight it could be bypassing pressure there and dumping it back to sump.Do you for sure have a transport valve? It'd be on the end of the remote line with a return dumping back in at the fill cap.    I'm thinking maybe all 45's had transports but not sure. On the "nail" tip,you'll see where to wedge them in the lever when you compress it down by hand.Once you've cleared the housing with the rollers and the pump is kinda hanging on the pickup tube,you can pull them out with pliers easily.Don't drop one inside housing!

Edited by Steve M C/IL - 24 Apr 2011 at 11:06pm

Getting copy's done today, will contact you folks for address.

It still aint right!! We took pump off and very carefully started our rebuild. Ordered a seal and plunger kit from Agco part#70255272. All control valves were not stuck and were oiled and correctly reinstalled. All springs were not broken but replaced anyway. The only issue was the unloading valve assembly which Agco told me was no longer available but had a outside supplier. After all linkage was adjusted the pump was just as weak as before we started. It only would put out 1500psi and would slowly drop!! What are we missing?? The unloading valve from the after market supplier or what?? I don't know whats left to work on. Ryan

Bump

I was wondering what each shim added to the unloading valve would really do in terms of psi increase. Ryan

CTucker, thanks for any info!!! My brother and I are running out of things to replace!! We were VERY CAREFULL and had alot of information in front of us as we started. Replaced all springs and orings with Agco parts. The only other thing we didnt replace was the unloading valve assembly which I was told by our dealer was no longer available through Agco but they gave me a phone number for a aftermarket one. Maybe shims could be the answer.

Yes Ted. We put in our 1950 WD and it read a good 3600 psi!! We are at a point were we will not let this pump beat us!! lol

CTucker, it wasnt cracked. I kinda figured if the unloading valve was no longer available through Agco it must not be a high wear item. Am I wrong?? Ryan

Years ago I put a new unloader in my 45 and it didn't help a bit.Had 11 shims and still eradic unload pressures.Doubt unloader is culprit but this seems to be the $64000 question no one can answer.I've got a 5/16 washer with the center trimmed out as an additional shim and it's useable.Always good pressure at/off idle but not at half throttle or more.Always suspected the check ball on back end of pump where it transfers to control valve of not holding and getting a "bounce back" of pressure which effects unloader but never went to the trouble to prove it.They didn't include that "valve" in my rebuild kit from AC years ago.It takes pressure on the outlet end of unloader to lift ball off seat.I don't understand how mine can vary so much but it's most effected by rpm.I quit beating my head on the wall on got it useable and quit.  

Edited by Steve M C/IL - 29 May 2011 at 12:00pm

.020-.025 inch should do it. I have a home made hole punch so i make em right on my bench in the garage. it helps to have shim stock available when you need it.