Hydraulic System Drain With No Pump

[CraneInnovation]

Hey guys,

As some may know, I'm digging into an old Gradall G3WD. Have a hydro system draining question.

How do you do drain a hydraulic system if the pump is inoperable? I need to service the pump PTO as well as reseal all cylinders. Is a full drain required, or should I just drain whichever lines I disconnect?

Thanks,

 

[BSAA65LB]

If you don't know the history of the machine, I would drain the tank and any lines/components you remove. Then start out with rebuilt cylinders and fresh oil and filter in the machine.

On a G3WD, make sure you have air out of the lines at the pump before start up. The pump is located above the tank and needs primed before you start it.

Adjust the pump engage linkage. People fix the pump drive and don't adjust the disconnect cylinder. Then you damage all of your nice new expensive parts. The service manual has a procedure in it to adjust the pump disconnect cylinder, linkage, and switch. On some of those machines, the linkage parts get worn and it is best to replace them when replacing the coupling.

 

[CraneInnovation]

Thank you!

History is relatively unknown. I do know that some things were done correctly (engine is in tip top shape) and others were done incredibly poorly. The hydraulics system seems to have been serviced by someone unfamiliar with the machine. It appears they were tasked with replacing the telescope hoses and destroyed the pump shifter during start up. The telescope circuit was never even primed and the boom is basically an air spring. This proceeded to slide back at the cab the first time someone went to drive the now-wounded machine and smashed the front windshield out and warped the cab. That's basically how it ended up in my hands for a song. Oh well....lots to learn fixing her up, I guess.

Have you replaced the PTO shifter on these before? I'm at a loss for information and it appears the part is inside the transmission. I'm searching for info on it right now. The service manual says it is a Funk 2000, but the 4x4 definitely doesn't have a 2000. The drawing in the same parts manual shows a very different outline (the one in the 4x4 (mine) is significantly shorter than the Funk 2000 in the 4x2). I'm not necessarily afraid of taking the transmission out, but at this point the only manuals I have from Gradall do not include any information on what transmission is in the 4x4 and what a parts list/drawing looks like.

 

[BSAA65LB]

I have changed a few Usually after someone else screwed them up.......

The pump is driven off the charge pump on the LH side of the convertor. A coupling, shift fork, and shifter are all involved. The set up is kinda of strange but does work. If it is adjusted correctly! A set screw replaces the usual detent at the shifter to keep tension on the shift fork. The air cylinder needs to be adjusted for proper stroke. A switch is provided to prevent the engine from starting until the coupler is engaged. You can crank the engine, but it won't start until the coupler is fully engaged.

You do not have to remove the trans to service the pump drive. All of that work can be done from the back of the torque convertor housing.

The switch can also come out of adjustment and cause intermittent shutdown when running. So getting the switch right is important.

The air cylinder mount can wear as can the yoke and pin that attaches to the shifter. If you have too much wear, you lose travel at one end or the other of the cylinder stroke affecting your coupler engage/disengage.

The machine used the Funk 2000 in either standard configuration (2WD) or as a remote mount (4WD). Same basic trans, just different configuration to allow 4WD.

Gradall has a fairly easy to use website to make sure you have the most up to date and complete manuals. You need the machine S/N and go to this site and type in the S/N to get up to date manuals: http://www.myexcavatormanuals.com/

 

[CraneInnovation]

Thanks for the tips. I'll definitely make sure I go through the adjustment procedure before startup.

I think I figured it out. Remote mount...as in farther back on the carrier? I wish I had the machine in front of me over the last few days, I might have noticed that...

On the 2WD drawings, the Engine, TC, and Transmission are bolted directly together. On the 4WD powertrain drawings (page 144 of manual 7733-1007 for SN 0138245) the transmission is not shown after the TC. Am I correct in guessing that they moved the transmission back to the center of the carrier? That would mean the assembly shown behind the engine IS the TC, not a different transmission.

So....does this mean that what I am looking for is the PUMP ADAPTER GROUP shown on page 165? The page title says "Charge Pump Assembly - Power Steering Pump Adapter Assembly" which is why I had glossed over it before. Is it actually showing me the hydraulic pump adapter group at the bottom of the page? It never says "Main Pump" or "Hydraulic Pump" anywhere on the page, but I think it might be. This would mean the part I'm probably going to need (barring more extensive damage) is 7738-4382 ADAPTER SLEEVE?

If you could take a quick look at that file and page (165) it would do me a huge favor! I think I'm finally barking up the right tree.... It is bizarre to me that they never mention that the little drawing at the bottom of the page is actually the MAIN HYDRAULIC PUMP ADAPTER??

Thanks so much!

File:

http://www.myexcavatormanuals.com/pdf/parts_manuals/7733-1007_Lot 229_G3WD_Gradall_Parts_Manual.pdf

 

[BSAA65LB]

I just had a chance to look at the parts book. I will reference the page number on the file along with the old Gradall page number in the book.

Page 174 (UN3-22) is the pump engage linkage - this requires adjustment and inspection to make sure it is not worn out or otherwise abused.

Page 202 (UN3-45) is the convertor housing overview. The main pump is on the LH side, as I remember, PS on the RH side

Page 203 (UN3-46) is the actual pump drive. You are looking at the charge pump which had an extension to act as the pump drive. It. 25 is the coupling that engaged the pump.

Either versionused the Funk 2000. 2WD had the unit type transmission (convertor and trans as one unit), the 4WD machines had a convertor attached to the engine with a remote mount trans mounted in the frame. The other major difference, the 2WD installation did not have a drive output in the front of the trans. A lot of the bits and pieces are the same between the 2 transmissions.

 

[CraneInnovation]

Wow, thank you. I checked out those pages and yes, I wanted the disconnect sleeve, not the charge pump drive adapter.... Got ahold of CN Wood in time to change it. Also located the Funk 2000 under the small access cover in the center of the carrier deck. Fluid looked to be in good shape.

Thanks so much for taking the time to help me out. I'll figure this service manual out eventually...

To the draining issue, I think I've found a few ways to drain the system. Was going to do that yesterday but this entire weekend was a washout. We did discover that the hydraulic fluid got water in it and will definitely need replacement. Good thing I'm still having fun.

 

[BSAA65LB]

If you look at page 131 (UN2-13) you will see a hex plug It. #15. That will drain most of the tank. There is a cleanout plate on the bottom and front to access the inside of the reservoir to clean it thoroughly.