YM2620D - Loss of hydraulic pressure to rear 3 pt. and front loader bucket?

Dick_Jermyn · Nov 16, 2014

I have lost pressure to the rear 3 pt. and front Bush Hog loader. Hyd. fluid res. is up to fill mark. Bubbles on dip stick when I check fluid level. I looked for cracked lines on both the pressure side and on the return side. Found none. New Hyd. filter has less than 6 hours use. I cracked the pressure line from the pump and started the tractor. I had very weak flow from the pump. Bubbles appeared in the out flow of the fluid. Where are the air bubbles coming from? Why do I not have more pressure from the pump? Could the keyway on the pump shaft be sheared part way? Could the pump be pulling air from it's drive shaft seal? Please help me figure this one out. Also: if the pump is the problem, do you need to remove the radiator support to get it off. It looks like a tight fit in the area of the pump. Again guys, thanks for your help with this matter. I look forward to hearing from you.

Dick

normde2001 · Nov 16, 2014

Probably a sheared pin. Friction and tight fit will allow some pumping. Do whatever is necessary to remove.

winston1 · Nov 16, 2014

Have you cleaned the suction strainer?

Dick_Jermyn · Nov 16, 2014

Thanks guys for the quick reply. Last year I had the rear end open and cleaned the screen. It had almost nothing on the screen.

Normde2001 - Are you suggesting the keyway on the hyd. pump?

Thanks Winston for you input. I have seen how helpful you have been to many of the yanmar owners.

If anyone else has any ideas, please chime in. Thanks, Dick

kenmac · Nov 16, 2014

I would say you have pump issues. Either bad pump or sheared key/pin

winston1 · Nov 17, 2014

With your symptoms and assurance of clean fluid, strainer, filter and good connections I would agree with Normde and Kenmac to pull the pump and have a look.

Dick_Jermyn · Nov 17, 2014

Thanks for the additional input on this matter, guys. I have Tuesday off and will attack the disassembly of the pump to check for a bad key way. I will let all know what I find. Again, Thanks. Dick

Note? If I find that the keyway is ok, is there a easy way to see if the pump is working properly?

kenmac · Nov 17, 2014

Dick_Jermyn said:
Note? If I find that the keyway is ok, is there a easy way to see if the pump is working properly?

If the key way is good & you have no suction restrictions & the shaft that turns the pump turns & the pump still doesn't pump. You most likely need a pump

Dick_Jermyn · Nov 18, 2014

Went at it today. I pulled the pump and removed the collar drive to exam the keyway. Key is good with no damage and the pump turns around ok. There are no cracks in the pump housing. I drained the sump and pulled the screen. Clean. I pulled the new filter. Looks good. I recharged the sump and put all items back in place. I have a little rise in the 3pt. and the front bucket. Not as fast as it should be. Power steering works good and all clutch packs make the tractor move just fine.

I had a nice discussion with Sam from Hoye's. He suggested that I look at the pressure manifold splitter that comes after the outflow from the pump. This has valves that may have gotten stuck by something. Friday I will pull off the splitter and check it's innards to see if something is preventing good flow. Will let you know what happens.

Have any of you had one of these splitters apart? I understand that they have ball checks inside. Any input will be appreciated.

Again, Thanks, Dick

kenmac · Nov 18, 2014

Ok, didn't know you has PS. If PS is working ok,,It very well could be something in the divider block . Best I remember the power shift has it's own pump.. Here is some info straight from my service manual....the flow control valve in divider block assures priority oil supply from the main HYD. pump to the PS valve..