Hydraulic screen on Yanmar 4220D

[Gary Fowler]

After setting idle for a few months, my hydraulic system completely failed and it was working perfectly when it was parked. I changed the filter and oil but could not locate the screen. I traced the suction line from the tranny and removed the line and circular plate with 3 hold down bolts. There was another circular plate behind the one holding on the suction line, but I could not get to one of the bolts with the tools I had available. Can anyone tell me if the hydraulic screen is behind this second plate. I could feel around inside the hole but could not feel anything. I looked through a diagramed operation manual, but all the listing were in Japanese and I did not see anything that looked like a screen. I emailed Hoye Tractor about a replacement pump, but they advised that it could not be the pump since the clutch also stopped working and it is on a seperate pump so the likely hood of both pumps failing at once is pretty low. They suggested cleaning the screen, and said the plate was directly under the PTO, but I did not see a plate at that point.
Some info please. If anyone has a photo or schematic of the location, I need that badly

 

[hazmatguy]

On my 3110 under the PIO shaft (down and to the right) as you look at the rear of the tractor is a Plate that has 3 bolts. The screen is behind that plate.

Good Luck

 

[Dick_Jermyn]

Gary,

On my YM2620D the suction screen is on the back, under the PTO, just to the right. It has three bolts, and the cover is semi triangular in shape. Note- I had the same problem the first time around too.

Dick

 

[Gary Fowler]

Thanks guys. Found the screen location as described.
I cleaned the screen twice, replaced the filter and oil and it is now dirty as muddy water.Has anyone any idea how long it takes to clean this crap out of the system?
Anyone with ideas on how long or how to clean this stuff out of the hydraulic system, please respond.

 

[Lasgambler]

Hi Gary, Welcome Home. Sorry to hear you are having problems. I don't have a clue how to flush the system. Sounds like a good question for Aaron.
Good luck.

 

[kenmac]

Thanks guys. Found the screen location as described.
I cleaned the screen twice, replaced the filter and oil and it is now dirty as muddy water.Has anyone any idea how long it takes to clean this crap out of the system?
Anyone with ideas on how long or how to clean this stuff out of the hydraulic system, please respond.

Is yours one of the VN "recons" ? If so, there's no telling what they put in the systen for hyd. fluid. So, it may take seversl flushings

 

[California]

... replaced the filter and oil and it is now dirty as muddy water. ... how to clean this stuff out of the hydraulic system, please respond.

My experience was a little different. The hydraulic fluid was neglected but not contaminated. I poured a little diesel in the transmission fill hole then scrubbed the filter's cavity and the transmission sump with a parts brush until the diesel ran out clear. I didn't have hydraulic problems, before or since, this was simply preventative maintenance.

I think on yours I would open the hydraulic circuits at the far end, at the loader cylinders, to purge the bad fluid as completely as possible. Also purge both sides of the cylinders to assure they refill with clean fluid.

If your fluid looks that bad, there is still water in there somehow.

I've read that the simplest way to prevent water entering, is to replace the gearshift lever boot.

 

[YanmarFever]

My experience was a little different. The hydraulic fluid was neglected but not contaminated. I poured a little diesel in the transmission fill hole then scrubbed the filter's cavity and the transmission sump with a parts brush until the diesel ran out clear. I didn't have hydraulic problems, before or since, this was simply preventative maintenance.

I think on yours I would open the hydraulic circuits at the far end, at the loader cylinders, to purge the bad fluid as completely as possible. Also purge both sides of the cylinders to assure they refill with clean fluid.

If your fluid looks that bad, there is still water in there somehow.

I've read that the simplest way to prevent water entering, is to replace the gearshift lever boot.

I (think) the 4220 is a collum shift machine, the advice using the diesel fuel is good. I have done that a few times and it works.