JD 4020 loader

gwillhoite

New User
Been searching for a picture or schematic on how to plumb a 148 loader to a 1970 JD4020. I have used the search tool but didn't have any luck. Would someone please help or point me to a page where I may get the information. thanks so much.
 

My advice would be to acquire/install a PBY block between LH SCV & rockshaft housing to attach the loader valve hoses.

https://www.ebay.com/itm/JOHN-DEERE-POWER-BEYOND-KIT-1969-or-Later-4020-4430-4440-/273236588599?oid=282914572107
 
On my 3020 I removed the pressure line from the priority valve to the rockshaft and had a hydrulic place cut out a section of the line and flare the ends and place a JIC tee in the line. I put a flat face connector where it comes out under the platform so it is easy to disconnect when removing the loader.
 
The on line parts I'm not seeing what I remember ? Must be more choice in my owners manual for the loader ?
 
(quoted from post at 16:02:37 06/04/18) On my 3020 I removed the pressure line from the priority valve to the rockshaft and had a hydrulic place cut out a section of the line and flare the ends and place a JIC tee in the line. I put a flat face connector where it comes out under the platform so it is easy to disconnect when removing the loader.

Where did you attach return oil hose from control valve to tractor (ported hyd filter cover,RS return oil line or sump)?
 
(quoted from post at 16:02:37 06/04/18) On my 3020 I removed the pressure line from the priority valve to the rockshaft and had a hydrulic place cut out a section of the line and flare the ends and place a JIC tee in the line. I put a flat face connector where it comes out under the platform so it is easy to disconnect when removing the loader.

Where was the oil returned to the tractor ?
 
I have been wanting to plumb my 148 loader to my 1970 4020 as well. Also after 40 years the loader control valve was leaking internally and externally. So after numerous internet searches I decided to put a power beyond block on the left circuit SCV. This was partially due to my lack of understanding of some of the methods described but lacking pictures. The power beyond block was $166.00. I have had one problem that I'm not sure is solved yet. The top pressure outlet on the block keeps blowing the 0-ring under the adjustable boss no matter how I put that elbow on. Maybe someone else on here can set me straight. I put a straight fitting with 0-ring boss and put an elbow NPT fitting on that and it seems to work so far. The hoses I pushed under the platform from back left to front right. First one went the first time. The second hose took 10+ tries. I put quick couplers on the front end of the hoses so I can take the loader off, which is for me an extremely rare occurrence. If I can get the pics to load, I hope this helps.
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Your hyd plumbing looks very good. Is shiny large hex nut in photo a closed center plug? Did you tighten relief valve FEL control valve totally closed?

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The large hex nut on the loader valve is a closed center plug, I think cost around $22 shipped. I have not touched the relief valve so far. Have not used the loader much because of leaking boss fitting on top of power beyond block and having just finished this project 5 days ago. That leaking o-ring on that boss fitting first blew out the o-ring because I had it too loose. Then in the picture I thought I had it installed properly, but leaked out of the jam nut on the fitting. Tried again it did the same thing. That is when I purchased a straight boss type fitting and then put a 90 degree elbow on top of that to the hydraulic hose. Seems to work so far. I did need to cut the tin work around the seat to allow the SCV to protrude back a little farther than the tin work.
 
Thank you everyone. I think that the power beyond block is the way to go for me.
The pictures sure did help.
Thanks,
Gary
 
(quoted from post at 12:39:29 06/05/18)
(quoted from post at 16:02:37 06/04/18) On my 3020 I removed the pressure line from the priority valve to the rockshaft and had a hydrulic place cut out a section of the line and flare the ends and place a JIC tee in the line. I put a flat face connector where it comes out under the platform so it is easy to disconnect when removing the loader.

Where was the oil returned to the tractor ?

Ported filter for return
 
Nice, clean install!

I'll second TxJim's advice - At some point in time you should consider cranking in the relief valve on your aftermarket control valve. This would be the simplest way to prevent issues down the road.

Unless the manufacturer of the SCV provided a definitive value for the setting on the relief valve (I.E. 2500 PSI or higher) you run the risk of the relief valve opening prematurely and bypassing high pressure oil in the circuit. This will cause unecessary heat & a loss of hyd. performance.

Ideally the relief valve should be set 200 PSI +/- higher than the compensator setting / standby pressure. This would provide a redundancy of circuit protection in the event of a stroke control failure but would require a more lengthy set up procedure than most people are inclined to undertake.....


I have not touched the relief valve so far.
 
Power beyond block was easy enough and I was able to plumb under the platform so a good clean install. I have everything running however when I use the loader with my hay grapple on front, I loose hydraulic pressure after a few seconds of the clutch being depressed. No brakes, steering either.
I am going to change screen, filter and new fluid so is there anything else that I may check or need to do.
Again, thanks for all the replies.
Gary
 
Hello all. I really need some help. I still have the pump quitting when the clutch is depressed but now after running a 615 new holland disc mower for about an hour, the hydraulic temperature slowly rises to the red area on the gauge. All new fluid, screen and filter. A friend told me the pump was bad. I hate to just replace parts, which is very expensiveso I thought that I would get the members here to help. What to check, how? The service manual is not to clear to me. Thanks
 
Sounds like a high pressure leak to sump.

Check all valves for heat as an indicator for the source: steering valve, PTO valve(if equipped), rockshaft valve, any "add on" valves that may have their returns plumbed to the sump.

I doubt it's the pump........


(quoted from post at 16:41:01 09/13/18) Hello all. I really need some help. I still have the pump quitting when the clutch is depressed but now after running a 615 new holland disc mower for about an hour, the hydraulic temperature slowly rises to the red area on the gauge. All new fluid, screen and filter. A friend told me the pump was bad. I hate to just replace parts, which is very expensiveso I thought that I would get the members here to help. What to check, how? The service manual is not to clear to me. Thanks
 
(quoted from post at 19:41:01 09/13/18) Hello all. I really need some help. I still have the pump quitting when the clutch is depressed but now after running a 615 new holland disc mower for about an hour, the hydraulic temperature slowly rises to the red area on the gauge. All new fluid, screen and filter. A friend told me the pump was bad. I hate to just replace parts, which is very expensive

Many hyd pumps have been replaced only to determine that the pump that was replaced was good & not the hyd problem.

Is hyd oil cooler very clean? Get a laser thermometer & take temp readings of each hyd component. The hyd component with the highest temp will be the one that's leaking internally.

Tim had a very good point about FEL control valve "relief valve" not set above 2250 psi. It's also possible FEL control valve closed center plug seal has failed. These 2 items can be checked by loosening FEL control valve return hose & with FEL control levers in neutral start engine & no oil should exit loosened return hose.
 
Thanks for all the info. Never thought about laser thermometer so thanks for that idea. I have just installed my FEL that I purchased used at it still has the JD controls but I will test as you stated. Thank you everyone
 

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