4020 Loader Hydraulics

Mr Wags

New User
I have a 1968 4020 diesel with a 148 loader.
Currently the loader is running off the rear two
remotes.

Isn't there a way to add a hydraulic pump to the
belly and run the loader off that one and free up
the rear remotes?

Any help, pictures, part numbers, links would be
great.

Thanks
 
You dont need to and another pump. There is a way to add a closed center valve and plumb it to a pressure line on the clutch housing and run the return to a ported filter cover on the LH side of the tractor. I cant remember exactly how to do this. Tim S or BuickandDeere probably know off the top of their heads.

JW
 
You can get your pressure from the elbow fitting that is on the right side right in front of the brake pedals. Install a tee in place of the elbow. Your return oil goes back to a ported filter cover on the left side. This works best with an indedpendent control valve. Good luck.
 
You can also add a second SVC (if you don"t have one already) and lines to run the second set of outlets for the loader. I did that on my 4010 and it"s great!
 
This is one of those topics where the "correct answer" depends on who you ask.Although most will agree the JD has a very robust hydraulic system with plenty of pressure and flow for a loader.
Ideally the high pressure oil is "T" tapped to an independent set of closed center control valves for the loader.
Then the oil is returned via a ported filter cover. The ported filter return ensures and front pump does not run dry and cavitate.The transmission supply pump has limited flow and it quits pumping when the clutch pedal is pushed.

(AR75603), and one for the longer filter (AR94510)

L55982 COVER (SUB FOR T31170)

Running a loader from the scv's is a mickey mouse arrangement at best.Return flow to the pump is limited and the scv's are tied up.
 
I am with B and D on this tractor. I had mine off the sCVs (158 loader) and it was abysmal, I mounted a closed center joystick the rh fender and had my JD dealer tap the filter cover for 1/2" pipe and T'd into the rockshaft feed line below the brake pedals, works so much better now, i am a firm believer in this set up for 4020s, dad has his plumbed the same on his 4020 with a 148 loader, much nicer.
 
The way JDTECH discribed is the best way to hook the loader valve up, and make 'sure' you use a closed center valve for the loader,,accedently putting a open center valve on will cause havic with the system.
 
How does supplying from one scv remote get around the front pump starvation problem?
Plus it looks silly with a piece of baling wire holding the scv valve open.
 
buick and deere, you must understand the return oil from the scv returns to filter cover via "internal" routing and oil pipes. But I agree returning oil direct to ported filter is better.
 
If I recall right (at least someone stated it here before) one of the 2 scvs returns to sump, and one is routed back into the circuit. When I had my loader on the scvs, the mast cylanders never drained the pump prime but the bucket cylanders did every time when I was dumping a load. After I replumbed it that problem is gone. Im not a hydraulic expert just speaking from experiance as a user and someone who spends to much time reading posts here....
 
I didn't realize pump starvation was the main point of this post, I thought it was suggestions of how to free up the rear SCVs. I haven't mounted my 148 on my 3020 yet, so I don't know, but why does the pump get starved? I'm guessing the wieght of the loader sucks oil into the lowering side of the cylinder faster than the pump can supply it?
 
Pump starvation is due to the rear sump not having the same volume output of the front hydraulic pump. So it easily gets behind the needs of the front pump. It is something to be aware of with your loader. If you plumb the system correctly then your 148 will work great, wrong and it will be slow and cumbersome.
 
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.

IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
hello, you wouldnt happen to have the part number for this? I see it in my 48 loader manual but had no luck finding it on computer at john deere.
thank you
buickanddeere wrote:
(quoted from post at 18:34:02 11/20/09)
Plus it looks silly with a piece of baling wire holding the scv valve open.


IIRC JD had a spring loaded clip available from parts that caught SCV lever when pushed in correct position to lock lever to eliminate need for baling wire on early & late model New generation Waterloo tractors.
 
(quoted from post at 09:35:56 11/22/09) I didn't realize pump starvation was the main point of this post, I thought it was suggestions of how to free up the rear SCVs. I haven't mounted my 148 on my 3020 yet, so I don't know, but why does the pump get starved? I'm guessing the wieght of the loader sucks oil into the lowering side of the cylinder faster than the pump can supply it?

The point of this post is how to properly connect the tractor hydraulics to the loader hydraulics.
Proper connections do not starve the front pump. Hence the concern if Bubba goes and dumps the loader return oil direct back to the trans sump.
 

crowntowing
Although not the best way to power the loader ind. control valve via a hyd SCV(remote valve) a locking clip was offered to keep the scv lever in a position to route hyd oil to the loader control valve. I also couldn't locate the clip in the JD parts catalogs although I know it's there. This clip was also used for hydra-push manure spreaders.
 
I've read this posting several times and decided to hook up my loader to free up the remotes. I hooked the pressure line with a tee to the pressure line just in front of the brake pedals and a tee into the return line behind the battery box on the left side. My loader is so slow and now the three point is slow. I thought the tee would be easier and cleaner then drilling and putting a fitting into the filter cover. Can anyone tell me why this didn't work? Haven't tried hooking to filter cover yet to see if that cures problem. One I ran out of time, two I think a rocker arm broke and motor now not running right. Typical day of farming. I had also seen a posting from someone with a part number for a filter cover, I think for a different model tractor, that had the fitting already in it, but now can't find posting. would anyone know the number? would like to fix problem quickly, have two hundred bales in the field and am down to hauling one bale at a time with my 20,000 plus lbs 7060 Allis with three point hitch.
 

flatheadvff
Welcome to YT
If 3 pt is slow how FEL control valve return hose is attached to tractor isn't the problem. Is your FEL control valve for closed center hyd's? If not nothing you can change except to change to closed center valve or install a closed center plug will help speed of FEL & 3 pt hitch.
 

Is the outside line in photo the line you have your FEL control valve return line Attached to??

mvphoto38991.jpg
 

If they are using an SCV. If returning oil elsewhere it has to be either T d I to the return like or a ported filter cover used .
Returning oil direct to the transmission case is folly.
 

The loader valve is either open Center or the relief valve is set too low . Actually a relief valve is not required on a closed Center system . The other possibility is that the closed Center plug in the loader joystick valve has a blown seal . Are the hoses properly connected to the joystick valve ?
 

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