Turn in destroking screw every time to start

I have to turn in the destroking screw anytime i want to start it. If i dont the motor will barely spin over. I do have a new starter and battery! Time for a pump rebuild?
 

There are several things that can cause a closed center hyd pump to fail to go out of stroke or cause engine to be slow to rotate with starter. It will surprise me if a pump rebuild will cure the the slow engine revolution when attempting to start problem.
 
Does shaking the steering wheel back and
forth not do the trick? If you can't find
the leak with a heat gun you aren't going
to without going through the entire
system. As expensive as they are an
electric de stroker would be much cheaper
than that.
 
I don't know why any one things it is unhandy to jiggle the steering wheel a bit when starting,,destroking valves are a pain to deal with,,and older tractors will have a lot of little internal leakage that most likely you will never solve all of them.
 
Turning the steering wheel does help turn it over a little faster but not fast enough. With the destroking screw turned in it fires up realky fast. The only hydraulic leak i see is where the 3pt hitch bar goes through the tranny. Its a very slow drip
 
I always leave my 3pt down. I try using the loader lever while spinning over the tractor but it doesn't spin over as fast as turning the steering wheel. But still have to use the destroking screw
 

Not a pump problem. Glad you checked here because we regularly have people here all grumpy because they changed an $$$ pump with no improvement .
 
The leak I am talking about would be "Internal"....and you are not going to eliminate all of them on a 4020
 
What tractor? Gas or diesel? What size battery and how are your cables? How cold of weather? How many hours on the engine? Those questions can make a difference in the answers you get. Tom
 
You state that you have new battery and starter.One large battery will usually work but two are what they came with and many times cables can be a problem.Most everytime I have one that doesn't start it is connections.If I get a tractor in that has the replacement ends I change them'If 3 pt settles at all it needs to be down.The injection pump can cause harder starting but there are other signs such as erratic idle that usually signal pump problems.You didn't say what year 4020 you have and if has a lot of hours it can be tired.Usually turning the wheel will help get them going.Thatys why the power shift tractor have a disconnect
 
Its a 301A gas engine. Around 3900 hours. Negitve cable is grounded to the frame. If i hook up my jumper cables directly to the starter it has the same slow turn over. How do i test for hot spots on thr hydraulics?
 

Jiggling a steering wheel sure does help as I do this trick, but when I need to get the 4020 started on a cold day in January when I did not plug the heater in there is no comparison to actually turning in the destroke screw. Night and day difference on how that engine will crank using that $20.00 screw or an $800.00 electric destroke kit.
 
To test your tractor, you need to put plugs on the high pressure line.

First on line going to the priority valve. This will isolate the pump. You should change or work on your pump only if the tractor does not start good during this test.

Second you can plug the line going from priority valve to steering, etc... To isolate the issue.
Difflock or pto valve cannot be forgoten.

My 4020 did the sale and it was because a little pin holding a roller in an scv had broken.
 
Heat temp gun. Front to back every line
and component in the hydraulic circuit.
Won't find the internal ones though. You
are looking for a rise in temp. Find one
and there's a leak.
 
I don't remember from your past posts if you have the service manual for your machine. If you do it should have something similar to the clip below, about checking for leaks in the troubleshooting section, from a 2030 manual on checking that closed center system. As described the unit is running. The temp at a leak should be higher than the rest of the system, even as it is warming up. Warmer oil may pass easier than cold so it may show better warm. I think a while back you posted it started better cold than hot, so the hot oil may be leaking by easier/more. I think you also mentioned an external leak on your loader valve. Did you get that fixed? It might have some affect here, depending on where it is and how much it leaks.

mvphoto28779.jpg

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Earlier this year it didnt have this problem. It seem to start this problem all of a sudden. I scrapped snow yesterday and farted around on it and shut it off and went to restart 10 min. later and had to turn in the destroking screw.
 
The pressure control valve gives priority to the steering, so it is the priority valve. I expect it is located on the right side of the transmission behind the transmission oil filter as many others are.

Just trying to clarify; In your posts in November, when you were having problems, you mentioned it dragged more when hot and said it had had that condition since you bought it. If one looks back at your earlier posts it would seem to me it has had a leak and it is getting worse; as you are indicating the dragging is getting worse.

If you have a technical/service manual, study the hydraulic section, it will help clarify some of what folks are suggesting and help you locate points/components. If you don't have a service manual you really should get one, it is going to help you in the future. There is a used one on eBay right now as inexpensive as I've seen lately.

301A manuals: Technical manual - TM1088, Operator's manual - OMT79303, Parts catalog- PC1429 (parts catalog is available for free viewing on line at JD Parts Advisor)
 
Yes it seemed worse this summer when tractor was warm. Know it doesnt matrer if its hot or cold. After the tractor is warm and i have run the loader fpr a while it seems to make a hydraulic squel when using the loader but only after it warms up.
 

Denmarkmaine,

What David wants to know is if your loader is connected hydraulically to the tractor like the hoses in the attached photo or if the hoses are hooked in differently.

Jim
mvphoto28821.jpg
 
Cleaned up the snow this morning and after i ran the tractor for a while the loader going up seemed to surge like. It didnt go straight up it would have a pause every second . i was not running any other hydaulics at the time.
 
Something doesn't look right. I know attachments fit different machines and parts catalogs aren’t always right; it may be fine; but if I look in the parts catalogs your loader's frame doesn't match the loader drawings in the 301A parts catalog (PC1429). The large hydraulic filter does not either. The filter shows up in parts catalog PC972 for a 300 tractor. The 301A returned the loader oil to a ported transmission filter like the one in the 2030 photo I posted according to the parts catalog I looked at. A loader, framed like yours, shows up in PC1111, Loader, 300 (7320). The supply pressure line to the valve should be coming from just behind the pressure relief valve, like the 2030’s, which is hidden by the filter. The loader control valve in that parts catalog has a relief cartridge in it, which a 301A wouldn’t want.

Some more info may help. What is the complete serial number of your tractor? What is the info on the tag on the side of the loader seen in your photo? Can you find a tag on the loader control valve and get some photos of it? If by chance it has an open center loader valve on it that could be most of your problem. Again, this is just my view, but things don’t match up with the info I can see.
 
By the numbers you don't have a 301A, you have a 300.

7320 is the 300 loader , parts catalog PC1111.

Tractor may be a 1972. They were built 1965 t0 1973.

T = Tractor
4 = JD300
W = Industrial
1 = Gasoline
D = Collar shift with Reverser
116270 = Serial number
T = Dubuque Tractor Works

Need to figure out what your loader valve is.
 
Review the control valve in the 300 loader parts catalog # PC1111 (the 7320 is the series of 300 loader you have) and see if it looks like yours.

The tractor parts catalog for your 300 should be # PC972. I got the breakdown of your tractor serial number from introduction section of that PC. I didn't find a serial number to year chart for the 300s to be able to confirm the 1972, but it is the right range for a 300.

Do you have any couplers for remote hydraulics on the back of the tractor? There would be another valve and lever behind you lever that controls the 3 point hitch. I can't tell for sure in your photo of the tractor. Loader hydraulics and the SCV (control valve for the remotes) are a couple places that can have internal leaks. If your oil level is full in the transmission, the loader valve may be the problem, given the new symptoms you are experiencing.
 
There are no quick connects on the tractor. The 3ph lever is under the seat area and the height adjustment is in the same area . i can get more pictures tomorrow if you need them. Thanks again
 
If you don't have remote couplers on the rear or another valve above and behind the 3 point lever you don't have the SCV, it can't leak, one possibility eliminated.

The simplest test as a next step is to try the temp gun as has been suggested by others. With the tractor running, without moving the loader controls, check the temperature of the oil supply line and the oil return line of the loader. If the return is warmer then the supply, when just setting there running, it is a sign of an internal leak in the loader control valve.
 
Just FYI.

Tractor Parts catalog # PC972 (available free to view on line)
Loader parts catalog # PC1111 (available free to view on line)

Operator's manual for 300 with 7320 loader # OMT32951

Service manual for 300 # SM2073 (I didn't see anything in the description about the loader)

Technical manual #TM1068 is for a 300 with 7310 loader and 9520 hoe. You may want to check with JD about which service/technical manual is best for your machine.
 

Sorry, My answer's wording didn't match your question well.

No, the loader control valve is not different from the valves connected to your loader lever (joystick). If you look at the parts catalog that is the name for that group of valves. We need to determine what brand and type control valve you have to control the loader functions as it may have been changed from the one shown in the parts catalog. Details can help find your problem.
 
As for the jerky operation of your loader, it could be low oil. Have you checked the oil level on the transmission dipstick? I believe on the 300, like a 2030, the cap should be unscrewed and setting on the top of the threads when checking the level.

Your valve appears to be the original, or similar, control valve (singular) shown in the parts catalog (PC1111). It is a sectional control valve. It is made up of end plates and two valve sections, one for boom and one for bucket, more sections could be added such as for a grapple or 4-way bucket. According to the catalog it does have a shim adjustable relief valve in it.

See if there is a tag on the main hydraulic pump (in front of the radiator) to identify it. If no tag with numbers, try for a couple photos. They apparently used 3 different size main pumps on the 300s.

It appears there were two different pressure control valves used, 1 for the small displacement pump and another with the two larger pumps. The pressure control valve is on the side of the transmission in the area of the large hydraulic filter you posted a photo of. The pressure hose for your loader may be connected to it. See if you can get a photo of it. Getting all the components identified should help to be sure the right things are checked.

All you can do to figure out where the internal leak is; is to eliminate functions that use oil. The hydraulic pump should build to pressure almost immediately and de-stroke itself, if all is working right. Getting a manual with the hydraulic schematics would be a benefit. Where you don’t have quick couplers on your loader hoses, I am thinking you can unhook the loader pressure hose from the loader control valve and cap it. Plug the opening the hose was connected to on the valve. That should take the loader valve out of the system. If you starting issue goes away when the loader is “bypassed” it will tell you the internal leak is in the loader valve. My question with this is, how does having a relief valve in that loader control valve fit into this? It may be shimmed to a higher pressure than the pump, so it would do nothing. Again, that answer may be in the manual or perhaps someone will post more info. Hopefully if I have misconstrued any of this someone will speak up.
 

First couple pictures is the loader valce. I was cleaning up the storm after work and blew the house going to the loader controls.

This the back side of the loader valve

This the pump and best shot of the number on fron of the pump

 
It appears you have either the 2.4 or 3.3 cu.in. pump, both used the housing with the casting number you have in the photo. The pressure control valve in you photo matches to those pumps. That valve monitors system pressure and diverts flow to the steering when pressure drops. Sometimes it is called the priority valve for that reason. It's not a loader valve, as even tractors without loaders have them.

I am guessing you haven't had a chance to check the loader outlet oil temp yet. Get your new hose on, get running again, and do that check. Also with the tractor running, remove the full cap for the transmission oil and look in there to see if you see a lot of oil spraying inside there.
 
When i took off the hose i noticed it was much warmer then the metal incoming line.
If i plug the line that blew that blew will that tell me if the valve is bad or do i have to plug the income metal line?
 
The hose you blew should be supplying oil to the inlet port of the loader valve. As the guys have posted, you need to check the temperature of the outlet line of the loader valve. That should be the hose from the loader valve to the filter on your tractor, I believe. See if it is hotter than the supply oil. Oil is ported from the pressure control valve to your 3 point hitch (rock shaft) valve, inside the transmission case. Look inside the fill opening and see if there is a lot of oil blowing out in there.
 
Got the new hydraulic hose made up and installed. I ran the tractor for 20 minutes and the hose that i just replaced that goes from the valve to the joy stick valves was warmer then the hose coming from the Filter housing. The loader operation started making that whining noise after it warmed up a bit and i could feel it in the new hose and not really in the hose coming from the filter housing.

So i am guessing it must be the valve under the floor boards. Where do i go to get the schematic and get a part number?

Thanks again for all of the incredible help!!!
 
Are you checking temps with a temp gun or just by feel? With a temp gun check and record temps at the steel supply line to the pressure control valve, the valve itself, the new hose up at the loader control valve. Also at the loader control valve check the hose going to the filter. Check the steel line that comes off the supply line ahead of the right footrest, where it goes into the side of the steering column. Check the temp of the supply line at the hydraulic pump. Did you look in through the rockshaft cover fill opening to see if there is oil spraying inside there?

Nortrax in Westbrook is the Construction and forestry (yellow) dealer, as I expect you know. I am sure they can sell you manuals and parts. Hall's and Hammond are Ag (green) dealers and may, or may not, be able to help if it is a part common to both sides.

You don't have to purchase parts catalogs, unless you want to. Those can be viewed on line by searching either "JDParts Homepage" or "JDParts Advisor". Search "John Deere Bookstore" to get to the technical publications site. You can purchase your manuals there (printed, CD, DVD, or downloads). Downloads are least expensive usually. I posted the manuals I think apply to your machine on 1/1/19. The TM 1068 I don't think applies to yours. The service manual should have the schematics in it. eBay is a source for used manuals and some reprints. It looks like the JD300 manuals in the store on this site are all for the lawn and garden 300's, not the 300 Industrial.
 
I looked in the fill hole and no fluid was splashing around. I dont have a temp gun yet. This was just by feel and was definitely warmer and the other hoses including the metal supply line?

Does it seem bad if i can feel it squealing when i put my hand on the hose?
 
No doubt, something is wrong. It is a matter of pinpointing the problem, not just throwing parts ($) at it. It may be an issue in that pressure control valve as you say that is the only place you feel heat. That valve is different from the ones on the ag tractors I have and I don't have a schematic of it. If all the heat is at that pressure control valve you can drain the transmission and remove the valve, take it apart and see if something is stuck in it or a spring broke. Watch out for small pieces and shims as you disassemble it. Taking photos as it comes apart helps reassembly sometimes. There are only a few O-rings needed to do that. You want to look at the pressure control valve for the 2.4 - 3.3 cu.in. pump in the parts catalog. You have a plug in the back where the diagram shows the steel line for the SCV, that you don't have. Get your manuals so you have specifications to check things to.
 

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