caterpillar guy

Well-known Member
Having trouble with a 2940 starting. Acts like the starter is weak. Have also been told about the hydraulic pump not releasing pressure and loads the starter. So how do I determine whether it is the starter in fact, or the hydraulic system causing it? In the past it would start with the starter then later it got so if you didn't turn the steering wheel while starting it would not spin fast enough to start. Now he drag starts it. Going out on a limb here, I'm guessing the hydraulic system was the problem, and now the extra demand on the starter has caused the deterioration of the starter maybe. I just know with planting just around the corner, I would like to cure this problem.
 
Disconnect the pump drive coupler under the rad and then try starting it. If no difference, then the starter is the problem.
Ben
 
Thankyou guys. Never thought about the pump coupler that is what I needed. Wanted to check that first. I i'am trying to eliminate things one at a time. Will check that tomorrow when I'm over there. I'll have to see if we have an over the wire gage for the amp draw test.
Will get back with the results.
 
Hopefully it is the starter or batteries, the hydraulics on those models are known for internal leaks causing the pump to try to build pressure when cranking. If the starter spins it with the coupler removed you are going to have to start trouble shooting, and those tractors test the abilities of even the best deere technicians out there.
 
(quoted from post at 22:22:37 04/23/19) Disconnect the pump drive coupler under the rad and then try starting it. If no difference, then the starter is the problem.
Ben

Why go to the bother of uncoupling when for less than $20 a pump destroker can be installed . Handy any time the battery is low or during low temperatures .
I have seen no mention of the voltage being measured across the starter while cranking . For reasons unknown, tinkerers will spends hundreds of $$$ throwing random parts at a machine . While refusing to trouble shoot the problems .
 
Well I have not thrown $$$ at it before research yet. I have not been around it much since it sets 10 miles away from me at my brothers place. I did look at the option of jumping the starter with it in neutral, and it would only click. So I will need to pull the starter on it and look at that first and go from their.
As for the destroker kit not sure what that is. This is the only Deere out of 13 tractors the rest are all red and those are so much easier to work on with the time we have had those around. Mostly a familiarity thing.
So B&D I think you could get off your high horse about some simple questions before you know the whole story. Since I tried the jump thing today. If the high low thing is the lever on the left of the steering wheel it worked fine today when I used it. First time I have been there in 3 weeks. What he does when he is there I don't know.
 
(reply to post at 19:33:53 04/24


You could have been more forthcoming with data from your second post and included it in the first post .
I was also referring to Tinkerers in the post so unless you are a tinkerer , don t take the bulk of the post personally. In fact don t feel too special, everyone is referred to in the same manner .
As for the voltage testing under load , it is very effective to find most of the problem(s).
However many dozens of question askers have refused to trouble shoot and spend $$$ on random parts instead . It is a sore point of trying to help people save time and money . And instead they balk and do the opposite .
A de-stroker takes the pump out of stroke , thus no cranking power is wasted pumping hydraulic oil . A simple , quick, effective and low cost starting assist.
 
B&D Yes I know some people will spend good money after bad, rather than checking and testing. That was why I was asking about how to separate the hydraulic part from the starter. So I didn't waste money on one when it might happen to be the other. I have read many of your replies to other posts ,and some of them do sound somewhat abrasive at times. Probably why I jumped at this time on yours. I am sorry if the attitude was uncalled for.
I suppose I could have added some of the information to the first post. Though I guess I didn't see how not being around the tractor all the time or the number of them really mattered.
I try to not write a book and still get the information out that seems pertinent to the issue. I will be over there today so will probably pull the starter to look at the solenoid and brushes in it. Will also look at the bushings.
How does that destroker deal connect up? I am going to guess without seeing one it must go between the crank and the pump connection in front.
 

caterpillar guy
Kit(key 6) for destroking screw is NLA so individual parts shown below must be ordered. Part numbers are for hyd pump without a serial number plate.

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The front pump is a variable displacement design and is used on JD closed Center hydraulic systems of that era.
When the hydraulic system reaches 2250psi the variable stroke control in the pump "de-strikes" the pump so it is no longer pumping . The "manual de-stroker" is a little T handled bolt and bosse that threads into the top of the pump .
Manually turning the de-stoker in will prevent the pump from robbing power from the starter . Particularly effective in old tractors that have minor internal leaks in the hydraulic system.
Due to the brakes, high/low shifter, the PTO clutch if so optioned and the PTO brakes using wet friction material. Foreign material such as condensation , rain water through cracked shifter boots or the wrong specification of oil will totally ruin the friction material. $$$.
Safest to just use Hy-Gard from the JD dealership . The industrial , military , marine and agricultural industry as a whole has problems with counterfeit oil for sale at jobbers.
Obtain a new transmission oil filter and clean the transmission sump screen . If either are loaded with friction material there is trouble . If there is fine grey metal in the filter, the tractor will cost as much to repair as what it is worth .
The engine as with all wet sleeve diesels can be damaged with old antifreeze that has depleted corrosion inhibitors. Deere sells a test strip kit to test and bottles of additive compound .
 

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