Destroke Valve

[Anonymous-0]

Why does turning the steering wheel relieve the pressure on the pump and make the engine crank easier? You would think the load of the steering motor would make it crank harder not easier. Please explain.

 

[JDemaris]

On some, it DOES make it crank harder. And, on some it make it easier. Small internal hydraulic leaks are what cause hard cranking. Seems it all depends on what is actually causing the problem to start with.

With the steering wheel? I worked for three Deere dealers over the years and know it works on some. Also had to rebuild or repair many pumps and many steering-valves. That being said, I still can only guess.

In a perfect system, 2200 PSI has been achieved and is not bleeding off anywhere - so the pump turns easy because it maintains 2200 PSI with no flow.

In an imperfect system (probably 99% of all used tractors), something is leaking slightly just enough the make the pump try to pump oil under pressure. Jiggling the wheel might get a faulting valve to close . . . or . . . might let oil from the pump free-flow with NO pressure for a few seconds - thus allowing better cranking. Cranking and making flow with no pressure works well, and pumping little at high pressure also works well. Pumping a moderate flow at high pressure does NOT work.

 

[tim s]

When you bump the steering wheel a bit left a right it keeps the pump from building up to operating pressure, you bump it enough to unload the valve but "not" enough to turn the wheels, some times when you have a weak battery this will help just enough to let it start, and like JD stated the manual screw is better, but this helps..

 

[buickanddeere]

Get a destroker and unload the pump instead of the farmer fix of rocking the steering wheel.
The destroker actually takes hydraulic pump load off the starter motor.
The wiggly giggly on the steering wheel just bleeds some pressure while the pump and starter are still trying to build pressure and flow through a leak.

 

[tim s]

Yes the rocking thing isn't the best but it has kept me from walking home a couple of times

 

[rustyfarmall]

Back in the '70s, when we were using John Deeres, the wiggly-jiggly on the steering wheel was the recommended fix direct from the John Deere dealer. That little glitch didn't occur too often, but wiggling the steering wheel ALWAYS cured it. The dealer never mentioned anything about a de-stroker valve, in fact, this is the first I've ever heard of such a thing.

 

[JDemaris]

Obviously that dealer wasn't very knowledgeable. Deere discussed pump destrokers every winter in their service schools dating back to the 1960s.

Jiggling the wheel may of always improved the cranking on your tractor, but did not, and does not work on all.

 

[Mike M]

I think I had that experience on our 4020 when the battery was low and/or starter was not really good. I tried the steering wheel thing and it seemed to crank harder.

 

[jddriver]

why is always a farmer fix for an engineering mistake ?It must be hard being so perfect as you.

 

[tim s]

Farmer fixes paved the way for many factory improvements over the years...

 

[buickanddeere]

There are farmer fixes and there are farmer fixes.We all have seen the smart clean jobs. We have also seen the hack cob jobs. Wiggly jiggly leans into the hack fix category.

 

[buickanddeere]

You are going to have to get off the farm more.

 

[buickanddeere]

No problem then.
Any repairs or upgrades to nuclear, aviation, rail, public transportation, medical, legal or government. Can be the cheaper, faster & easier cob jobs for you.

 

[jddriver]

Glen you are just very very impressed with your self.I have been to some of the engineering "cobb jobs" in Canada

 

[Anonymous-0]

ok if you dont want to wigle the steering wheel , just move your hydralic lever, that will do the same thing.

 

[LarrySTN]

Yes jiggling the steering wheel does work. I've seen it many many times. It's not ideal but does dump the pressure off resulting in less work for the starter. I can give you names of people who have used this method on a regular basis, then come to me to fix their tractors so they no onger had to jiggle the steering wheel.

 

[JDemaris]

I don't need names. I was a mechanic and shop foreman at three John Deere dealerships from the late 1960s up to 1991. Like I said, that trick works on some but not all.

I know you haven't seen them all, but I also know I've seen "some."

 

[buickanddeere]

Probably on my maternal Grandfather's farm. What an example of how not to do things.

 

[Kevin Schmidt]

Kinda funny to me that there is an argument about wiggling the wheel or putting in a destroker kit.

They are both a cobble fix in my mind. I just fix the leaks on the tractor (both internal and external), then you don't need either one, and the tractor works as it is designed too......