old harv

Member
I have a hard time turning the wheel to increase or decrease the cylinder spacing on my JD 4400. Is it normally hard to turn or do I need to check for something wrong? I thought that one turn of the wheel should equal one notch on the gauge beside the cylinder but I need 2 turns per notch. Example, after I have opened the cylinder to clean it out after a plug and the gauge reads 14, I need 24 turns of the wheel in the cab to get it down to 2 again. Has anyone ever set up an electric or hydraulic way of changing the cylinder spacing on one of these? Thanks, Harv.
 
The adjustment is more or less a bike chain that often never gets moved. I would replace it with a new one and keep it lubed up.Maybe just spraying a good lube on it will be enough. They get stiff from dust and dirt. Tom
 
May be the chain as Tom said but more likely The grooves that the variable pulley slides on. Happened on my Massey. The grooves get so packed full of old grease and dust that it gets just like concrete. I took pulley apart and cleaned everything up and lubed with some diesel fuel. Unbelievable how easy it cranked after that. If you do that, then never grease that zerk again.
 
It sounds as though the screws inside the pulleys need taken apart and cleaned. This is not an uncommon thing to have to do. Your operator's manual will instruct you on how to take this apart on the top and bottom and how to retime it after you do so. Put never-seize on the screw so this doesn't happen to you again. Look to see if the plastic bushings in the pulley that fit over the locator pins are in good shape at this time as well. Combines draw trash and trash draws moisture. This is why the screws do not operate like they should, as well as probably not adjusting the speed very often. Mike
 
OLD Harvey these guys are talking about the Cylinder SPEED adjustment. Your talking about the cylinder spacing adjustment. Two very different things!!!! On the spacing adjustment. You need to have the rock trap clean when you tighten the cylinder down and dirt/trash in there and your trying to crush it when you close the cylinder. Then check the worm and worm wheel on the right hand side. If the teeth are full of dirt/mud then clean it out. To check and see if it is the adjustment shafts just roll it back and forth. If you have about a turn to turn and a half that is easy then the hand wheel an shafts are free. The concave itself is binding to the sides of the combine. If the concave has been bent by rock damage it will adjust hard as the concave is binding on the walls of the combine. Running the cylinder while adjusting the concave can help. I think it is the vibrations helping. Some machines just adjust hard. My 1985 JD 6620 has always adjusted hard. I replaced the concave a few years ago and all the adjustment cranks and shafts are free but the concave is just tight on the sides of the combine.
 
JD Seller, You are correct that you have to clean out the rock trap to close the concave after running it open. I had the same problem as "Old Harvey" on my 4420 one time. Then I thought about cleaning the rock-trap. And guess what? It closed down very easy just turning the wheel in the cab. Not sure why cleaning the trap works as one would think the trap full of grain would aid in closing the concave. Also, one turn of my cab wheel seems to change the concave setting by 1 number on the guide. Al
 
Your right JD, I'm talking about the spacing adjustment. It does seem to have about 1/2 to one turn that is OK and then it is very hard. There is a home made seat in it that is very wide and makes it hard to adjust the crank and it takes 20 minutes of work to get the seat out so I can access the door under the seat. I will change that seat and recheck to make sure the shafts and gears are clean. I do think the cylinder had damage in the past. I am not familiar with combines yet and after I used it for a bit I saw that some of the bolts holding the cylinder in were missing and the rest were grade 5. I took it to a local JD mechanic and we changed all of them to grade 8. That makes me think we were not the first to work in there. This combine is teaching me a lot about combines and being a mechanic, that's for sure.
 
AJB-830 The Rock trap is raised when you close the concave. The back of the concave is stationary and the front is raised. That is why it pinches things when closing if you do not clean it out. Opening it is when it gets wider so you do not have to clean it out then. Even though you should.
 
You are right. It has been years since I worked on 3300-4400 combines and my first thought was the cylinder speed adjustment that always seemed froze up.I should have thought a little more before answering,thanks for posting the correct answer. Tom
 
Yep..missed that part of his question. Did that off my phone with a small screen. Worn pivot surfaces and wear will cause the concave to adjust hard. Some even get sprung from debris going into the cylinder concave area. Be sure the pivots are not worn and get the concave proportioned and it should work much better. And as JD mentioned, get the rock trap area cleaned out occasionally as well. Mike
 
My dad and uncle had a 4400 back in the day. I remember the concave was always difficult to adjust. Always took two people, one in the cab and one guy with a big crescent wrench on the adjustment bracket wiggling it. Always harder to close than to open. On the other hand my 6620 opens and closes with no effort.
 
Thanks for all the replies. MN Scott, mine adjusts much easier than the one you talked about, I can do it myself from the cab, although I have to use my foot to turn it part of each turn. I guess, after cleaning the gears, I will just have to live with it unless I want to take the feederhouse off.
 

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