Combines Intermittent header lift problem

[John]

Had that same problem with a CII many years ago, the oil was getting too hot and even foaming. looked and looked and found no line leaks or cylinder leaks to get the foaming and heating. Drove me NUTS for 1 season. Finally started the next season and did what the dealer said he had only seen once before, my head liked to leak down and jump back up(causing the heating problem),this was after the header height valve had been rebuilt twice. Dealer had me play with the HOT oil and tear apart the valve and THEN the Crack was visible. Header height valve had a crack that would open up when the oil got hot and let the head leak down and overload the system with use when hot. Hot oil doesn't lift near as well as cold or cooled oil. Check your cooler and lines to make sure they are free and clear so that the oil is flowing and cooling properly.

 

[Deadeye]

I had the same problem on a M2 several years ago. I findly found a broken wire on the moter on the oil pressure switch. It is the safty switch for the header lift (must have oil pressure to move the head). The wire was broke back in the coating about a 1_2 in. from the end. Took a lot of luck and about 2 years.

 

[tbran]

The tiny oring around the header raise poppet seat is bad and thus allowing the seat to move with the poppet. If you click on 'tips' then upgrades you will find the breakdown on the valve and the 71321101 oring that is the culprit. We have devised a tool which is a super long nose pliars which we heated and bent the tips 90 degrees so as to reach in, expand the jaws (grind ruff ridges on the outsides of the tips) and extract the seat, replace the oring and seat. Murphy's law states it has to be the inside poppet between the combine and the valve thus really hard to get to with the block on the machine. Thus the special tool. Also there is a square cut oring in the block around the raise poppet which is almost impossible to replace w_o removing the header lift valve. In rare cases this blocks the poppet from moving sometimes. Try the seat oring first.

 

[ag__teacher]

I have an early N6 so this may not apply, but we had a similar problem. It turned out to be a loose connection where the wire connected to the valve body. However, ours was the main valve that supplied oil to all of other valves and nothing was working right including the hydrostatic drive.

 

[Walt]

Here is another possibility, I had a CII that started

 

[Dan]

We've been installing enough oil to get to the top of elbow with it installed in lower hole for years. That should be close to what you drained out. We use about a quart and a half for changes and have next to no gearbox trouble. Parts guys sell two quarts of synthetic to the quys and they have some left over. I'd check with your dealer and double check your manual. I know back in the 80's some N6 books said 5 quarts to change gearbox oil when it was only 5 pints. All new combines come in with level to the top of elbow with it installed in the lower hole. Good luck.