Combines 6620 hyd thanks but

I know this isnt a combine but, last spring we had our tractor hydraulics vibrating horrible.. it was so annoying you could barely stand to sit in the cab.It turned out to be a broken valve inside the hydraulics. I cant exactly remember where the valve was located and what it did but i think i know what you are talking about as far as sound goes. I realize there is a difference between the tractor and the combine. Even on our old 4020, there is a vibration in the line, i think it could be because of a bad charge pump, or i see there is a good size kink in one of the lines going to the front hydraulic pump. Do your hydraulics function normallyIJ Other then the noise and vibrationIJ Just my thoughts on the problem.Hope maybe i can help. Good luck! Chad

I may be off base on this but, on my 6600 if I have the header off and have the hydraulic motor hoses disconnected and don,t hook the disconnected hoses together so the oil has a free path back to the reservoir, the relief valve will blow continuously. Just a thought. I don't know if a 6620 is the same or if you are using a hydraulic motor on the header or not. On mine the releif valve is on the upper right corner of the main 3 spool control valve. If you hold your hand on it you should be able to tell if it is blowing or not. I worked,during the '70s, for Eaton Charlynn for 8yrs in the product testing dept. and some times I would find a relief valve that would act strangely no mater what and would just have to throw it away. I'd also ck relief for broken or hung up spring.

Yes the hydraulics work fine. They don't even seem to get hot. When I replaced the relief valve , I did it with another used one I had, What's the chances of both of them being badIJ Thanks for the ideas.

I'll try again. You have an old combine. There is bound to be more vibtations. Speaking of the steel lines to the controls, why don't you change them to rubber braided hoses. I did this on an old 7720 and it quieted right down.

was the relief valve clean or did you clean itIJ Are you using the right relief valveIJ 95

the line from the tank to the pump you say is double clamped so i take it we have a flex rubber pipe on it have you checked this pipe out for intenal damage which means the pump is starveing and cavatating air been sucked in BUT should make hydraulic movement jumpy the relief valve was the spring and seats in good repair..why was the old one on the shelfIJIJIJ are all the hydrailic functions closeing down when not in use we had the cylinder speed one on a 7720 stay open and cause a vibration one partly open can cause oil to flow through a small gap causeing the relief valve to open and close causeing a hammer affect through the lines cut open a filter if you have one that has been on the machine for awhile and see if any metal is floating around we may have some metal stuck in a valve is there a screen filter in the bottom of the tankIJIJIJ well just a few ideas.. pity we can't hear the noise good luck and keep us posted please

Checking the intake line is on the list. The relief valve I put on was off a salvage combine, what's the chances it's bad tooIJ There's nothing in the filters but the usual stuff. Thanks for the thoughts.

I wonder if you could isolate where the noise is coming from by using a stethescope to listen to the various componants of the hydraulic system as the machine is running at whatever rpm this noise shows up. Has your main hyd valve under the cab floor ever been rebuilt. I would tend to agree with a previous post that something is broken and oscillating inside that valve.

Would suggest putting a pressure gauge in the system to help determine if the vibration is due to hydraulic oil pressure fluctuations. Once that is known for sure then the relief valve sure could be the culprit and for sure the used one could be bad..

I have a 7720 that has also started to chatter. I have tracked the chattering sound to the Dial-Matic electric valves located to the left of the hydraulic reservoir next to the steps. local dealer told me that because these valves are very active when in use that the internal valve centering springs will become weak and need replaced. These valves chatter when the Dail-Matic is turned off. Something to consider.