Is there a common valve for oil to bypass in these machines causing the oil to get close to the red on the gauge quick ? What's the best way to locate this bypass? I'm nearly certain its bypassing in a valve because all cylinders have been replacked and recently had a new oil cooler installed and its heating up just like before all this was done. This hot oil is causing the brake pistons not stay released when walking it not to say the brake pistons seals dont need to be replaced but they wont lock down when walking it when the machine is cool. The only way I know to locate the problems is to shoot temp of inlet and outlet lines of each valve with temp gun and to work each function for a period of time and monitor temp. I realize it could be bypassing in the pump also. This machine has 6800 hrs on it. Any advise and/or recommendation would be appreciated.
You don't happen to know which model series of machine. It could be a 2800C, CII or Quantum. That's a pretty old machine in any case.
It is a Quantum..a friend and myself shot some temps with a heat gun the other day. Didnt really know what we was doing but we tried. It's definitely bypassing in a drive motor by the increase in temp and opposed to the other drive motor. We a had one of them stethoscope looking things and by listening to the oil at the inlet and outlet lines at the pilot valve. Differential temp oil at the oil cooler was about 15degrees. It was noticeably hotter at the right final drive motor after picking it up and spinning both finals. Seems like it was 140 degrees when the other side 100 or so. We did all this before the machine got good and warm. The right drive motor will pull initially but lock down after walking it when it's up to temp. Thanks alot for any help John.. tell me a better way to isolate this bypass/overheating problem.
Sounds to me like you have the problem diagnosed pretty well. You can confirm the problem by doing a case drain test. There should be two small hoses going into the travel motor. One is to work high speed travel and the second is case drain. Generally you cap the hose off and put a second hose on the connection at the motor and run the free end into a bucket. You need to lock the track with a pin between the sprocket and the track frame. Then run the track to travel looking at the amount of oil going into the bucket. A good motor will barely pass any oil into the bucket while I've seen motors like what you are describing send the end of the hose out of the bucket from the flow and pressure. If it's bad it will have to come out and usually be replaced. Parts prices for one of those was more than the cost of a new one. Also as I recall you had to purchase the motor and final as a set. Good Luck!
Thank ya John.. yea I got a cx160 case hoe that had a final drive motor shaft strip out. I pulled the outside planetary apart initially and seen what happened. So I had to order both shaft as they spline together. Well I'm hearing I need to pull that drive off and put on a table so its vertical before I open it up because **** will scatter and itll be impossible to assembly if not. I thought damn that's alot of work to bust that track down and all them bolts were bad rusted. I just stood the machine up with the boom and put it on the counterweight. Took a ladder to get out. It wasnt vertical but was close for springs yo stay in place with grease. U are definitely right about parts. I wished I would have got a reman drive instead of trying to part it for damn sure. In fact, I got that side plugged off right now sitting on hill loading gravel with it. I'm close to 4g in that drive and the sob still got too much case drain keeps blowing the motor shaft seal. I ended up putting a new rotor and new pistons in it. Where else can it be bypassing at? I got another on for ya john. On the link belt. The drive motors are a little bit different not much but some. I got the brake piston seals and was skeptical about opening that motor up. It's the one that keep locking down when it gets hot. Do they open up like the case drives. I done got deep on that link belt and damn thang didnt come with air. Might oughta ship that sob before I get balls deep in it. Lol