We have a Cat 950G that came from Belgium. We got it with around 3,000 hours on it. Currently it has between 11,000 and 12,000 hours. A couple thousand hours ago, it started making grinding noises every now and then under the cab around the transmission and controls. We've had it into Ziegler Cat about 4 times, and they've had the cab off of it and everything else and cannot figure out what it is and they said it's something we're just going to have to deal with. It hasn't hurt the machines performance or anything as far as I can tell. It seems like from the last time that I ran it, it seems to stop if you hit the brake a little, but not all the time. Has anyone had this problem or dealt with it? What is it?
We had a 950 doing the same thing. What we found was someone had dropped a screwdriver in the hyd tank and over time the oil had separated the handle from the metal shank. Now the handel was small enough to get sucked up into the pump and was being ground away by the vanes. Shut it off and the handle would fall out back into the tank and then float around until getting sucked back up. It could happen quickly or take a few days. does it sound like the pumps?
What kind of oil are you using in the drive axles? Most wheel loaders now days with the internal wet disk brakes use tractor hydraulic fluid. That stuff is expensive so some people were putting in engine oil instead. They would develop chatter at times and I've had the return springs on the brake piston break and then the chatter would keep getting worse. Anyway it is just a thought. Good Luck!
It kinda sounds like the pumps. I haven't looked at it personally but I have definitely heard it. It's pretty loud in the cab when it happens, and I can almost feel it in my feet on the floor. Now that I think of it, it sounds like something is getting sucked up in there but who knows. The chatter hasn't gotten worse over time, and it sounds like its more in the pumps area.
Does it happen when you start up after a weekend of being off. Do you see oily dirt on the suction hoses. Have you done cycle times on the boom up function? Pumps usually put metal into the system if they are going bad. You could be sucking air through the suction hoses or as stated before, you got something blocking the suction.
It usually happens no matter what. It can go for a day without doing it, or only a few times a day. Some days it's worse than others. The lift cylinders are still as fast as they were when we got it, maybe a little bit slower. There isn't any metal in the system. I think Cat flushed it out a couple times when they were checking it out and they never found metal
Worn high hour vane pumps make a terrible noise. When they get worn the cartridge may also crack. Under the cab mounted to the trans are the pump stack. The 1st pump is the steering, piston pump, mounted to this is vane, implement pump and then on that is a double vane pump, brake and pilot pump. As John said, check the cycle times of the loader, if ok then the imp pump is probably ok also. Then check the brake and pilot pressures, if needed these pumps can be remove without removing the cab but, the imp and steering normally need the cab removed..
Okay, thank you for the replies you guys
Oil sample should tell of any mechanical failure, when you find it its gonna be something dumb...lol
i agree with lee, check the brake pilot pump, may be the seals or the vanes have worn out, and before dismantlling look for the brake accumulators. you can do that by installing a 3000 psi gauge in the testing port of them, turning off the machine and hitting the brakes 5 or 7 times, you will see a gradually decrease of pressure if they are precharged and working correctly until the moment you get the prechage pressure after that the pressure will decrease suddenly
well i guess i didn't know this, but Cat has had the cab off and replaced ALL of the hydraulic pumps twice and it didn't solve it. I forgot that it pretty much goes away when it gets all the way up to operating temperature.
just an idea.. does it sounds when its moving? have you check bearing in the drive shaft within front axle and transmission ? or you may have losse bolts on spider