Where is the best place to get a new / rebuilt hydraulic pump. It is a 45 part # 25C13969 Thanks for the help.
That would be a #46 Cat hydraulic control. What all did you check to determine a new pump is required. Lots of possibilities for poor performance. s/n 25C13969 uses a 1J0783 pump group with a 1J0784 pump cartridge which is equivalent to a Vickers #171217 or 923231. There are or used to be a couple of places that did exchange cartridges. The one I've used is Attica Hydraulic Exchange Corp, Chesterfield, Michigan 1-800-422-4279 The other unknown is www.Proactivefluidpower.com in Clin... possibility is [url]www.Knighthawksupply.com Been several years since I've made a purchase so no guarantees.
Do not know a lot of background on the machine. The blade will come up, as soon as you turn loose the control it starts inching down and will not hold position. As it gets hot the hydraulics is slow. I removed front cover and oil tubes to check for problems; One of the four plungers was stuck and would not work in the bore. I freed up the plunger, reinstalled and had same problem right on. It acts to me like a relief is dumping or bypassing in the control somehow. Cylinders were supposed to have been rebuilt a couple of years ago. No knowledge of this system and no books. Open to suggestions.
Those four plungers are make up valves and would not likely be the cause of blade control problems. I'd be more suspect of the hydraulic cylinders, either a leaking end of travel relief valve in the rod piston or the piston itself is loose on the rod. Had almost the same situation on a unit discussed on the ACMOC bulletin board recently. Turns out the piston was loose on the rod, worked fine in one direction but would leak down in the other. If you put your ear to the cylinder you may be able to hear the leakage or work the blade and if one cylinder gets warm before the other that is more likely where the problem is. Almost never hear of a relief valve issue with the #46 but anythings possible. Pumps do wear eventually but they are also stout built.
Old Magnet, Thanks for the input. Never seen a cylinder bypass this badly, if it is. But I will pull them down and check them in the morning. I'll update tomorrow.
The similar case I was referring to where the piston got loose managed to blow out the piston key so that when the piston was against the rod it sealed but in the other direction the piston moved and allowed flow through the keyway. Piston retaining nut needs to be torqued to 725-875 ft-lbs.
Test ran unit with control valve tied to the upward position. One cylinder got hot and the other did not get hot. The nut was tight and the o ring from the piston to the rod was intact.There was no fresh oil between them. Took the checks out of the piston, the springs were not broke and appeared to be seeting. The packings are snug in the bore. Do you have any new ideas?
I trust you took the hot cyl apart? Later Bob
No I took the cool one. I assumed that bypassing it The cool cylinder would be the one because of the oil flow.
The good news is that now you know how to do it. The bypassing oil being pushed thru a constriction heats the cylinder up at the leaking spot. You are not the first one to think that and I'm quite certain you will not be the last. Still much better than having to get into the pump and controls.
I could be wrong but I would be thinking the hot cylinder would be the leaking one. Thought is the oil is being forced through a restriction causing it to get hot. With no flow in the other cylinder it would have oil for a good part that has not even been circulated through the system.
Instructions were to go for the warm one??????
Thanks, for the input. I'll check the other side tomorrow and let you know.
Tieing back the control lever is not a good test. The piston will travel until it hits the end of the cylinder which dumps the end of travel relief valves. Working the piston between end of travel reliefs would be the best check to obtain heating from internal leakage.
Thanks for the information and feedback. The problem ended up being when the hydraulic cylinder was rebuilt someone had twisted the locking washer tab off; This allowed the washer to turn to a position to where it got against the check. It had it open and cocked a little side ways. I cut a new washer, put it together and it works fine. Thanks.
Thanks for relaying the results.....another variety to add to the list of trouble shooting items. Was beginning to scratch my head as to what to check next. Have fun with the dozer.