Your the one reading it ,again a 35H is a 173B 3 valve hyd group.
That number is all Cat needs for parts.
Bob
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Cat D7F will not lift blade
- Thread starter Mobilewrench
- Start date
That number is all Cat needs for parts.
Bob
Old Magnet
Senior Member
By my parts book 35Hxxxx is a two valve unit.
Correct for 94N with dozer and ripper and uses a 60 gpm vane pump.
Correct for 94N with dozer and ripper and uses a 60 gpm vane pump.
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Old Magnet
Senior Member
Cover plate gasket is a 5J3140
Causes for excessive lift cylinder drift:
1. Worn piston seal rings
2. Worn spool valve
3. Lift circuit make-up valves not seating
4. 0-ring seal failure in circuit
5. Worn bypass valves in lift cylinder pistons
The fact that the problem is intermittent would lead me to check the make-up valve seating and the operation of check valves in the control valve.
Also the main relief valve (pilot operated) protects both the lift and ripper circuits which may explain the influence on both circuits although that seems like a long shot.
Causes for excessive lift cylinder drift:
1. Worn piston seal rings
2. Worn spool valve
3. Lift circuit make-up valves not seating
4. 0-ring seal failure in circuit
5. Worn bypass valves in lift cylinder pistons
The fact that the problem is intermittent would lead me to check the make-up valve seating and the operation of check valves in the control valve.
Also the main relief valve (pilot operated) protects both the lift and ripper circuits which may explain the influence on both circuits although that seems like a long shot.
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Mobilewrench
Senior Member
Hey, thanks. I am sorry for the delay. Somehow the forum didn't let me know about the new reply.
Mobilewrench
Senior Member
Piston seals had nice protrusion. So 1 is off the table.
Worn spool valve makes sense. But it doesn't seem to explain the reverse operation of the lift function when the ripper is held in relief.
Actually, nothing does. I have gone through the schematics and theories of operation a bunch of times and can't get my head around how there could be any crossover between the two valves. I am starting to question whether the guy I had operating the machine actually had the levers in the right directions.
I agree that the relief valve is a long shot. One relief, two circuits. One circuit has a problem.
I was starting to toy with the idea of the make up valves. I don't know how to test them. Same for the bypass valves.
I am just not sure what to do next. It seems like any further testing means that I need to reseal the hydraulic tank. And it looks like I need to pull the tank apart to look at the rest of the likely problem.
Worn spool valve makes sense. But it doesn't seem to explain the reverse operation of the lift function when the ripper is held in relief.
Actually, nothing does. I have gone through the schematics and theories of operation a bunch of times and can't get my head around how there could be any crossover between the two valves. I am starting to question whether the guy I had operating the machine actually had the levers in the right directions.
I agree that the relief valve is a long shot. One relief, two circuits. One circuit has a problem.
I was starting to toy with the idea of the make up valves. I don't know how to test them. Same for the bypass valves.
I am just not sure what to do next. It seems like any further testing means that I need to reseal the hydraulic tank. And it looks like I need to pull the tank apart to look at the rest of the likely problem.
Mobilewrench
Senior Member
Honestly, guys. I am thinking about eating the time that I have spent on this and having the client find someone else.