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cat_engines_only, Other
Category: Medium and Heavy Trucks
Satisfied Customers: 2314
Experience:  Repair CAT machines only
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I have a cat d3 c hystat series 3 the blade move side to

Customer Question

I have a cat d3 c hystat series 3 the blade move side to side when pushing or back dragging I had both cylinders rebuilt still the same problem had the control valve apart nothing noticeable wrong
JA: OK. Anything else you want the equipment mechanic to know before I connect you?
Customer: No that's all
Submitted: 5 months ago.
Category: Medium and Heavy Trucks
Expert:  cat_engines_only replied 5 months ago.


What is the complete machine serial number of this tractor?

Have you checked the pressure settings of the relief valves?

How easily does the blade move?

Will the blade move back if it is angled all the way in either direction?

Customer: replied 5 months ago.
Sr number is4TS00594 the blade does go right or left only in the air if it's on the ground it will not move it tries but it won't yes it will move if it's angled one in the air
Expert:  cat_engines_only replied 5 months ago.

Have you checked the pressure settings of the relief valves?

Customer: replied 5 months ago.
No I have not yet
Customer: replied 5 months ago.
The blade will group and down it will lift the machine up
Customer: replied 5 months ago.
Any ideas
Expert:  cat_engines_only replied 5 months ago.

Thanks for the serial number. This machine does not have relief valves for the angle cylinders. I think you have a problem with the valve.

To prove it is the valve, remove the lines at the cylinders and cap the cylinders and plug the hoses. Try pushing dirt to see if the blade will stay mostly in the same place. It may move a little but, should not go far. Try to keep the cylinders full of oil when you cap them the less air in the system the better.

Speaking of air, I assume you are keeping the tank full and the pump is not making noise.

If the cylinders hold, try plugging the lies at the valve and see if they still hold.

If they remain steady, the issue is in the valve. If they keep moving, your cylinders may be "bell" shaped and the tube will need replacing.

Customer: replied 5 months ago.
I had a local hydraulics shop test them said they were good
Customer: replied 5 months ago.
the tank is half way in the sight glass
Expert:  cat_engines_only replied 5 months ago.

Are you certain a line is not crossed somewhere? I really do not think you could do that but it could happen.

I would still test them to prove a valve problem or a cylinder problem.

Expert:  cat_engines_only replied 5 months ago.

Does the tilt cylinder hold steady?

Expert:  cat_engines_only replied 5 months ago.

You could swap the sections around, the tilt and angle are the same parts.

Customer: replied 5 months ago.
Ok I got a schmetic on the line they all appear to be on right everything functions correctly the dozer had a broken c frame and the right side cylinder rod was snapped off when I got it it fell off a trailer
Expert:  cat_engines_only replied 5 months ago.

I think the only item left is the valve. No reliefs are in the lines so, that leaves only the cylinders or the valve.

I agree a valve should not cause this without showing some signs of a problem.

The only way to find the trouble is to isolate each item. Try blocking off one cylinder at a time, then do both and then the lines at the valve. If that does not find the trouble spot, I would then swap the tilt and angle valves around to see if the problem moves to the tilt cylinder. At least that way you will know what to buy before hand.

Expert:  cat_engines_only replied 5 months ago.

How did the repairs go? Do you need more help with this? Was my answer helpful?

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