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catmastertech, Technician
Category: Heavy Equipment
Satisfied Customers: 2477
Experience:  19 years Cat, 3 years Case
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My 1986 428 series 2 stick cavitates when I am grading I

Customer Question

My 1986 428 series 2 stick cavitates when I am grading I have replaced primary and secondary resolver seals all other functions are good. any help would be helpfull
Submitted: 1 year ago.
Category: Heavy Equipment
Expert:  catmastertech replied 1 year ago.
Hello, I am not sure I understand your problem. Can you provide more details about this issue?
Is this the loader or the backhoe with the problem?
Expert:  catmastertech replied 1 year ago.
Please include the full machine serial number with your reply.
Customer: replied 1 year ago.
Grading with backhoe
Customer: replied 1 year ago.
When grading with backhoe
When pressure comes on stick tit slows and boom wants to raise. And you need to hang onto the. Controls really tight
Expert:  catmastertech replied 1 year ago.

Thanks for the reply.

It sounds like you are dealing with contaminated oil or sticking flow compensators.

Is the oil getting too hot? Do you have auxiliary circuits that are sticking? (Like extend-a-hoe or hammer valve?)

Did you replace all the valve's seals recently? Was any metal or other debris seen in the valve or oil?

Have you had any major failures in the hydraulics recently?

Do you have pressure gauges to check pump and signal pressures?

As far as the boom raising, is the boom able to lift the machine off the ground and hold it without drifting?

Do any of the cylinders drift loaded or not?

When you say controls are tight, do you mean they are stiff even when the machine is off?

Or do you mean they get tight when operating and are pushing back against your hand?

Customer: replied 1 year ago.
Oil is not getting hot. Can lift its self at tick over and hold. When you grade the boom wants to lift faster than the stick comes in when the bucket starts to come under load. It as if the stick cylinder is cavitation as it comes under load. Pressures all seem fine.
Expert:  catmastertech replied 1 year ago.

I am sorry, I still do not understand what is happening to your machine. I will OPT-OUT so others can see your question.

Customer: replied 1 year ago.
Thanks for trying