Boom Cylinder Drift T5C

[JonnyRed]

I have owned this machine for a couple of weeks and noticed this issue pretty quickly into operating it. The drift in the boom is intermittent and occurs both when the machine is cold or hot. It may happen twice in 2 or three hours of use. I have attached a video so you all can see for yourselves and provide any insight into the cause. I am a novice when it comes to hydraulics and I appreciate any input or troubleshooting ideas you may have.

If you get tired of watching the boom drop, fast forward to 1:45 in the video and you'll see the situation go away and return to normal operation.

Terramite Backhoe Drift - YouTube

 

[guy2073]

I never had that happen on mine

 

[JonnyRed]

I never had that happen on mine

Thank you, that is very helpful.:thumbsup:

 

[the old grind]

Symptoms described and action in the video suggests to me that it's not a result of low oil level and/or foaming, although IIRC the boom lift cyl is first in line in the circuit. (15w40 spec'd for T5 hydraulics) Spool sticking or internal spring not centering properly? I ask because the 'drift' we see looks as rapid as if one were powering down (empty bucket) vs if the spool had float or a full bucket.

I've had linkage issues that I thought were the valve itself. Pad hung up and it was a bear to center it to start up w/out loading the pump. (There was more to lube that the grease fittings on the linkage.) Servicing the a valve/stack is either easy or intimidating, perhaps based on past experience. Sure hope you don't have to 'go there'.

I'm trying to imagine a cyl seal allowing drift 'off and on', but not how a particular one is designed or seated. Merely reversing the lines (up/down) should show uncontrolled boom 'raise' when it acts up if the valve is causing the issue. Good luck, and keep us informed. tog

 

[guy2073]

Sorry my post didn't post did you check to make sure there was motor oil in the Hydraulics instead of hydraulic fluid a worn-out control and thin fluid may cause this

 

[JonnyRed]

Sorry my post didn't post did you check to make sure there was motor oil in the Hydraulics instead of hydraulic fluid a worn-out control and thin fluid may cause this

The machine did this right after I bought it, so I changed the hydraulic oil and filter out with fresh 15w40 Rotella T since. This issue occurred before and after fluid change. I have done a lot of reading and reviewed the hydraulic system diagram for the T5c. I am leaning towards a gummed up spool at this point. The fact that it is intermittent is what makes it a little more challenging to me.

I will post up any progress made as I try different things out to remedy the situation.

Thanks

 

[Alexhasson]

my loader arms did this, i rebuilt them with a new ring kit. the internal seals were rolling over on themselves and allowing internal bypassing. they would roll back and hold again for bit then roll again and drift.

it could also be the control valve, you could test this by swapping hoses. so down is up and up is down. also swap them to a different spool. you can isolate where the issue is located through the swapping process.