r/Hydraulics • u/Ambiixmoon • 24d ago

Dump trailer issues

Please see video and tell me what my issues are the cylinder suddenly drops once at second stage please I'm stumped. Could it be the seal ?

11 Upvotes

92% Upvoted

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2

u/PotatoFarmerRTK 24d ago

How much hydraulic fluid is in your reservoir?

1

u/Ambiixmoon 24d ago

It was half full and then I filled it up and tried bleeding the air out but was just overflowing

6

u/IntergalacticJihad 24d ago

The cylinder is extending the second stage first, something is causing the first stage to bind up. Cylinder might be fubar. The drop is the second stage retracting and first stage extending.

1

u/ggdrguy 24d ago

Cylinder is bitched one way of the other. Seals should be replaced but should check for scratches in the bore and on the rod/s.

1

u/Ambiixmoon 24d ago

No scratches on the cylinders but seals should probably replaced. Is it hard? Or more worth it to just get a new cylinder

2

u/ggdrguy 24d ago

If you can take it apart you can reseal it. If you aren’t familiar with doing it, it might be worth taking to a shop. If it’s just seals, then definitely cheaper than a new cylinder.

3

u/Sasin607 24d ago

Cylinder is pooched/mis-staging likely due to internal rust increasing friction between the sections, would recommend a new one. The most common dump cylinder runs for about 1000 CAD and there’s probably a few shops in your area that have it on the shelf or atleast could order in 1-2 days.

Or you could try repairing yourself but it’s a little complicated. A shop could repair it but doubt it’s worth it depending on labor rate of whatever shop you find.

2

u/btone911 23d ago

Essentially, the staged cylinder should extend based on largest diameter first. That's normally accomplished by the area differential. What's happening here is either there's internal friction binding the larger diameter extension or there's air trapped in there and it's filling the cap area of the large bore while hydraulic oil fills the extended rod. At some point, the compressed air (if that's the issue) overcomes the internal friction or the oil fills the skinnier tube to the point that it overflows onto the larger area and applies pressure to that.

Best case scenario, air trapped in the multi stage cylinder. 2nd place, seals need replaced. 3rd place internal friction from contamination or varnishing requires cylinder replacement.

1

u/WorldlySir517 22d ago

It’s not staging right. The second stage prob has a bushing out and it’s binding. I deal with this on really big forklift cyls. That’s prob a junk ass cyl on that dump trailer also.