Slacker
Gold Member
Backhoe stabilizer, dipper and boom cylinders drift down after a day or so. Using the transport tabs isn't an option. I'd like to use check valves to hold the boom and stabilizers where I put them. Any reason i can't do this?
Check valves on my Backhoe?
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tommu56
Elite Member
I assume you mean piloted checks.
That will work unless you have piston leakage and it will still leak down.
I use a ratchet strap on my outriggers.
A couple links of chain and keyholeded pieces welded on would work for the other stuff I just haven't taken the time to make them up for my outriggers.
tom
That will work unless you have piston leakage and it will still leak down.
I use a ratchet strap on my outriggers.
A couple links of chain and keyholeded pieces welded on would work for the other stuff I just haven't taken the time to make them up for my outriggers.
tom
AKKAMAAN
Veteran Member
That depends on how cylinder is hooked up...pressure on capped side and pilot checks on both capped and rod side will "seal the deal", even if piston seal leaks. It can not drift unless rod seal leaks externally.
We had a video clip about this a few days ago
J_J
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Like tommu56 said, and even then if the cyl is bypassing, they will only leak down until the pressure is equalized on both sides of the piston. If it leaks all the way down, it is the worn valve causing the leak down. However, you could install a needle valve, or gate valve in series with the boom cylinder, and or stabilizers, to lock it in place.
J_J
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I was sure that the cylinder would drop some before it equalize. What say you.
AKKAMAAN
Veteran Member
ok but not more than what it take to compress the oil due to the increased pressure which is for sure less than 1%...(where should that displaced oil volume go??)......ok cyl could drop a 1/64 to 1/32" from that compression and hose/cylinder expansion....it depends on total contained oil volume...?? The volume for the displaced "rod" is the "missing link".....
J_J
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If the piston seals are leaking/bypassing, and you restrict the output flow from the cyl, does it not seem reasonable that if the cylinder had a load pulling on it, that the fluid would leak by the seals until the pressure equalize, and then would stop, because there would be no differential between base end and rod end. Just thinking here, please enlighten me if wrong.
Stonehaller
Platinum Member
AKKAMANN has a valid point about the rod volume if you are compressing the cylinder. If, however, you are extending the cylinder, like in drift down of most backhoe stabilizers and booms, then the back side of the cylinder can cavitate so the pressure will not equalize and the cylinder will move.
oldnslo
Super Member
Are talking about drifting down during transport or when using the stabilizers to support the tractor while digging?
Most stabilizers come factory equipped with P.O. checks on them to lock them down when supporting the vehicle while digging.
Be very careful about P.O. checks on both ends of a cylinder. If stored cold and then brought out into the sun thermal expansion can blow cylinders apart.
Roy
Most stabilizers come factory equipped with P.O. checks on them to lock them down when supporting the vehicle while digging.
Be very careful about P.O. checks on both ends of a cylinder. If stored cold and then brought out into the sun thermal expansion can blow cylinders apart.
Roy
AKKAMAAN
Veteran Member
OP
Slacker
Gold Member
When I take the BH off the tractor, I need the stabilizers and boom to lift it off the subframe. They then leak down making it a PITA to get things lined back up when I want to reattach. In my mind, if the boom and stabilizers had check valves then they would not be allowed to leak down, making re-attachment much easier. I'm just looking for a way to keep the BH in the same position as when I left it. Getting the PTO pump hooked up then re-positioning it is time consuming because of the leak down issue.
Stonehaller
Platinum Member
Yes good point. I forgot about that too.
The P.O. Checks are typically incorporated into the control valve. You do not want to add external P.O. Checks if there are already checks in the control valve as you can get pressure trapped between them and they will not open. Your only choice may be to rebuild or replace the control valve.
AKKAMAAN
Veteran Member
I think you need to secure the boom with a chain strap or something....and the whole BH need to rest on a sturdy box type thing, instead of it舖 own hydraulics .... to park hydraulic equipment, and having it to rest on its own hydraulics is a challenge and might not be safe either.....
Can you post a picture of this BH when it is attached to the tractor and also deattached from the tractor
I see what your saying. Can you use something like bottle jacks or a preset size of block that you can back up to and use backhoe to lift rear end up enough to slide blocking under? (Just a thought may not be possible.)
OP
Slacker
Gold Member
Backhoe won't pick up the rear of the tractor. Wouldn't even come close, even when it was brand new.
PTO pump or tractor hydraulics, makes no difference.
J_J
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This backhoe can certainly pick up the tractor.
So You Think You?re a Backhoe Operator? Oklahoma College of Construction News
So You Think You?re a Backhoe Operator? Oklahoma College of Construction News
tommu56
Elite Member
something isn't right every backhoe I'v run would lift the tractor are you sure pumps are working correcly
maybe I missed it but what type of tractor and hoe do you have?
tom
OP
Slacker
Gold Member
Farmtrac made the hoe in Tarboro NC. It's the 4008 model. Curl seems strong enough but the other cyliders seem weak to me. I do have oversized loaded rear tires. I've run the hoe on the tractor hydraulics and a PTO pump. No difference in strength that I noticed.
Have you run many compact tractor backhoes or just commercial ones? Eventually I'll plumb a pressure guage in and see what I've got for pressure. I've always suspected the relief valve needs to be set higher but I'm new to hydraulic's so it's a little intimidating.
tommu56
Elite Member
Ive run a varity of equipment but the loaded tires might be the issue none that I have run were loaded that I know of
Mostly case 580 and ford 550 and some jd 110's and my baby the 23 and all those could lift the rear with the out riggers and the hoe.
Ive crabbed quite a few over a trench with the hoe to finish it.
tom
