440 Auxiliary Hydraulics Reversing

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tyman00

New member
Joined
Nov 8, 2019
Messages
2
I have a early 80's 440 (pre 440b days) with auxiliary hydraulics. Currently the hydraulics are only used for a snowplow with a double acting cylinder for angling the plow. It works great.
I picked up a used rotary broom that was once PTO driven and now has a hydraulic motor that is rated for 9gpm. The 440 is a bit underpowered, but I'll take it easy on it. I built a temporary mount and hooked up the hydraulics and it works pretty good. Researching the motor shows it will reverse but it does not when I attempt to reverse the hydraulics. I will admit I do not have a strong understanding of hydraulic systems so I know I am missing something either about the Bobcat system or on the attachment. I did reverse the hoses on the downstream side of the tee/checkvalve manifold (shown below) and the broom did rotate in reverse.
When I try to reverse the system it behaves as if I have maxed the full extension or retraction of the plow's hydraulic cylinder. I do notice the hoses move as well.
I don't need reverse, but curiosity is getting the best of me. If I wanted to reverse the motor do I need a dual crossover hydraulic relief valve in place of the H manifold with the one way check valve?

https://i.imgur.com/Lfr3Mhb.jpeg
 

flyerdan

Well-known member
Joined
Mar 7, 2009
Messages
983
If you put a double check valve in there, it will be in bypass no matter which direction you run it.
The purpose of the check valve is to keep heavy rotating masses (like a bush hog) that spin at a fairly fast clip from grenading things when suddenly stopped. An auger, for example, doesn't need a safety check valve because it spins slowly, and if it binds the machine's bypass system protects everything.
You should be able to reverse the sweeper with the brush in the air, for cleaning or whatever, but the oil will follow the path of least resistance and will bypass soon after it contacts the ground, depending on the rating of the check valve. If the brush spins fairly slowly, you might not need the check valve at all. It would depend on whether it keeps spinning after the flow is shut off.
 

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