Adding auxiliary hydraulics to a 642B

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GOM

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May 9, 2019
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I recently purchased a 642B, It came with a deluxe enclosed cab with a lexan door, but was never equipped with auxiliary hydraulics! The third spool is present in the valve, and the tubes run to the left side of the machine and are capped. I can create a linkage for the valve myself. It probably won't allow me to use the auxiliary circuit "on the move" but I don't think for my purposes I'll miss that ability. I'm considering using hose for the rest of the circuit instead of buying the (expensive) OEM tubes. I think I can attach the hoses to the inside of the loader arm so they will clear everything nicely and using a pair of hoses deletes four extra connections which can leak. Does anyone know what diameter of hose and what diameter and type of fitting is necessary to connect to the existing tubes in the tractor? For a machine this old, would the quick connect fittings be the common agricultural type connectors? I'm not sure they had flat face couplings back then, and anything I may use will certainly be either old, or something I'll make myself (so I can choose whatever fittings I want.) As near as I can tell, about seven feet of hose will be approxiomately the right length. Does this plan sound reasonable? I'm trying to keep this a low-budget project; I'm not sure how often I'll even use the extra hydraulic function so I want to minimize cost and inconvenience. Any input will be appreciated. Thanks!
 

Tazza

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I think 1/2" hose was all you need. The OEM setup ran 2 tube lines along the bottom of the lift arms
Making a linkage up should be all you need, it may be a bt tight from not being moved for a long time, possibly even rusted, but hopefully it will work just fine.
 

SkidRoe

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Dec 10, 2009
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1,885
I put aux. hydraulics on my 440b a number of years ago.
I was going to do the same as you, run all hose, but then I found out how little clearance there was to run the lines down the boom to the couplers.
I did end up buying the tubes in the end. They were $50 each (CAD), which I didn't think was too bad.
I did end up running hose from the control to the boom hinge and it worked out great.
I ended up sourcing all of the other parts from Bobcat (except the hoses, fittings, and couplers). When the smoke cleared, it ended up costing about $800, including the spool kit (the spool was blanked in mine). Long story short, the parts from Bobcat were not outlandishly priced, in my opinion. And the whole system works like a factory fit.
Hope this helps - SR
 
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GOM

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May 9, 2019
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I put aux. hydraulics on my 440b a number of years ago.
I was going to do the same as you, run all hose, but then I found out how little clearance there was to run the lines down the boom to the couplers.
I did end up buying the tubes in the end. They were $50 each (CAD), which I didn't think was too bad.
I did end up running hose from the control to the boom hinge and it worked out great.
I ended up sourcing all of the other parts from Bobcat (except the hoses, fittings, and couplers). When the smoke cleared, it ended up costing about $800, including the spool kit (the spool was blanked in mine). Long story short, the parts from Bobcat were not outlandishly priced, in my opinion. And the whole system works like a factory fit.
Hope this helps - SR
After a long, busy summer, I'm back to the Bobcat aux. hydraulics project. I've got plenty of room for hydraulic hoses to run the length of the boom (rather than the tubes) and I have the third spool moving freely when the unit is not running, so the valve seems OK. I've got the linkage issue figured out. Basically now I need to know what couplers are used for the old, low flow aux. circuit on one of these machines. Are the couplers the same as the ones on my farm equipment for the remote hydraulics? I can get those at Tractor Supply. Does anyone know how long the hoses should be, off hand? I'll measure, but if some one has done this before, I'll compare notes before buying. I don't have a Bobcat dealer anywhere near here, so I'll have to source everything locally or via the internet. I'm hoping to do this as inexpensively as possible, since this is a limited use feature for my applications.
 

foton

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Mar 1, 2018
Messages
1,278
After a long, busy summer, I'm back to the Bobcat aux. hydraulics project. I've got plenty of room for hydraulic hoses to run the length of the boom (rather than the tubes) and I have the third spool moving freely when the unit is not running, so the valve seems OK. I've got the linkage issue figured out. Basically now I need to know what couplers are used for the old, low flow aux. circuit on one of these machines. Are the couplers the same as the ones on my farm equipment for the remote hydraulics? I can get those at Tractor Supply. Does anyone know how long the hoses should be, off hand? I'll measure, but if some one has done this before, I'll compare notes before buying. I don't have a Bobcat dealer anywhere near here, so I'll have to source everything locally or via the internet. I'm hoping to do this as inexpensively as possible, since this is a limited use feature for my applications.
I would go to the newer style connectors any newer attachments you pick up will have the newer style connectors on it. So why not do it now, vs changing to it later. I do not know on length. I did this to a 500 to add a grapple but the machines are way different.
 

DonaldSkidrow

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Joined
Oct 20, 2019
Messages
1
After a long, busy summer, I'm back to the Bobcat aux. hydraulics project. I've got plenty of room for hydraulic hoses to run the length of the boom (rather than the tubes) and I have the third spool moving freely when the unit is not running, so the valve seems OK. I've got the linkage issue figured out. Basically now I need to know what couplers are used for the old, low flow aux. circuit on one of these machines. Are the couplers the same as the ones on my farm equipment for the remote hydraulics? I can get those at Tractor Supply. Does anyone know how long the hoses should be, off hand? I'll measure, but if some one has done this before, I'll compare notes before buying. I don't have a Bobcat dealer anywhere near here, so I'll have to source everything locally or via the internet. I'm hoping to do this as inexpensively as possible, since this is a limited use feature for my applications.
Hello, when you're done, show how it look.
 

bobbie-g

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Joined
Mar 15, 2004
Messages
577
Hello, when you're done, show how it look.
I use these connectors from ebay: https://www.ebay.com/itm/3-4-SAE-12-Flat-Face-Hydraulic-Quick-Connect-Couplers-Bobcat-Skid-Steer/272318880758?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 I like the quality, and that outfit (Summit) has a lot of variations of the same sort of connectors. However, they have an O-ring boss arrangement on the backside which connects to existing lines on my Bobcat. In your case, i would think you would want something compatible with whatever fittings you put on your hoses. But you'll have to figure out some way to mount the fittings on the end of the lift arm and that may dictate what sort of fittings you have put on your new hoses. Interesting challenge, but not rocket science. :) ---Bobbie-G
 
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GOM

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May 9, 2019
Messages
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I use these connectors from ebay: https://www.ebay.com/itm/3-4-SAE-12-Flat-Face-Hydraulic-Quick-Connect-Couplers-Bobcat-Skid-Steer/272318880758?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 I like the quality, and that outfit (Summit) has a lot of variations of the same sort of connectors. However, they have an O-ring boss arrangement on the backside which connects to existing lines on my Bobcat. In your case, i would think you would want something compatible with whatever fittings you put on your hoses. But you'll have to figure out some way to mount the fittings on the end of the lift arm and that may dictate what sort of fittings you have put on your new hoses. Interesting challenge, but not rocket science. :) ---Bobbie-G
I think I've got the hose routing in mind, and I may simply sleeve the hoses for protection and let them protrude through the mounting tab on the arm a few inches with a standard coupler threaded directly to the end of the hose. A worm drive hose clamp would prevent them from pulling back through. A buddy of mine has offered me the use of several attachmemts so I need to look at the fittings on his machine if I want compatibility. Otherwise I'll use standard agricultural couplers like I've got on my tractor. Now I've got to get the time to actually do the job! Thanks to all for your help. By the time I get this done, maybe I'll have the technology to post pictures.
 

craigb93

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Joined
Nov 9, 2010
Messages
163
I think I've got the hose routing in mind, and I may simply sleeve the hoses for protection and let them protrude through the mounting tab on the arm a few inches with a standard coupler threaded directly to the end of the hose. A worm drive hose clamp would prevent them from pulling back through. A buddy of mine has offered me the use of several attachmemts so I need to look at the fittings on his machine if I want compatibility. Otherwise I'll use standard agricultural couplers like I've got on my tractor. Now I've got to get the time to actually do the job! Thanks to all for your help. By the time I get this done, maybe I'll have the technology to post pictures.
As noted above, the Bobcat original fittings have adapter bases that are already mounted on the support bracket. They have a flair nut taper on the inlet end and a straight thread outlet that seals with an O-ring. A bulkhead nut is in the middle. Much more rigid to push against if the mounting is solid. I have a set of the OE style quick couplers and a set of newer flat-faced couplers. I use mostly the OE ones but it only takes a couple of minutes to swap as needed. -Dick
 

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