Quick attach and grapple select option

   / Quick attach and grapple select option #1  


Platinum Member
May 4, 2010
Jessup Mill, NC
Rk55HC 4n1 fel/bh, Power-Trac 1850, 425d, Terex pt30, Kubota kx033, bx1880, yanmar 8x8 dumper, Magnatrac mh5000 w/ loader, six way blade & backhoe, Dew-eze ATM72LC Slope Mower, Terramite t6 4wd, DR Power brush mower
This post is intended to help power trac owners add a select function to choose when your knee knocking lever [SUP]tm[/SUP]actuates the quick attach (qa) cylinder OR another cylinder function (ex: grapple, 4n1 bucket, tree shear, mini hoe...).

Problem : at times it is difficult to change the attachment and reconnect the small lines with the quick disconnects (qd) from the qa cylinder to attachment function because of pressure and temperature differences between the machine and the attachment. Frustrating, oily, finger smashing...insert expletive here.

There's lots of approaches to this problem... Here's one that does not directly involve law enforcement.

Parts required :

Valve - six port selector valve like item 220962 at Baileyhydraulics.com. This one is manual, lever actuated, you can also use a 12v solenoid selector valve or 2 3-way ball valves.

Fittings/adapters: fittings are crimped to hose/tube, adapters change the standard, gender or size allowing connections to otherwise incompatible ports. the above valve uses sae 8 (also called orb 8). Depending on where you place the valve you might need 90 degree, 45, long etc...

Hose: #4 aka 1/4" rated for 3000+ psi (more for the big machines)

Machine off, arms mostly up and blocked so they can't fall when you bump the loader joystick...

Trace the path of each hose from the qd, through the metal protector to the valve body. Mark both ends of each... I use zip ties to color code... Remove the hose from the adapter at the valve body, leaving the adapter in place.

PT used different parts here but most likely you have a cone shaped (jic) male on the valve side and jic female in the hose end.

Using string, or better yet the seamstress tape measure you swiped, measure the path to the location you plan to mount your new selector valve.

Consider : allowing for the motion of the arms and hoses ; can you reach the lever of the selector? Is the selection lever adequately protected (you can modify the length or bend as needed) ?

If the considerations above are resolved, the measurement just taken indicates the length of extend and retract hose you will need to plumb the select valve to the knee knocking directional valve that is the source.

If you need to order hose and adapters, stop here, reattach. Order the parts... You can still use the machine.

If you are in the Napa parking lot w your piggy bank... Proceed.

Depending on where you are locating the valve, you may be able to attach the original hoses to the new valve. You may also need to shorten/lengthen them.

If you need to shorten them, one option is new hose cut and fitted, another option is to use a cutoff wheel and a reusable/field repair fitting. Northern tool usually has 1/4 or #4 on the shelf....just watch a YouTube and keep the inside of the hose clean!

For the qa cylinder circuit, you are running new hose from the existing valve to the in/out of the new selector, then from two sae 8 work ports attach either new hose or the existing ones w the qd ends. You'll just plug in the qa disconnects one last time... Then leave them. The qd male and female ends accept 1/4 npt male hose ends usually on #4 (1/4")hose.

For the new attachment function circuit, you'll run two new hoses w appropriate fittings/adapters from the sae8 work ports to wherever you want to mount them, keep in mind that the hoses on your attachment is long enough to go right where they always have... So consider mounting (zip ties?) right next to the original ones.

Note :You may have heard about additional valves and 90 degree adapters adding heat or reducing pressure... Totally true... However a negligible effect given the low flow and duration of flow in this subcircuit. So it's okay to do what you need to get the hose to the destination.

Terminate the new hose with 1/4 npt male ends and qd to connect with the qd of the attachment.

A word about qd compatibility... Grrr.

I love PT, but I don't like the limited compatibility of their choice of qd... I replaced all the stucchi ones with more common ones and noticed better reconnect... I buy the new qd 5pr at a time on eBay for less than a pair of the stucchi ones...

For hose, fitting, adapters or even the valve, surpluscenter.com is a good source as are discount hydraulic hose, hydraulic warehouse and others. Locally, Napa $, Northern tool, tractor supply...

In a nutshell you've done this : lost no fingers, connected your knee knocker lever to a selector then connected one set of work ports to the existing small qd's added 2 qd terminated hoses to the other set of selector valve work ports to power the attachment function.

Hope this makes sense... I'll reread this pm to check for clarity... Others will chime in.
   / Quick attach and grapple select option #3  
Thanks Andrew - excellent tutorial.

I suppose there have been many PT plumbing configurations over the years but mine includes one of the QD couplings on the knee knocking directional valve that is easy access (large red circle in pic) and one that is COMPLETELY buried behind many other lines/fittings (see small red circle in pic). I think I'd either need to remove many of them or try to take the entire valve off to access it.

As I consider whether the effort is worth the reward, it occurs to me that if I performed the attachment connect/disconnect in proper sequence, I probably wouldn't need this feature. Unfortunately, more than once, I've hooked up my new attachment and connected the QD coupling before realizing that I hadn't locked in the QA on the new attachment so I have to undo, redo, and hope the pressure in the line doesn't lead to law enforcement involvement. This gizmo would definitely cut a step when switching between mini-hoe/4n1/grapple.

Couple of questions:

The selector valve you call out only shows 4 ports. I'm assuming there are two more (in/out) on the other side of the valve?
Does the system need to be bled after removal of these hoses?
   / Quick attach and grapple select option
  • Thread Starter
Pic didn't make it... But I think i follow.

So you could do this by removing the Small qd's and pulling them back through the protective pipe... Then use those as the supply/return to your new selector valve. Then you don't have to mess with the hornets nest at the back(arms side) of the knee knocker...you also don't have to use qd's on the qa lines if you use #4 female jic swivel or fjx4 (verify) ends on the hoses to the qa cylinder.

Also, there are charts that tell you how to identify hydraulic fitting, adapter and hose size... Including what the proper wrench sizes are.... Saves a ton of aggro.

If you have a flex head or crow foot type wrench... The fight is not as bad as you may think.

That part# should be 6 port... Ck the drawing in the document at Bailey (or customer service) to confirm. 2 ports are in/out 4 are paired work ports.

To your question about bleeding the lines. Yes, many scary things are said about the need to do this... However, cylinders are waaay more forgiving if line air than motors, pumps and vehicle brakes....the fluid leaving the cylinders on the PT goes back through the source valve and down the exhaust rope to the tank... Best practice = backfill lines, minimize air, bleed. But under no load, low rpm the cylinders will purge air just by cycling slowly a few times... So put that stress aside. Of more importance is garbage, grit and especially metal bits... They should definitely not be in the system ever. So if you wheel cut to shorten a hose ensure that the part you're keeping is above the part you a cutting off... So gravity helps you keep it clean.

If I can answer any questions, I will. There's a lot of skills in this forum and I am am learning too... This task is a pretty good confidence building exercise with a super practical payoff....worth it. My $0.02.
   / Quick attach and grapple select option #5  
Thanks for the follow up - very much appreciated!