setting up my J.D. 450b for a backhoe attachment?

[wyooter]

Hello everyone, wondering if anyone has any ideas on how i should set up the hydraulics on j.d. 450b crawler for a j.d. 9450 backhoe attachment. The crawler has blade with a open center valve block while the hoe attachment is a closed center system. I figure i will need a selector valve to choose one circut or the other, and also some type of releif/pressure unloading valve down stream of the selector valve going to backhoe with return to tank. Don't know my valves that well and not sure if can use some type of relief valve or a pressure unloader valve? If i need a unloading valve where do i find one? Or..... has anyone converted the valve block on a hoe like this to a open center by machining the end plate? Not sure?
Thanks for your reply.

 

[J_J]

Some valves are adaptable for open center, closed center or power beyond, etc. I would check and see if there is an adapter for converting to open center on the BH valve.

Closed center operation simply blocks the flow of fluid through the valve. Any fluid used by the cyl is sent out the return/out port. If there is an extra hex plug on the end plate, it might be adaptable.

This is a closed center plug. Check your valve and see if there is something like this.

Surplus Center - CLOSED CENTER PLUG PRINCE RD5000 VALVES 660312005

If your crawler valve has PB, then you can connect the valves in series, but only if the BH valve is converted to open center.

If it is possible to convert, and your crawler does not have PB, then the pump flow can be switched using a valve like this.

Manual selection valve, pull or push to operate

http://www.surpluscenter.com/item.asp?item=9-6134&catname=hydraulic

Electric selection valve, just flip a switch to operate

http://www.surpluscenter.com/item.asp?item=9-7986&catname=hydraulic

http://www.surpluscenter.com/Instruct/I9-7986.pdf

Can you show some pictures of the end plate on your BH valve.

Could change out your BH valve for this opencenter joystick valve.

http://baileynet.com/index.php?dnfwd=1&page=ProductDetails&line=CVTJ&baileyno=220-951

 

[wyooter]

Thanks for your reply J.J.

The end plate on the B.H. does't have any type of plug on it. looks like the words Cessna on the end plate. Maybe I could possibly change the end plate? Anyway do you know if there is some type of valve out there that i could use so that when the B.H. circut is selected and its not in use the fluid will relief and return back to tank? I dont think a regular relief valve will work.
Someone told me i need a unloading valve, but they dont seem easy to find for your average joe and the few i have found seem spendy.

Thanks again J.J.

I'll have to keep diggen around.

 

[tlbuser]

Your current valve spool has an aux port and you will need a power beyond sleeve. Converting the cc system to open? New spools? According to my service manual, the difference is a flow divider and a manual selector valve. My 350B loader is setup for backhoe/rippers and uses a manual selector valve for on/off. My buddy has a 450B loader and his setup is the same, we have been sharing a model 93 hoe (rotary vane) and a set of rippers.
Cessna manufactured the pumps for JD.
Are you sure the model number is right for your hoe? It doesn't show up in Deere's tech. support.

This came from my 350 service manual, group 30
The backhoe control valve is an open-center, sixspool,
stack-type ‘valve.
All six valve sections are separate bodies containing
single spools. All valve sections contain lift
checks which serve as one-way valves to prevent
pressure oil from entering the port passages and
causing cylinder movement.
The crowd, boom and swing sections contain direct
acting circuit relief valves to protect their circuits
from excessive pressures.

maybe you could/should check with your local hydrauilic shop and see if you all can decide what the spools really are.

 

[wyooter]

Thanks for your response tlbuser!

Instead of using the aux port like you mentioned i ran the pressure line from the pump into a selector valve. Then i can switch from either dozer or hoe.
I think my next plan is to take the end plate off the hoe valve body and convert it to o.c. by drilling and tapping it to 3/4" pipe thread inline with the center port. If it doesnt work out i'll put a plug in it figure a different plan.

the data plate on the hoe says 9450. i got it from an outfit that had it on the back of a 444c j.d. loader. It seems like a newer hoe with the swing cylinders instead of the rotary vane style (9300 series).

 

[tlbuser]

Aha, that's a beast. Don't think I've seen one configured like that. Found a spec. sheet but still doesn't answer the question......
http://murphyused.com/images/specs/349.pdf

You can download a service manual for $18.55. May find what you're looking for there, before you modify.
https://www.johndeeretechinfo.com/i...tributes=division,model&model=94&menuModel=94

 

[wyooter]

Thanks again for your reply tlbuser.
I took the valve body apart yesterday and pretty sure my plan of making it open center isnt gonna work. Looks like the c.c. valve spools have a different configuration all together.
Looks like I'll either have to find a o.c. valve body from a 9300 series hoe or replace the gear pump on the dozer with a piston pump.
Guess i'd rather replace the valve body. you would think there would be a few of those 9300 series hoes around for parts being that the swing motors they had are now hard to get parts for.

If anyone has what I'm looking for give me a shout. Thanks..

 

[J_J]

Thanks again for your reply tlbuser.
I took the valve body apart yesterday and pretty sure my plan of making it open center isnt gonna work. Looks like the c.c. valve spools have a different configuration all together.
Looks like I'll either have to find a o.c. valve body from a 9300 series hoe or replace the gear pump on the dozer with a piston pump.
Guess i'd rather replace the valve body. you would think there would be a few of those 9300 series hoes around for parts being that the swing motors they had are now hard to get parts for.

If anyone has what I'm looking for give me a shout. Thanks..

What are the specs on the gear pump on the dozer?

Most open center system uses a single stage gear pump, so why change it?

If you can put an open center valve BH in series with that pump, you should be OK.

Closed center system usually use a variable speed pump, but a fixed gear pump can be used with an unloader valve and an accumulator.

 

[tlbuser]

Thanks again for your reply tlbuser.
I took the valve body apart yesterday and pretty sure my plan of making it open center isnt gonna work. Looks like the c.c. valve spools have a different configuration all together.
Looks like I'll either have to find a o.c. valve body from a 9300 series hoe or replace the gear pump on the dozer with a piston pump.
Guess i'd rather replace the valve body. you would think there would be a few of those 9300 series hoes around for parts being that the swing motors they had are now hard to get parts for.

If anyone has what I'm looking for give me a shout. Thanks..

That's why I mentioned a good local shop earlier. I have 0 clue if you could just buy new spools and use the porting in the old valve body.I also missed out on the separate pump, I thought you were referring to the machine's pump. What powers the pump? Does a 450 have a pto shaft?
With a separate pump, why couldn't you just fab up a special hyd. tank?