New Backhoe Control Valve Question

[Charles84]

I have a 1968 John Deere 500. It has around 23 gpm flow from the hydraulic pump. The tractor has a 13ft backhoe and is 80 hp. I need to replace the 6 spool backhoe control valve because it can't be repaired correctly.
The only good quality aftermarket part that I can find only has 12 gpm. It's a prince valve (6 Spool Hydraulic Valve w/Joysticks Prince SV | Directional Control Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com)

My question is: Does anyone know if backhoe control valves utilize the full gpm flow from the hydraulic pump? Trying to figure out if I am going to be severely limiting the functionality.
Thanks.

 

[BigGG]

I have a 1968 John Deere 500. It has around 23 gpm flow from the hydraulic pump. The tractor has a 13ft backhoe and is 80 hp. I need to replace the 6 spool backhoe control valve because it can't be repaired correctly.
The only good quality aftermarket part that I can find only has 12 gpm. It's a prince valve (6 Spool Hydraulic Valve w/Joysticks Prince SV | Directional Control Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com)

My question is: Does anyone know if backhoe control valves utilize the full gpm flow from the hydraulic pump? Trying to figure out if I am going to be severely limiting the functionality.
Thanks.

Can't answer your question, but summit hydraulics has a 21 gpm bh valve.

 

[Charles84]

Thanks for the info. I've found quite a few of 'questionable' quality. Summit looks like they have the exact same one that many others have. I can buy it on eBay for $235, but I have no idea how long the thing will last, if it works at all. I'd rather have something made in America, but if not possible, i'll buy a few of the cheaper ones.

 

[oldnslo]

12 GPM valve would not work very well on a 23 GPM system. It will have excessive pressure drop creating excess heat.

What is unrepairable on the original valve? I suspect the original valve has features you won’t have on the $235 specials.

 

[TractorTech]

What is not repairable on your valve. You can buy used sections from salvage yards and most likely whole valve banks. The problem with an aftermarket looks like it will work valve is that you don’t have the individual reliefs for the circuits.
Might not be the best option and could get you killed.

 

[Charles84]

My system is closed center. I'm under the impression that it doesn't need reliefs.
I've been through the whole backhoe control valve twice. All new Deere OEM o rings. 2 of the spools just wont stop leaking. Also VERY hard to find perfect valves for a 1968 JD 500. I'd rather buy something new. I love the old tractor, but the hydraulics need an upgrade. Losing too much fluid and there is too much internal flow where the backhoe drops every 1-2 min to the ground.

 

[4570Man]

I think you’re going to be disappointed with the performance of a not even close to right generic replacement at the best and more likely have a backhoe that’s not even operational. I realize they’re expensive but I’d look for a salvaged OEM valve or at least an after one that claims to fit. There’s a lot of precision in a backhoe valve and a few hundred bucks won’t buy an acceptable replacement.

 

[TractorTech]

Are they leaking between the sections externally? Some of the sections have circuit relief valves.
Which sections are leaking down so fast?

Also, you would be smarter to try and retrofit a newer valve bank from a newer Deere model.

 

[Charles84]

2 of the spools are leaking out of the top. Pulled them out and tried to reseal with new oem o-rings, but no luck. (After all internal o-rings have been replaced).
I'm assuming there is a lot of internal leaking due to how fast the backhoe drops to the ground so that's why i'm looking for something new. Some of these old deere parts, I have learned, should just be replaced.
I didn't know that there would be such a difference in functionality between a good quality modern valve body and an older one.
I do like the idea of looking for a newer deere model valve.
Thanks for all the suggestions.

 

[Charles84]

I'd be willing to spend up to $2000 for a good new aftermarket 6 spool valve body with joysticks. I would rather not go used, because hydraulic components can wear so much. I've got so many leaks in my loader backhoe and need them to stop. (Addressing many right now)