448 backhoe control valve

[Cloudy53]

Hi All,
New guy trying to learn new stuff:

The sad story: As I was remounting my JD 448 backoe attachment onto my 2006 JD 3120 compact tractor, I failed to hook up the return line to the power beyond connection. I started the tractor and subsequently broke the bucket control valve. The back side of the valve body burst out 2 good sized chunks. JD wants $1627.50 for this valve (JD part # LVA13656). I'm seeking help from JD Customer Support on this as I think the valve had an inherent flaw in the casting. Shouln't a hose or connection have blown first?
Anyway, any help anyone could provide , ie used valve or advice would be very much appreciated. Thanks guys!

 

[Cocre]

I do not believe anything should have blown. I have failed to properly attach the return hose a couple of times on my 06 3320 with a 447 hoe. If I recall correctly the implement pump went into immediate relief and did its job. At any rate, there was no damage done to system.

 

[J_J]

Your BH just plugs in to QD's correct. I am not sure what you mean by not connecting the PB port on the rear valve. It either has a plug, or a sleeve fitting, and a hose.

The part that broke just happened to be the weakest link in the system. It could have been anything in the flow path. I believe what you did , was to deadhead the pump flow, and something had to give, and it was the valve.

I think that if you search around you can find a replacement valve, much cheaper that the manufacture.

Two things I try and tell people, and that is to get a hydraulic gage, and put a relief valve across the pump.

That relief valve across the pump would save you most of the trouble with wrong hook up, dead-heading, etc.

 

[kennyd]

Hi All,
New guy trying to learn new stuff:

The sad story: As I was remounting my JD 448 backoe attachment onto my 2006 JD 3120 compact tractor, I failed to hook up the return line to the power beyond connection. I started the tractor and subsequently broke the bucket control valve. The back side of the valve body burst out 2 good sized chunks. JD wants $1627.50 for this valve (JD part # LVA13656). I'm seeking help from JD Customer Support on this as I think the valve had an inherent flaw in the casting. Shouln't a hose or connection have blown first?
Anyway, any help anyone could provide , ie used valve or advice would be very much appreciated. Thanks guys!

Welcome to TBN

Wow, what a story! I do a agree that the system should have protected itself and the valve should not have broken. Hopefully your dealer will see it that way!

 

[dfkrug]

The back side of the valve body burst out 2 good sized chunks.

Wow, that's quite a failure....got pix?

Since your hoe was set up to run off the tractor's PB circuit, you were
protected by the system relief valve (about 2500 psi), but the hoe's
return line is for low pressure only (500psi). It saw the full system pressure
since there was a QD blocking the OUT hose.

If JD uses a 6-spool stack valve, can't you just replace the broken parts?
If not, you can often find 5 or 6-spool valves new for under $500. I
hesitate to buy used hyd components, but that may work too....try eBay.
There is a new Prince 6-spool hoe valve for sale there now for under $500.

 

[Cocre]

Just no way, unless the system pressure relief valve is set wrong or the BH control valve was defective. A deadhead should unseat a properly set relief way before it should destroy a component.

The relief valve, according to the schematic, is before the 3 spool scv, and the PB which feeds the BH is fed through that open center scv.

 

[J_J]

Just no way, unless the system pressure relief valve is set wrong or the BH control valve was defective. A deadhead should unseat a properly set relief way before it should destroy a component.

The relief valve, according to the schematic, is before the 3 spool scv, and the PB which feeds the BH is fed through that open center scv.

After looking at that schematic, I have to agree. Perhaps the relief is set too close to pump pressure. I would certainly check the relief pressure before putting the valve back in operation.

Do you think a pressure spike might pulse back through the PB line, and blow out the side of the valve before the relief had time to react, since the pulse would have to go through the valve, and back to the relief?

I would loved to have worked in a hyd test and evaluation lab doing destructive testing to see how things react to set situations and limitations. I don't think Cloudy53 knows what caused this failure, and we are only guessing, using some common logic of course.

 

[Cocre]

According to the technical manual and jdparts it is a stack valve. If you google LVA13656, this same guy was told this about a month ago on ssbtractor.com

 

[Reg]

I only just stumbled across this thread.
I know, a couple of years stale, but I am still interested in the final outcome.

I have a similar hoe, it is OEM'd from Amerequip and I just gotta b'leeve they used a stack of stock off the shelf valves for this - probably a Prince 6 pack ?

So, if the O/p still gets updates on this thread, please let us know the final outcome ?
If it is still sitting out behind the barn waiting for $1627.50 funding, let me know that too, I might want to take it off your hands for parts (-: