B7100 cracked diverter valve

[B7100dJames]

Hello, I have a 1982 b7100d-p, with front end loader. It’s been working good, but this last weekend I was headed out rototilling and was lifting the tiller with the 3pt hitch. When the 3pt hitch lifted up all the way, it maxed out the pump like usual before before I returned the lift handle to the neutral position, but this time the pressure actually cracked the diverted valve housing. Some of the drawings I’ve seen call it the cylinder cap assembly. I’m now trying to find a new one, but haven’t found a definite part number yet.

Why did this crack? The housing cracked at a casting line, so I’m guessing a poor cast job on the part. But shouldn’t the relief valve have protected this? I have never messed with the relief, but I have only had the tractor a few months. The FEL I have maxed out before, but I’m guessing the external valve assembly for it has a built in relief valve that would limit the loader pressure.

I’m just looking for some input, maybe I need to put a pressure gauge inline somewhere before I fix and run things again?

Thanks, James

 

[B7100dJames]

Here is the crack.

 

[B7100dJames]

Here is another picture. Sorry I’m still figuring out to post pics.

 

[kubotasam]

Do you know how to get to the Kubota illustrated parts list? If your in the united states go to kubotausa.com/illustrated-parts/ agree to their conditions, then put in your tractor model. It looks like part #96319-01410 is what you need.

 

[B7100dJames]

Thanks for that part number! I’ve been in contact with my local dealer, and they can not get the cylinder cap, it’s discontinued apparently. I’ve been looking on Kijiji for something used, but the closest I may have found is a cylinder cap that does not include the diverter valve. I’m running a loader on my tractor. I’ve seen on OTT others have cut into the pressure hardline coming from the pump, and used compression fitting to loop in the loader valve. I think that would work for me, but I can’t tell if I have a open centre loader spool valve. I’m guessing I do because it’s fed from the diverter valve port on my tractor, and the return line goes back to the reservoir. If I get a non diverter valve cylinder cap, can I then loop into the pressure line with my loader valve?

 

[kubotasam]

A B7100 has an open center valve. Yes you can tap into the high pressure line that runs from the pump back to the 3 point control valve. There probably is a rectangular steel block built into this line next to the fuel filter. It was designed so you can replace the cover with a style that has fittings to add your hydraulic lines. Not sure if that part is still available or not. It is relatively easy to make one. I just drilled and tapped a small piece of steel plate to make one.
If you do decide to change from the diverter valve for your loader flow make sure the loader valve has a pressure relief built into it. One B7100 that I previously owned had the loader plumbed from the diverter valve and the loader control did not include a pressure relief valve. When using the diverter valve the 3 point control relief valve protected the loader circuit.

 

[Lil Foot]

Try these guys for used parts:
http://wkytpstore.com/

 

[B7100dJames]

Thanks for the help Lil_Foot and Sam. The 96319-01410 valve assembly is no longer agailable from anywhere new, and so far I haven't had any luck finding a used one. What I may end up doing is cutting the pressure line from the pump and using pipe compression fitting to hose in and out for the loader. Maybe I can remove the valve handle from the cracked diverter valve body, and then weld the crack and valve port up solid.

Does anyone know off hand what size is the pressure line to the pump? Is it metric or std? I have seen Vic's great video of how to tap into the line, but I am not able to braze on fittings, so that's why I'm hoping there are compression fittings that would work. I also do not have a block on that line for some reason..

 

[kubotasam]

Hoye Tractor is a company that sells parts for Yanmar tractors. On their website you will find an article on installing loaders on Yanmar tractors that do not have the hydraulic tap in point. They discuss using compression fittings to break into the high pressure line from the pump. So yes it is possible to use compression fittings. I am sure they are not the brass ones you find at the local hardware store. I would consult a company like Discount Hydraulic Hose to see what would work.
Sorry I do not know the specks on the tubing. I would assume it is metric.

 

[B7100dJames]

I haven’t found a cylinder cap yet, but I did get the loader hydraulics hose up by tying into the hard pressure line coming from the pump. The loader valve that I have has a built in relief, which I set at 1800psi. I was able to find compression fittings that would crimp to the hard pipe, and then go to my in and out hoses. I tested it last night and the loader works great! The nice thing about this setup is now I can run the loader and 3pt hitch at the same time, though very slowly I’m sure.

As for the cylinder cap / diverter valve, I no longer need the diverter valve, so I’m going to try weld the old cracked cylinder cap up solid, and if that won’t hold, than I may find a chunk of 3/4” aluminium and machine a cap.

 

[torch]

Does your loader valve have Power Beyond? ie: 3 hoses: 1 from the pump, one back to the interrupted hydraulic line, and one back to the reservoir? Or just 2 lines, one from the pump and one back to the interrupted hydraulic line?

If it only has 2 lines, then I fear you are compounding the relief valve settings and may cause more damage. If it has PB with 3 lines, then the loader relief valve has an independent outlet to the reservoir and you are safe -- but, you cannot use both FEL and 3ph simultaneously -- use of the FEL will interrupt flow to the 3ph temporarily, until the FEL control(s) are returned to the neutral position.

 

[007kubotaguy]

Hello
I have a used cap if you still need one. Send me a PM if you're interested in it.
Thank You Lance

 

[B7100dJames]

The loader valve I have is a BLB BM20/2, pt number 905051. I’m not sure how it’s working inside, but it only uses two lines. Originally it was hosed from the diverter valve, through the loader valve block, and then back to the fill port on the transmission case. Now it goes from the pump line, through the loader valve, and back to the 3pt hitch control valve pressure inlet.
I have ran the tractor and it seems to work well, I put a gauge on one of the loader cylinder ports, and it’s set to relief at 1800psi. I’m guessing this means the loader valve is a open spool type. My only concern is that when the 3pt hitch hydraulics are activates, will the loader cylinders be backpressured?

 

[torch]

Here's the problem: the relief valve in your control (1800psi) discharges to the 3ph relief valve. That's another, say, 1700psi for a total of 3500psi if both controls are operated simultaneously. That could lead to some serious damage.

You need to get a Power Beyond adapter for your BLB valve. The second hose, that you now have feeding into the 3ph, will be routed to the reservoir (add a 1/2" nipple and tee to the fill hole). Then you add a third hose from the PB outlet to the 3ph.

When the BLB valve is in neutral, fluid flows to the 3ph via the Power Beyond outlet. When the BLB valve is actively controlling the FEL, the 3ph is cut off and fluid is returned directly to the reservoir, ensuring the relief valve is not compounded behind another relief valve.

 

[Dave_eng]

The loader valve I have is a BLB BM20/2, pt number 905051. I***8217;m not sure how it***8217;s working inside, but it only uses two lines. Originally it was hosed from the diverter valve, through the loader valve block, and then back to the fill port on the transmission case. Now it goes from the pump line, through the loader valve, and back to the 3pt hitch control valve pressure inlet.
I have ran the tractor and it seems to work well, I put a gauge on one of the loader cylinder ports, and it***8217;s set to relief at 1800psi. I***8217;m guessing this means the loader valve is a open spool type. My only concern is that when the 3pt hitch hydraulics are activates, will the loader cylinders be backpressured?

First looking at your broken part, it is screaming someone hooked things up wrong!! Too much pressure where there should be little.

The loader valve WILL be open center. You need a serious hydraulic system to switch to closed center such as a big excavator.

In the quote above you talk of changes of hoses connections to other ports being made. Sounds ominous to me.

Take some time and google "power beyond," or sometimes called "High pressure Carry Over," and read everything you can find on the subject.
There are youtube videos with animation which will be a big help in learning about this feature

Tank or return ports on any valve are not to become supply ports for another valve. Using them as such breaks expensive things!

This is where "power beyond" steps into the picture. The "power Beyond" sleeve connects into the high pressure side of the FEL valve where it can deal with high pressures. The return or tank port is in the low or no pressure side of the FEL valve block

In my experience using compression fittings in home made tractor hydraulic system alterations can have serious consequences.

A tiny leak, you think you see one, you hold your hand over to make certain you are seeing a leak and now you have had hydraulic fluid injected into your body.

Every Kubota manual of recent times has this caution.

Dave M7040

 

[B7100dJames]

Thanks for the power beyond info everyone, I should have checked for replied on this this weekend! It makes perfect sense what you said about the bypass/relief side not being rated for pressure. I will fix.

I have managed to make a new cylinder cap out of a 1.25x3.5x4.5 block of aluminium, using a lathe and a drill press. I installed new Orings, and it works perfect, Im very happy. I was able to rototiller the garden finally. That being said, Im still not confident the relief valve is working properly. The engine boys down heavy when the lift lever is partly engaged. Ive set the implement height stop adjustment so that it kicks out the handle before the 3pt hitch lifts all the way up, thus never maxing out the pressure, but tonight I plan to open up the relief and inspect it.

In other news, bad news, Ive managed to strip the threads on the hydraulic pump, the pressure side for the bango bolt. Im guessing I torqued it to tight, as it was dripping from the crush washer from day one. Im hoping I can helicoil the threads, as in put new threads in it, otherwise its a new pump?! This tractor is getting expensive, well my DIY fixing might be the source of the problem..

 

[B7100dJames]

The new Cylinder cap

 

[Dave_eng]

Thanks for the power beyond info everyone, I should have checked for replied on this this weekend! It makes perfect sense what you said about the bypass/relief side not being rated for pressure. I will fix.

I have managed to make a new cylinder cap out of a 1.25x3.5x4.5 block of aluminium, using a lathe and a drill press. I installed new Orings, and it works perfect, Im very happy. I was able to rototiller the garden finally. That being said, Im still not confident the relief valve is working properly. The engine boys down heavy when the lift lever is partly engaged. Ive set the implement height stop adjustment so that it kicks out the handle before the 3pt hitch lifts all the way up, thus never maxing out the pressure, but tonight I plan to open up the relief and inspect it.

In other news, bad news, Ive managed to strip the threads on the hydraulic pump, the pressure side for the bango bolt. Im guessing I torqued it to tight, as it was dripping from the crush washer from day one. Im hoping I can helicoil the threads, as in put new threads in it, otherwise its a new pump?! This tractor is getting expensive, well my DIY fixing might be the source of the problem..

If the banjo fitting washer is copper, when you reuse it it should be annealed.
Annealing copper washers makes them soft and compliant to the two surfaces irregularities thus making a better seal.

Annealing is simple. Hang the copper washer from a nail or similar held in a vice. Slide the washer unto the nail so very little of the copper and nail surfaces and in contact. This step is necessary to have the copper washer not being cooled down through heat transfer into something else. For example, you lay the copper washer on the end of your vice because it is a flat surface. This will provide far too much copper to cold steel contact and the annealing process wont work.

The actual annealing calls for using a propane torch to heat the copper to a dull red and then withdraw the heat and allow it to cool slowly.

As soon as it is cool, it is ready to be reused just like a brand new washer.

Under the pressure of being squeezed in a connection, the copper becomes work hardened and no long able to conform to a new place in the joint.
Dave M7040

 

[B7100dJames]

Thanks Dave, IVe never heard of being able to anneal the crush washers, great idea, and something I will try!

 

[B7100dJames]

Just a last update. The tractor is finally working great. I found the source of my hydraulic woes, the hydraulic pressure relief in the 3pt hitch control valve was assembled wrong. Who ever had it apart last, put the ball bearing back in in the wrong order, and the result was that the relief would never open. I’m not sure how the ttractor has worked for so long with out breaking anything, but leave it to me to break both the cylinder cap, and strip out the pump housing, before figuring why. I tapped the aluminium cylinder cap I had made and put a gauge on it, and I was running over 2000psi (maxed out my gauge), so the relief was not opening. After I bought new relief valve parts and installed them, the relief was opening at 1800psi, as it should.

I’m very happy with the tractor now, and just finished back blading my snowy driveway for the first time. I should also say, my local Kubota dealer has been working wonders with finding all the parts I have needed, and usually getting them the next day. Thanks Gord!