It's time; either get started or....

[aczlan]

I think it's a MB series, right? If so, this is it: Joystick Kit For Wolverine MB Valves 6661 | Valve Parts & Accessories | Hydraulic Valves | Hydraulics | www.surpluscenter.com

Aaron Z

 

[NormL]

The four spool valve I have is a BM 40 manufactured in Italy by BLB Hydraulics. I checked to see if they offer a joystick kit and it appears they don't. For now, I'm going to go with getting this plumbed and tested as is. In future, I can always go back and modify if it looks to be beneficial. That's just one of the perks in this game of DIY. Thanks for all the helpful advice!:thumbsup::thumbsup:

 

[NormL]

The weather began to cooperate recently and I have been able make progress. Since the next part of the project will be mostly hydraulics I will open a thread on that forum. I'm hoping that way to avoid making goofy mistakes. I'll call it "Hydraulics 101 on my Mini Backhoe build".

 

[NormL]

This project has reached the point where a lot of little things need to be addressed. The engine had not been running for some ten years so its no surprise it was reluctant to just start and run as if that kind of down time was without consequences.
First, the reason I parked it all those years ago was its appetite for ignition modules. At $200 Cdn a pop, it was getting expensive to replace them! Now, with internet shopping I'm able to replace a module for about 30% and I found out the cause - two plugs gapped at .030 firing at the same time is the same as one plug gapped at .060. Running at full throttle for two or three hours while mowing and you get an overheated module with a greatly reduced lifespan. I've reduced the gap to .020 to mitigate this and will experiment with even smaller gaps till I find that "sweet spot" that allows the engine to run smoothly at mid to high rpm's with normal power output.

Second, the valves were not closing enough to create proper compression at first so that even with a new ignition module and fresh sparkers, it refused to start. That eventually cleared up and I got it to run for a few seconds if I primed the carb with a few tablespoons of fuel. Turns out the pulse type fuel pump, another weak link which is a carb - mounted setup, needs a complete rebuild. Time to convert to low pressure electric fuel pump. I "borrowed" one off another garden tractor try it.

Third, Found out the 12 volt feed from the ignition switch no longer functioned reliably. It was more off than on, so, another internet shopping spree. By the time I get the ignition switch and fuel pump, the hydraulic hoses I have on order should be all hooked up. Then I hope to finally get everything tested for the first time.

 

[NormL]

It's over three weeks since I posted to this thread and in that time I have made some progress. The engine starts and runs since figuring out the scrambled terminals on the new ignition switch - totally different from the one I took out. I have all but one of the hoses hooked up. That last one needs an adapter to complete the circuit. Hope to have it tomorrow. I drove the backhoe out of the shop yesterday and took some pix.

The first one shows the machine after driving it out of the Quonset. Pic #2 is the seat ready for backhoe operator. #3 the seat for driving. That "snarl" of hoses will need some tidying up to make room for my left foot!! #4 the bucket with its teeth. That long pin will be shortened after I determine how I'll attach the chains if needed for helping with dumping out sticky clay that wants to stay in there.

 

[NormL]

I got that fitting installed so all the hoses are in place. I found some minor leaks and fixed them easily enough. The thing that had me worried was would that old pump off the bale loader still pump. Well, it pumps alright!! The bale loader was a tractor towed machine so the pump was PTO driven at 540RPM max. The way I am running it is probably quite a bit faster. I'm guessing the engine is running a minimum 1200 RPM or more and the drive pulley to driven pulley cuts it down to half that. I'm going to have to find flow restrictors for all the cylinders as they're moving far too fast. The problem I'm having is sourcing those restrictors. Anyone know where to look?

 

[Xfaxman]

I would change both pulleys to slow the pump more.

 

[NormL]

I would change both pulleys to slow the pump more.

The pulley off the engine is a five inch that originally powered the mower deck on this garden tractor and if I'm not mistaken it and the drive pulley for the tranny are one unit. The driven pulley is ten inch and that is already pretty big. I'll have to look under the tractor tomorrow and see what the possibilities are.

 

[Xfaxman]

Can you do a speed reducer like you did on your drill press?

 

[NormL]

Can you do a speed reducer like you did on your drill press?

View attachment 696601

That is what I'll try if I take that route. What I hope to do first is fashion homemade restrictors for the individual cylinders. The location of the pump drive is under the tractor because the engine is a vertical shaft type. Not really a fun place to work .

 

[NormL]

I took a hard look under the tractor and I think it can be done. I have the shaft material and probably the pulleys too but if I opt for a 2" / 6" combination I can run the engine a bit faster and hopefully prevent the stalling that is happening now. So 5" on the tractor to a 6" turning a 2" on the same shaft that is belted to a 10" pulley on the pump. I might not have to clutch like I'm doing now but if starting is troublesome then I'll use the idler pulley as a clutch again. I would like to run the engine a bit faster than high idle so it has the power to run the hydraulics. I'm still going to go with the restrictors so I can control everything better. I'll start with 1/16 diameter openings and see how that works. It looks small to me but that's what I see on some fittings I have but are the wrong size. I can drill them bigger if need be.

 

[Xfaxman]

Sounds good, keep us posted.

 

[NormL]

Here it is over half past May and after a few Spring like days we've got summer! I slowed down the drive to the pump, maybe a bit too much as the boom has become sluggish. The dipper and bucket move ok but I have yet to try with a working load. I can't do that till the boom issue is resolved. The restrictors I made up may not be needed once I get the pump speed right but the belts are running into a bit of money each time I change pulley size. I'm also having to beef up some welds I forgot were only spotted on. The swing system also is in need of a redo and there is very little space to work. Sorry, no pix yet but I'll do a few soon. So, bit by bit things are getting done. I sure hope to be digging before Summer is officially here.

 

[Xfaxman]

 

[Williy]

All you guys building something and may need a
tractor part to complete you project you can check
out these web sites and perhaps you will find just
the part you need??

used tractor parts at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

willy

 

[NormL]

Bad news. The pump which I salvaged from an old bale loader/stacker has barely enough pressure to move the dipper and bucket when the load is light. The load for the boom is never light and consequently it can't lift the weight of the dipper and bucket. Grrrr!! Plan A: I have another salvaged pump but I have doubts about its suitability on this machine. It came off a Toro mower which I think had all functions hydraulically driven. The pump appears to be "stacked" with pumps for various functions. I'm not sure which one to use and which ones to plumb to circulate a bit of oil through a manifold. Plan B: Take a deep breath and buy a new pump. If I go this route, how much pump do I really need here. All my cylinders are two inch and none of them should be moving at more than a moderate speed at any time. Thoughts?

 

[NormL]

I dug out the pump I mentioned in Plan A.
IMG 2722 and 2723 show the ports on opposite sides of the pump. All three shown in 2722 deliver a detectable push on a finger placed over the opening while turning the shaft clockwise. The ports on the opposite side are larger and I don't feel either push or pull by turning the shaft by hand. IMG 2728 offers information on the manufacturer. Can anyone offer instructions for plumbing this into the backhoe?

 

[NormL]

I have a thread going in the hydraulics forum and one of the TBN'ers cautioned me about my routing of the line to tank from the four-spool vale set into one of the tank ports of my secondary valves served by a power-beyond from the primary valves. This could block the flow from the primary valves, he warned me, and in retrospect considering the issue I'm having, he may well be right. So, before I do anything rash and change out the pump, I'll follow up on this advice before I proceed.

 

[Xfaxman]

 

[aczlan]

I dug out the pump I mentioned in Plan A.
IMG 2722 and 2723 show the ports on opposite sides of the pump. All three shown in 2722 deliver a detectable push on a finger placed over the opening while turning the shaft clockwise. The ports on the opposite side are larger and I don't feel either push or pull by turning the shaft by hand. IMG 2728 offers information on the manufacturer. Can anyone offer instructions for plumbing this into the backhoe?

The two bigger ports are suction, the 3 ports are pressure out.
The big one will be high volume, the smaller ones are lower volume.
Might use one of the smaller ones for swing circuit, the other for the outriggers and the big one for the rest.

Definitely do not use the port on the valve marked as Tank for anything but a low pressure return to the tank.

Aaron Z