Another Motorgrader - Page 2

DRohacek · #11 02-20-2021, 11:16 PM

I haven't fully decided on how I will synch the front drive with the rear. I think to start with I will mount an electric clutch on the hydraulic motor so I can completely disengage it from driving the front differential when not needed. I know Case 220 and 446 tractors have hydraulic motors that are control with a valve mounted under the dash. If I can use something like that I may be able to connect it to the lever control on the cub rears. I think it would be a trial and error situation to sync them as close as possible. Additionally I consider the front an "assist" rather than full time. I think if I have a momentary switch hooked to the electric clutch I could just engage the front when needed. Lots to figure out there yet. My plan is to get the grader functional with the rear drive first befor I tackle the addition of the front drive.

DRohacek · #12 02-23-2021, 06:46 AM

For the front drive I am planning on using a Case 220 speed controller and hook it to the other linkage and see if I can synchronize them.

I have a hydro question if someone can answer it. One of the rears I am using has the manual release valves. Can I replace them with the automatic valves?

I looked at the post that shows a place to order them and in the pictures they appear to be the same.

DRohacek · #13 02-23-2021, 07:42 AM

I'm using a one inch driveshaft between the hydros. That should reduce any flex. I have mounted a pillow block as well. I wanted to bolt the pillow block directly to the front rear as there are bolts already in the top but the bearing was too tall to fit.

The engine is a K582 Kohler. 58 cubic inch opposed twin. It came off a Jacobsen commercial reel mower that was used by a golf course. I wanted to use an electric clutch to disengage the drive during start up but the 1-7/16 shaft size presents a problem. Not truly impossible to find one but at $350 I decided to put a manual release on it.

Leadslingingdaddy · #14 02-23-2021, 08:02 AM

That's the size of a JD 318 shaft... see if you can find a parts machine on CL or FB for the clutch...

DRohacek · #15 02-23-2021, 05:14 PM

Quote:

Originally Posted by Leadslingingdaddy

That's the size of a JD 318 shaft... see if you can find a parts machine on CL or FB for the clutch...

Thanks. I will look around some more. Something else that I am unsure of is if the charge pump will have enough volume to run a hydraulic motor for the front wheel drive. I am only planning on using the front drive on an as needed basis.

Ambush · #16 02-23-2021, 05:23 PM

Short answer is no. But you could easily mount a pump to the front of the front hydro. Be tricky to synchronize the front drive speed to the others. Best would be a small, mechanically variable displacemnt piston pump to a geroler motor and a separate oil tank. Probably cost a $1,000.

sawdustdad · #17 02-23-2021, 08:07 PM

And yes, you can exchange the manual release valves for the auto version, no problem.

My front hydro is ported and that's what I used for all the hydraulics. If you do the same, you'll have a problem with room to mount a pump there. You, of course, could use the pump for all your hydraulics, and won't need to use the ports.

DRohacek · #18 02-25-2021, 06:03 PM

Quote:

Originally Posted by sawdustdad

And yes, you can exchange the manual release valves for the auto version, no problem.

My front hydro is ported and that's what I used for all the hydraulics. If you do the same, you'll have a problem with room to mount a pump there. You, of course, could use the pump for all your hydraulics, and won't need to use the ports.

Do you have a recommendation for a pump? What pumps did you have mocked up when you were thinking of driving with hydraulic motors? I will need a pump and motor for the front drive system. I am assuming I can drive off the rear shaft if the direction is ok. I hear you on the front pretty tight in there if I use the ports. I was thinking of using the ports for the power steering and everything else from a separate pump. Also, if I add an additional inline filter would it be ok to use the rear hydro for a tank? I'm also running a trans cooler.

sawdustdad · #19 02-25-2021, 08:02 PM

Quote:

Originally Posted by DRohacek

Do you have a recommendation for a pump? What pumps did you have mocked up when you were thinking of driving with hydraulic motors? I will need a pump and motor for the front drive system. I am assuming I can drive off the rear shaft if the direction is ok. I hear you on the front pretty tight in there if I use the ports. I was thinking of using the ports for the power steering and everything else from a separate pump. Also, if I add an additional inline filter would it be ok to use the rear hydro for a tank? I'm also running a trans cooler.

Northern Tool has a wide selection of hydraulic pumps and motors. A 6 gpm pump at about 2500 psi is about 8 hp which would work pretty well for your front axle. You need one that can handle the 3600 rpm engine speed unless you belt drive one at lower speed. (some don't handle side loads with a pulley).

This is the one I bought--bi directional/3600 rpm, pump or motor. Probably not "industrial" grade, but for my needs I felt the price was right.

https://www.northerntool.com/shop/to...1989_200641989

I don't know about using the rear axle for a reservoir for a gear pump. Ambush talked me out of it, basically. He's got a lot more experience with such stuff. It was enough uncertainty for me to fall back to the belt drive which is much simpler.

I am using the rear axle reservoir for my tandem dump, and it has a motor running constantly, (about 2 gpm) circulating to the rear axle reservoir, but it's not doing any work unless it's lifting the bed which is pretty infrequent. So the work being done is much less (like 5%) of the work being done by a full time hydraulic drive system which is constantly under a lot of load. That heavy load creates a lot more heat and potentially more wear on components, which creates the concern that Ambush identified.

What's the worse case? A failed hydro? What's that cost to replace? Like $50 to $100, so not a huge consequence if you decide to go down that path anyway. It's not like you are building something for market, it's a toy, so who cares if it has an occasional failure? You know, how many hours will it actually be used anyway? Maybe 10 to 20 hours/yr?

A filter would certainly be a good idea. The fluid fed from the axle's reservoir to the axle's hydro is filtered by the hydro's own filter so I think any debris sent to the axle reservoir would get filtered out before it got to the hydro itself. If I needed to drive the front axle, I think I'd seriously consider using the rear axle for a reservoir, despite the risks, since the consequences are rather small.

Maybe Ambush will add some advice.

Here's the Tandem set up. I used the forward axle's housing for the reservoir to avoid all the plumbing right beside the Lovejoy driving the pump behind the rear axle.

DRohacek · #20 02-25-2021, 09:47 PM

Excellent information! Thank you. i'm still sorting out the front drive but I want to know more about what I am doing by the time I get there. I picked up a speed control from a Case tractor and I think it is going to work for controlling the front axle. I still have to build the rear bulkhead and seat box but I want to get the hydraulics worked out while everything is still wide open. On a side note a friend on mine who just found out that I am building this offered me a 905E Kubota diesel that I would have loved to use for this but I already have the K582 in place and don't want to change it. I am going to pick up the Kubota anyway. I will need it somewhere!