Making an older skid steer 'auto stop'

[anesthes]

I bought an old Ford (made by erickson) CL340 skid steer. It's a cool little machine, however with the controls in the neutral position it rolls. It is designed with a service brake pedal to stop it.

It's a typicl (I think) setup with hydraulic motors and chains on each side to control the wheels.

For you folks who know more than may, can you give me any hints or help getting it to 'stop' in the neutral position like a modern bobcat skid steer?

The previous owner uses power forward and back to stop/slow it, however if the engine stalls and you are on a hill it's all over.

The service brake, while with some new pads could provide reasonable stopping, cannot be locked either so if you exit the machine it will again - roll down the hill.

Thanks!

-- Joe

 

[TraderMark]

Hey Joe,
Welcome to TBN.

I did a little research on your machine. From what I saw just looking at the parts diagrams, there's not much way to give this machine static braking capabilities.

The parts list shows the hydraulic drive system using a gear pump, a metering valve and a drive motor. They don't say what kind of motor and don't show a break down of the motor so it could be a gear motor, a piston motor or an orbitrol motor.

When a gear pump and metering valve are used to power a motor, the valve usually has what's called a "motor spool" in it. This allows free flow of the oil when the valve is in the neutral position. The oil is not blocked in any way so the motor has no braking effect. The reason for the motor spool is to allow the motor to come to a stop slowly and freely so as not to damage it. Just imagine if the motor was turning full RPM's and the valve suddenly closed and trapped the oil. It would have nowhere to go so something would have to give.

Your best bet would probably be to repair the brakes on your machine.

Hope this helps.

Mark

 

[anesthes]

Hey Joe,
Welcome to TBN.

I did a little research on your machine. From what I saw just looking at the parts diagrams, there's not much way to give this machine static braking capabilities.

The parts list shows the hydraulic drive system using a gear pump, a metering valve and a drive motor. They don't say what kind of motor and don't show a break down of the motor so it could be a gear motor, a piston motor or an orbitrol motor.

When a gear pump and metering valve are used to power a motor, the valve usually has what's called a "motor spool" in it. This allows free flow of the oil when the valve is in the neutral position. The oil is not blocked in any way so the motor has no braking effect. The reason for the motor spool is to allow the motor to come to a stop slowly and freely so as not to damage it. Just imagine if the motor was turning full RPM's and the valve suddenly closed and trapped the oil. It would have nowhere to go so something would have to give.

Your best bet would probably be to repair the brakes on your machine.

Hope this helps.

Mark

Hi Mark,

Well you sure do know a lot more about hydraulics than I do!

Thank you for taking the time to review my question. sounds like I will just repair the service brake. My big issue with the braking system is no parknig break. My oliver is set up so you can press the brake pedals and lock them in place, so you can exit the machine and do something. I will have to review the parts illustrations and see if their is missing parts.

Curiously, how does hydraulic braking work on a bobcat?

I have one last question. This machine runs pretty well, but does have a little blowby and oil consumption. The selling price was reasonable, and lower than most machines with missing engines so I took it.

The seller has a "spare" 30hp wisconsin engine (same engine that powers this, he believes) that he wants to sell for $250. Would you recommend me picking up the spare engine, or holding out until this machine breaks down and replacing the air-cooled 30hp engine with something better?


-- Joe

 

[TraderMark]

Joe,
I looked all over the parts catalog and I couldn't find any parking brake mechanism either.

You can go to the Ford/New Holland website and see the parts catalog online.

NEW HOLLAND CONSTRUCTION | BUILT AROUND YOU

Just click on the red link that says, Parts Catalog, then type in your model number. It'll show you the complete parts catalog.



Static breaking on newer skid steers is done through the hydrostatic drive which is a completely different set up than your machine has. Hydrostats use piston pumps and piston motors. Normally the pumps are variable displacement, meaning they can put out different amounts of flow and pressure from 0 to their rated capacity. Piston motors can be fixed displacement meaning they have a specific torque and speed at max input, or variable displacement, meaning the torque and speed can be varied without varying the flow from the pump.

To get static braking with hydrostats into a nutshell, the oil is trapped between the motor and the pump. There is no control valve or metering valve between the two. When the levers are in the nuetral position on the drive pumps, the pump is set to 0 flow so the oil trying to get out of the motor is trapped, giving the machine some braking.

Most people don't realize that static braking like this is not complete and total immobility. IF the motor is worn there is chance that internal leakage inside the motor can allow the oil to bypass and the machine can move. It won't move fast, in fact it's barely noticable over short periods of time, but I have seen machine with hydrostats and static braking that would creep down a steep slope overnight.

If you can get a good used 30hp replacement engine for your machine for just $250 it would make good sense to get it. I'd see and hear it run before I bought it to make sure it was a good running engine. But you can't even begin to rebuild a Wisconsin for that price, nor could you convert to liquid cooled or diesel for that price.

 

[anesthes]

Joe,
I looked all over the parts catalog and I couldn't find any parking brake mechanism either.

You can go to the Ford/New Holland website and see the parts catalog online.

NEW HOLLAND CONSTRUCTION | BUILT AROUND YOU

Just click on the red link that says, Parts Catalog, then type in your model number. It'll show you the complete parts catalog.



Static breaking on newer skid steers is done through the hydrostatic drive which is a completely different set up than your machine has. Hydrostats use piston pumps and piston motors. Normally the pumps are variable displacement, meaning they can put out different amounts of flow and pressure from 0 to their rated capacity. Piston motors can be fixed displacement meaning they have a specific torque and speed at max input, or variable displacement, meaning the torque and speed can be varied without varying the flow from the pump.

To get static braking with hydrostats into a nutshell, the oil is trapped between the motor and the pump. There is no control valve or metering valve between the two. When the levers are in the nuetral position on the drive pumps, the pump is set to 0 flow so the oil trying to get out of the motor is trapped, giving the machine some braking.

Most people don't realize that static braking like this is not complete and total immobility. IF the motor is worn there is chance that internal leakage inside the motor can allow the oil to bypass and the machine can move. It won't move fast, in fact it's barely noticable over short periods of time, but I have seen machine with hydrostats and static braking that would creep down a steep slope overnight.

If you can get a good used 30hp replacement engine for your machine for just $250 it would make good sense to get it. I'd see and hear it run before I bought it to make sure it was a good running engine. But you can't even begin to rebuild a Wisconsin for that price, nor could you convert to liquid cooled or diesel for that price.

Ok I'll make sure I can hear it run and pick up the spare engine.

I created an account on that website, but I can't seem to locate the CL340 ?

-- Joe

 

[TraderMark]

Joe,
I didn't have to create an account......

Try this link and see if you get to the parts catalog.

There'll be a box in the upper left corner of that page that says "Model".

Just Type in CL340 and hit Search. Should bring it right up for you.

Here's the link.

https://webparts.pvassociates.net/cnh/launch.php?DealerID=PVA-9SYXB-QHF3&DataSet=001NHC


You may have to go through a verification page first to get to the parts catalog.

Mark

 

[slowzuki]

The parking brake on most old equipment is putting the loader to the ground and lifting the tires.

You probably could convert the motor spool to something else with a relief valve in it and a damped pilot type circuit so you can't change direction fast enough to break something but we're talking hundreds of bucks and maybe custom machined valve block to install the valves in.

 

[anesthes]

Joe,
I didn't have to create an account......

Try this link and see if you get to the parts catalog.

There'll be a box in the upper left corner of that page that says "Model".

Just Type in CL340 and hit Search. Should bring it right up for you.

Here's the link.

https://webparts.pvassociates.net/cnh/launch.php?DealerID=PVA-9SYXB-QHF3&DataSet=001NHC


You may have to go through a verification page first to get to the parts catalog.

Mark

That worked, thanks a bunch. I just bought this thing and i'm dragging it home this weekend. Hopefully it will be a good replacement as a manure mover compared to my 1958 Oliver 550!

Thanks!

-- Joe

 

[anesthes]

So I've been playing with this thing a little bit. I like it but some things I noticed:

1) It jerks and jumps a lot if you give it too much umm. push forward. I hit my head on the roll cage. Operator error there, but I wonder why the jerkyness.

2) The foot gas pedal can't be in a worse spot. Horrid design. I'm going to mount a throttle lever on the side.

3) The ignition, gauges, start switch, and choke all need to be mounted at the hood of the cage, not between my legs. It's almost impossible to start it without having a knee into one of the controls!

4) No toe guard. After only brief ownership, I almost lost my food putting the loader down because my foot creeped beyond the front step into the path of the loader cross bar. I'm going to have to weld up something to keep from that happening!

5) I'm not sure if the best thing to do is turn the machine off before exiting/entering, or develop some sort of safety but it is impossible to get in or out without bumping the controls and lurching forward or back. The loader is controlled by the top of the joystick, so it's not as scary as a bobcat or something with foot pedals, but the fact that you can run yourself over isn't cool. I know sometimes when working you need to jump out and move something quickly.

-- Joe

 

[BHD]

another option one could use is a high pressure hydraulic, ball valve in the line that one can just turn when you stop to get out,