Koehring Bantam 266-C pedal sticking

[razerface]

Hi,,I have purchased a Bantam 266-C to dig my basement, driveway, road thru woods, ect. I plan to sell after I'm done with these projects.

Everything is ok until we found 1 problem. This machine has the "stick" controls and "bucket curl" on floor pedals. When bringing stick in, at the last of the travel, the pedal sticks down,, and you must STOMP the "out" pedal to unstick it. While it is stuck, it drags rpm way down,,as expected, but does not kill engine.

This excavator sat for 2 yrs. We did not get it to stick while testing function before purchasing,,,,,,,,naturally

Any suggestions for fix? I'm guessing a valve?

 

[willie59]

Could be the centering spring mechanism on the backside of the valve, could be linkage/pivots. Disconnect the linkage where it connects to the valve spool, then see how free the pedal is. If it's still sticky or stiff to move, you've got a rusty linkage or linkage pivot problem.

 

[razerface]

Could be the centering spring mechanism on the backside of the valve, could be linkage/pivots.

Pedals seem to work easy when machine not running. I will disconnect linkage to be sure though.

Is this "centering" spring mechanism external, or inside valve?

 

[willie59]

Pedals seem to work easy when machine not running.

Huh???

Mind you, I haven't worked on one of these, but that sounds weird. I was thinking the machine might have linkage controls as opposed to hyd pilot operated controls because hyd pilot controls generally don't have "sticking" problems. Can you give us a little more description of how the controls and pedals work the valves?

 

[razerface]

Huh???

Can you give us a little more description of how the controls and pedals work the valves?

The pedals are on linkage as you say. They go thru the floor to a swivel point. There they are connected by adjustable linkage to a long rod which goes back to the valve,,maybe 6-7 feet back.

When I say the pedals seem to work easy when machine is not running,,,,I meant they will not stick when pressed to the floor,,,they come right back up. So I assume it is a hyd problem as they only stick when machine is running.

When you press the left pedal,,it forces the right pedal back up,,since they both cannot be down at the same time,,,,,,but when it sticks,,,you must literally "STOMP" hard on the opposing pedal to make the other unstick and return upwards.

If it makes any difference,, the pedal that sticks is the one that makes the "stick" come toward the operator. The pedal to extend the "stick" does not stick(so far).

 

[handtpipeline]

Sounds like the spool is sticking under hydraulic pressure for some reason. We used to have a 451 (predacessor to the 166) with the same controls. Left outside pedal stick out, inside stick in, right outside pedal bucket dump, inside pedal bucket curl, right stick boom, and left stick swing. Then travel levers beside the seat. I don't remember ever having them stick, of course by the time I started running it, everything was so worn out on it that it had miles of slack. You had to practically be an octapus to get the thing on or off a trailer. My 266 has the long joystick type levers, that come out of the floor, and travel pedals.

 

[handtpipeline]

here's the 2 machines. I still have the 266.

 

[willie59]

The pedals are on linkage as you say. They go thru the floor to a swivel point. There they are connected by adjustable linkage to a long rod which goes back to the valve,,maybe 6-7 feet back.

When I say the pedals seem to work easy when machine is not running,,,,I meant they will not stick when pressed to the floor,,,they come right back up. So I assume it is a hyd problem as they only stick when machine is running.

When you press the left pedal,,it forces the right pedal back up,,since they both cannot be down at the same time,,,,,,but when it sticks,,,you must literally "STOMP" hard on the opposing pedal to make the other unstick and return upwards.

If it makes any difference,, the pedal that sticks is the one that makes the "stick" come toward the operator. The pedal to extend the "stick" does not stick(so far).

Well that certainly is a wacky problem you got there razerface! I would sure like to know the components of the machine. How does it "make the other pedal come up since they both can't be down at the same time"? Never seen anything quite like this problem, I curious as to what's causing it.

 

[spitzair]

Since we're on the topic of Bantams here's a picture of the one I used to have before the ex made me sell it :Banghead... And coincidentally it had the same problem except on mine the pedal would get stuck in the out position... I never did get a chance to fix it... I sure wish I still had it! It was old, slow, about as worn as it gets, but had good power and best of all I got it on trade for a small load of lumber! Atco, on my machine, and I'm pretty sure it's the same on his as well, the two pedals were connected to opposite sides of a shaft so that when one went down the other would go up, and then would go back to the valve bank via a long rod. Clear as mud I hope, I'm not very good at 'splainin how things work...

 

[willie59]

Since we're on the topic of Bantams here's a picture of the one I used to have before the ex made me sell it :Banghead... And coincidentally it had the same problem except on mine the pedal would get stuck in the out position... I never did get a chance to fix it... I sure wish I still had it! It was old, slow, about as worn as it gets, but had good power and best of all I got it on trade for a small load of lumber! Atco, on my machine, and I'm pretty sure it's the same on his as well, the two pedals were connected to opposite sides of a shaft so that when one went down the other would go up, and then would go back to the valve bank via a long rod. Clear as mud I hope, I'm not very good at 'splainin how things work...

Great post spitzair.

"before the ex made me sell it." Now there's a phrase that'll put a burr under yer saddle!

I haven't worked on any of the Ko-ring hoes, seen plenty around in my life, just haven't worked on one. That's interesting you had the same/similar problem. I wish I knew more about the components on these rigs. I want to know what is causing this.

 

[D5G]

Great pics guys, I love seeing the old Koehrings!

handtpipeline, any more pics of the 266? its a gem!

 

[handtpipeline]

yep

 

[razerface]

Well that certainly is a wacky problem you got there razerface! I would sure like to know the components of the machine. How does it "make the other pedal come up since they both can't be down at the same time"?

I will be getting greasy this week end I guess,,if the rain holds off and lets me thru the mud,,learning exactly how this all works I should know how those pedals work when I'm done.

spitzair,,, were you gonna work on the spool valve to fix yours?

Mine is a twin to the last pic above except I think my tracks are wider. Dirt looks same color as machine!

 

[D5G]

thanks handtpipeline!:drinkup That machine is a true beauty.

 

[spitzair]

Razerface, I had planned to open it up and look to see what the problem was but it wasn't really that big an issue for me so I never got around to it... I kept thinking it was likely a broken return spring... As an aside I found a C366 during my travels last week but never got a chance to stop and take pictures of it... That's a nice machine you have there handtpipeline!

 

[handtpipeline]

thanks handtpipeline!:drinkup That machine is a true beauty.

We bought the 451 new in '73, then the 266 new in '78. The 266 still looks about the same, except it's been sitting in a field for about 10 yrs, and someone vandelized the dash.

 

[dozerdave]

Hi razerface,

I had the same problem one time but with a G1000 Gradall. It was the control valve body for the swings and the night shift mechanics said they used a wheel cylinder hone to clean up the valve body bore.

 

[razerface]

Hi razerface,

I had the same problem one time but with a G1000 Gradall. It was the control valve body for the swings and the night shift mechanics said they used a wheel cylinder hone to clean up the valve body bore.

hey Dave, that could be good info,,thanks. I went out and looked for the valve. It is pretty easy to get to for working on. May put some wrenches to it this weekend. Was your bore scarred, corroded, ridged, or something else?

 

[95zIV]

Ok, I just need to say this, can we get some pictures please? That would help us to understand this a bit better.

 

[willie59]

hey Dave, that could be good info,,thanks. I went out and looked for the valve. It is pretty easy to get to for working on. May put some wrenches to it this weekend. Was your bore scarred, corroded, ridged, or something else?

Easy now guys, be very easy with this. And I'm not saying it wasn't a proper fix for dozerdave, I'm just saying be gentle doing this. The tollerance's between a valve spool and the valve body bore is very very close. If the bore is too large, by mere thousandths, you'll have excessive internal leakage that will affect function performance and generate heat. You would only want to hone the bore if you knew for sure this was a problem. And even then...very carefully.