Operating 3120; Parking brake & LoadMatch question

[DayDreamer]

A couple of observations after this weekend with my 3120 (only 8 hours, 300CX and 448 backhoe) working on a slope (about 30 degrees).

1. I had parked it on the slope, FEL uphill, and turned off the engine. I had the parking park engaged and left it in “A” range. As we were filling the 300CX FEL up with cut wood, the whole tractor moved on it’s own about six foot rearward. I quickly jumped on the tractor and rechecked the parking park position. It was in the up location. By this time it had stopped. We had about 4 feet of clear space left before series problems would have occurred.

My thinking is the brake lining is not “broken in” and is not able to support a parking brake load of this type yet. I hope it gets better with more usage. Until then I’m a little paranoid about relying on the parking brake on a slope. Any other ideas?

2. This issue deals with the use of LoadMatch going up the some slope as above. The following occurred two different times: Had LoadMatch engaged and while moving uphill increased the RPM’s with the hand throttle lever. Upon stopping the tractor, the RPM’s increased rapidly on its own. Example, I thought I set it at 1500 RPM’s going up the slope but when I stopped it went up to over 2500 RPM’s on its own. I was able to move the hand throttle lever to lower the RPM’s.

This is maybe my lack of understanding how the LoadMatch feature works, but, my impression is that if you use it, do not adjust the RPM’s with the hand throttle lever once you’re in motion or working the FEL. It appears LoadMatch will adjust the RPM’s as needed, but, I’m not sure the Tachometer is reading the true RPM’s when this is happening. Does someone have a better understanding?

Otherwise, this tractor set-up exceeds all of my expectations. Thanks in advance for any insight on the above issues.

 

[jd110]

The load match does not adjust engine rpm's. It adjusts hydro position to compensate for decrease in rpm's under load to prevent bogging down of the engine. As far as the park brake, you may need some adjustment there. I would hope the brake is "broken in" when shipped from the factory. I know this can be an issue with new shoes though.

 

[HuskerInVA]

I've notice that with the parking break there is on and then there is really on. Just pulling up with out depressing the break pedals does apply the parking break, but when I depress the break pedals and pull up I get a entra few clicks and it seems to grab much better when parked on a slope.

 

[RogerH]

Parking Brake - On a good hill or with a heavy load you need to pull up on the park brake handle pretty firmly. If it was clear at the top and it still rolled, then I would take out some of the slack. I can't remember the location, but if you follow the linkage you will see a turnbuckle or yoke that can be screwed in/out to adjust the slack. When adjusted correctly, it should take a pretty strong person to pull it up to the last notch.

Load Match - The symptoms you describe actually sound like load match was off rather than on. First check the obvious, that the top of the switch (with the "1") is depressed rather than the bottom (with the "0"). If you switch was in the right position, then check to see if load match is actually working. The easiest test is to drive up the hill at a constant speed and turn the switch on then off. Going from off to on should cause the tractor to slow momentarily while engine speed jumps up then the ground speed should slowly climb. Going from on to off should cause the engine speed to drop while the ground speed initially jumps up a bit, then slowly drops off with engine speed. If you find this to not be true, then call your dealer to have the system checked out.

What load match attempts to do is to maintain the engine speed near where it is set by the throttle. It does this by reducing the ground speed as engine speed drops, then letting ground speed climb as engine speed climbs. You should be able to adjust the throttle while driving and load match will allow the engine speed to follow the throttle.

If you look on the right side of the engine you will see a sensor connected to the injector lever. That sensor tells the computer what engine speed is expected, then the computer controls the HST to allow it to be nearly achieved.