Certain Pavers May Turn Slightly When Starting And Stopping Caterpillar

Certain Pavers May Turn Slightly When Starting And Stopping

Usage:

PAVING PRODUCTSAP-1055B (8BM, ABB),
BG-2455C (6TN, ACM) ASPHALT PAVER

Problem:

The machine may "index" or turn slightly when starting and stopping. This condition can be caused if the left and right propel pumps neutral and initial current adjustments are not closely matched.

Solution:

A pump matching procedure is outlined below. This procedure is to be used if two multimeters are not available to check currents during initial current calibration.

1. Start the engine. Place the machine on a flat surface. Warm the machine until the oil is 100°F or higher. Remove the limp home switch cover located on the lower right side of the operator console.

2. With the engine at high idle, simultaneously lift both switches. This will make the machine propel forward. As the machine propels forward, take note of how straight the machine travels and also look at the fpm gauge to see machine speed. For this case, straight travel is defined as less than 5 inches of drift in 20 feet of travel.

3. Now push both limp home switches down. This will make the machine propel in reverse. Take note of the machine speed on the fpm gauge.

NOTE: The goal is to match the pumps using the limp home switches, the machine travels straight in the forward direction on flat pavement. The machine also travels the same speed forward as it does in reverse to within 8 fpm. The maximum permissible drift in reverse is 40 inches in 20 feet of travel.

4. The pump neutral adjustment located on the main body of the EDC requires a 4 mm allen wrench to make the adjustment and a 13 mm wrench to loosen and tighten the locknut. Adjusting the null screws will cause the following reactions:

Make no more than a 1/8 turn adjustment of the null screw before rechecking machine travel with the limp home switches. Step 5 outlines how to adjust the pump for all possible conditions.

5. Use the chart below to determine how to adjust the pump neutral. After each adjustment, retest the machine using the limp home switches and perform readjustments as specified in the chart. As the machine gets closer to tracking straight, it may be necessary to make adjustments smaller than 1/8 turn.

6. Using the limp home switches, verify that the machine does not drift more than 40 inches in 20 feet of travel when in reverse. If the machine drifts to the right in reverse more than 40 inches, troubleshoot the right hand EDC. If the machine drifts to the left in reverse more than 40 inches, troubleshoot the left hand EDC.

7. Perform initial pump current calibration. Start the engine, put the propel MPC-10 into calibrate mode "2". The MPC-10 will automatically increment to "c12". Set the engine to high idle, propel lever forward, propel speed dial at 50%, pave range and parking brake released. After the propel status light begins flashing, move the propel lever to reverse. Wait until the propel status light begins flashing again and then move the propel lever to neutral. Change the propel MPC-10 to operate mode "0".

8. The machine should start and stop without "indexing" in forward. Some slight "indexing" may be noticed in reverse depending on how much difference exists in the left and right reverse initial current values.