Instructions To Eliminate Water Leaking From Roof Air Conditioner Into Cab Caterpillar

Instructions To Eliminate Water Leaking From Roof Air Conditioner Into Cab

Usage:

WHEEL LOADERS992D (7MJ1-449),
988F (8YG1-1208) WHEEL LOADERS;
836 (3RL1-95) COMPACTORS

Problem:

Water from the roof mounted air conditioner may leak into the air vents and drip into the operator's cab. The water is due to excess condensation from the heater and evaporator cores.

The air conditioner case assembly is designed to allow the water to accumulate behind a dam. The dam is attached to the bottom of the air conditioner case assembly to keep the water away from two vent holes. If the water builds up behind the dam, it is allowed to drain through four drain lines. However water is flowing around the dam in two ways (see Illustration 1).

1.Water is leaking under the dam because of an incomplete seal between the dam and the bottom of the air conditioner case assembly. The dam is spot welded to the bottom of the case assembly, and then sealed with a silicone sealant. The seal may be incomplete in the machines listed.

2.Water is not flowing through the four drain lines because of a vacuum created by the air conditioner blower fans. The vacuum keeps the condensed water in the case assembly, and eventually allows the water to flow over the top of the dam.

Solution:

Use the following procedure to clean and seal the air conditioner case assembly.

1.Open the air conditioner case assembly and remove any standing water. Disassemble the air conditioner assembly to allow access to bottom of case assembly and dam.

NOTE: The heater and evaporator cores should not have to be removed to access the bottom of the case assembly and dam.

2.Remove any existing loose sealant from the dam, and thoroughly clean the entire length of both sides of the dam.

3.Apply a 6.4 mm (.25 in) minimum bead of 8T-0065 Silicone Sealant along the entire length of both sides of the dam, and also up the sides of the dam. See Illustration 2.

4.Apply a bead of the silicone sealant around the studs (five places) as shown in Illustration 2.

There are four drain lines coming out of the air conditioner case assembly (two on each side). The four drain lines are merged into two lines which run to the back of the operator's cab. See Illustration 3.

To make sure the water drains from the case assembly correctly, an additional 61 cm (2 ft) of hose is added to each of the two drain lines. Each hose extension also contains a rubber check valve. See Illustration 4. Refer to the following chart for the parts required to extend the two drain lines, and the procedure to install the parts.

Procedure To Add Two Air Conditioner Case Assembly Drain Line Extensions

1.Cut two 61 cm (2 ft) lengths of 5P-6129 Tubing. See Illustration 4.

2.Insert one 6V-2372 90° Elbow into one end of each drain line extension.

3.Insert one 7T-9793 Rubber Check Valve into the opposite end of each drain line extension.

NOTE: It may be necessary to lubricate the rubber check valves prior to installation to allow for easier insertion.

4.Insert the other end of each 6V-2372 90° Elbow into each existing drain line. The additional drain line extensions should be routed down the rear side of the operator's cab. See Illustration 3.

5.Locate two 7T-1099 Links approximately 102 mm (4 in) from the end of each drain line extension on the rear of the operator's cab. See Illustration 3.

6.Move the drain line extensions out of the way to allow the links to be spot or tack welded in place. Clean, prime, and paint the welded areas as required. Use 3S-2093 Cable Straps (Plastic) to secure the drain line extensions to the links. See Illustration 3.Illustration 1

(1) Drain Line (four places). (2) Evaporator core. (3) Heater core. (4) Dam. (5) Vent hole (two places).Illustration 2