DA Form 2440, Suggestion Title: Truck, 20 Ton Dump, Relocation of Hoist Filter Assembly,. 222-C-77
(3) The hoist filter housing orientation, the additional 90 fitting installed on the filter outlet part, and the
additional 45 fitting installed on the tank nipple result in an unacceptable installation and flow restriction for the hoist
system's flow and volume. Any added restriction of oil flow on the downstream side of the hydraulic filter that increases
back pressure in the line to the hydraulic reservoir could result in a safety hazard (exceed the burst strength of the filter
housing), collapse the filter element, or, at the least, seriously degrade the filter's operation. The hydraulic hose line
bends are also critical. The bend radius must never be smaller (sharper) than the minimum bend radius allowed by SAE
J517 for SAE 100R2 hose. For 1 1/4 inch size hose involved, the bend radius must be greater than 16 1/2 inches and
should be as straight as the installation layout will permit.
d. The hydraulic hoist filter and reservoir tank problems have been previously evaluated and answered for EIR Case
No. DE37-4301, Sep 76. The solutions were as follows:
"The pipe and support bracket can be reinforced to support the oil filter the oil filter can be relocated onto the truck
frame to alleviate the problem.
To support the oil filter in its existing location, fillet weld vertical gussets k of the triangular type, between the pipe and
the lower reservoir head sheet. Weld one gusset on the inner side pipe radius and one on the outer side pipe radius to
stiffen the pipe primarily from up and down vibration and secondarily from transverse horizontal vibration. One, single
gusset, under the pipe, won't provide sufficient side-to-side support for the heavy oil filter, so twin parallel gussets are
needed. Next reinforce the old or make a new support bracket for anchoring the oil filter housing to the reservoir tank.
Since the truck frame and the reservoir do not vibrate together, do not mount this bracket to the truck's frame or to the
frame mount of the reservoir. Instead, weld the support bracket to the top of the reservoir tank head sheet and bolt the oil
filter housing to the bracket. Near the oil filter end of the bracket, intentionally add vertical gussets so that mechanics
cannot use the oil filter as a step surface to support their weight.
To relocate the oil filter to a new location, be sure to choose a place and method that will not interfere with the air flow
around the frame mounted air drier for the air brake system. This air drier is just ahead of the hoist reservoir and needs
all the air flow it can get to cool the hot, compressed air from the air brake compressor and take out the moisture before
the flow into the first air reservoir. Obstructions and brackets near the air drier will cause it to run hot and increase truck
air brake
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