User's Manual
4
SM-79D
Rotor Blades - Generally these are the only parts requiring replacement after long
service. Always replace the rotor blades in a set of 4 only, whenever they are broken or
cylinder edge is gouged, worn uneven or worn down 1/16". This would cause the blade
edges to be 1/16" below top of its slot in rotor drum.
Cylinder and Rear End Plate - Replacement is required only if part is broken or
rubbing surfaces are gouged.
Ball Bearing - normally these ball bearings should not require additional lubrication
during tool life. However, whenever tube roller is disassembled for servicing, the mo-
tor ball bearings should be lubricated with light oil (SAE #10) while the drive ball
bearings should receive a small amount of bearing grease. All ball bearings should turn
smoothly and freely with no noticeable looseness. There should be a snub fit with no
shake both in their housings and on their shafts. However, the front motor ball bearing
is a mild press fit on its rotor shaft.
Intermediate Spindle Assembly and Drive Spindle Assembly - Do not disassem-
ble planet gears from their spindles unless the gears do not move freely about their
planet pins. Be careful not to lose any one of the nine needle rollers assembled within
each planet gear. Lubricate planet gear and needle rollers with a good bearing grease
only.
Caution: Note position of planet pin milled step in relation to steel retaining ring or
turned step on drive spindle on assembly drawing before reassembling either spindle.
Air Screen - Throttle valve air screen assembly should be cleaned by reverse flush-
ing when necessary. Before reassembly note on drawing that air screen cylinder is as-
sembled within the throttle valve cap. Also when reassembling be sure small end of
conical throttle valve spring rests against the 3/8" diameter hardened steel ball. Be sure
air screen flange comes to rest correctly within its counter-bore in steel seat insert.
Air motor disassembly procedure
(A) Hold Tube Roller fixed with offset handle upwards.
(B) Prevent rotation with wrench locked on 2” hexagon located against torque cali-
brated index plate.
(C) Tap motor handle with a soft-faced mallet in a counterclockwise direction when
viewed from offset handle end.
(D) Unscrew and remove air motor and offset housing assembly complete.
(E) Remove intermediate spindle assembly from air motor assembly or from within
internal gear.
(F) Unscrew adapter ring (Pc #63 ) out of cast aluminum motor housing.
(G) Rotor with 4 rotor blades, front plate spacer, ball bearing and separator can now
be lifted out.
Note: Leave cylinder and assembled rear end plate within motor hous-
ing. Refer to assembly drawing on page 6.
To reassemble AIR MOTOR follow disassembly steps in reverse.
MAINTENANCE & SERVICING
REASSEMBLY
5
SM-79D
PROBLEM CAUSE & REMEDY
Motor will not run.
1. Inefficient air supply
—Check 90 psi and 32 CFM air supply.
2. Clogged air inlet screen
—Replace-see pg.6 (pc #75)
3. Broken or severely worn rotor blades
—Replace-see pg.6 (pc #69)
4. Rust due to improper storage of tool
—Disassemble and clean– Refer to Disassembly
p
rocedure.
5. Broken throttle valve pin or lever
—Replace–see pg.6 (pc. #78/80)
Motor will not reach
RPM.
1. Insufficient air volume
—Check 32 CFM supply.
2. Dirty air inlet screen
—Clean –see pg. 6 (pc.#75)
3. Worn rotor blades
—Replace-see pg.6 (pc #69)
4. Air supply hose chocked or too small
—See Operating Procedure recommended hose.
Motor stalls at high torque
1. Insufficient air pressure
—Check 90 psi supply
2. Dirty air inlet screen
—Clean –see pg. 6 (pc.#75)
3. Rotor blades worn, chipped or broken
—Replace-see pg.6 (pc #69)
Motor fails to stop
1. Broken throttle valve spring
—Replace-see pg.6 (pc #76)
2. Valve ball does not seal
—Replace or rework valve seat-Refer to pg. 6
(pc.#77)
TROUBLE-SHOOTING