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H.E.R.O. INDUSTRIES 300S / 300SL LEGEND Owner’s Manual
26
DIAPHRAGM REPLACEMENT
Tools or Supplies Required
♦ 1/4 Allan wrench ♦ 4-45-3 Pressure cap ♦ Torque Wrench ♦ 3/8” Open end wrench
♦ 1/8 Allan wrench ♦ H.E.R.O. hydraulic oil ♦ Rags ♦ Drip / collection tray
1. Tilt unit up onto its’ nose ( resting vertically on handle, ref# 130). See Fig. 1, page 27.
2. Remove the eight bolts ( ref# 17) securing the paint head ( ref# 18) to the hydraulic head ( ref# 53).
3. Remove diaphragm ( ref# 51) from the hydraulic head.
4. If the diaphragm’s metal hubs are rough or sharp, replace with complete diaphragm. Continue at
step 11.
5. If the diaphragm’s hubs are smooth and unworn, replace with repair kit ( ref# 52).
6. Dismantle old diaphragm.
7. Slide “large” steel hub (A) onto new screw (B) provide in kit. The screw should fit in counter sunk
hole, leaving the flat side of hub facing away from screw head.
8. Thread the small nylon disc (C), diaphragm pad (D) and second small disc (C) onto the screw.
There is no correct side to the pads. They MUST be threaded on to avoid leakage due to the hole
being enlarged.
9. Slide the smaller hub (E) onto the screw, being certain the beveled edge of the plate is next to the
nylon pads. During operation the diaphragm flexes over the beveled edge. If reversed, ( flat edge
against diaphragm ) the diaphragm will be cut on the sharp edge while in operation. Thread on and
tighten nut (F), supplied in kit. DO NOT re-use old nut.
10. Fill the hydraulic head cavity with genuine H.E.R.O. hydraulic oil, before placing diaphragm onto
hydraulic head.
11. Place new or repair diaphragm onto hydraulic head with the large hub facing up ( Screw head
visible ). Ensure diaphragm is centered and within the hydraulic head’s recessed area.
12. Place paint head / endcap assembly onto the hydraulic head. Ensure correct orientation.
13. Install mounting bolts, and using a criss-cross pattern, tighten bolts to 30 foot pounds.
14. Purge hydraulic oil system per instructions on page 19.
♦ The diaphragm will take on a wrinkled or puckered appearance almost immediately after operation
begins. Do Not be concerned by this. A diaphragm requires replacement when hydraulic oil appears
in the spray material. Annual replacement of the diaphragm is recommended as part of your
preventive maintenance procedures.
Items marked
with * are
included in
4-22CRK
Repair Kit
Small steel
Plate “E”
Large steel
Hub “A”
D*
C*
C* F*
B*