
22
J125: Maintenance Instructions
Safety Shut Off Units - Continued
Safety Shut-off Rebuilding Procedures.
NOTE: Inspect all sealing "O" rings, diaphragms and gaskets and replace where necessary (a soft spares kit is
available for this purpose see page 16).
The use of Molykote 111 "O" ring lubricant is recommended during the rebuild- unless for use with oxygen when
no lubricant should be used.
1.
Fit new "O" ring (72) into rear "O" ring groove in body (70) and apply "O" ring lubricant. Replace rear "O" ring
retaining washer (82) and secure with new starlock washer (77), making sure starlock washer is central in
bore.
2.
Locate lever retaining plate (61) into recesses in body (70).
3.
Position trip-off bush (75) with slots engaged with rails of trip-off latch (83) and arrow facing away from steel
needle rollers. Relocate assembly into body (70) making sure that the needle roller is correctly positioned in
raised recess in body (70).
4.
Push valve spindle (73) and cap assembly (65),(78),(79),(80) & (81) through rear of body (70), trip-off bush (75),
lever retaining plate (61) and front of body (70).
5.
Slide trip-off bush (75) up against lever retaining plate (61) and fit a new circlip (65) into groove on valve
spindle (73) furthest away from trip-off bush (75).
6.
Slide trip-off bush (75) back against 1st circlip (65) and fit a 2nd new circlip (65) to groove on valve spindle (73)
which clamps trip-off bush (75) to valve spindle (73).
7.
Fit new "O" ring (72) into front "O" ring groove in body (70) and apply "O" ring lubricant, replace front "O" ring
retaining washer (71) and secure firmly with new circlip (69).
8.
Replace valve spring (64) into front face of body (70).
9.
Locate valve spring cup (67) over spindle (73) and into valve spring (64)
10.
Push valve spring cup (67) to compress valve spring (64) until circlip (65) can be assembled into groove in
spindle (73) nearest body (70).
11.
Fit new "O" rings (63) and (68) into grooves in front face of body (70).
12.
Reassemble adaptor plate (47) to body (70) and secure with four screws (49).
13.
Place gasket (91) into centre hole of valve (66). Insert "O" ring (90) into centre hole of valve (66).
14.
Push valve assembly (66) over spindle (73), align hole in valve (66) and spindle (73), assemble together with
"R" clip (89).
15.
Align hole in diaphragm (85) with convolution upper most, with hole in lower diaphragm plate (84). Locate
spigot of top diaphragm plate (87) through diaphragm (85) and into recess in lower diaphragm plate (84).
Secure with diaphragm clamping screw (50).
16.
Position slot in lever arm (62) over spigot on lower diaphragm plate (84) and align holes, replace needle
roller (76) through holes.
17.
Unscrew reset end cap (78) and withdraw it, until it comes to a stop.
18.
Locate diaphragm assembly and lever arm (62) into recess between lever retaining plate (61) and body (70),
ensuring bead of diaphragm (85) locates into groove in body (70).