CHAPTER 4
Maintenance Procedures
S36 ROCKDRILL | PARTS & SERVICE MANUAL
January, 2021
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13. The idler gear Ref. 50 is carried on a shaft Ref.
47 secured to the reduction housing by four cap
screws Ref. 45. If the screws are removed, the
shaft may be withdrawn and the gear allowed to
drop out of the housing complete with its bearing
Ref. 49.
14. From the back of the machine the backhead Ref.
18 may be removed complete with the water tube
Ref. 8 and fittings. Be careful not to bend or
damage the water tube if it is not removed from
the backhead initially.
15. Remove the water tube from the backhead by
unscrewing the plug Ref. 6 and pushing the tube
from the front. The water tube seal Ref. 9 should
be removed.
16. Remove the backhead spacer Ref. 21 and the
dummy rifle bar Ref. 20 with its seal Ref. 19.
17. The valve assembly may now be removed
completely by pushing the piston Ref. 62 up the
bore and if necessary hammering on the end of
the piston with a copper mallet and suitably
shaped drift. The valve box locating pin Ref. 23
will come out with the assembly.
18. The piston may now be removed from the
cylinder.
19. The valve box assembly may be dismantled, by
driving the plug Ref. 25 out of the valve box. This
may be done easily by fitting a suitable punch
into the centre hole. Hammering on the punch will
drive the valve plug out of the valve box Ref. 22.
The valve Ref. 24 may then be lifted off the plug.
20. The air stem Ref. 1 and the other air inlet
fittings may be removed from the backhead by
unscrewing the air stem nut Ref. 4.
21. The water stem Ref. 11 may be removed from
the backhead by unscrewing the nut Ref. 13.
Make sure that the internal components, the
thrust pad Ref. 17, thrust washer Ref. 15 and
rubber Ref. 16 are not lost.
22. The front cylinder Ref. 67 need only be removed
from the cylinder when either of these
components is to be replaced. If the front cylinder
is tight, insert the piston the wrong way round into
the cylinder and push it down the bore until it
contacts the front cylinder. Press on the end of
the piston with a hydraulic press to separate the
front cylinder from the main cylinder.
23. The feed nut Ref. 64 can be removed from the
front cylinder by unscrewing the nut Ref. 66.
24. The front cylinder liner Ref. 63 should be pressed
out of the front cylinder if it is to be replaced.
This can be done with the front cylinder still
installed by turning the cylinder on end and
pressing the liner out using a suitable punch.
25. The chuck bushing Ref. 70 should be pressed
out of the chuck from the rearward side.
