MAINTENANCE MANUAL
GP/146/99. Issue 9. October 2005
Beneath the piston in the cylinder bore are 4 socket head screws retaining an end
cap which in turn retains an O ring, a metal sleeve with an internal 2 piece glyd ring
and a variseal in the bottom of the bore. If these components are withdrawn, the
seals should be renewed before assembly.
Careful examination of the cylinder bore and piston rod should be carried out and if
any serious scoring or wear has taken place, should be replaced. The thrust face on
the end of the piston rod is not serviced separately. The piston rod slides in
composition bearings mounted in the cylinder stem and it is extremely unlikely that
these bearings will need to be replaced.
Reassembly
Assuming all components have been cleaned, carefully insert the variseal, using
special Tool No PSK2880 into the cylinder (grooved side down) into the inner recess,
followed by the metal sleeve (cross hole must align with the drain hole in the
cylinder), plain end towards the variseal. This sleeve has a recess to accept the 2
piece glyd ring, the inner component being a PTFE sleeve. Around the outside
diameter of the metal sleeve is fitted an O ring. The whole internal assembly should
be approximately flush with the seating for the end cap, which is retained by 4 small
socket head screws which should be retained using Loctite 262 on the screw
threads. Piston seals, if replaced, should be fitted with the O ring first followed by
the PTFE sleeve which must be gently stretched over the piston and into the groove
progressively. It is recommended that Tool No PSK2956 and 57437 should be used
for reassembly of the piston to cylinder, and all parts must be cleaned. Apply a
smear of engine oil to the piston rod. Locate the flats of the piston rod, fit the spring
carrier and spring. Place Tool 57437 on to the rod spigot and offer the cylinder
assembly over the piston rod.
Using tool PSK2956, compress the spring with the cylinder assembly, carefully
passing the piston rod through the cylinder seals until the shoulder on the rod is well
clear of the clamp plate in the bottom of the cylinder clamp (and remove the seal
spreading Tool 57437) to hold the cylinder in this position whilst the piston is inserted
into the cylinder bore and seats on to the piston rod spigot. Before inserting the
centre retaining screw, apply Loctite 601 to the screw threads and Loctite 510 under
the screw head. Insert and tighten the screw into the piston rod. The piston and
cylinder assembly may now be safely removed from the assembly fixture.
An O ring oil seal is fitted to the location diameter on the cylinder which should also
be renewed before installation to the bearing housing, together with an O ring in the
face of the feed tube which contacts the lower rear face of the cylinder.
IMPORTANT
When piston primers are fitted the minimum idle speed of the pump should be
at least 1200RPM. This speed will allow the pump, when primed with valves
closed, to generate sufficient pressure to disengage the primers. Idle speeds
lower than this will cause the primers to work continuously resulting in
excessive load and wear on the piston primer components. Failures due to
insufficient idle speed may not be covered by warranty.
©Hale Products Europe LTD, Warwick
GP/146/99
WTmaint - Issue9. 10-2005October 2005
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