MBW VS77M - Manual (Page 10)

- 7 -
Tamper Assembly
Refer to Tamper Assembly, page 14.
1. Replace O-rings (#32) on the guide bushings and
replace the packing set (#33)
2. Insert the upper guide bushing (#31) into the cylinder
(#27) using a mild soap solution as a lubricant.
3. Insert the packing set (#27) such that the thin solid
base is closest to the shoe.
4. Use the mild soap solution again, insert the lower
guide bushing (#35) into the cylinder until it seats
against the packing set. The small diameter on the
bottom of the bushing should be proud of the cylinder
(#27) end.
5. Thread the packing nut (#37) on to the cylinder. Stop
when the lower edge of the guide bushing(#35) and
the packing nut are flush.
6. Lubricate the interior of the cylinder and the stem of
the plunger (#30) with SAE 15W50 air tool oil and
reinsert plunger. Packing nut may need to be
loosened.
It is important the faces of the valve be lapped to a
smooth and flat finish before reassembly.
7. Replace the lower valve block o-ring (#18) and twist
the lower valve block (#25) into place.
8. Insert the dowel pin (#26) and center plate (#23). Lay
valve disc (#24) into recess in center of plate.
9. Use a new O-ring (#19), and place the upper valve
block (#22) over the center plate.
10. Tighten the blackhead (#16) down onto the cylinder.
Be careful as to not dislodge the valve discs.
11. Tighten the packing nut (#37) hand tight, then back
off to previous notch and snap the locking clip (#36)
into place. Plunger should offer light resistance when
pulled and spring back a small amount after released.
12. Position the tool in a horizontal orientation and cycle
the tool in and out by hand. In both directions,
resistance should build until close to the end of the
stroke when it’s released through the valve. If this
release is not similar in both directions the valve is not
sealed properly and the tool needs to be
disassembled to be inspected. Re-lap or replace any
parts that may be damaged by rust or deep
scratches.
13. Use impact wrench to tighten the shoe (#38) and
clamp screw (#40) onto shaft.
14. Tighten the connecting pipe (#12), or Vibration
suppressor, if equipped, into the backhead(#16) as
far as possible then tighten the locknut against the
back head.
Suppressor Replacement Cycles and Tolerances
Tamper Replacement Cycles and Tolerances
Bearings When bearing material has deep gouges or is worn to 0.065” (1.65mm) or thinner
Seal and Wiper When air leakage occurs
Springs When significant wear is noticed
Tube When inside of tube becomes scoured or galled
Shaft When shaft become bent or surface becomes scratched
Seal Replace when tightening the packing nut no longer seals oil. See Tamper Assembly
Shaft If shaft is bent it needs to be replaced