Technical Information · issue 3 of 1997
Service notes; Service times
IssueTI 3/1997
Full text
Page 1 of 6
Technical Information
03.97
Service notes, pole pruner STIHL HT 75 - type 4138
The machine may only be inspected, serviced and repaired by trained, authorized personnel.
Note:=`onsult the illustrated spare
parts list for better orientation.
1.===Telescoping shaft
1.1=Drive shaft
390RA003 KN
The drive shaft comprises a profiled
392RA128 VA
shaft running in ball bearings in the 4
rigid part of the telescoping shaft
and a shaft with inner profile running
in protective tubing and ball • Undo screws on the clamping • Pull out profiled shaft (4).
bearings in the telescoping part. collars for the control handle.
qhese=two=sh~fts=must always be
Note:=ff a shaft has to be replaced:
replaced as a pair=on=~ccount=of============================================================================repl~ce=both=sh~fts=~t=the=s~me
their very high precision. time!
- Remove gearing, see 2.1 - Shafts are oiled prior to delivery;
only the profiled inner shaft
running in the protective tubing
need be lubricated.
2
Important!=qhe grease must be
uniformly applied to the drive shaft;
it must never be forced directly into
the protective tube.
Note:=ff the drive shafts have to be
390RA001 KN
390RA002 KN
cleaned before being assembled,
1 3 they must be taken apart
completely. The profiled shaft
• Pull out profiled inner shaft (1) • Unscrew fixing screw (2) from should be lubricated with a silicone
together with the protective the AV sleeve. spray lubricant such as WD40 or
tubing and circlip. equivalent prior to assembly; then
- Remove protective tubing and • cir-
Undo clamping screw (3). proceed as specified.
clip.
- Pull out protective tube.
)Technical Information 03.97 - Page 2
390RA004 KN
4
• Slide profiled shaft (4) into the • Push the protective tube in until • Remove screw in carrying ring.
protective tube as far as the holes are lined up. If neces-
possible; only the square should sary, an assistant must turn the
still be visible. drive shaft while the
protective tube is being pushed
in.
- Tighten the fixing screw with
2.5Nm (2lbf.ft.) and the clamping
screw with 5Nm (4lbf.ft.).
- Mount the gearing, see 2.1
390RA005 KN
- Slide ring and protective tubing • Draw carrying ring apart and
onto profiled inner shaft. remove.
- Draw telescoping shaft fully apart
to facilitate assembly.
The profiled shaft should be
steadied by an assistant when
=====================================================1.2=Protective tubing and bearing
inserting the profiled inner shaft so
that it is not pushed out.
• Slide profiled inner shaft (1) as
far as possible into protective 3
1
tube together with protective
tubing and ring. Turn the shaft
back and forth while inserting it
so that the circlip does not catch
on the stop or fixing rivet.
Do not push the shaft into its
390RA007 KN
390RA006 KN
final position with force. Only the 2
square should still be visible. 4
- Slide the telescoping shaft
together. The inner shafts must not
be pushed out in the process. • Mark the motor side on the • Unscrew star-handle nut (1)
handle hosing of the protective and screws (2) on clamping
tube. element (3).
• Pull off clamping element (3).
- Remove drive shaft, see 1.1 - • Pull out long protective tube (4)
the protective tubing is drawn out at on gear side.
the same time.
)Technical Information 03.97 - Page 3
5 11
390RA013 KN
390RA011 KN
390RA008 KN
6 12
7
• Undo screws (5) on clamping • Hole in bearing (12) and 2.===Cutting tool
element (6). protective tube (13) must be li-
• Pull off clamping element (6). ned upK===========================================2.1=Gear
• Pull out short protective tube (7) • Secure bearing (12) with pop
• Undo clamping screws on gear
on motor end. rivet (11).
box.
• Pull gear box off protective tube.
1
9 9
9 10 9 fo
10
8 8
390RA014 KN
390RA009 KN
390RA012 KN
2
8 8
• Remove bearings (8) and On the marked motor-side end of - Remove sprocket cover and
springs (9) from outer protective the protective tube: sprocket gear.
tube (10). - Remove oil tank, see 2.2.
• Slide bearings (8) (ball-bearing
end first) and springs (9) into ou- • Pull ring (1) off shaft (2).
ter protective tube (10).
The remaining parts are assembled
in reverse order.
11
4
3
390RA010 KN
390RA015 KN
12
1.3=Protective tube
- Replace worn bearings. - Remove drive shaft, see 1.1. • Remove screws (3) on gear
- Remove protective tubing and cover (4).
In the case of riveted bearings: bearings, see 1.2. • Remove gear cover (4).
• Remove pop rivet (11) and pull - Replace broken/bent protective
off bearing (12). tube.
)Technical Information 03.97 - Page 4
11
2 9
6 10
7
390RA022 KN
390RA019 KN
390RA016 KN
5
• Remove pinion assy (5) from • Pull ball bearings (10 + 11) off • Press in ball bearing (9).
gear housing (6). shaft (2). • Fit circlip (7).
9 11
5
8 2
10 fo 6
390RA017 KN
390RA023 KN
390RA020 KN
• Remove circlip (7) with pliers (8) • Press ball bearing (10) onto - Place 8 g (0.3oz.) gear lubricant
0811 611 8200. pinion end of shaft (2). into cavity of gear housing.
• Pull off ball bearings (9). • Press ball bearing (11) onto
shaft (2). • Insert pinion gear (5) in gear
housing (6).
6
390RA018 KN
390RA024 KN
390RA021 KN
2
2
• Remove shaft assy (2) from gear • Insert shaft assy (2) in gear • Thinly coat edge of gear
housing (6). housing (6). housing with Dirko sealant
0783 830 2120.
)Technical Information 03.97 - Page 5
4
2
390RA027 KN
390RA025 KN
390RA030 KN
1
• Fit gear box cover EQFK=============================2.2=Oil tank====================================2.3=Oil pump
• Turn screws (3) into gear box
cover (4) and torque all except • Remove filler cap complete with - Remove oil tank, see 2.2.
cap retainer.
the clamping screws (arrows)
• Pull rubber buffer (1) out of gear
down to 6.5Nm (5lbf.ft.).
housing.
• Remove strainer (2).
390RA031 KN
390RA028 KN
390RA026 KN
• Press ring (1) onto shaft (2). • Remove screws from oil tank. • Turn M5 screw (at least 25mm
long) into oil pump.
- Slide gear box onto protective tube, • Grasp screw to pull oil pump out.
turning the gear box back and forth
at the same time so that the square
in the drive shaft can engage the
internal square in the drive pinion.
- Slide gear box on as far as
possible and line it up.
- Torque clamping screws on gear
box down with 6.5Nm (5lbf.ft.).
390RA032 KN
390RA029 KN
• Swivel oil tank counterclockwise • Insert oil pump as indicated by
to remove it. the symbol beside the opening.
The full-length groove must face
- The parts are assembled in reverse towards the tube mount.
order.
)Technical Information 03.97 - Page 6
Code Type of Repair HT 75
1 Crankcase 2.1
390RA033 KN
2 Crankshaft and/or bearings 2.2
3 Crankcase gasket, sealing 2.0
4 Crankshaft seals 0.7
• Turn M5 screw into oil pump and
press oil pump into position. 5 Cylinder and/or piston 0.8
6 Ignition 0.5
• Remove M5 screw.
- The remaining parts are 7 Fuel hose, fuel supply 0.5
assembled in reverse order.
8 Replace gear box assy 0.5
9 Carburetor 0.7
10 Fan housing, clutch housing 0.8
2.4=Chain tensioner
11 Front handle, throttle 0.6
See Repair Manual E 14, E 20.
12
13
Recoil starter
Clutch
0.5
0.5
14 Replace drive tube, shaft, bearings 0.8
3.===Service times
15 Muffler 0.4
The service times specified apply
16 Air filter, filter cover 0.3
for duly trained personnel and a
fully equipped customer service 17 Stop switch 0.4
workshop.
18 Fuel tank 0.4
The service times are specified in
19 Replace drive gears 0.7
tenths of an hour (0.1 = 6 minutes).
20 All other repairs & misc. repairs 0.5
Note:=qhe table of service times
✂
for the pole pruner can be transfer-
red to the STIHL repair timetables
manual in the brushcutter section.
Andreas Stihl D1/MTK-na
© 1997 Andreas Stihl Technical Documentation 6021 Page 2 of 6
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