Manitowoc 2250 Service And Maintenance Manual

Reference Only
Manitowoc Published 11-06-15, Control # 040-13 2-7
2250 SERVICE/MAINTENANCE MANUAL HYDRAULIC AND AIR SYSTEMS
2
TIGHTENING HYDRAULIC CONNECTIONS
General
1. Make sure fittings and o-rings being used are the proper
size and style.
2. Flush sealing surfaces with clean hydraulic oil to remove
any dirt.
3. Carefully inspect threads and sealing surfaces for nicks,
gouges, and other damage. Do not use damaged parts;
they will leak.
4. Carefully inspect o-rings for cuts and other damage. Do
not use damaged o-rings: they will leak.
5. Lubricate o-rings when assembling to fittings.
6. Be careful not to cut o-rings when assembling to fittings.
Use thimble as shown in Figure 2-4
when assembling o-
ring over threads.
Pipe Thread Connection
1. Apply sealant (Loctite 92 or equivalent) to male threads,
never to female threads. Do not apply sealant to first two
male threads.
2. Tighten fittings about 4-1/2 turns by hand and then 3
additional turns with a wrench.
Table 2-3 Pipe Thread Leakages
SAE Straight Thread Connection
This type of connection leaks most often because the jam
nut and washer are not backed up before assembly.
When the jam nut and washer are not backed up, there is not
enough room for the o-ring when the squeeze takes place
and the washer cannot seat properly as shown in Figure 2-5
,
View A. The compressed rubber between the washer and
the spot face will cold flow out of compression, causing the
fitting to loosen and leak as shown in Figure 2-5
, View B.
Tighten SAE straight thread connections, as follows:
1. Back up jam nut and washer to end of smooth portion on
fitting as shown in Figure 2-6
, View A.
2. It is very important to lubricate o-ring with clean oil.
3. Thread fitting into port until washer bottoms against spot
face as shown in Figure 2-6
, View B.
NOTE: If an elbow is being used, back it out as necessary
to align it with hose.
CAUTION
Hydraulic System Damage!
Do not use FTE-fluorocarbon tape to seal threads; pieces
of tape will enter hydraulic system and cause damage
Causes Cures
Fitting loose Tighten
Fitting too tight causing thread
distortion
Replace damaged
parts
Threads on fitting or in port wrong
size
Use proper size threads
Threads dirty, galled or nicked Clean or replace parts
Straight thread used instead of
tapered thread
Use proper type and
size thread
FIGURE 2-4
O-Ring
Plastic or Metal
Thimble Covering Threads
S103
Female threads expanded from
heat.
Tighten when hot
Fitting loosened by vibration. Re-tighten
Causes Cures
FIGURE 2-5
Washer cannot seat properly
on spot face. Compressed
rubber between washer and
spot face will cold flow out of
compression, causing fitting to
loosen and leak.
When jam nut and washer are
not backed up, there is not
enough room for O-ring when
squeeze takes place.
Jam Nut
Washer
O-Ring
S107
View A View B
FIGURE 2-6
Nut and washer backed up to end
of smooth portion on fitting.
Jam Nut
Washer
O-Ring
S106
View A View B
Spot Face

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English