6
Servicing and testing
6.3
Test instructions
Depending on the conditions of use, but no later than every 50,000
km or every six months, the fifth wheel coupling, the mounting plate,
the slider and the king pins should be checked for:
Function
Wear
Correct position of the fastening elements (check prescribed
torque values)
Damage or distortion
Cracks
Corrosion
To ensure adequate lubrication
To ensure the smooth running of the mechanisms
and repaired where necessary (see the appropriate JOST repair in-
structions at www.jost-world.com).
6.4
Wear test
Fifth wheel couplings and king pins are subject to more or less wear
depending on the conditions in which they are used, and this wear
is noticeable by play towards the front of the vehicle. Excessive play
causes shocks and may lead to instability on the road and damage to
the fifth wheel coupling, mounting plate, sliders and vehicle chassis.
JOST fifth wheel couplings have a manual infinite adjustment facility
for the locking mechanism to extend their service lives.
ATTENTION!
The wear on the king pin must not be compensated for
through adjustment.
71
-73 mm
84-82.5 mm
49
-50.8 mm
JSK40/05
When the wear limit on the king pin has been reached, it must be
replaced. After the king pin has been replaced, the locking mecha-
nism must be adjusted again.
Play caused by wear on the king pin should either be accepted if
within the permitted wear limit for the king pin (see Figure JSK 40/05)
or should be rectified by fitting a new king pin.
ADVICE!
After work on the locking mechanism or after replace-
ment of the lock jaw, wearing ring or locking bar, the lock-
ing mechanism must always be readjusted in order to en-
sure the base clearance of 0.3 mm.
20
MUB 002 004 M01
(REV-C)
04-2019
JSK 36 & JSK 37
JOST IND (REV-A) 06-2019
JSK 39
& tear(wearing ring, lock jaw, locking bar & rubber bush,etc.)
1. Lock jaw 2. Wearing Ring
3. Pivot 4. Socket cap head screw
12
2
4
2
105
22
JSK 39
22
JSK 39
6.4.2 To remove and install locking mechanism
Summary of Contents for JSK 39
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