USER MANUAL Tractor semitrailers PTL
46
bend back and remove the cotter-pin;
loosen the nut;
check the rotational freedom of the wheel. If necessary, remove the obstruction (the brake
drum is pressed by blocks, broken bearings). Adjust the bearings only after that;
tighten the nut so that the wheel could rotate with effort without wobbling. Turn the wheel in
both directions so that the bearing rollers take in the correct position. Further, while rotating
the wheel, tighten until the wheel stops;
turn the nut back by 1/4 - 1/6 of a rotation and fix it by inserting a cotter-pin;
check the rotational of the wheel. The wheel should rotate freely without sensible wobbling;
install the hub cover.
If the wheel hub heats up when driving, release the nut by another 1/6 of a rotation.
After the bearing space is adjusted properly, the wheel should rotate smoothly, without disruptions and
unusual sounds. If the semi-trailer is new or the brake blocks are newly replaced, some friction may be felt
between the blocks and drum. It is a normal phenomenon.
ATTENTION!
It is prohibited to perform adjustment works if the tractor engine is running.
7.1.5.
Maintenance of the steering axles of the three-axle chassis
Routine maintenance. If the semi-trailer is used intensively, the following shall be performed every 3
months:
lubricate the vertical axles of the hub turns 3 (Picture. 19);
tighten up the screw connections of the assemblies mounted on the axle (brakes chamber,
wheel locking hydraulic cylinder, shock absorber, and tie-rod);
make sure that the adjustment rods 7 have not bent;
if the axle vibrates when driving, check the shock absorbers. A trace of lubricant does not
indicate that it is unsuitable for use, but if the leak of lubricant is large, the shock absorber
should be replaced. The shock absorber should be replaced if resistance is felt when pushing
the cylinder by hand after disconnecting the shock absorber from one side, or if the shock
absorber is bent;
check and eliminate any leak of air or lubricant (the brakes chamber, hydraulic cylinder, shock
absorber).
Alignment of axles. The axles of the chassis must be in parallel. If necessary, the position of the axle in
respect of the frame in the longitudinal direction can be adjusted by changing the length of the adjustment
rod 4 (Picture. 20).
Picture 19. Diagram of a steering axle. 1 – axle; 2 – hub; 3 – hub turning axle; 4 – lubrication point; 5 – brake chamber; 6 – wheel
locking hydraulic cylinder; 7 – adjustment rod
