188
ADJUSTMENT 
 E756 E757 
BLEEDING THE TRACTOR BRAKE 
SYSTEM 
To bleed the tractor brake system, al-
ways proceed in the following order: 
1.  pressure air brake system for trailers 
2.  rear wheels service brakes 
3.  brake system of front driving axle 
4.  hydraulic brakes of trailer 
 
 
 
 
 
 
 
 
 
 
Bleed the pressure air system for trailers 
and rear wheel service brakes with brake 
pedals unlatched, separately for each 
wheel. 
Bleed the brake system of front driving 
axle and hydraulic brakes of trailer with 
brake pedals latched. 
During the bleeding watch the brake fluid 
level in the equalizing tank to avoid suc-
tion of air into the system. 
After each two years it is necessary to 
replace the brake fluid in the entire brake 
circuit. 
 
 
 
 
 
Caution: 
When bleeding the pressure air 
system of trailers and rear wheel 
brakes, it is always necessary to 
depress one pedal (1) by 7,5
+0,5
 
mm when measured on the pis-
ton rod of the main brake cylin-
der, i.e. 3
+0,2
 mm on the adjusting 
screw (2) and to use the second 
pedal for bleeding. To keep the 
right distance, insert the flat 
gauge of corresponding thick-
ness, i.e. 3
+0,2 
mm, between 
pedal (1) and adjusting screw (2).