B42.10-0348-07
1 Automatic Perrot governor
2 Automatic MB governor
3 Governor fastening
4 Adjustment crowns
5 Opening for adjustment on the brake plate
6 Adjustment screws
a Governor expansion measurement
b Governor expansion measurement
| Remove and install | ||
1 | Remove the brake drums | ||
| Check | ||
If the moving parts are worn or corroded, replace the automatic governors for both wheels. | |||
As a rule, at each wheel brake repair, review whether the adjustment screws gently turn in the adjusting crown thread. If necessary, clean and lubricate with grease. | |||
Automatic Perrot brake governor | |||
2 | Release the fastening screw (3) of the governor from the brake plate | ||
3 | Move the automatic governor (1) on the brake plate | Slightly tighten the automatic governor fastening screw. | |
Screw the adjusting crown (4) of the set screws (6) so that both screws provide the same governor expansion dimension (b), and check the governor expansion dimension (a) between the bottom of the groove of the set screws. | |||
Dimension "a". | |||
Dimension "b". | |||
3 | Install the brake drums | ||
4 | Using a feeler gauge, check through the brake plate windows the clearance on both brake shoes | Universal feeler gauge | |
If necessary, offset the adjustment by moving the governor in the oblong hole. | |||
Warning: Do not set the parking brake too tight (at least five teeth) because the automatic governor works with greater clearance on the brake shoes. | |||
5 | Tighten the bolt of the automatic governor (1) on the brake plate | | |
Check the brake shoes clearance again. | |||
6 | Check the operation of the automatic governor | During the test, pump the brake pedal five times in drive and five times in reverse. Since, when braking forward, only the secondary brake shoes are adjusted, you should sometimes brake in reverse, pressing hard the brake pedal, so that the primary brake shoes are adjusted as well. | |
Automatic MB brake governor | |||
7 | Adjust the regulator expansion dimensions (a) and (b) | Rotate the adjustment crowns (4), as required to obtain the expansion dimensions. | |
Governor expansion dimension (distance between the bottom of the groove of the set screws (6)) | |||
Dimension "a" | |||
The governor expansion dimension (distance between the bottom of the groove of the screws and the wheel cylinder housing) should be the same for both set screws (6). | |||
Dimension "b". | |||
8 | Install the brake drums | ||
Check | |||
9 | Using a feeler gauge, check through the brake plate windows the clearance on both brake shoes | Universal feeler gauge | |
Warning: Do not set the parking brake too tight (at least five teeth) because the automatic governor (2) works with greater clearance on the brake shoes. | |||
10 | Check the operation of the automatic governor | During the test, pump the brake pedal five times in drive and five times in reverse. Since, when braking forward, only the secondary brake shoes are adjusted, you should sometimes brake in reverse, pressing hard the brake pedal, so that the primary brake shoes are adjusted as well. |
Brake shoes
Número | Denominação | Eixo 743.410/411/413, 743.414/415/432, 743.436/437/438, 743.439 | |||
BE42.10-B-1003-13A | Clearance between the brake linings and the brake drum | Mechanical regulator | mm | 0,3 ... 0,4 | |
Automatic regulator | mm | 0,4 ... 0,5 | |||
Test values for mechanical system
Número | Denominação | Vehicles 688.1 with drum brake rear axle | |||
BE42.15-B-1001-01B | Automatic regulator expansion measurement | Measure a | Perrot device | mm | 86,0 |
MB device | mm | 0,4...0,6 | |||
Measurement b | Perrot device | mm | 85,0 | ||
MB device | mm | 12,5 | |||
Drum brake
Número | Denominação | Vehicle 688.1 | |||
BA42.10-B-1003-16A | Fastening bolt of the clearance regulator | Nm | 45...50 | ||
Produtos para reparos
Número | Denominação | Número de pedido |
BR00.45-B-1008-06A | Grease | DBL 6898.0 (Molykote HTP) |