SI42.60-L-0004A | Service information: Compressed air support for hydraulic external brake system | 12.12.01 |
MODEL 668, 670 with CODE (B16) 2-circuit hydraulic brake / 2-circuit compressed-air brake
Modification notes
Use of EC four-circuit valve and check valve
For specific reasons we would like to inform you of the following.
In context with the change of the laws with Guideline 71/320 EU Amendment98/12 Appendix 5, Supplement Point 2.3, obligatory as of 04/01, the following mofications apply for external brake, CODE B16:
1 Pressure tank V5 for auxiliary equipment (CODE B64) is ALWAYS under full operating pressure.
On vehicles with auxiliary equipment (CODE B64), always install a check valve part no.: A 003 429 07 44 on the 10 l compressed air tank V5 as of production date 15.08.2001 and as of chassis end no.:*101954 to fulfill the change in the above law.
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This has the result that the compressed air tank always remains at the full operating pressure of 8.5 to 10 bar
Before connecting auxiliary equipment to this compressed air tank, always release the pressure by separately removing the drain plug for safety reasons.
2 The four-circuit protection valve (Knorr), part no.: A 003 431 76 06, can release air
This valve is installed beginning on 20.09.01 as of vehicle chassis no.:*102610 for vehicles with CODE B43 and / or CODE B64 and beginning on 29.11.01 as of vehicle chassis no.:*103672 continuously instead of the previous BOSCH valve A 003 431 41 06, in production.
The new (Knorr) valve is compatible with the old (BOSCH) valve, but not vice versa
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Reason:
The characteristics of this valve, which was equipped with an additional integrated directional valve to fulfill the abovelegal guideline is that when th pressure in circuit 21 falls to below 4+0.5 bar, circuit 23 is vented into the atmosphere to prevent release of the parking brake.
This venting (blow-off) is not leakage, it is a result of the technical design and can be heard as a blow-off noise.
Venting is accomplished in the middle of the valve between the four spring domes