Incorrect vacuum pump assignment often occurs due to a change of cylinder heads in the VW T4 engine with the code letter AAB. If an incorrect pump is installed, claims cases will not be recognised.
In order to prevent damage, it is essential to check the chassis number, registration date and/or the part number of the old pump!
If an incorrect pump has been mounted, this will lead to breakage of the pump housing (see Fig. 1) during the initial engine start following installation, or even to breakage of the camshaft – and therefore to severe and expensive engine damage.
Assembly instructions: See reverse ▸
|Model year||up to 5/1994||from 5/1994|
|Chassis number||up to 70-R-180 000||from 70-R-180 001|
|VW part number||075 145 100; 075 145 101; 075 145 101 A||074 145 100 A|
|VW cylinder head no.||074 103 351 A||074 103 351 D|
|Motorservice cylinder head no.||50 003 101||50 003 113|
|Cylinder head cover surface||11 holes; Ø 5 mm||without holes|
|Pierburg tappet number||3.52124.06.0||3.52124.05.0|
|VW tappet number||075 145 307||074 145 307 B|
|Tappet length||71.0 mm||67.5 mm|
In order to mount the pump with only a minimal amount of preload (max. 2 mm gap), the cam on the camshaft for driving the vacuum pump must be positioned on the opposite side of the connecting tappet (see Fig. 3) during mounting:
If it is not possible to press the vacuum pump to the flange (approx. 5 mm gap) without great effort, even with the cam on the opposite side of the connecting tappet, an incorrect assignment has very likely taken place.
It is essential to check the chassis number, registration date and/or the part number of the old pump! Never attempt to solve this problem by modifying the connecting tappet (e.g. regrinding)!