Document Transporter 7D, vacuum pump making noise (Solution)

Vacuum pump is making noise.

Cause:
Improper installation of the vacuum pump plunger can cause noise or damage to the vacuum pump.

Solution:
When replacing the vacuum pump, it is essential to ensure that the correct plunger is used.
AAB engine up to chassis number 70R - 180,000.
Vacuum pump: No. 075 145 100.
Piston: No. 075 145 307 with a length of 71.0 mm.

AAB engine, from chassis number 70R - 180,000.
Vacuum pump: No. 074 145 100 A
Piston: No. 074 145 307 with a length of 67.5 mm.

ACV, AJA, AHY, AHD, and AGX.
Vacuum pump: No. 074 145 100 A.
Piston: No. 074 145 307 with a length of 67.5 mm.