Many popular ATE vacuum brake boosters for Volvo, and other marques experience leakage through plunger seal 03.7718-5028.1, which is characterized by a loud hissing noise and reduction of braking power assist.
Reduced power brake assistance can increase stopping distances, while vacuum leakage can affect the fuel injection system and other components that rely on specific vacuum levels. The only repair option from the dealer is to purchase a complete brake booster assembly, which is exorbitantly expensive.
Fortunately we have a simple solution for failure of ATE seal 03.7718-5028.1. This Repair Kit from ÜRO parts provides a new replacement EPDM brake booster plunger seal, a seal driver tool, and a tube of silicone grease, which repairs the failure much more economically than replacing the complete booster assembly.
3 pcs available 
