Many popular ATE vacuum brake boosters for Mercedes Benz, Volvo, and other marques experience leakage through plunger seal 03.77185028.1, which is characterized by a loud hissing noise and reduction of braking power assist. This seal is known to be used on the following ATE brake boosters:

Mercedes 001 430 0708
Mercedes 005 430 8530
Mercedes 005 430 5530 28
Volvo 30793673
Volvo 31273684 *
Volvo 8649491 *

(URO is also considering a kit to replace ATE seal 03.77185018.1, which is slightly different and is found in other vehicles, including SAAB and Volvo.)

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 ÜRO Parts has developed a simple solution for failure of ATE seal 03.77185028.1. ÜRO Repair Kit part number 001 430 0708S 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.

SEAL REPAIR KIT FITS THE FOLLOWING VEHICLES (and possibly more): http://www.uroparts.com/uro/inventory...


*** UPDATES: **
6/11/19: Volvo S60 enthusiast and DIY expert "Peppermint" posted a detailed video showing how to replace this seal with the booster still in the car:    • ATE Brake Booster Servo SEAL replacem...  

5/7/18: DIY pro "Arthur" (see his comments below) was able to install the new seal without removing the booster from his vehicle, thanks to his idea to cut the seal driver tube in half. ÜRO hasn't tried this and it sounds challenging, but it worked for Arthur.

3/5/18: When installing the new seal, some technicians placed the booster and seal tool in a press instead of hammering the new seal into place with a sledge hammer. They used the press to apply force to the plastic tool and drive in part of the seal with the pointed end of the tool, then relax the pressure, rotate the tool slightly, and then press again. Continue to press and rotate until the seal is fully installed. Our engineers found that the sledgehammer worked fine, but do let us know if the alternate press method works better for you.

2/20/18: Some users have reported that the replacement seal can also be installed by placing the booster in a press and depressing the plunger about an inch, which allows the white plunger tube to be moved sidetoside by hand. This is said to create enough space for the seal to be pushed into place by hand.

11/16/17: The seal driver tube included in this kit is being lengthened to 9inches to fit certain Volvo models. If the driver tool you received isn't long enough to clear the plunger fork on your booster, please contact us for the lengthened tube.