I'm not sure whether my experience with my one-year-only Kelsey-Hayes booster on our 1955 C-300 is applicable, but I was able to disassemble and clean the check valve. The body was torqued very tight, but a hex socket, breaker bar and a vise sufficed for disassembly. There was a synthetic ball and a light spring inside that could probably have been cleaned with solvent and checked for seal using lung power without disassembly. Turns out there was a tear in the booster diaphragm, but I felt satisfied. Best guess is that your booster diaphragm has developed a hole. C-300'ly, Rich Barber Brentwood, CA 1955 C-300 -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of goldenlion413@xxxxxxx Sent: Thursday, July 20, 2006 11:59 AM To: chrysler300@xxxxxxxxxxxxxxx Subject: [Chrysler300] brake booster check valve quest. Hi everyone. Do brake booster check valves go bad its the part that has three hoses hooked to it right from the brake booster itself.And today while driving my 300f the vacuum pressure left and the car didn't have its breaking power and the pedal was harder to push because the vacuum pressure was not there thanks for any help tom from catskill ny. [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links ------------------------ Yahoo! Groups Sponsor --------------------~--> Check out the new improvements in Yahoo! Groups email. http://us.click.yahoo.com/6pRQfA/fOaOAA/yQLSAA/8LmulB/TM --------------------------------------------------------------------~-> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/