what master cylinder are you using? Bob Hayen ----- Original Message ----- From: "Michael Moore" <mmoore8425@xxxxxxx> To: "Paul Martin" <paul_martin78ca@xxxxxxxx> Cc: <chrysler300@xxxxxxxxxxxxxxx> Sent: Sunday, May 06, 2012 10:42 PM Subject: Re: [Chrysler300] Brake booster > Paul, my 300H had that problem. After trying eveything else, I decided the > low pedal was caused by the pushrod between the master cylinder and the > booster needed adjusting, something the shop manual says not to do. > > There needs to be a small amount of clearance between the master cylinder > piston and the pushrod from the the booster to accommodate expansion of > brake fluid. > > On another make car I have, I found that too little clearance will cause > the brakes to set up. I never found a reference to how much clearance > there should be on my car, but decided .060 was a good place to start. > > It's tricky to measure the depth of the piston in the master cylinder, but > by measuring that and the length of the adjustable rod coming out of the > booster, and a little arithmetic, I found I had something like 1/2 inch > clearance. > > If you consider the pivot point of the brake pedal as a reference, then > measure from the pivot to the booster rod, you'll find a small number , > say 2 inches. Then measure from the pivot to the brake pedal, you may > find 11 inches. This is a multiplier of 5-1/2 to 1. So if you have 1/2 > inch clearance and can reduce it to .060 (1/16), you'll raise the brake > pedal by ca 2-1/2 inches. (I have made up the lever numbers as I forgot > the real numbers, but you get the idea.) > It made a huge difference in my brakes. > Best Regards, > Mike Moore > > > On May 6, 2012, at 9:10 PM, Paul Martin wrote: > > I am just finishing up the AAJ disc brake conversion on my 300F. I have > evacuated the air from the lines and have a good solid pedel with the car > not running, however when I start it up and apply the brakes the pedel > goes low to the floor,not all the way and the car still stops but not > well. I double checked to make sure all the air was out of the lines. > > Ant tips? Is there something I need to do to the booster. > > Any help would be appreciated. > > Paul Martin > > [Non-text portions of this message have been removed] > > > > > > [Non-text portions of this message have been removed] > > > > ------------------------------------ > > To send a message to this group, send an email to: > Chrysler300@xxxxxxxxxxxxxxx > > To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or > go to http://autos.groups.yahoo.com/group/Chrysler300/join and select the > "Leave Group" button > > For list server instructions, go to > http://www.chrysler300club.com/yahoolist/inst.htm > > For archives go to > http://www.forwardlook.net/300-archive/search.htm#querylangYahoo! Groups > Links > > > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.1913 / Virus Database: 2425/4982 - Release Date: 05/06/12 > ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or go to http://autos.groups.yahoo.com/group/Chrysler300/join and select the "Leave Group" button For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/search.htm#querylangYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: Chrysler300-digest@xxxxxxxxxxxxxxx Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> 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/