Re: [Chrysler300] 300F Brakes

Terry -

Are you saying that the pedal was fine before you had the work done and now is too low ? If this is the case, then your mechanic did not adjust the shoe to drum clearance correctly. Take the car back in and have him check this on all four wheels. You should not have to touch the m/c pushrod.

Ron

----- Original Message -----

From: Michael Moore mmoore8425@xxxxxxx [Chrysler300]

To: Terry Mctaggart

Cc: Chrysler300@xxxxxxxxxxxxxxx

Sent: Monday, July 14, 2014 10:13 AM

Subject: Re: [Chrysler300] 300F Brakes

Terry,
I don't know about about brakes other than 300H, I bet they're the same though. I had the same problem. There is an adjustment on the master cylinder pushrod which comes out of the power brake booster. My factory shop manual makes an issue about only having a dealer adjust it and to never do it yourself.

I used to have a gauge someone made for me to set the pushrod, but I have lost it. Since my booster has been rebuilt and my master cylinder was new, it seemed reasonable that it needed to be adjusted, What you are doing is setting up backlash between the master cylinder piston and the booster pushrod. It must have clearance to accommodate expansion of the fluid in the system which will push the piston back. If you don't have enough clearance, the brakes will drag, get hot, expand more, drag more etc etc and the brakes will really drag.

There are two tasks-the first is to figure out a method of reliably measuring the depth of the piston recess on the booster wide of the master cylinder. I used a straight edge and a depth gauge portion of my calipers. Then you have to measure how far the pushrod sticks out from the booster. If you subtract one from the other, you'll get a number (mine was around .090). That's the number you want to reduce. I do no know the correct clearance, I think I left mine at .060. But, if the brakes don't drag when it gets warmed up, it'll be fine I think. That raises the pedal quite a bit because of the difference between the pivot point and the pushrod and the distance between the pivot point and the pedal. Good luck!

Mike Moore

300H

ps-that rod on miine unscrews very hard. I had to use vise grios and a tiny pipe wrench.

On Jul 14, 2014, at 6:38 AM, Terry Mctaggart terrymct999@xxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

I recently had some major work done on the brakes (new wheel cylinders, new master cylinder) and the car stops straight and true, but the brake pedal is lower than I like. Is there an adjustment I can make to raise up the effective point on the pedal? Terry McTaggart

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Posted by: "Ron Waters" <ronbo97@xxxxxxxxxxx>

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