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Author Topic: brake pedal travel  (Read 582 times)

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Offline tow hook

brake pedal travel
« on: June 23, 2020, 02:32:14 PM »
i did a herm's dual master set up, and im starting the bleed the system. the rears did fine. still working the air out of the fronts. how much pedal travel should i have ? i have about an 1" now.

 thanks for any input :)

Offline Rus Curtis

Re: brake pedal travel
« Reply #1 on: June 29, 2020, 05:22:11 PM »
Hope you got this sorted out.

My SM says "at least 1/2" free pedal travel ...."

I would think no more than an inch, the pedal doesn't have far to travel before bottoming out on the toe board. 


'54 CJ-3B "Green Gruntt"
Bantam T3-C

Offline tow hook

Re: brake pedal travel
« Reply #2 on: July 07, 2020, 02:25:06 PM »
Hope you got this sorted out.

My SM says "at least 1/2" free pedal travel ...."

I would think no more than an inch, the pedal doesn't have far to travel before bottoming out on the toe board.

i believe that i do. i used a small washer on the inside of the master. ( between the master and the bracket ) so it kicks it in just a tad, the brake rod fit much better. and i only had to push the rod in a tad to get it on the brake pedal. so yes i have about an inch of travel. just need bleed.

Offline tow hook

Re: brake pedal travel
« Reply #3 on: July 21, 2020, 10:28:06 AM »
Quote
and i only had to push the rod in a tad to get it on the brake pedal.
We are talking FREE TRAVEL, the amount the pedal moves BEFORE it starts to actuate the piston in the master cylinder. If you had to push the master cylinder piston in slightly before you were able to connect the push rod to the pedal, the push rod is TOO LONG and should be shortened up.  You should have about 1/2" free travel of the brake pedal BEFORE the push rod makes contact with the master cylinder piston.



oh :o ! so how does the rod stay in place ? if you have a half inch of free play....  thanks for the info i wouldn't have known that

Offline tow hook

Re: brake pedal travel
« Reply #4 on: July 24, 2020, 11:01:46 AM »
The push rod just fits loosely into the hole in the master cylinder piston, the rubber boot will help hold it centered. It's held to the brake pedal with a cotter pin on the other end. When you start pushing the brake pedal down, you should have about 1/2" of pedal movement BEFORE the push rod contacts the master cylinder piston and starts to move it. The master cylinder piston should be completely back against the snap ring in the bore in the rest position, and the pedal return spring should move the push rod and pedal back the additional 1/2". You may have to adjust the length of your push rod to get the required pedal free play.
Same thing happens if your brake pedal return spring is broken or missing, the weight of the pedal constantly pushing against the MC piston is enough to cause slight pressure in the system and can cause the brakes to drag.

thanks that helps alot :) i don't have the rubber boot over the rod  yet, the cotter pin is in place

Offline tow hook

Re: brake pedal travel
« Reply #5 on: July 28, 2020, 11:17:18 AM »
i emailed herm, no free play, the rod should rest against the master. an the pedal should have 1" of travel