Brake pedal travel is to high/play

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REVIVER

REVIVER

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1973 Duster father son project, had 4 wheel drum with no power. Converted to front wheel disc with power. The problem is that the pedal travels up way to high and when depressed it travels down quite a ways before the normal braking area. The brakes work great and contact pressure where it should. Is there a difference between power and non power brake pedals? I am looking at modifying the stop braket and light switch to stop the pedal from coming up so high but I would rather get the correct parts if that is the problem. Its my sons first car we have been working on for 3 years and I want it right before he drives it. He gets his license in a few months and running out of time. Not to mention money!
Thanks
Reviver
 
I'm not quite understanding the problem. With the engine off, pump the pedal a few times to use up any residual vacuum assist.The pedal should be hard and within a inch or so from the top. Let the system rest a minute then set your foot back on the pedal. It shouldn't drop more than an inch or so. If it does pump it again and see if it comes back to the top. I'm thinking there is still air in the system.
Most likely cause... Calipers on the wrong side throwing bleeders to the wrong position.
Altering the pedal stop and brake lamp switch location isn't common practice.
 
I thought maybe air was the cause of some of the problem and we bleed them to death just last night. The brakes work great and the point where the pedal gets hard is where it should be. The problem is that when you put your foot on the pedal, first you have to lift your foot several inches higher then the gas pedal, second the pedal travels down about 2 inches before getting to the normal height and then you contact the brake pressure. Its like the pedal travels 2 inches higher than normal after you release the brakes. 2 inches of travel play. I will look at the calipers again but I was very careful to follow the instructions that came with the kit to get the calipers on the correct side. It is always a possibility that they got it backwards but it surely would not be that I didnt follow instruction correctly, right? Famous last words.
 
REVIVER said:
I thought maybe air was the cause of some of the problem and we bleed them to death just last night. The brakes work great and the point where the pedal gets hard is where it should be. The problem is that when you put your foot on the pedal, first you have to lift your foot several inches higher then the gas pedal, second the pedal travels down about 2 inches before getting to the normal height and then you contact the brake pressure. Its like the pedal travels 2 inches higher than normal after you release the brakes. 2 inches of travel play. I will look at the calipers again but I was very careful to follow the instructions that came with the kit to get the calipers on the correct side. It is always a possibility that they got it backwards but it surely would not be that I didnt follow instruction correctly, right? Famous last words.
Click to expand...

With everything correct, light pedal pressure, start the engine and the pedal should drop another inch or so. That is normal. I suggested the calipers being switched because it is such a common mistake.
I've never measured the distance from accerator pedal to brake pedal but they should be a distance between them.
 
Did you change the rod that connects the pedal to the master cylinder? There is a difference in rod length between power and manual brakes.
 
Redfish, I will look at the calipers tonight to make sure I have them mounted with the bleeders high. Its a good suggestion.
Demon 408, That seems like the problem, it is that either the bend in the pedal is different or I have a (short rod) go ahead everyone-have your fun. I have to look again to see which bolt hole I used on the pedal arm but I believe I used the lower one which should have helped to stop the tavel a little sooner. Like I said, the brakes function great and in the range they should, the pedal just keeps coming up well after the brakes are released and you really have to lift your foot up high to get on the pedal. A longer rod would take up the play but would still leave the pedal resting very high, thats why I was wondering if there are two different pedals.
Thanks
 
whats the bore size of the master cylinder you are using? A smaller bore requires more pedal travel, bigger bore, less pedal travel...
 
After some research I can honestly say I do not have enough info to help you any further. I've attached a parts list from 73 catolog. There are different pedals but it depends on your trans and original engine size of car, or donor car. See 5-27-1, first column "V" for Valiant (applies to Duster).

But I can tell you that there is a difference in pedal rods for sure that may be causing you a problem with pedal hieght.

Lots of unknowns. We need more info on your original car and where you got new/donor brake parts:

Manual or auto?
340 car?
Year of donor car (if used for parts)
List of all new/donors parts you changed
 

Attachments

  • Part Numbers.jpg
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Seems to me that if it had the shorter push rod in it, the beginning no assist stroke would be way low or more than 2 inches travel before braking begins but... the pedal would return to the same stop position. If the rod between the booster and master was set too short, same conditions.
There may be enough adjustment in the pedal stop and brake light switch to make you happy. Just dont know. Good luck
 
Thanks Redfish, Long story short-I purchased the car 3 years ago and the first thing we started was rebuilding the front suspenssion and converting the brakes so I drove the car home once and never noticed the pedal travel with the non power brakes. After the conversion and bleeding I noticed the pedal position and play. We moved from North Carolina to Florida a year ago and drove it down like that. The brakes work great but the padel just comes up too high and 2 inches after the brakes disengage. I have adjusted what I can and if there is not a different pedal to be had I will do a custom mod to get the pedal and switch to contact sooner.
 
Sorry about lack of info on the car. 1973 /6-225 Automatic Duster at the moment. After my son gets some experience under his belt we will be dropping in a V8 or modding and rebuilding the slat 6. The rest of the car is finished except for a drivers door panel and swapping out the rearend. It has the 5 on 4 bolt pattern and we had to use a 5 on 4-1/2 adapter to put the wheels he wanted on it which moves the tires in danger range of the wheel well lips if the airshock decide to exhale. The brake conversion is from a full kit and I dont remember who from. I have the manual and can reference it if needed.
Looking at the parts listing it appears that the only difference is manual or auto trans for both the pedal and shaft. doesnt seem to be any difference between power and non power brakes. It is an original auto slat six car so it should have the correct parts already in it.
I really appreciate the help and fast responses guy.
 
Finally got it fixed. I made an L braket that I bolted under the nut that secures the pedal to the rod. It is located perfectly in front of the brake light switch and with a long slot cut allows for alot of adjustment. I cut the 2 inches of play down to 1 inch and the pedal has a better alignment to the gas pedal. I would like to lower it more but it gets too close to the release point in the valve and caused the brakes to drag.
Thanks for all the help and info. My son drove the car out of the neighborhood for the first time yesterday with a big grin.
 
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