Brake Pedal Travel More On Highway

[viper00085]

long story!! Ill make it as short as i can.

 

2007 Express 3500 van (same as hd pick ups,etc) sat for a 1.5 years, 91k on it.

Rotors all corroded/rusty from sitting. was vibrating bad under braking. pedal had exteded travel to it every now and then (specially on highway speeds)to engage the brakes, but then brakes did feel okay, once you got to them!!

 

had a shop replace rotors, replaced master cyl and hydro brake booster. did brake bleed/flush and power strg flush for booster.

 

got it back and it still shook and now pulled to left. brought it back and they had to cut new rotors which thankfully took care of pulling to left and it brakes smoothly now.

Now Pedal had to much free play in it all the time, even after master/booster and bleeding. i was not happy... brought it back again.

 

They dicked around with it for another day or so before i finally did some checking on line and suggested maybe they needed to do the recommended ABS bleed procedure with a scan tool and then rebleed the base system. wow, they call me and say its finally right. Wow imagine that!!!!

 

And it is 98% better. around town driving the pedal is high and hard and engages right away and stops like every other express van/HD pick up i have driven (we have a fleet of like 15 of them) Minor problem I still have is an intermittent extdended pedal travel after driving a little bit without braking and especially on the highway. If i drive for 5 or 10 minutes at 70mph and then go for the brakes you can feel it has additional length in the brake pedal to get to the brakes compared to around town driving. No if i go right back to brakes again after initial braking (within a minute or so) the pedal is high again.

 

i have read about maybe ft wheel brgs causing rotor wobble and pushing caliper pistons away from rotors and thus the first brake after they are pushed back has longer pedal travel. I will check this. But other than this anyone else have any other ideas to look into???