have brake pedal, will travel

Discussion in 'Classic Mustang Specific Tech' started by 67coupestang, Aug 23, 2003.

  1. alrighty i know this has been covered a million times, but Just got to bleeding the brakes after the disc swap. The pedal almost hits the floor. I bleed the system long and good (even when you pump it fast it doesn't get higher). I'm using discs and rear drums of a 73 grande. the prop valve was from the same car. the M/c is from the 74 maverick W/o power assist... there appears to be no leaks, and the car stops well, at least in my driveway :rolleyes: but the only thing i can think of is that the M/c has too small a bore... any clues??
     
  2. Check the brake linkage from the petal to the power assist unit,
    your petal travel may be to long before the brakes are applied.
    IE. petal is traveling half the distance before the power assist unit allows the M/c to start to pressurize the brake system.



    Still with me? :lol:
     
  3. sounds like you didn't bench bleed the M/C
     
  4. oops sorry I'm running a manual setup... and the pushrod fits in the piston with no clearence....


    I bleed the M/c with the little plugs provided and with them in the pedal is nice and firm right at the top where it should be...
     
  5. bleed slow; pumping the pedal fst forces air INTO the system. I assume you are bleeding them manully. And do check your free play (travel before it engages the MC) should not be much more than 1/4" at the pushrod (I think, FM in truck).
     
  6. If you have a good hard pedal chances are they are bled properly, so either the rears are out of adjustment, the discs are retracting too much, or the M/C is too small. Did the master come out of a Disc car also?

    Another thought, if the two cars don't have the same length pedal and the same distance form the pivot to the m/c rod, you will have a rod travel problem. Don't know how you would check that unless you had all 3 pedals to measure.

    Someone on these boards,( can't remeber who) had a very nice webpage on brake swaps, I'm sure he would know what mixes and matches.
     
  7. how would the rear out of adjustment cause that?? the drums spin really freely as if the pads arent dragging at all... can i have someone watch the m/c and if the rear brake chamber goes down fast then they are filling a fully retracted drum?
     
  8. Adjust the rears, and see if the pedal comes up. the rear drums should not spin free, you should be able to feel the shoes.
     
  9. update: i hae noticed a leak some where in the system, front and rear resovoirs will drain after sitting a while, havent tracked the leak yet, but i assume if fluid can get out then air is getting in.. It WILL stop just not fast and I have to put the pedal almost to the floor, but then its firm (before it hits the pan) the car is siting until spring so i have plenty of time to poke around
     
  10. You will need a MC with a larger front reservoir as disc brakes consume more fluid than drum brakes (assuming properly adjusted).
     
  11. UPDATE: i got an 98 expo m/c with a 1 1/8" bore... it did the trick... pedal is nice, not too firm, but doesn't go to the floor... and the expo unit is a lot lighter and better looking...
     
  12. What do you mean lighter and better looking? I've been messing with different M/Cs for months and am about ready to put a M/C from an F350 on there... That should fix it! Of course I'll probably need a danged engine hoist to hold that sucker in place, while I bolt it down. Its friggin' HUGE!!!
     
  13. its aluminum bodied, plastic resevior, with ports on the outside, a built in bleeder screw... just a few switches on it i dont need. $20 at the yard. :nice:
     
  14. what is an expo? Sorry for old post.