Hi guys, New to the Forum and looking for a little help.We have changed the front brake pads on the Mustang as per normal wear maintainance.Problem we are having, after replacement, we have lost brake peddle. Makes no sense.Any of you guys have a clue what the problem may be? Thank you for helping out. . .
well ... a few things..how did you retract the brake caliper pistons???did you just push them back. with C clamps or big pliers... and force the fluid backward thru the antilock control block and the master cylinder/??usually professional mechanics... retract the caliper pistons in several different ways..one way... using a round faced tool to squeeze the brake hoses between the inner fender and the caliper.. this blocks the hose... at this point the caliper is isolated from the rest of the system.. a retracting tool.. either a C Clamp or caliper spreader is inserted and SLIGHT force is applied to the piston.. at this point. the brake bleeder screw is opened.. the pistons are retracted to their max.. but before the retraction pressure is released.. the bleeder screw is closed.. the pinch off tool removed ... pads dropped in.. caliper installed.. the second way... is used by skilled experienced techs... its a free hand version of the above...position the retracting device... loosen bleeder screw.. retract pistons.. tighten the bleeder screw... release the retracting device.... this is a FAR better way to do this... as there is less chance of damage to the vital brake hoses... the inside of the brake hose is only about 1/8"... its mostly cords to hold the pressure in.. so if you crush it too much.. you will ruin it.. if you exert too much pressure... either with the retractor or the brake pedal while the hose is pinched.. you have a fairly good chance of tearing a flap of material loose inside the brake hose... not a good thing...lastly.. did you replace the rotors... or how much LIP is at the outer edge... that lip was the thickness the rotor was ... the rest is worn away.. if the rotors are worn ... they will be worn at a taper... so the center of rotor is slightly thicker than the outside... this causes the rotor to contact the inside of the rotor before it contacts the outside of the rotor... since the calipers are parallel... the new pads are parallel... and the rotors are tapered... something has to give...usually this results in a very soft or spongy brake pedal... once in a while you will run into worn rotors that the wear LIP holds the pads up along the outer edge.. say.. why open the bleeder screws.. because of the heat... the brake fluid in the calipers can gather up some crud... pushing this backwards thru the system is NOT a great idea with antilock brakes... the seals inside are as soft as the skin on your shoulder... easily torn or scratched.. then it won't build pressure...check by pumping the brake pedal with the calipers and pads installed to see if the pistons are extending.. it takes several pumps to push them out... describe what you have done ..i will be around... keeping an eye out..
Thanks for your input sir, it is much appreciated. Will let you know how we make out. We used a tool designed to retract the piston(s) back into the calipers. The rotors are used but look to be in reasonable shape.
Hi Wayne, We found that the right front caliper was frozen on the slides. the left front was Ok. We replaced both calipers, bled them and all went fine. The pedal is back to normal and the car stops well under heavy braking. Thank you again for input on our problem. All ends well!! Denny
locked up brake caliper slides are because at some point.. somebody either left out the caliper slide LUBE..or used the INCORRECT caliper slide lube.. incorrect is Dielectric tune up grease.. or thermal compound grease... this has dissolved silica sand in it.. heat it and the sand comes out of suspension... LOCKS the caliper slides so tight.. i had a lady come into a shop i worked at.. caliper slide locked up hard.. i took it to the 20 ton press.. it WOULD not budge at 20 tons of pressure... the proper lube is white lithium grease... SIL GLIDE in a sil glide labeled tube.. there are several brake caliper slide greases available..glad you were able to fix it..i would really want to research who worked on the car that could have used the incorrect grease...