Big Brakes

[pormgb]

Got my wife to help me bleed the brakes and the problem still exists, I don't think there is air in the system, something else must be wrong. When I pump the brakes, the pedal does get hard but wait a minute or two and the pedal goes to the floor.

I took a look at the front calipers and there is quite allot of visible piston (3-5mm), this is with the pads against the disk. This space is due to the large calipers with 11" Granada rotors, If I add this space up on all pistons, its quite allot.

I am wondering if the pistons could be riding back and have to travel too far when the brakes are applied.

[patrickt]

Originally Posted by pormgb

I took a look at the front calipers and there is quite allot of visible piston (3-5mm), this is with the pads against the disk. This space is due to the large calipers with 11" Granada rotors, If I add this space up on all pistons, its quite allot.

What is the thickness of the Granada rotors? The rotors I'm running with my Sierras are part #003-1162 and are 1.25". Old page on them is here: Sierra Racing Products - Vented Rotors

[patrickt]

If your Granada rotors are these: 11" Granada 5 Bolt Rotors,Available in Ford or Chevy Bolt Pattern then they are just 1" thick, at best, and could be 7/8".

[pormgb]

Originally Posted by patrickt

If your Granada rotors are these: 11" Granada 5 Bolt Rotors,Available in Ford or Chevy Bolt Pattern then they are just 1" thick, at best, and could be 7/8".

Yep, they are 1".

Pumping the pedal builds good pressure, I can't imagine where air could still be in the system.

[patrickt]

Originally Posted by pormgb

Yep, they are 1".

Pumping the pedal builds good pressure, I can't imagine where air could still be in the system.

Try putting 1/8" shims, for test purposes only (not driving) between your pads and rotors and see if you can firm up the pedal feel in the garage. That will at least answer the "do I need a fatter rotor" question.

[pormgb]

Originally Posted by patrickt

Try putting 1/8" shims, for test purposes only (not driving) between your pads and rotors and see if you can firm up the pedal feel in the garage. That will at least answer the "do I need a fatter rotor" question.

Put shims behind the four front pads, pistons were as far back as possible but there was no difference in the pedal, still goes to the floor.

I am thinking I either don't have enough volume due to the 1" MC or there is still air somewhere in the system.

[patrickt]

Originally Posted by pormgb

I am thinking I either don't have enough volume due to the 1" MC or there is still air somewhere in the system.

I would temporarily cap off the rear lines and see if you can firm up the pedal using nothing but the front Sierras. If you can't do it, then it's got to be air in the lines.