Swapping Brakes (GT to Cobra) NO Pedal Feel, Can't Find Problem!

Blinkstang · Jun 15, 2007

I have an 02' GT. I recently swapped brakes with a friend with an 03' Mach. He wanted my smaller brakes so he could run skinnies up front.

Ok on to my brakes. We put them on, bled both sides and still had NO pedal feel. So we took the calipers apart and fully compressed the pads and put it all back together (as the pads were not gripping before). We again bled the brakes some more and yet again my brake pedal has no feeling what so ever - however the brakes do lock the rotor somewhat, they will stop it from spinning.

So we did some research and decided to bleed the Master Cylinder - we used the front bleeder screw. Even after this attempt I still have NO pedal feel. The pedal goes straight to the floor without any resistance when I start the car.

So what can we look at next for a problem.

Another problem we noticed: when bleeding the brakes, hardly any fluid was coming out - just a little bit with no air. After bleeding BOTH sides the Master Cylinder NEVER went empty. Not much fluid was moving out.

So what would cause this, what should we look at? And is there any other bleed valves on the Master Cylinder?? When doing a search on here, some people mentioned more than one - but there were no specifics.

Thanks for the help!!

urban96 · Jun 15, 2007

how long was the system open? if you let the ABS block run dry you will need the dealership to bleed that (takes special computer/tool)

PJx5x · Jun 16, 2007

urban96 said:
how long was the system open? if you let the ABS block run dry you will need the dealership to bleed that (takes special computer/tool)

Do you mean calipers disconnected and the hard-line open?

Rusty67 · Jun 16, 2007

From my Ford service DVD for a 2002 Mustang GT:

Master Cylinder Priming — 4.6L

CAUTION: Use only bleed screws on the engine side of the brake master cylinder (2140). The hydro-boost bleed screw, located near the dash on the hydro-booster casting, is for the booster cavity filled with power steering fluid, not brake fluid.

Connect a clear waste line to the bleed screw closet to the booster first and the other end in a container partially filled with recommended brake fluid.

Open the bleeder screw, have an assistant push the brake pedal down slowly through full travel, close the bleeder screw, then return brake pedal slowly to full released position. Wait five seconds, then repeat operation until air bubbles cease to appear.
Repeat Step 2 for bleeder screw farthest from hydro-booster.

AND a little down the line on the same page:

NOTE: It is not necessary to do a complete brake system bleed if only the disc brake caliper (2B120) was disconnected.

Place a box end wrench on the disc brake caliper bleeder screw (2208). Attach a rubber drain tube to the disc brake caliper bleeder screw, and submerge the free end of the tube in a container partially filled with clean brake fluid.

Have an assistant pump the brake pedal (BP) (2455) and then hold firm pressure on the brake pedal.
Loosen the disc brake caliper bleeder screw until a stream of brake fluid comes out. While the assistant maintains pressure on the brake pedal, tighten the disc brake caliper bleeder screw.
Repeat until clear, bubble-free fluid comes out.
Refill the brake master cylinder reservoir (2K478) as necessary.
Tighten the disc brake caliper bleeder screw. Refer to Specifications.

Mustang5L5 · Jun 16, 2007

What he said.

There isn't an issue of running the Mach brakes on a GT. I have Mach 1 brakes on my '03 GT and the pedal feel is great. Just sounds like you have some bleeding issues

urban96 · Jun 16, 2007

PJx5x said:
Do you mean calipers disconnected and the hard-line open?

yeah

thomas91169 · Jun 16, 2007

happens to me everytime i take off my calipers

bleed them from the master cylinder and it should remedy the situation.

Dragstr05 · Jun 16, 2007

You dont have pedal feel because you stopped bleeding before you had fluid coming out.

thomas91169 · Jun 16, 2007

if air got into his lines far enough, then it wont matter. i can bleed them all day from the calipers and have fluid still run out and have zero brake pedal, but as soon as i tackle the master cylinder, takes me about two bleeds and bam, brakes are back.

i use a vacuum hose and run it from the nipple to the brake bottle, that way air rushes out, and only fluid is sucked back in(if you dont close the nipple in time youre still good).

Blinkstang · Jun 17, 2007

Thanks for all the help guys! It was indeed the Master Cylinder. We overlooked the second bleed screw the first time and still got no pressure. Once we found the second screw and bled from there, the pedal finally had resistance.

I did however notice that my pedal feel is pretty much the same as before. I've always had to go a good way down on the pedal before the car starts braking. Before we swapped brakes, I drove the Mach around and the brakes began doing their job way up top - without having to press the pedal down much at all. The same brakes on my car, feel just as stock did.

They do brake fine with no problem, but like I said you just have to push the pedal down a lot further before you feel a reaction. I'm wondering if I need to have the ABS bled as someone else mentioned or if something else may be causing this??

Thanks again for the help!

PJx5x · Jun 18, 2007

Push it in a river

Rusty67 · Jun 18, 2007

Could be a booster issue.

Swapping Brakes (GT to Cobra) NO Pedal Feel, Can't Find Problem!

Blinkstang

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urban96

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PJx5x

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Rusty67

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That is…until I whipped out my Bissell

urban96

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thomas91169

I'd donkey punch my sister.

Dragstr05

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