No brakes after caliper rebuild

[derek murray]

I have rebuilt the front calipers, installed new pads and have had the rotors machined. I bled and re-bled the braking system many many times over. I used the two person method and a pressure bleeder. As far as I can see there in no air in the lines.... however. I have absolutely no brakes, whatsoever! And I mean, none, nada. When I push the brake pedal it goes to the floor with no resistance at all and there is no movement of the pads that I can see (rear or front). I have searched the archives, but every suggestion suggests air in the system... and I'm pretty sure there is none.

What have I missed? (BTW, the master cylinder was replaced about 2000 miles ago.)

[Oh Haha]

Have you pressed the brake pedal enough to move the new pads out to touch the rotors?

No obvious leaks at the calipers or lines?

not being a smarta$$, I am just throwing out ideas to you.

[derek murray]

When I installed the pads I extended the pistons out so I needed to lightly tap the pads into place with a hammer. I extended the pistons manually.

When I press the brake pedal there in no movement of the pads / pistons at all. The pedal presses to the floor with virtually no effort.

No leaks at all (as far as i can see).

I appreciate the response.

[James Brown]

Quick answer: there is air in there, sounds like the master cylinder is dry, try bleeding just that first till the pedal has some feel to it then move down to the wheel cylinders to get the trapped air out. Keep at it!!

[Oh Haha]

Well, crap.

Here's a thread i found that might help you.Brake upgrade/bleeding question

I agree with Mr. Brown on air in the system.

It's the only logical explanation given your reply to my questions.

[burgermeister]

It is possible to install the calipers upside-down ... they don't bleed well in that state. Just something to check ...

[derek murray]

Originally Posted by James Brown

... sounds like the master cylinder is dry, try bleeding just that first till the pedal has some feel to it then move down to the wheel cylinders to get the trapped air out. Keep at it!!

Thank you.

I've never bled the master cylinder before. Does it need to be removed from the car, or can I do it in place?

Oh Haha... thanks for the link.

[tangerine911S]

I would pump the pedal, let it sit for a while, and repeat. There might be some bubbles or micro-bubbles stuck in the line that dont come out through the caliper bleeder when bled. They might come out through the MC.

[derek murray]

Originally Posted by burgermeister

It is possible to install the calipers upside-down ... they don't bleed well in that state. Just something to check ...

Calipers are properly installed... thanks for the idea, though.

[Dixie]

A couple suggestions:

It is possible to install the calipers upside-down ... they don't bleed well in that state.

You'd think installing them upside-down would be an anomaly, but it's rather common based on post I've seen on this forum. Check that the bleeders are on TOP of the calipers.

I extended the pistons manually.

Can you elaborate on this? I've never had a need to do this, on any car. And no, I'm not saying you did anything wrong. It's just an unusual thing to do. leading to suspicions the issue is somehow related.

Also...

Try simply gravity bleeding the system. Open all four bleeders. and let gravity pull the fluid through. I's the simplest and best way to eliminate air in the system.

[James Brown]

yes try gravity, it takes time and can be messy but it does work, just make sure the resevour is kept full

[derek murray]

Originally Posted by Capt. Carrera

Can you elaborate on this? I've never had a need to do this, on any car....

Before installing the calipers back into the car, I used compressed air to force the pistons back out after installing the dust boots. Once I got the pistons pushed out just a little I test fitted the calipers on the car with the pads installed. Once everything was perfect, I bolted them to the car, tapped in the pads and re-installed the bleeder screw that was removed for re-building.

As background, I was reading a post by Warren Hall where he suggested to install the pads with the pistons out a little so that the pads needed to be lightly tapped into place with a hammer.

[tomphot]

After I rebuilt mine, it took forever to get a good pedal.
I bleed about 1 gallon on fluid before I was satisfied.
How much have you gone through?

[McLovin]

I agree, there is air in the system somewhere. It doesn't take a whole lot of air to make the pedal go all the way to the floor.

Before you unbolted the calipers, did you use a brake lock (or stick, etc.) to hold the brake pedal down an inch or so for the entire time you had the calipers unbolted?

[James Brown]

Please, call me James or Jim, Mr Brown is my parole officer....

[Oh Haha]

Gotcha Jim.

I thought you might take the reference more from "Resorvoir Dogs".

[James Brown]

good point and yes, I don't sing!! but I do "feel good"

[derek murray]

Originally Posted by tomphot

How much have you gone through?

About 2 litres, maybe 2.5

Originally Posted by McLovin

Before you unbolted the calipers, did you use a brake lock (or stick, etc.) to hold the brake pedal down an inch or so for the entire time you had the calipers unbolted?

No... I forgot.... which equals lots of air, doesn't it?

[James Brown]

ding, ding, ding

[Oh Haha]

Yep, I think the problem has been diagnosed.

I remember now that I used a chunk of 2x4 to hold my brake pedal down when I rebuilt my calipers.