I changed my brakes this weekend to a set of 07 Z51 brakes. Calipers, brackets and rotors.

For some reason, i cannot get the pedal pressure to build up. I bled them several times, starting from the right rear, left rear, right front, left front.

I bled them several times, and still cannot seem to build up the pressure. I have to pump it to get it to stop. Made for an exciting ride home.

Anyway, anyone have any ideas as to what I might have done wrong?
When i bled the rears the pedal would not go all the way to the floor. When I did the fronts, the brake pedal would go all the way to the floor board.

I have done a caliper swap before and had no issues, so this has me puzzled.

I am thinking about triple checking the lines and making sure they are super tight. I changed all the brass washers, but maybe I didn't get them tight enough. I will also check the bleeders to make sure they are super tight.

 

There is a seqience you are supposed to bleed them in. Maybe someone can chime in on it.

 

As far as I know it is how I stated in my post. It is basically start from the brake that is furthest from the master cylinder and work your way towards. RR, LR, RF, LF.

 

1997 - 2000 RR, LR, RF, LF
2001 - 2004 RR, LF, LR, RF

The pairing changed in 2001 to (RR & LF) (RF & LR)

EDIT:
2001 -2004 - (Start with the REAR and go diagonal to the front)

 

I think he meant 2001-2004 RR,LF,LR,RF

 

Yes I did - you are correct. (Start with the REAR and go diagonal to the front)

 

That is odd. I don't think I did it that way last time. I guess i will try the diagonal process. Seems odd you would go from the fartheest to the closest to the master cylinder.

Hope that fixes it. I have to wait till the weekend to even try.

 

 

For a 2001

Hydraulic Brake System Bleeding Manual
Caution
Refer to Brake Fluid Irritant Caution in Cautions and Notices.


Notice
When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.


Notice
Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.

Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.
With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps:
Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary, add Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal.
With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.
Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.
Reconnect the brake pipe to the master cylinder port and tighten securely.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
Loosen the same brake pipe to purge air from the open port of the master cylinder.
Tighten the brake pipe, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps 3.3-3.7 until all air is purged from the same port of the master cylinder.
With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps 3.3-3.8.
After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
Fill the brake master cylinder reservoir with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Ensure that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve.
Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
Tighten the bleeder valve, then have the assistant slowly release the brake pedal.
Wait 15 seconds, then repeat steps 8-10 until all air is purged from the same wheel hydraulic circuit.
With the right rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the right rear hydraulic circuit, install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
With the left front wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left front hydraulic circuit, install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
With the left rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left rear hydraulic circuit, install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve.
Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.
After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
Slowly depress and release the brake pedal. Observe the feel of the brake pedal.

Important
If it is determined that air was induced into the system upstream of the ABS modulator prior to servicing, the ABS Automated Bleed Procedure must be performed.


If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps:
Inspect the brake system for external leaks. Refer to Brake System External Leak Inspection .
Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.
Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.

Important
DO NOT allow the vehicle to be driven until it is diagnosed and repaired.


If the brake system warning lamp remains illuminated, refer to Symptoms - Hydraulic Brakes .

 

The reason for the two different bleed sequences .....

Let's take a simple example, a car with no ABS ..... it can be any car made after about 1960, by any manufacturer, so long as it was for sale in the US ...

If you look at the brake master cylinder, you will see that there are TWO feeds out from it, with each feed then splitting and going to an individual slave cylinder.

This is done so that, say, you suddenly have a massive failure of a single brake line .... that brake and the other brake controlled from that master cylinder feed will not work .... BUT ... you will still have two working brakes out of 4 .

Up until the 1990's the split was the front two brakes were serviced by one line and the rear brakes served by the other. Hence, you bled the brakes from furthest to closest.

On the Corvette, starting with the 2001 model, the split was made to be diagonal .... one front and one rear brake share one master cylinder feed, and they are diagonally opposed.

This was done for several reasons ...

With the old system, if you lost a front brake, all you had was the rears, and rear brakes only provide about 10 to 20 percent the stopping power of the front brakes.

By going with a front/rear split, if a brake fails, you will always have one working front brake .... much more stopping power than only rear brakes.

Finally, the split is diagonal so you don't end up getting a huge "pull" to one side or the other, the remaining brakes will be more "balanced" than two brakes on the same side of the car working with no offsetting brakes on the other.

So, that's why the change in the bleed sequence, the brake lines are routed differently today .....

 

Also make sure your bleeder nuts are pointed up on all of your calipers.

 

I had the same problem, try bleeding the fronts first then the backs.

 

NO .... .... STUPID ... THAT IS THE WRONG ANSWER ..............

As has already been explained the correct sequence is RR/LF/LR/RF for a 2001 Model Year, or later, vehicle.

Try reading some prior posts before you post garbage.

 

I had the same problem and got several codes when I changed my calipers.
I had to bleed the brake lines several times before the problem was corrected.
You also might check all of your connections to make sure you are not sucking air into the brake lines.

 

Well, I bled them again today. It got better but not as good as i had expected it to get.

I am wondering if maybe the master is going bad or something. I am not getting any leaking form any of the lines. I drove the car about 12 miles from my house to work and there was no fluid leaks. I also checked them with a wrench to ensure they were tight.

A guy was telling me that bleeding the brakes and making the pedal go to the floor numerous times is bad for the master. never heard of that before, but it has me wondering. I have changed calipers before so they have been bled alot now.

I will probably bleed them again next week when I put the bilsteins on and if they don't get better will replace the master.......or have the dealer look at it.

 

Have you checked to make sure that your calipers were not installed upside down ?

All of the bleeders on the calipers should be pointing up. The symptoms that you are posting are a classic sign of this.

 

The fronts are up. The rears shoot to the side so i am not sure what you mean by up on those. I did try and install one of the rear calipers and had to take it off since the line was not reaching, which of course meant i had it on the wrong side.

 

The brake bleeders are the little valve that you open to bleed the brakes. They should be at the top when mounted up, if not you won't be able to get the air out of the brake lines.

The brake line going into the caliper is on the bottom (i.e. lower than the bleeder).

 

Might want to try some speed bleeders, you might be bleeding them the wrong way

 

Sequence actually has very little to do with a full brake system.

If the system is full, then its not important. I bleed and replace my brakes 6-7 times a summer, we bleed each corner when we change, in no particular order. Its more meant to get air out of the ABS unit and your not bleeding the ABS unit unless your using a TECH II so order is moot. If you are using a TECH II it will guide you through the process.

First go with what was said above, the bleed screw, no matter where it is should always be in the up position.

Second if you have a leak trust me you'd know it, 2000psi with even a pinhole will make quite a mess.

Somethings to check:

1. Is the fluid level in the resovoir consistent? If its not the fluid is going somewhere.
2. Did you accidently knock off the vacuum hose on the booster(will not effect pedal pressure)?
3. Sounds silly...but you did put the pads in the calipers, right?
4. Do the brakes actually work? If you have the car in the air and spin the tire and hit the brakes, does it stop?

Brakes are not rocket science its just pressure applied to a fluid which moves a piston.

When you bleed the brakes you are closing the valve after you pump,correct?

Pump the brakes three to four times, then hold, crack open the bleeder, then shut, repeat.

Did you fill the calipers with fluid before you put them on the car? If not as your bleeding hit the calipers with a rubber mallet to knock some air that might be trapped loose.