How do I bleed the brakes?

Tiny
VACARRIER1@YAHOO.COM
  • MEMBER
  • 2002 CHEVROLET SUBURBAN
  • 6.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Have replaced master cylinder and all brake lines and brakes will not bleed. What else could I check or do?
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Monday, July 4th, 2016 AT 10:04 AM

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Tiny
HMAC300
  • EXPERT
It may have an air lock in abs unit try renting a power bleeder to do this it can take up to and including three quarts to get it bled. is still not a sufficient brake pedal a local mechanic will have to hook up a scanner and open abs unit valves to bleed the system. Here is a video and guide below to help you bleed the brake system correctly.

https://youtu.be/w7gUsj2us0U

and

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

and

https://youtu.be/WDxvEQrMkBg

Please run down these guides and report back.
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Monday, July 4th, 2016 AT 10:16 AM
Tiny
UPMM019
  • MEMBER
  • 2001 CHEVROLET SUBURBAN
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 234,000 MILES
My suburban has announced it needs new brakes/rotors with lots of grinding. So I have new pads and new rotors and plan on doing the work myself. I am wondering about brake bleeding, etc. The brake pedal has been spongy as long as I can remember. I have never bled the brakes. I am hoping that new brakes/brake bleed will solve the spongy brake pedal. Wondering if you can give any guidance on the spongy pedal/brake bleed procedures for best results.
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Monday, March 15th, 2021 AT 11:26 AM (Merged)
Tiny
MHPAUTOS
  • EXPERT
Brake bleeding is fairly simple. One good method is to get a large clear glass or plastic jar and put some brake fluid in the bottom not a lot is required, use a clear plastic hose that fits over the bleeder and place other end into jar with brake fluid. Open bleeder and pump pedal slow down, not all the way about 3/4 stroke and return to top, bubbles then fluid will start to come from brakes into jar, (with each stroke) the hose in the fluid will stop air being drawn up into the brakes, pump pedal slowly until fresh fluid is seen flowing in the hose. With the pedal down, lock off the bleeder and move on to the next wheel, do all four rear rear first then front, this method should work for you.
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Monday, March 15th, 2021 AT 11:26 AM (Merged)
Tiny
COOLDOGG
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 239,000 MILES
So I have the vehicle listed above k1500, 4wd, LT. I cannot get the brakes to bleed out. As soon as I pulled into work I hit the brakes and my pedal grabbed then went to the floor. Made me curious. Got off work had an employee hit the brake pedal and found that I had blown a hole through the brake line due to being rusted. So no one had a brake line. So I had to go old school and get plugs to plug out the line then found the brake reservoir to be bad. Replaced it I cannot get the brakes to bleed out so I have brakes. Anyone that could help please. It has ABS. I got new brake lines for both sides finally. Been frustrating. Thanks in advance.
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Monday, March 15th, 2021 AT 11:26 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

When you say plug, do you mean you eliminated the brake line?

Next, let me know the sequence and procedure you are using.

Here are the directions for manual or pressure bleeding. See if this is what you are doing.

_____________________________

1999 Chevy Truck K 1500 Suburban 4WD V8-5.7L VIN R
Manual and Pressure Bleeding Procedures
Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures Manual and Pressure Bleeding Procedures
MANUAL AND PRESSURE BLEEDING PROCEDURES

pic 1

If air has entered the hydraulic brake system, bleed the system. You may need to bleed the hydraulic brake system at all four wheels due to one of the following conditions:
Air entered the system due to a low fluid level.
The brake pipes have been disconnected at the master cylinder.
The brake pipes have been disconnected at the combination valve.

If a pipe is disconnected at one wheel, then only bleed that wheel.

If the master cylinder has been removed, bleed the master cylinder before installing it on the vehicle. This will reduce the time required to bleed the system.

NOTICE: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers, and fender covers to prevent brake fluid from contacting these areas. Always re-seal and wipe off brake fluid containers to prevent spills.

MANUAL BLEEDING

Tools Required
- J 28434 Wheel Cylinder Bleeder Wrench

1. If the vehicle has a vacuum booster, apply the brakes several times with the ignition OFF. This relieves the vacuum reserve.
2. Fill the master cylinder reservoir. Use Delco Supreme 11(R) Hydraulic Brake Fluid GM P/N 12377967, or equivalent DOT 3 motor vehicle brake fluid. Maintain the fluid level during bleeding.
3. If the master cylinder has air in the bore, bleed the master cylinder using the following procedure:
3.1. Disconnect the forward brake pipe connector at the master cylinder.
3.2. Allow the brake fluid to flow from the connector port.
3.3. Connect the brake pipe connector. Do not tighten the brake pipe connector.
3.4. Slowly apply the brake pedal. Allow the air to bleed from the loose connector.
3.5. Tighten the connector before releasing the brake pedal.
3.6. Wait 15 seconds.
3.7. Repeat this sequence, including the 15-second wait, until you purge all the air from the master cylinder bore.
3.8. Repeat this procedure for the rear brake pipe after you purge all the air from the forward pipe connection.

4. If you replaced the Brake Pressure Modulator Valve of the 4WAL system, or if you suspect that air is trapped inside, bleed the Brake Pressure Modulator Valve next.
5. Using J28434, bleed each wheel cylinder in the following sequence:
5.1. Right rear wheel cylinder
5.2. Left rear wheel cylinder
5.3. Right front wheel caliper
5.4. Left front wheel caliper

6. Attach a hose to the wheel cylinder/caliper bleeder valve.
7. Immerse the opposite end of the hose into a container partially filled with clean brake fluid.
8. Slowly apply the brake pedal one time and hold.
9. Loosen the bleeder valve in order to purge the air from the wheel cylinder/caliper.

NOTICE: Refer to Fastener Notice in Service Precautions.

10. Tighten the bleeder valve.
Tighten the bleeder valve to 13 Nm (110 inch lbs.).

11. Slowly release the brake pedal.
12. Wait 15 seconds.
13. Repeat this sequence, including the 15-second wait, until you purge all the air from the wheel cylinder or caliper.
14. Repeat steps 6-12 at each wheel until you purge all the air from the brake system.
15. Check the brake pedal for sponginess. Check the brake warning lamp for an indication of unbalanced pressure. Repeat the bleeding procedure in order to correct either of these conditions.

PRESSURE BLEEDING

Tools Required
- J 29567 Brake Bleeder Adapter
- J 28434 Wheel Cylinder Bleeder Wrench

pic 2

Use a diaphragm-type pressure bleeder. The pressure bleeder must have a rubber diaphragm between the air supply and the brake fluid. This prevents air, moisture, oil and other contaminants from entering the brake hydraulic system.

1. Fill the pressure tank at least 2/3 full of brake fluid.
2. Charge the pressure bleeder to 140 - 170 kPa (20 - 25 psi).
3. Bleed the pressure bleeder each time you add fluid.
4. Install the J 29567 Brake Bleeder Adapter to the master cylinder.
5. If the Brake Pressure Modulator Valve of the 4WAL system is replaced, or if you suspect that air is trapped inside, bleed the Brake Pressure Modulator Valve first.
6. Using J28434, bleed each wheel cylinder or caliper in the following sequence:
6.1. Right rear wheel cylinder
6.2. Left rear wheel cylinder
6.3. Right front wheel caliper
6.4. Left front wheel caliper

7. Connect the hose from the bleeder to the adapter at the master cylinder.
8. Open the tank valve.
9. Attach a hose to the bleeder valve.

Pic 3

10. Immerse the opposite end of the hose into a container partially filled with clean brake fluid.
11. Slowly open the bleeder valve at least 3/4 of a turn. Allow the fluid to flow until you see no air in the fluid.

NOTICE: Refer to Fastener Notice in Service Precautions.

12. Tighten the wheel cylinder or caliper bleeder valve.
Tighten the wheel cylinder or caliper bleeder valve to 13 Nm (110 inch lbs.).

13. Check the brake pedal for sponginess. Repeat the bleeding procedure if the brake pedal is spongy.
14. Repeat steps 9 - 12 at every wheel.
15. Disconnect the hose from the bleeder adapter.
16. Remove the J 29567 Brake Bleeder Adapter.
17. Fill the master cylinder to the proper level.

_________________________

Now, there is a good chance the ABS system will need bled. THis will require an automated bleed procedure. Here are the directions for that.

________________________

1999 Chevy Truck K 1500 Suburban 4WD V8-5.7L VIN R
Automated Bleed Procedure
Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures Automated Bleed Procedure
AUTOMATED BLEED PROCEDURE
IMPORTANT:
Use the two-person bleed procedure under the following conditions:
- Installing a new Electro-Hydraulic Control Unit (EHCU) or new Brake Pressure Modulator Valve (BPMV).
- Air is trapped in the valve body
Do not drive the vehicle until the brake pedal feels firm.
Do not reuse brake fluid that is used during bleeding.
Use the vacuum, the pressure and the gravity bleeding procedures only for base brake bleeding.

TWO PERSON PROCEDURE
1. Raise the vehicle in order to access the system bleed screws.
2. Bleed the system at the right rear wheel first.
3. Install a clear hose on the bleed screw.
4. Immerse the opposite end of the hose into a container partially filled with clean DOT 3 brake fluid.
5. Open the bleed screw 1/2 to one full turn.
6. Slowly depress the brake pedal. While the pedal is depressed to its full extent, tighten the bleed screw.
7. Release the brake pedal and wait 10 - 15 seconds for the master cylinder pistons to return to the home position.
8. Repeat the previous steps for the remaining wheels. The brake fluid which is present at each bleed screw should be clean and free of air.
9. This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every four to six strokes of the brake pedal in order to avoid running the system dry.
10. Press the brake pedal firmly and run the Scan Tool Automated Bleed procedure (below 15,000 GVW) once, or run the Function Test (above 15,000 GVW) four times. Release the brake pedal between each test.
11. Bleed all four wheels again using Steps 3 - 9. This will remove the remaining air from the brake system.
12. Evaluate the feel of the brake pedal before attempting to drive the vehicle.
13. Bleed the system as many times as necessary in order to obtain the appropriate feel of the pedal.

__________________________

Keep in mind, if you can not get a brake pedal, there are no leaks, you repaired the brake line, and there is no air in the system after doing the above procedures, the master cylinder may have been damaged.

Let me know if I can help or if you have other questions.

Take care,
Joe
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Monday, March 15th, 2021 AT 11:26 AM (Merged)
Tiny
BNKM1LL3R
  • MEMBER
  • 1994 CHEVROLET SUBURBAN
The suburban's brakes began feeling inadequate (the rotors, pads and shoes are relatively new). I replaced the right front caliper and hose (was not fully releasing) cut the rotors, sanded the pads (getting rid of any glazing) and thoroughly bled the entire system (replaced fluid as well). The initial bleed was at the replaced caliper followed by the standard routine*.

The pedal still has excessive travel, a semi soft feel and aprox 70% braking ability.

Next I examined the entire system - no leaks and the rear brake area is dry. So I removed and replaced the master cylinder, which was thoroughly benched and re-bled the entire system once more. I don't believe the booster is at fault, I checked it as well.

The pedal is still semi soft with excessive travel and about 70% braking. There is no pulsing in the pedal (like ABS activation). As a matter of fact, I can't brake hard enough to activate the ABS. What is going on here?

PS. There are no lights lit on the dash and all of the
lights are functional.

* Bleeding was accomplished as always beginning at the right rear, left rear, front right, front left.
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Monday, March 15th, 2021 AT 11:27 AM (Merged)
Tiny
2CEXPT
  • MEMBER
On some ABS-equipped vehicles, you may also have to cycle or reposition the ABS solenoids or valves with a scan tool. Many also have additional bleeder screws on the ABS unit for bleeding the system.

Try rebleeding it start with the M/C then the ABS unit if it has one-then the wheel sequences
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Monday, March 15th, 2021 AT 11:27 AM (Merged)
Tiny
BNKM1LL3R
  • MEMBER
I followed the instructions for bleeding the 4wal kelsey hayes system as specified on cardone. Com. Actuated the selenoids while holding the high pressure acumulator buttons and having the internal bleeds open 1/4 to 1/2 turn.

I've now bled the system to the tune of 1 gallon of fluid.

I bled with the method described on cardone, then bled them thoroughly twice using the "standard method".

The brakes still are soft and will not kick the abs function. I did notice that my front tires will lock on gravel (but only under extremely hard braking).

And. As before no lights - no codes. Please advise.
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Monday, March 15th, 2021 AT 11:27 AM (Merged)
Tiny
2CEXPT
  • MEMBER
The wheel cylinders are they okay not leaking and also the brake shoes are they adjusted properly.
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Monday, March 15th, 2021 AT 11:27 AM (Merged)
Tiny
BNKM1LL3R
  • MEMBER
Yes. Rear drums have a very slight drag (when brakes are not applied), the calipers are working correctly (wheel bearings are not wobbling) and the entire system is dry.

I took it to a dealer today. They bled the brakes using the special tools to depress the buttons on the high press. Accumulators and distr. Block while actuating the ABS unit. ! No air ! Unbelievable! The tech then asked if I had the rotors turned lately (and I did), he then asked if a "special fixture" was bolted to the rotor while it was turned (which wasn't). He said that composite rotors require this fixture and a different cutting bit. They recommended to change / cut the rotors and put new pads on it.

They told me several stories of composite rotors not being turned correctly and crappy pads which caused the driver to use excessive pedal force to stop the vehicle. I didn't know which pads were installed (installed by the previous owner), so I replaced the rotors and pads when I got home.

I installed pads which have very distinct burnishing procedures - so I'll know in the AM (after they've cooled) if it worked.

Is this BS or could there be some truth to all of this? And. How can you tell by looking at a rotor, if it is a composite rotor? I assume composite means composite alloy.

! Thank you for your continued diligence !
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Monday, March 15th, 2021 AT 11:27 AM (Merged)
Tiny
2CEXPT
  • MEMBER
Here's some info on it

Composite brake rotors have been around since the early 1980s. When they were introduced, everyone was worried about soaring fuel prices (just like today), and auto makers were scrambling for ways to take weight out of their vehicles so they could meet government Corporate Average Fuel Economy (CAFE) standards. So one of the changes that was made was to replace heavy cast iron rotors with lightweight composite brake rotors.

COMPOSITE ROTORS SAVE WEIGHT

This type of rotor derived its name from the fact that it combined a stamped steel center hat with a cast iron rotor. Thus, it was a composite of two different materials. The new design proved to be about 20 percent lighter than a conventional one-piece cast rotor and saved up to a couple of pounds per rotor.

The composite design also allowed the rotor disc on some applications to be cast out of a special "dampened" gray cast iron for added noise suppression (dampened cost iron is not structurally suited for use in a one-piece cast rotor).

Some of these rotors also featured redesigned cooling fins for better heat management. Some were also directional for use on either the left or right side of the vehicle. Directional rotors are not interchangeable side-to-side because reversing the direction of rotation changes the cooling characteristics of the rotor.

COMPOSITE BRAKE ROTOR APPLICATIONS

Some of the earliest applications for composite rotors were the 1982 Lincoln Continental, 1984 Ford Mustang SVO, 1987 Ford Thunderbird Turbo Coupe, and 1988 Ford Taurus and General Motors front-wheel drive "W" body cars (Buick Regal, Oldsmobile Cutlass Supreme and Pontiac Grand Prix). Since then, the number of vehicle applications has continued to grow.

SERVICE PRECAUTIONS
As the vehicles with composite rotors accumulated mileage and came out of warranty, the aftermarket discovered that composite rotors required some special service procedures. Because the stamped steel center hat is not as thick nor or rigid as that in a one-piece casting, the center hat on a composite rotor must be fully supported with special adapters or oversized bell caps when the rotor is resurfaced on a brake lathe. The other alternative is to bolt the rotor to the hub (with the lug nuts reversed to provide better support and to prevent deforming the center hat) and to then resurface the rotor with an on-car lathe.

If a composite rotor is not supported properly, it can wobble and flex creating runout and surface finish problems. Both sides of the center hat must also be clean and rust-free for the rotor to turn true.

ROTOR RECALLS

Some of the early composite rotors experienced corrosion problems and were recalled for replacement. Ford switched some of its models back to conventional one-piece cast rotors for awhile, and issued a service bulletin (#91-8-9) saying it was okay to replace composite rotors on the 1986 to 91 Taurus and 1988-91 Continental with one-piece cast rotors (P/N F10Y-1125-8). The corrosion problem is mostly history now because the OEMs now apply a protective coating to the stamped steel center of the rotor to inhibit rust. Aftermarket composite rotors typically use stainless steel for the center section to prevent rust, and the circumference of the center section is also dovetailed (notched) for increased strength where it mates with the rotor.

Vibration problems were also blamed on the design of the composite rotor. But the underlaying cause more often than not turned out to be improperly torqued lug nuts. Any rotor can warp if the loading on the lug nuts is not even. That is why an impact wrench should never be used to tighten lug nuts, unless it is used with a torque-limiting socket. Otherwise, a properly calibrated torque wrench should be used to tighten the lug nuts in a star or cross-pattern sequence.

REPLACE ROTOR
When worn or damaged composite rotors need to be replaced, be careful not to intermix rotor types side-to-side. Rotors should always be the same type on both sides. Replacing a composite rotor on only one side with a cast rotor may create a brake pull. So do not replace a composite rotor on one side of a vehicle with a cast rotor unless the rotors on both sides are being replaced.

Cast replacement rotors for vehicles that were originally equipped with composite rotors are available from various aftermarket suppliers. But other aftermarket suppliers recommend against substituting one type of rotor for another because the cross-section of the center hat on a cast rotor is significantly thicker than the stamped steel center hat on a composite rotor.

The difference may range from 1/8 to 1/4 inch or more depending on the application. This may not sound like much, but it does reposition the wheel slightly further out on the hub. This adds positive steering offset and alters the scrub radius of the steering geometry. The amount of change is not great, but neither is the amount of scrub radius that is designed into many vehicles. Scrub radius affects steering feel, steering effort and steering feedback. It also plays a role in the way braking and engine torque affect steering.

The change created by replacing a composite rotor with a one-piece cast rotor may be enough to alter the scrub radius from negative (which is the case on many front-wheel drive cars) to zero or positive offset. This, in turn, may create a noticeable difference in the way the steering feels and reacts, especially on cars with rack & pinion steering that are especially sensitive to steering feedback.

There is also a concern that substituting a thicker cast rotor reduces the overall length of the lug studs, which reduces the number of threads available for the lug nuts to retain the wheels (especially on thicker alloy wheels).

Suppliers who subscribe to the "replace same with same" philosophy say you are apt to encounter far fewer problems when you install replacement parts that are the same design and function as the original. Those who do not subscribe to this philosophy say there is often room for improvement over the OEM design
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Monday, March 15th, 2021 AT 11:27 AM (Merged)
Tiny
MY SUBURBAN
  • MEMBER
  • 1988 CHEVROLET SUBURBAN
I just replaced the rear bearings and seals then moved on to the brakes, the reason I took the rear axles apart in the first place, I replaced the shoes, wheel cylinders and the short brake line to the drivers wheel from the back of the rear end.
After I put the drums on I started to bleed the brakes. I now have no brake fluid getting to the wheel cylinders. I took the line off that goes into the valve on the rear end and when the brakes are applied no fluid comes out. I went to the master cylinder and, removed the lines, got fluid to squirt out when pumped. I found another valve box under the radiator. I was able to get fluid to come out of it on all of the lines. Went back to the rear and got no fluid, but now a soft pedal to the floor. I kept the master cylinder reservoirs full the whole time while following the general brake bleeding rules.
Short of ripping out all of the brake lines and replacing all the valves I don't know what to do. Is this bis expense the only way to go or am I missing something in my work? Could you tell me how I should have done my brake work from start to finish for this vehicle?
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Monday, March 15th, 2021 AT 11:28 AM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
1988 correct? Is the red brake light on the dash illuminated? If so then you probably tripped the pporportioning valve and we have to unstick it.
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Monday, March 15th, 2021 AT 11:28 AM (Merged)
Tiny
MY SUBURBAN
  • MEMBER
Tim,
yes, the light is on.
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Monday, March 15th, 2021 AT 11:28 AM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
That means the porportioning valve is stuck. One way to get around it is to vacuum bleed the system to get fluid through it and equalize the pressure on both sides of valve so it will unstick. This is very common and happens alot. 99 percent of the time you dont have to replace any parts just bleeding it. Sometimes its just a lucky push of the pedal that opens it or sometimes I take them for a careful ride and eventually brake fluid gets past it enough so it can be bled, but vacuum bleeding is the most successful.
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Monday, March 15th, 2021 AT 11:28 AM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
Also when bleeding, use slow steady presses of the pedal not fast jerking ones, that will just make air bubbles in the line
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Monday, March 15th, 2021 AT 11:28 AM (Merged)
Tiny
MY SUBURBAN
  • MEMBER
Tim,
So. For the not so smart (and my fancy worthless Chilton's) that don't know how to vacuum bleed the system can you give some directions?
John.
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Monday, March 15th, 2021 AT 11:28 AM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
You will have to either borrow one from the parts store or purchase one. It basically attaches to the bleeder screw and it has a pump that is either hand operated or air compressor powered, and when you apply vacuum to the bleeder it will suck brake fluid past the porportioning valve to the bleeder and once the air is out it makes it easier for the valve to reset.
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Monday, March 15th, 2021 AT 11:28 AM (Merged)

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