how you bleed air and old fluid from brake lines

grumpyvette

Administrator
Staff member
There are a few different systems for bleeding the brake system (2-person, 1-person vacuum, pressure, etc.). Which one of them would you consider the best and why? Do you have a preference?[/QUOTE]
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http://www.ecklers.com/master-cylinder- ... ool-1.html
medical supplys can be useful bleeding brakes
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Ive only found one semi-fool proof way, and thats with two guys, doing the old...
check the fluid level, pump the brake pedal,several times,....., hold it,firmly to the pressure point f,...release the bleeder valve, on the wheel, let the pedal hit the floor,...close the bleeder valve, only then, let the pedal up, repeat, about 4 times than refill the master cylinder,repeat untill you get clear new fluid and no air in the clear tubing, routine, on each wheel with a 1/4 dia section of 3 ft long clear plastic tube routeing the old brake fluid into a large plastic container, all the time getting feed back on feel from the guy pumping the brakes whos also and making sure the brake fluid resavoir never gets low

read this
http://www.popularmechanics.com/automot ... 13448.html
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marv02 POSTED THIS INFO

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Get your self a rubber hose about 1.5 foot long that fits tight over the Brake bleeders on the wheel caliper put the other end into the 2 liter don't forget to put some brake fluid into the bottle also crack open the bleeders open not full open but enough so the fluid will flow out when pushing down on the brake pedal.
now I recently found these little clear canisters deals (medical vacuum fluid containers) with taps for clear plastic hose that when used with a vacuum pump gun make bleeding the air, out of a hydraulic clutch or brake lines far easier and far less messy,
( a 6 ft section of clear vinyl hose over the bleed valve and some practice helps)
suction-canister-hi-flow-1200-ml-1200-cc-with-self-sealing-lid-sold-as-each-by-bemis-484410-for-a-discount-by-a-full-case-48-cs-click-here-3.gif
you simply crack the bleed valve, on the brake caliper or clutch slave cylinder, then slip a clear plastic hose that fits tightly on the bleed valve nipple
(usually 1/4" or 5/16" plastic hose)between the brake slave cylinder or calipers and route one end to the canister, route a second plastic tube to your vacuum gun and pour brake fluid into the master cylinder while pumping the gun, the old fluid collects in the canister.
the great thing hear is it makes it a one man job and you can use longer plastic hose so you can stand next too the master cylinder to make sure its never going low on fluid, as you keep it topped off, while you pump out the old brake or hydraulic fluid


http://www.aaawholesalecompany.com/bem-484410-pk.html
NOTICE THEY COME 12 to a carton and cost about $40 a dozen so get two buddies to split the cost
medical supplys can be useful bleeding brakes
vacbra.jpg


http://www.harborfreight.com/mityvac-va ... 39522.html



http://www.mityvac.com/pages/products_hvpo.asp#

http://www.mityvac.com/pages/products_hvp.asp

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Do one brake at a time.

The reason you are puttting some Brake fuild into the 2 liter and sumerge the rubber hose into it so when you cycle the brake pedal you will not suck air back into the brake system when you release the pedal.

Keep on cycling the brake pedal untill the air is gone start from the farthet to the closes brake as in rear right then rear left then front right then front left.

Make sure you shut the bleeder off when you done with each brake at a time.

Also you need to keep a eye on the MC to make sure you dont run it dry bleeding the brakes this way.

I normaly go though at least almost a full bottle + on the first wheel it has a long way to go to get rid of the air the next rear wheel 1/4 bottle or so the first front 1/2 a bottle next front 1/4 bottle.

Brake fluid is cheep.

You might not need so much fuild but I like to make sure I get all the air out.

This also works for replacing old nasty Brake fluid for freash Brake fuild.

This way beats yelling at someone else open close open close or pedal up pedal down"
 
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https://www.aa1car.com/library/abs_bleeding.htm

http://www.stoptech.com/technical-support/technical-white-papers/bleeding-abs-brake-systems

https://www.autozone.com/repairguid.../Bleeding-The-ABS-System/_/P-0900c15280090074

auto bleed procedure

https://www.machinerylubrication.com/Read/30614/know-brake-fluids

https://help.summitracing.com/app/answers/detail/a_id/414/~/what-is-the-difference-between-brake-fluids?

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DOT 3 vs. DOT 4 vs. DOT 5 vs. DOT 5.1
Obviously, the braking system on any vehicle is a critical safety system. It becomes even more critical in race and performance applications. Bringing your car to a stop generates a lot of heat. The heavier the vehicle and the faster it is going, the more heat is created. Brake fluid must be able to stand up to all this heat and still do its job: transfer force from the brake pedal to the caliper or wheel cylinder.

To ensure everyone's safety, brake fluid must meet certain standards. The standards are set by organizations like the SAE and the Department of Transportation (DOT). The standards are what designates the fluid as DOT 3, DOT 4, DOT 5, and DOT 5.1.

The important factors involved when comparing brake fluids are:

  • Boiling Point
  • Viscosity
  • Corrosion Prevention
  • Compressibility
What is it made from?
Before we get into the specific standards, it is important to know what the different fluids are made from. DOT 3, DOT 4, and DOT 5.1 are all glycol-ether based. DOT 5 brake fluid is silicone based.

Glycol based fluids are hygroscopic, meaning they gradually absorb moisture from the atmosphere and disperse it throughout the system. As the water content of the fluid increases, its boiling point decreases. The additional moisture in the fluid will also start to corrode the metal components of the system.

The silicone based fluid is hydrophobic, meaning it will not absorb moisture. If any moisture is introduced into the system, it can collect in pockets that can either freeze or boil off. This can lead to damage to the brake system and/or brake failure. Silicone is also more compressible than glycol, which can lead to a "spongy" feeling brake pedal.

Because of the way they deal with water, glycol and silicone based fluids are NOT compatible with each other. Never mix the 2 types of fluid. Only add DOT 5 silicone brake fluid to a completely dry system or a vehicle that already has DOT 5 in it. Do not add anything other than DOT 5 to a system that calls for DOT 5 brake fluid.

Boiling Point
When it comes to performance applications, boiling point is probably the most critical. Brake fluid must withstand very high temperatures without vaporizing in the lines. Vapor is highly compressible, compared to fluid. So, if the fluid is vaporized, it fails to transfer the force from the pedal to the caliper or wheel cylinder and the car will not stop.

Don't forget to consider the water content of the fluid. Remember that the glycol based fluids will absorb moisture over time. Brake fluid must meet standards for both a wet and dry boiling point. The wet boiling point is defined as 3.7% water by volume.



Dry Boiling Point

Wet Boiling Point

DOT 3

401° F

284° F

DOT 4

446° F

311° F

DOT 5

500° F

356° F

DOT 5.1

500° F

356° F

**Some manufacturers sell brake fluid with much higher boiling points. These fluids are intended for use in race vehicles only and should not be used in daily drivers or street vehicles.**

Viscosity
Viscosity is basically the thickness of the fluid. For example, oil has a higher viscosity than water. Brake fluid must maintain its viscosity through both extreme heat and cold to provide reliable, safe braking. DOT 3 has the highest viscosity. As the DOT number increases, the viscosity goes down.

Corrosion Prevention
In addition to withstanding heat, brake fluid must also not corrode the metal brake system components. Additives are added to the fluid to accomplish this. The added chemicals protect the metal parts from corrosion, but they will damage painted surfaces.

The glycol based fluids are very harmful to paint. If the fluid is spilled, or leaks onto a painted surface of your vehicle, the paint will be damaged. DOT 5 silicone based fluid is much less harmful to paint.

Compressibility
Brake fluid is intended to transfer force. If the fluid compresses, even a little bit, the force is reduced. Brake fluid must maintain a low level of compressibility to maintain the feel of the brake pedal and provide consistent performance.


1995-96 Vehicles


On 1995-96 vehicles, if the proper pedal height and feel is not achieved after the regular bleeding procedure is completed, you must perform the Auto Bleed procedure. This procedure requires the use of a Tech 1®, or equivalent scan tool.

The auto bleed procedure is used to provide a complete brake system bleed on 1995-96 vehicles, which are equipped with Bosch 5 ABS. The procedure cycles the system valves and runs the pump to purge air from secondary circuits which are normally closed off during non-ABS/TCS mode operation and bleeding. This procedure is primarily to be used when it is suspected that air has been ingested into the system secondary circuits, or when the Brake Pressure Modulator (BPM) valve has been replaced with a new unit.

In order to perform this procedure, you will need the following:




Tech 1® or equivalent scan tool with MSC.


A pressure bleeder capable of producing at least 30 psi with suitable adapters and filled with the proper type of brake fluid from a sealed container.


A hoist, or jack and stands to safely support the vehicle.


A suitable bleeder bottle to receive the vented brake fluid. The bottle should be unbreakable plastic, with a clear plastic hose that fits snugly on the bleeder valves. The hose should protrude into the bottle, with its end immersed in brake fluid.


An assistant to pump the brake pedal during the procedure.


Proper attire, including safety glasses.


The auto bleed procedure may be stopped at any time by pressing the "EXIT" button the scan tool. No further prompts pertaining to the bleeding procedure will be given. After pressing the "EXIT" button, relieve the bleed pressure and disconnect the bleed head from the master cylinder, making sure to follow the bleed equipment manufacturers directions.

  1. Raise and safely support the vehicle.
  2. Remove all of the wheel and tire assemblies.
  3. Check the brake system for leaks or component damage. Make sure to fix all conditions before starting the bleed procedure.
  4. Make sure the vehicles battery is fully charged.
  5. Connect the Tech 1® scan tool to the DLC.
  6. Turn the ignition switch to the RUN position, but do not start the engine.
  7. Establish communications with the scan tool and select ABS/TCS system features.
  8. Press "F4: Misc. Tests"
  9. Select "Automated Bleed Procedure"
  10. Bleed the brake system, as outlined earlier in this section.
  11. Press the "UP" button. This conducts several tests which determine whether the ABS/TCS system condition is such that the bleed procedure can be performed. If any malfunctions are found, the bleed procedure will be aborted. If DTCs are present, the scan tool will display "DTCs PRESENT", or list the DTCs, depending upon when the codes were set. The codes can be displayed or cleared as necessary in the "F2: Trouble Codes" mode. Make sure to correct any system malfunctions before trying to repeat the bleeding procedure.
  12. Connect the pressure bleed equipment, following the manufacturers directions, then press the "UP" button.
  13. Apply bleed pressure, minimum 30 psi. Check for leaks at the master cylinder reservoir bleeder cap and fix, if necessary.
  14. Have an assistant pump the brake pedal continuously from this point on, with long, steady strokes. Press "UP" on the scan tool.
  15. Open the left rear bleeder screw, use the bleeder bottle. Press "ENTER" when prompted. Press the "UP" button.
  16. Close the left rear bleeder screw when prompted on the screen. Press "ENTER" when prompted.
  17. The left rear bleed is complete. Press "UP".
  18. Repeat the previous 3 steps on the right rear brakes.
  19. Open the right front bleeder screw, use the bleeder bottle. Press "ENTER".
  20. Have an assistant pump the brake pedal continuously, with long, steady strokes. Press "UP" on the scan tool.
  21. Close the right front bleeder screw when prompted on the screen. Press "ENTER" when prompted.
  22. The right front bleed is complete. Press "UP".
  23. Open the left front bleeder screw, use the bleeder bottle. Press "ENTER".
  24. Have an assistant pump the brake pedal continuously, with long, steady strokes. Press "UP" on the scan tool.
  25. Close the left front bleeder screw when prompted on the screen. Press "ENTER" when prompted.
  26. The left front bleed is complete. Press "UP". At this time, the scan tool performs several tests to recheck system operation. The scan tool does not check bleed success. If any malfunctions occur, relieve the bleed pressure, then disconnect the bleed equipment, as outlined by the manufacturer. If any DTCs are present, the scan tool will show them. The codes can be cleared in the "F2: Trouble Codes" mode. Press "EXIT" to return to the scan tool main menu. Make sure to correct any system malfunctions before trying to repeat the bleeding procedure.
  27. If the screen shows "BLEED PROCEDURE COMPLETE", press the up button.
  28. Release the bleed pressure, following the tool manufacturers directions, Press the "UP" button.
  29. Disconnect the bleed equipment. Immediately clean up any spilled brake fluid, by wiping it up with a cloth, then flushing with water. Do NOT let any water get into the master cylinder. Press "EXIT".
  30. DEpress the brake pedal. It should be high and firm. If not, recheck the brake system thoroughly. If the brake system is OK, but excessive pedal travel exists, repeat the auto bleed procedure.
  31. Turn the ignition OFF .
  32. Disconnect the scan tool. Reinstall the wheel and tires, then carefully lower the vehicle.
  33. Check the brake fluid level and refill if necessary. Road test the vehicle, making several ABS and traction control stops, in a safe area. The brake pedal should stay high and firm after the road test.



Perform a manual or pressure bleeding procedure. If the desired brake pedal height results are not achieved, perform the automated bleed procedure below.

The procedure cycles the system valves and runs the pump in order to purge the air from the secondary circuits normally closed off during normal base brake operation and bleeding. The automated bleed procedure is recommended when air ingestion is suspected in the secondary circuits, or when the BPMV has been replaced.

Automated Bleed Procedure

Notice: The Auto Bleed Procedure may be terminated at any time during the process by pressing the EXIT button. No further Scan Tool prompts pertaining to the Auto Bleed procedure will be given. After exiting the bleed procedure, relieve bleed pressure and disconnect bleed equipment per manufacturers instructions. Failure to properly relieve pressure may result in spilled brake fluid causing damage to components and painted surfaces.

1. Raise the vehicle on a suitable support.
2. Remove all four tire and wheel assemblies.
3. Inspect the brake system for leaks and visual damage. Refer to Brake Fluid Loss or Symptoms - Hydraulic Brakes. Repair or replace as needed.
4. Inspect the battery state of charge.
5. Install a scan tool.
6. Turn ON the ignition, with the engine OFF.
7. With the scan tool, establish communications with the EBCM. Select Special Functions. Select Automated Bleed from the Special Functions menu.
8. Bleed the base brake system.
9. Follow the scan tool directions until the desired brake pedal height is achieved.
10. If the bleed procedure is aborted, a malfunction exists. Perform the following steps before resuming the bleed procedure:
- If a DTC is detected, refer to Diagnostic Trouble Code
(DTC) List and diagnose the appropriate DTC.
- If the brake pedal feels spongy, perform the conventional brake bleed procedure again.
11. When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
12. Remove the scan tool.
13. Install the tire and wheel assemblies.
14. Inspect the brake fluid level.
15. Road test the vehicle while inspecting that the pedal remains high and firm
 
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