Air in my master cylinder

Is it hydraulic.Or cable operated

Try bleed

1. Check the fluid level in the master cylinder. ...
2. Locate the bleed screw on the slave cylinder. ...
3. Attach the hose to the bleed screw. ...
4. Open the bleed screw on the slave cylinder. ...
5. Have a friend press the clutch pedal in and hold it. ...
6. Close the bleed screw. ...
7. Have your friend release the clutch pedal.

Bleeding Clutch by Blocking the Slave Cylinder

Did you properly refill the brake system? Did you bleed it to get rid of air?

Hi there:
I suggest to check this procedure, when the hydraulic brake system must be bled whenever a fluid line has been disconnected because air gets into the system.

A leak in the system may sometimes be indicated by a spongy brake pedal. Air trapped in the system is compressible and does not permit the pressure applied to the brake pedal to be transmitted solidly through the brakes. The system must be absolutely free from air at all times. If the master cylinder has been overhauled or a new cylinder has been installed, bleed the cylinder on a bench before installation. When bleeding brakes, bleed at the wheel most distant from the master cylinder first, the next most distant second, and so on. During the bleeding operation the master cylinder must be kept at least 3 / 4 full of brake fluid.


The ABS bleeding procedure is different from the conventional method. It consists of the following three steps:
Step 1: Conventional manual brake bleed.
Step 2: Bleeding the system using the DRB scan tool.
Step 3: An additional conventional manual brake bleed.

The recommended ABS bleeding procedure is as follows:

1. To bleed the brakes, first carefully clean all dirt from around the master cylinder filler cap. Remove the filler cap and fill the master cylinder with DOT 3 brake fluid to the lower edge of the filler neck.
2. Bleed the master cylinder first. Have a helper operate the brake pedal while bleeding each master cylinder fluid outlet line. Do not allow the master cylinder to to run out of fluid,as this will allow additional air to be drawn into the cylinder.
3. Bleed the brake system in the following sequence:
   1. Master cylinder
   2. HCU valve body (at fluid lines)
   3. Right rear wheel
   4. Left rear wheel
   5. Right front wheel
   6. Left front wheel
4. Clean off the bleeder connections at all four wheel cylinders. Attach the bleeder hose to the right rear wheel cylinder bleeder screw and place the end of the tube in a glass jar, submerged in brake fluid.
5. Open the bleeder valve 1/2 - 3/4 of a turn.
6. Have an assistant depress the brake pedal slowly and allow it to return. Continue this pumping action to force any air out of the system. When bubbles cease to appear at the end of the bleeder hose, close the bleeder valve and remove the hose.
7. Check the level of fluid in the master cylinder reservoir and replenish as necessary.
8. After the bleeding operation at each wheel cylinder has been completed, fill the master cylinder reservoir and replace the filler plug.

Do not reuse the fluid which has been removed from the lines through the bleeding process because it contains air bubbles and dirt.

1. Perform the "Bleed Brake'' procedure with the DRB II scan tool. This procedure is described in the DRB II software information and diagnostic guide.
   1. Attach the DRB II scan tool to the diagnostic connector.
   2. Run the Bleed Brake procedure as described in the DRB II tester guide.
2. Repeat the conventional bleeding procedure as previously outlined.
3. Fill the master cylinder reservoir to the proper level.
4. Check the brake operation.

Hope this helps.

Do you mean the brake master cylinder? As long as the fluid is at the full mark, and you have no air in the brake lines, it is fine. A spongy brake pedal and poor braking operation happens when air is in the lines. Air can get into the lines when the fluid in the master cylinder is very low, almost out, or when a brake line is pulled apart (like when replacing calipers). To get the air out, one has to bleed the brakes-starting at the rear tires-the longest run from the master cylinder-and ending at the driver's wheel -nearest the master cylinder. Opening the bleed valve at each wheel in turn and pumping the brakes will force fluid into the lines and push the air out the bleed valve. When done properly, all the air in the brake lines should be expelled, and the brake pedal returns to it's firm pedal and good braking efficiency.

you must have a lot of air in system. the brakes need bleed to let the air out of system. did you bench bleed the master cylinder before putting it on car ! if not thats why no brakes. to bench bleed a new master cylinder, put it in a vise. fill it full or the proper level of brake fluid. push on the plunger with a dowel or another object. pump it till all air is out of master cylinder, you can tell when no air. it will be all fluid coming out of cylinder. keep checking brake fluid in master cylinder.make sure you push plunger in all the way.when all air is gone replace on car. if you do not loose any fluid from the master cylinder lines, then you can replace it without having air in system. bleed each wheel if needed. good-day!

did you bleed all of the air from the master cylinder before you installed it, this has to be done. also when replacing the master cylinder, all 4 wheel cylinders will have to be bled, in order to get all of the air out of them. while doing the wheel cylinder bleeding , you will have to make sure that the master cylinder doe's not run out of brake fluid, check it each time you bleed a wheel cylinder , add brake fluid to the master cylinder each time or when it is getting low. hope that this has helped you.

you have to keep master cylinder topped up as you bleed brakes
start at the furthest wheel from master cylinder slow pumps on the pedal holding down as your companion opens open bleed nipple'if your doing it yourself open bleed screw and fit small tube over nipple and put tube into small container half filled with brake fluid and just pump pedal yourself goodluck

The brake system bleeding procedure differs for ABS and non-ABS vehicles. The following procedure pertains only to non-ABS vehicles. For details on bleeding ABS equipped vehicles, refer to the ABS procedures later in this section.

WARNING Make sure the master cylinder contains clean DOT 3 brake fluid at all times during the procedure.

1. The master cylinder must be bled first if it is suspected of containing air. Bleed the master cylinder as follows:
   1. Position a container under the master cylinder to catch the brake fluid.
   2. Loosen the left front brake line (front upper port) at the master cylinder and allow the fluid to flow from the front port.
   3. Connect the line and tighten to 24 ft. lbs. (32 Nm).
   4. Have an assistant depress the brake pedal slowly one time and hold it down, while you loosen the front line to expel air from the master cylinder. Tighten the line, then release the brake pedal. Repeat until all air is removed from the master cylinder.
   5. Tighten the brake line to 24 ft. lbs. (32 Nm) when finished.
   6. Repeat these steps for the right front brake line (rear upper port) at the master cylinder.
      

WARNING Do not allow brake fluid to spill on or come in contact with the vehicle' finish, as it will remove the paint. In case of a spill, immediately flush the area with water.

1. If a single line or fitting was the only hydraulic line disconnected, then only the caliper(s) or wheel cylinder(s) affected by that line must be bled. If the master cylinder required bleeding, then all calipers and wheel cylinders must be bled in the proper sequence:
   1. Right rear
   2. Left front
   3. Left rear
   4. Right front
2. Bleed the individual calipers or wheel cylinders as follows:
   1. Place a suitable wrench over the bleeder screw and attach a clear plastic hose over the screw end.
   2. Submerge the other end in a transparent container of brake fluid.
   3. Loosen the bleed screw, then have an assistant apply the brake pedal slowly and hold it down. Close the bleed screw, then release the brake pedal. Repeat the sequence until all air is expelled from the caliper or cylinder.
   4. When finished, tighten the bleed screw to 97 inch lbs. (11 Nm) for the front, or 66 inch lbs. (7.5 Nm) for the rear.
3. Check the pedal for a hard feeling with the engine not running. If the pedal is soft, repeat the bleeding procedure until a firm pedal is obtained.

Fig. 1: Loosen the front brake line in order to bleed the master cylinder

Fig. 2: Connect a bleed hose from the bleed valve on the front caliper to a jar of brake fluid

Fig. 3: Always follow the lettered sequence when bleeding the hydraulic brake system

Hope this helps to solve it; remember to rate this answer.

loosen the front brake line that goes to the master cylinder fill master cylinder up with fluid and bleed it first by attaching a flexible line from master cylinder front brake side submerge that line into jar of brakefluid keeping air from entering line get someone to pump brake pedal while ur holding line in a jar keep refilling the brake resivoir so no air gets in, once the master is bled front brake side then reattach the origional brake line then remove bleed screw from caliper and let fluid gravity flow down to calliper then bleed the normal way. more than likely your master cylinder has air trapped in the front portion good luck