What causes the Pistons to stick on a master cylinder?
When a master cylinder is assembled, the seals and cylinder bore are lubricated for a positive seal. This combined with air trapped in the system can cause a vacuum lock in the cylinder, causing the pistons to stick.
Why is the master cylinder not resting against the snap ring?
You will notice that the master cylinder piston is not resting against the snap ring, figure 3. Occasionally connecting a pressure bleeder and opening wheel bleeder screws will cause the piston to return. You can also tap lightly on the housing, with the bleeders open, to free the piston.
Why is there no pedal on my new master cylinder?
No Pedal with New Master Cylinder Installation – Quick Fix or Check? A “no brake pedal” condition can be encountered after a new master cylinder is installed, leading the technician to believe that the master cylinder is defective.
Why does my brake pedal stick when bled?
When the system is manually bled, the pedal is often depressed completely, moving the primary and secondary pistons to their extreme forward position (figure 2). The primary piston can stick even though there are springs attempting to push it back in position.
Where is the bleeder valve on the master cylinder?
On models so equipped, begin at one of the bleeder valves on the master cylinder. On models where the master cylinder has no bleeder valves, begin at the load sensing valve attached to the right frame rail, in front of the fuel tank. After bleeding the sensing valve, bleed the rest of the brake system. ragenasian July 5, 2016, 7:31pm #14
No Pedal with New Master Cylinder Installation – Quick Fix or Check? A “no brake pedal” condition can be encountered after a new master cylinder is installed, leading the technician to believe that the master cylinder is defective.
When the system is manually bled, the pedal is often depressed completely, moving the primary and secondary pistons to their extreme forward position (figure 2). The primary piston can stick even though there are springs attempting to push it back in position.
When a master cylinder is assembled, the seals and cylinder bore are lubricated for a positive seal. This combined with air trapped in the system can cause a vacuum lock in the cylinder, causing the pistons to stick.