how do i replace the maser cylinder on a 1995 GMC Sierra
What cylinder? Master (brake) cylinder? Rear Brake cylinder? Lock cylinder?
At least the slave cylinder. The clutch master cylinder can be replaced at any time.
Replacing the master cylinder on any year celebrity is about the same as replacing a master cylinder on most any other vehicle. Use a flare nut wrench to remove the brake lines, put plugs in the lines to keep dirt out. Unplug the electrical connector if there is one. Remove the nuts that hold the master cylinder in place. Remove the master cylinder. Follow any manufacturers instructions on bleeding the replacement master cylinder as required. Bolt the new master cylinder in place, reconnect the brake lines and electrical connector. Bleed the individual wheel cylinders and calipers to insure there is no air in the system. Be sure to maintain the brake fluid level in the master cylinder while bleeding the brakes.
No, not unless there is a problem with the valve which is rare.
The clutch parts that wear out would be the clutch master cylinder and the clutch slave cylinder. Replacing the clutch master cylinder requires disconnecting the hydraulic line, unbolting and removing the master from the vehicle, bench bleeding the new master, install the new master then bleeding the system. Replacing the clutch slave cylinder requires removing the transmission assembly. I would recommend purchasing a shop repair manual for that vehicle if you want to DIY.
Normally it means the master cylinder has failed and needs replacing. It can also be a leak in the system or the master cylinder is extremely low of brake fluid.
Get your new master cylinder from the parts store and it should have instructions with it.
There was no Caprice in 2004...
On top of the brake master cylinder
There is still no fluid pressure. Make sure that the master cylinder was bled as well as the wheel cylinders. New master cylinders can be tough to bleed all of the air out. The new master could be defective.
Bench bleed it to avoid introducing air into the system.
you forgot to plug in the brake fluid sensor.