Master Cylinder Removal - F-Body Online

RamAirThree · 01-23-2007, 10:06 PM

To remove the master cylinder all you have to do is empty out any brake fluid in the front and back reservoirs of the unit. Some people, even myself use a turkey baster to do this for a cleaner job. You want to make sure that AT NO TIME, and I stress AT NO TIME get any brake fluid on your paint job! Brake fluid works well for a paint remover so be careful. Next, remove the front and rear brake lines from the unit making sure that you don't bend or twist the lines. I used a 9/16 open ended line wrench for this. Next, remove the 2 mounting bolts that holds the unit on the power brake booster. Now when you remove these 2 bolts, you will also notice that there is a bracket attached here that also holds the combination valve in place. Remove this and the unit slides right off. So now you are almost ready to install your new master cylinder but first you must bench bleed the new unit in order to remove any and all air from the unit. Typically, new units come with a simple kit to do this. There are 2 red plastic valves that screw into the front and rear brake line holes. Then attach the plastic tubes to them and run them up to empty into the front and rear reservoirs respectively. The kit also comes with a handy clip to hold these tubes into place. Make sure you fill the reservoirs with enough brake fluid to do the job. You need to run the ends of the tubes below the level of the fluid so that you don't suck air back in when you release. Clamp the new unit by the mounting bracket and NOT by the body of the unit. Clamp it in place and use a large Phillips screwdriver to slowly push the plunger in to circulate the fluid throught the master cylinder. This takes quite a few times to do this and you want to make sure all of the air is out of the unit. I did it about 20 times or so. Once you have successfully removed all of the air from the unit, place the caps back on the plastic fittings and mount the unit back in the car making sure that you also put the combination valve bracket back into place. Now that you have it mounted, go ahead and remove the plastic fittings one at a time and re-attach the front and rear brake lines again. Now you have to bleed the whole brake system to remove all of the air from the lines that may have entered the system when you made this change. You are now done.

Tips:

When bleeding entire brake system at the end it is best to start with the wheel furthest from the master cylinder (right rear or passanger rear) and finish with the closest wheel to the master cylinder (left front or drivers front ).

Bleeding order:

1.Right rear
2.Left rear
3.Right front
4.Left front

When removing front and rear lines from master cylinder, it is always helpful to tap the nuts lightly but firmly to disturb any rust and dried grime in the threads as to help avoid stripping the nuts due to being siezed up.

Picture 1 shows a typical looking Master Brake Cylinder and components.

Picture 2 shows a picture of bench bleeding a Master Brake Cylinder.

Picture 3 shows where the Master Brake Cylinder meets the Power Brake Booster.

19Stroked89 · 01-24-2007, 05:19 AM

Great article Lou!!

Korndogg · 01-24-2007, 04:55 PM

great post!

Rocket 442 · 01-24-2007, 05:13 PM

Very nice post. +rep for you

RamAirThree · 01-24-2007, 05:22 PM

Thank you guys........