Brake master cylinder removal

I had planned on tackling the remainder of the brake lines/hoses before giving the master cylinder a shot, but a combination of my attempts at tinkering, plus my having neighbor Frank come by to get some advice from him regarding some of the brake line nuts equalled the pair of us going to town on this part.

Here's the brake master cylinder. It's left of the engine, mounted onto the subframe with a pair of bolts on the forward end, and a bolt/cotter pin holding the rear end of the piston rod.

Forward end of the master cylinder, from below. Six lines enter in on this end - brake fluid reservoir, two to the filter, one for each front wheel, and one line snaking to the rear of the car, where there is a junction to feed fluid to the rear wheels.

Rear of the master cylinder.

The reservoir line nut came away with little fuss, but when I pulled the nut away, it was obvious there was still a lot of brake fluid in the master cylinder.

Fortunately I had not removed any other lines at this point, so I had a cunning plan... to prop my fluid pan up above the brake filter lines, bend the lines over a bit, and then to climb inside the passenger area and slowly depress the brake pedal. Out came the fluid!

A couple of minutes of careful pumping of the brake pedal and the remaining fluid (the vast majority, at least) is out.

Next order of business were the brake fluid lines. These came away with a bit more difficulty.

The three remaining lines - front brake lines and the line to the rear brakes - not so much. One of them did come off early, but the remaining pair simply would not budge. Every tool I tried to gain purchase on these nuts simply slipped. It was at this point I brought Frank over for a consultation, and he suggested simply cutting the lines off at the nuts. Fine by me, I said, as my intention was to go with new lines anyhow during the rebuild process. So we break out a cutting tool. Those lines didn't stand a chance!

Getting that cotter pin out from the back end was a fun task, considering the position and the semi-closed quarters. The piston rod slid right on out once the collar bolt was removed.

Next task, we thought, was to get the main body of the cylinder out. Frank and I double-team the pair of bolts holding the body of the unit to the subframe. These take a few minutes, with Frank below and me above, having to reach over and down into the engine compartment with the car up on jackstands - not the most comfortable position with the edge of the body digging into one's chest. But, the bolts/nuts surrendered in time.

At this point we realized our folly. The two brake line nuts from earlier, the ones that we cut the lines off of? The cylinder is not going to fit out of the hole with those nuts and line remnants remaining. So we cut off the remaining bits of line, down to the nuts. Still no go. I'm about certain that we're going to need to remount the pair of bolts/nuts to give the cylinder body enough stability in order to get the brake line nuts off - but no, now that the lines have been trimmed off enough to allow a socket onto the end of the line nuts, the socket gets the grip that I was unable to get before. I hold the cylinder steady within the mounting hole while Frank pops those suckers off pretty quickly and easily. Phew.

And now, the cylinder body passes out of the mounting hole easily, though there's still a little trick to twisting it out. I expect I'll end up tearing this part down and doing a cleanup and rebuild. The boot to the rear of the body looks like it's in good shape and may be reuseable, we'll see.