Info needed: M38A1 vent tube

[rob love]

Master cylinder isn't terrible, but it is a little tight working in that location. Remove the vent line (if it even still has one...most of them are long gone). Remove the banjo bolt at the back of the master cylinder (if memory serves the brake light switch is on the banjo bolt, so remove the wires from it before turning the bolt), then remove the two 3/8 bolts that go thru the master cylinder with a 9/16th wrench and you should be able to slide it away from the brake pedal. A ratchet wrench will be worth it's weight in gold for that last pair of bolts.

Leave the pushrod alone even though you may get a new one with the new master cylinder.

By this time you should be wearing a little brake fluid along with whatever crud the jeep has been into for the past decade. Put the new master in place in reverse order of removal, with the new boot attached to the rod. Check for freeplay at the pedal (you should have something....even a 1/4" will be enough, 1/2" will be ideal). Fill the master cylinder and bleed the brakes. While bleeding, or when the cylinder is empty, be careful not to bottom the brake pedal into the cylinder or you can damage the rubber cups.

If you have the vent line, great, reinstall it. If you don't, you cannot merely plug the vent hole. You can install a breather of some form, or your new master cylinder cap may be the type with the little vent holes built in. Not ideal if you ever want to drive through deep water, but OK for everyday use.

Master cylinders are cheap. Napa part no 2796 is a little pricey at 151.28 retail or 92.99 trade



however rock auto in the US has CENTRIC 13063003 for $38.13 CDN each.