I purchase a brake master cylinder repair kit and I received it but didn't have instructions included. Does anyone have the instructions they can share? Thanks.

 

I don't know that I've ever seen a instruction sheet with a master cylinder. I certainly don't want to sound bad about it, but I can only imagine that the people who make the kits presume you have the knowledge, experience?, to replace seals correctly. For me, on the master cylinders I've rebuilt, I disassemble, clean, look carefully at the seals as they are installed, and then install the new one in the same way as the old ones. I use brake fluid as the seal lubricant in reassembly. Usually not a very difficult job, even though I've not ever rebuilt a XJS master cylinder...

 

Without instructions or much help I went ahead and decided to take the master cylinder apart. I laid all the pieces out in the order the came out. Lined up the new parts and put it all back together in the reverse order. One thing I learned by trial and error is that the small pin that goes on the first section with the spring if not placed in the correct place by compressing the first section, then the pin, the second section won't go in all the way. I added break fluid and blead the air as I put it together. BE CAREFUL! The fluid SHOOTS OUT as you bleed the air out. I now have a wall stained with break fluid.

 

pretty much what has been said. Get a hose and run it on your fender or try to place a plastic bag and lots of stuff to clean up with when you disconnect the hoses, don't want to damage your paint.

Drain or clamp off the hoses from the reservoir and unbolt the master cylinder. Pull everything out and put it back in. The seals face specific directions and they MUST face the proper way or it won't work. The plastic things on the top can be a bit of a pain to remove.

Most kits I have ever bought come with a small piece of paper showing the seal directions, it is pretty much the same on every dual master cylinder.

Try to bench bleed the master to get all the air out of it before re-installation. Use brake fluid as assembly lube for everything.

I've never messed one up. The first two times I rebuilt master cylinders I didn't even understand how they worked, I just took them apart and copied the way they were assembled and they worked perfectly.

If you do understand how they work you can't really mess the assembly up since there is only one direction the seals can go to operate properly.

If you are more visual, a rebuild video of nearly any master cylinder will be the same process with a few differences, like the top pieces and what type of clip holds it all in.


If you think you messed something up, just post and we can help you get it sorted out. Try removing and replacing seals one at a time and taking phone pics (be careful with the brake fluid!) so you have less to keep up with