First, I bled the brakes down below —
the calipers. That’s something I forgot to record for you. Then, started undoing the screws
on the master cylinder. Then I covered the motorcycle to protect the paint
from any brake fluid that might remain. I might’ve gotten a little carried away
here. Heh! Shhh, don’t tell! Sometimes, it’s a little sticky so you have to pry it up. Then you remove the brake lever. Don’t forget there’s a return spring in there.
You don’t want to lose that. Pull the boot off the banjo bolt. Pay attention to what angle that bolt is. And, hopefully, you’re replacing
the original brake lines there with steel braided ones.
You’ll want to remember what angle those attachments go back on. I struggled with this one,
’til I looked online and found out there’s a hole under here, that you push up on somehow. And that is supposed to make it possible… Oh! There it is. Alright. That’s what you’re pressing up on. And, start taking off the rest of the
master cylinder. I wanna pause the video here for a moment, just
to point out: This is a good time to probably disconnect the master
cylinder, that wire, from the headlight assembly. That way, you can take it inside,
work on it, and not risk dropping things because it’s awkward and
attached to the bike, still. Not something that dawned on me, until after. C-clamp comes out. Set it aside. Now you can pull the float. Next you unscrew the bolt holding down
the sensor. Push it up to move it out. It can be stuck because of an o-ring in
there that’s seized up. Removing this switch turned out
to be one of the biggest annoyances. Let it soak for a little while. Some liquid wrench. and then tried pushing it out with my fingers… Tweezers. Tried pushing it out with a
screwdriver. Maybe a crowbar. A winch. Tried pushing it out with pliers. Tire iron. Squirted some more. More pliers. Jack hammer, if I recall. A wrench. maybe ratchet straps? My teeth. Don’t even know what I used there. I considered a torch. and more! and finally… this seemed to work. Two… hours… later…. It’s out! This is what I should have done before
taking parts out of the master cylinder. Disconnect the wire. I want ahead and got some tape
at a point you didn’t see on camera and marked a few of these so I
knew what they were. Pulled the plug. Be really gentle — these are
30-year-old plastic plugs. It’s not fun to break one of those
and have to replace it. There you go! See? I could have done all that other stuff inside Start pulling it all apart. ewww. Well, that’s what’s left of that. Holy hell. hehe. Right side mirror is a reverse-threaded.
Safety feature for an accident. I laid down some paper just so I could
see the parts, they’re small. and when you’re undoing everything
out of the master cylinder, put them down in order so you can see what order they go back in. That… went that way. Be careful with the spring. You don’t want it to fly across the room. Okay, don’t do it that way! hehehe. At least put your finger on the end of
it so you don’t look like a fool like I just did. Alright. That goes there. Oh nice! So that wasn’t
gonna last much longer. After a little bit of effort, you can see
I finally got it out. Very carefully. Used a few tools to scrape and a few tools to
pop — so I wasn’t scraping along the edge and the little metal piece popped out. Again, these come in handy. And there you go! I’ll clean that up
and on to the next thing. Since I didn’t video it, I wanna take a moment to
remind you, when cleaning the master cylinder, to make sure you get the small holes
in the bottom or you’ll have issues. This is not the same master cylinder.
This is off an, I think, an ’85 junkyard Virago. You can see it doesn’t have the low fluid sensor
hole. But, just to give you the idea. The holes in the bottom need to be cleaned out. So, when I took this apart, I found that
there was a little bit of pitting in there and you probably can’t see it, not
enough light. But it’s far enough back that it probably won’t be in the sweep of
the piston but, just in case, I went ahead and honed it slightly to clean it up.
Made my own. Two attempts. I tried this way first. That’s a smaller than 5/8 — that’s
the bore — dowel, that I put a little bit of two-sided mounting tape on and some 1500
grit sandpaper. That almost worked but it seemed a little bit small, so I went
ahead and used a 5/8 size, since it’s the same size. Sanded it down, smoothed it out
and cut a groove in it. And, with that groove, I can slot in some sandpaper. Add
WD-40 and sanded around I went clockwise. I don’t know if that
matters but that’s what I did. And, cleaned it up. We’ll hope that’ll work.
Otherwise, I’m blowing five hundred bucks or so on a whole new master cylinder. Here, I’m putting in the new sight glass First, you put a little bit of the black
adhesive. Of course, before all of this you hopefully have cleaned everything
out. No grease, no brake fluid, no anything. And it’s clean and smooth down
to the metal. No old glue in there or anything. And be careful when you sand it down.
You want to use really fine sandpaper. Twenty seconds or so. Next, I took some of the gasket
sealer and dabbed it around carefully. Pressed it in, no gaps. Probably safer
with a toothpick, just in case. But, I did fine with this. And you go around the outside.
Clean it up as best you can as you go along. And then, you’ll also want
to do the inside — if you can get to it. And once you’ve pressed all of that in
there to cover up any possible leaks, you can use something to clean off the
sight glass. Turpentine, whatever. I’m an artist, so I happen to have linseed oil nearby
and that’s what I use to clean it up with a q-tip. Maybe check the inside as well. There you have it. Let that set for a while before moving on. What I’m working with here is a master
rebuild kit from And it’s probably the best place to get any of
these replacement parts for our old XJs. There’s other sites out there you
can get it. But, odds are, you’ll get the wrong parts, or they won’t fit right.
Len, at XJ4Ever, has put the effort in to make sure that you’re getting
the correct things. Drop them a line, via email and he’ll set you up, give you a quote and you just pay through PayPal. Simple as that. In fact, just to help, I’ll leave
a link for his site down below. And here, I’ve been putting in new
o-rings for that sensor. That comes in the full rebuild kit. There’s a new screw to put it on
and, of course, washer — lock washer. In goes the float. And new e-clip. Man, them pliers have been really handy. Hopefully You didn’t skimp on getting a gasket for the lid, cover. and probably good idea to get some new screws too. Time to put it back on the bike! Reconnect. I won’t go into it in this video, but hopefully
you’re not using the original brake lines. You can see the date they were put on,
right on the rubber hose. I, uh… this bike was 1982 original brake
lines. These are some nice steel ones. Make sure you get new crush washers. And, as I said earlier, make sure that
when you put them back on that the angle of that banjo bolt there
is at the same angle. Also, make sure that the holes in the union bolt line up so fluid can
flow. Use new crush washers. They’re a soft
metal and really one-time use. Tighten everything down, per the manual. Fill it with fluid. Check for leaks. Bleed the brakes. Take it for a cautious test drive. And, there you have it.

XJ750J Master Cylinder Rebuild
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