This entry is number 2 in my series on working on motorcycles for mechanical idiots. The title of this installment is "How to install braided stainless steel brake lines on a Suzuki SV650."
I don't know about you, but when I was in high school I kept myself busy with classes like Calculus, Alcoholic American Authors, Physics, European History, and stuff like that. The mechanics classes were strictly for burnouts, male burnouts at that. So now, twenty years later, I retain some useless fragments of information about the War of the Roses, while important life skills like How To Repair My Own Vehicles elude me. (If I had it to do over again, I'd just take all the classes. I hate people who just say "huh?" when the War of the Roses comes up in casual conversation.) In an attempt to remedy this deficiency, I've been working on my own motorcycle whenever I can. I take a long time to do each task, because I'm nervous and unsure. The shop manual for my bike doesn't go into a lot of detail about how things work, exactly. Here I attempt to go into more detail, the kind of detail that can reassure somebody attempting a task for the first time.
All the images are thumbnails. Click on them for larger and more detailed photographs.
Why replace your brake lines with stainless steel braided lines? The squid answer is "because it looks cool", which indeed it does. But the performance answer is, "because it gives you more control over braking." Rubber lines can expand, especially when the fluid in the lines is hot. Remember the ideal gas law? PV = nRT? When temperature increases, either the gas is under more pressure, or it expands to fill a larger volume. And if it can expand, it will. Thus, a rubber brake line expands a bit, robbing you of some braking power. Braided steel brake lines don't expand (well, not much anyway).
I bought my new brake lines from Galfer. There are other brands available, like Goodridge. I did both the front and rear lines. You can skip replacing the rear line if you like: it's a pain to do and the rear brake is pretty unimportant anyway.
The SV650 front brake system has three lines: one from the bar to a splitter that's part of the (what's the word for this?), then one to the left caliper and one to the right. Most aftermarket kits will replace these three lines with simpler two-line system that goes directly from the master cylinder down to the two brake assemblies. Your kit should have those two lines, two short hollow bolts, one longer hollow bolt, and a bunch of washers.
Tools you'll need:
- 8mm wrench
- 10mm socket wrench
- 14mm socket wrench (your new bolts might be a different size)
- torque wrench
- Philips screwdrivers: #3 for removing the tail cover, #2 for everything else
- clear tubing that fits on the bleeder nipples
- glass jar with lid or other container for used brake fluid
- new container of DOT4 brake fluid
- shop rags
- pliers
The SV uses DOT4 brake fluid. DOT3 is compatible with it, but has a lower boiling point and is nastier in a couple of ways. For more information about the various types of brake fluid, read this description. Probably you should just stick with DOT4. Both DOT3 and DOT4 eat paint if left to sit. Use shop rags liberally to protect your bike.
The first thing to do is drain all the brake fluid out of your old brake lines. (For another description of brake bleeding, see Carolyn Boyce's page. Carolyn has some other useful information on bike maintenance.) Steps:
- Remove the cap from the bleeder valve nipple.
- Stick one end of the tubing on the nipple.
- Stick the other end of the tube in the jar.
- With the 8mm wrench, loosen the bleeder valve screw.
- Pump the brake lever (or pedal if you're doing the rear). Watch fluid drain through the tube.
- You can crack open the fluid reservoir to speed up the process.
If you're doing your rear line, you might want to read my description of how to loosen the tail cover. The SV650 shop manual is too terse on this topic to help a mechanical newbie.
My tube and collection jar, with old brake fluid already in it, and a
rag to catch drips. Brake fluid is mostly ethylene glycol. It smells funny.
Here's the tubing attached to my rear brake. Directly below the tube
you can see the old rubber brake line heading off to the right.
The ring fitting on the end of the line is the expensive part. Going
through the head is something called a "banjo bolt". I don't know the
provenance of that term, but the bolt does remind me of a guitar or
banjo tuning peg. It's hollow, so fluid can flow through it. Around it
is a groove with a small hole poking to the inside (like the spot where
the guitar string sticks through the peg). The ring fitting on the end
of the brake line goes over the groove.
Once you've drained most of the fluid out of the lines, loosen the banjo
bolts one by one. (I think this required an 12mm socket wrench. I forgot
to take note of it.) More fluid will drip out when the bolt comes loose,
so have some rags ready to catch the drips.
The other rear banjo was a bit of a pain to reach, particularly if you
have large hands like my husband does. I put the socket on the bolt for
him, then stepped back to take the snapshot. The front ones were very
easy. There's a single bolt up at the lever, two bolts at the splitter
(one long double-banjo, and one shorter normal one), and one bolt at
each brake. The ones at the splitter might be tricky.
The brake lines all run through brackets attached to the bike. The rear bracket is on the rear swingarm; the fronts are on the fork downtubes and also hold side reflectors. I used pliers to pry open the brackets and then clamp them shut again around the new lines.
Now start attaching the new lines. The rear one doesn't present many routing questions: just zip it through the bracket. The fronts are longer. They have to have slack for moments when the forks are extended. I used a few zip ties to keep them in place. Stick each banjo bolt through a ring fitting, with washers as necessary to make the grooves line up. Spin the bolts into their homes. Do not over-torque the bolts. They're hollow and not very strong. Use about 12 foot-pounds of torque on them. If you don't have a torque wrench, why not take this opportunity to pick one up? It'll be handy for other bike jobs.
Here are my new front lines, with shiny new copper washers.
Here you can see my new lines running down past the y-junction used by the
old lines. The top of the left brake line is still attached to the left
side of the splitter. (The front of the bike is to the left of this photo.)
The new front brake lines. You can see the bleeder screws and the
routing brackets clearly.
Here are the brake lines I removed from the bike. The long one is the
rear brake line. The short one goes from the front lever to the
splitter. The other two run from the splitter to each of the front
brakes.
I left replacing the brake fluid until I had all the new lines in place. Open your new can of brake fluid. Don't use an old one or one that's been sitting around open for a while. Try not to get junk in the fluid. Brake fluid is useful because it's not very compressible. When you haul on your brake lever, it pushes on the fluid in the brake line at your handlebar. Because the fluid doesn't compress much, most of that push is transferred down to the pistons in your brake calipers. They push on the brake pads, which rub against your rotors, and thus you come to a nice stop at the stop sign instead of flattening your neighbor's dog. Contaminants in the brake fluid make it more compressible, which makes your brakes feel spongy. The most common contaminant is water, which brake fluid absorbs slowly. Water lowers the boiling point of the fluid. Under a lot of stress, like if you're riding down a steep mountain, the fluid might boil, which would cause brake fade. That wouldn't be good. So you really should replace your brake fluid once a year, like your bike's owners manual says. (For more information on brake fluid, try this article.)
Hook up your tubing to a bleeder valve again. If you're doing a front brake, make sure the other valve is closed up. Open up your brake fluid reservoir and slowly pour the stuff in. Try not to agitate it too much. Air bubbles are your enemy right now. Pour away. Watch the fluid flowing out into your tube-- when it turns clear and clean, you've got all the old stuff out. Pour in enough to get near the high level mark. You'll be pumping fluid all the way through and out, so a little slop is not a problem. Close up the reservoir and cap the can of brake fluid.
Now the tedious part: the actual bleeding. The purpose of this exercise is getting air bubbles out of the line. Air is very compressible. Some air in the line, and you have spongy brakes. A few big bubbles in the line, and you have no brakes at all. So the air has to go. You get rid of it by pumping it through the system and out the bleeder valve. Start with the longer of your two lines, then switch to the shorter one. Steps:
- Close the bleeder valve.
- Pump the lever a bunch.
- Hold the lever to the bar.
- Open the bleeder valve for a moment, and watch air bubbles escape.
- Repeat.
- If the brake fluid level gets low, top it off.
It really helps to have another person around to hold the lever down while you bleed (or vice versa). I used a velcro strap to hold my lever to the bar while I bled. It took a long time before I felt any resistance at the lever at all. Keep at it! I hear that products like SpeedBleeders and Mity-Vac speed up the process, but I have no experience with them. (I'll probably check out the SpeedBleeders.)
Eventually you'll start to feel some resistance, then a lot of resistance, and then a nice hard brake. Clean up your tools and wash any brake fluid off of spots where it might have dripped. (It dribbled all over the outside of my brakes, no matter what I did.) Do a sanity check: walk your bike on a level surface and squeeze the brake. Did the pistons push? Did your bike stop? Good! If not, you probably need to bleed some more.
On the 1999-2001 SV650s, the rear brake fluid reservoir is underneath the rear seat. It's unfortunately badly positioned. To open the top, you have to loosen the tail cover and partially remove it. You don't need to take it all the way off, but it's almost as much work as removing it would be. First, take off both seats. Then start in on the tail cover. There were six places with fasteners you need to remove. Here are the spots:
There are actually four spots for bolts visible in this photograph. See
the big rubber bumpers? My husband has a screwdriver stuck into one of
them. There's a bolt in each one of them that needs to come out. Use a
large Philips-head screwdriver.
The bolts that hold the grab rail also fasten the seat cover to the
bike.
It took us a while to find these screws. There's one on each side underneath
the tail.
I also found it handy to remove the two screws that hold the left
and right pieces of the tail cover together. This made it easier
to pull the right side out and expose the brake fluid reservoir.
If you're taking the cover all the way off, you'll also need to disconnect
the seat lock cable.
Finally you can take the top off the rear brake fluid reservoir.