Front brake dragging

[JeremyL]

I thought I had my brake problem fixed last night and was in a great mood but apparently I've not completely fixed it. The front/right side was dragging. Not bad enough to overheat or anything but bad enough so that pushing the bike around in a parking lot was a pain and backing up had me straining. I flushed all the fluid, cleaned the MC, made sure the spooge hole was clear, and removed the pads and greased them and checked all the mounting hardware. This is a Special btw.

Well it didn't help a whole lot and then I noticed the brake lever adjustment wasn't set right so there wasn't any play in the lever... even at rest the lever was touching the MC a little bit. So I backed it off and it helped so I thought I had it fixed. Checked again this morning and it is definitely rolling easier but I took a screw driver and just barely pryed on the the edge of the front/right pad (the one against the caliper) where the lip is exposed and it moved. Didnt' move enough where I could even see that it moved but I could tell that it went from being unmovable by hand to being able to jiggle it a little so I knew it wasn't pretty against the pad. Then I pushed the bike back and forth and it a pretty good difference as far as how easy the bike rolls. But as soon as I squeezed the brakes again it went back to dragging a little.

So what do I check now? Take the caliper apart and clean it and check it out? I searched the forum for a step by step thing so I'd know what to expect going in and didn't find anything but how to assemble the caliper and pads, not actually taking the caliper apart. The other side doesn't stick so I'm only worried about this one side.

[XS1100 Newbie]

Did you take your caliper apart, and take the sealing ring out and clean the groove good? You need to clean that caliper good inside, and make real sure that the caliper mounting bolt is not bent, even a little.

[JeremyL]

Did you take your caliper apart, and take the sealing ring out and clean the groove good? You need to clean that caliper good inside, and make real sure that the caliper mounting bolt is not bent, even a little.

Nope, that's the thing I didn't do. Maybe I'm making into a harder job that it really is but I was hoping there was a little write up or something that I'm not finding that tells more about it. I have taken a caliper apart and cleaned it 10 years ago on a CB750 but wasn't sure if there was anything special to do on these bikes. Since the other side is ok I thought I could use the MC pressure to push the piston out but wasn't sure what to look for and clean (or make sure parts/seals/gaskets weren't missing).

[DGXSER]

For you, caliper disassembly will be fairly simple, since your brakes still move when you squeeze the lever.

You need to get the piston out of the caliper. Here is the process I use. Only work on one caliper at a time, the other stays on the bike with the brake disc in place. Remove the master cylinder cover and watch the brake fluid level so you do not go dry in the master cylinder reservoir.

Step 1 - loosen the banjo bolt, then snug it up so it does not drip. Loosen the bleed valve and tighten it. Just easier to torque on these when the caliper is mounted.

Step 2 - remove the caliper from the bike. and then remove the clip and the dust cover.

Step 3 - place a rag round the piston area to catch brake fluid when the piston pops out. And have a piece of rubber and a small squeeze clamp handy.

Step 4 - squeeze the brake lever and watch the piston slowly push out of the caliper, keep adding fluid to the master cylinder as you go and it will push it all the way out.

Step 5 - Once the piston is out, remove the banjo bolt holding the line to the caliper and wrap the banjo fitting with the rubber using the squeeze clamp to hold it in place to keep the master cylinder from draining out the open line.

Step 6 - Remove the seal inside the caliper. Now clean...clean...and clean. Make sure you get ALL...ALL...ALL of the crud out of that slot in the caliper where the seal sits. Get the crud off the seal and inspect if it is cracking. No cracks, you can typically reuse them. Clean the piston, inspect for pitting, very minor pitting or no pitting you can clean it up and reuse it, any more and you may need to polish it a bit or replace it. Same cleaning for inside the caliper where the piston rides.

Step 7 - Keeping the clamp good and tight on the open line, repeat steps 1 through 4 on the other caliper. Then repeat step 6 on the second caliper.

Step 8 - remove the brake lines all the way up to the master cylinder. Remove the master cylinder, and empty the cruddy fluid from it.

Step 9 - I use brake cleaner to spray into and thoroughly clean out the brake lines. Also disassemble the master cylinder and clean it similar to the caliper. Pay attention to the order of the parts, and which direction the cups on the seals is facing. There are lots of places on the site that show the spooge hole, I use a wire from a wire brush to clean those out.

Step 10 - put it all back together, and begin the joy of brake system bleeding. Start by "bench bleeding" the master cylinder. To do this, remove the brake line from the end of the master cylinder, hold your thumb over the hole good and tight. Now with brake fluid in the reservoir, squeeze the lever until it pushes your thumb off the hole. When you thumb gets pushed off, you will get either a puff of air, or a squirt of brake fluid. If its air keep repeating till it is brake fluid. When you get fluid, put your thumb back on and hold it till you get the banjo and washers arranged on the brake line and install the brake line. Now bleed one caliper at a time, squeeze the brake lever (but not ALL the way to the bars, stop when it is about 1/2" or so from the grip). Squeeze several times, and then holding the lever squeezed in, open the bleed valve and close it back before you release the lever. Repeat till only fluid comes out the bleeder. Now repeat on the other side. Then check both sides one more time.

Step 11 - If step 10 gave you some braking, but not a good firm lever, pull the elver back to within that 1/2", bungee it squeezed in like that with the wheel turned all the way to the left so the MC is at the highest point. And leave it sit that way overnight. In the morning, release the lever and it will likely be much better.

Now, if for some reason your caliper is stuck or you lose pressure at the MC and it will not push the piston out, there are a couple options.

A - if you have compressed air, remove the banjo and the caliper from the bike. Shove a good thick rag between the piston and the "legs" of the caliper and KEEP YOUR HANDS AWAY FROM THE PISTON!!! Use a piece of rubber for a good seal and put your air blow gun in the banjo fitting tightly, now shoot the compressed air in and the piston will come out like a ROCKET!! The rag will catch it, but it would break your fingers!

B - A little safer, but a little messier, instead of air, put a regular bolt n the banjo bolt threads to seal it, and put a grease gun on the opened bleeder valve and push grease in until the piston pops out.

Hope that helps you with a method to complete the task.

[JeremyL]

Thank you! That's awesome. And I'm glad you put the tip in about the banjo bolt and bleeder valve. It makes perfect sense but its one of those things I may not have thought about until the caliper was already off the bike and I was having to fight with it... like loosening lug nuts on a car rim while its still on the ground.

I'll pull the caliper soon and hopefully this will take care of the dragging. Maybe then I won't tear my guts out just trying to push the bike backwards out of a parking space.

[JerseyJon]

Great tech tip

Don,

That was a great and useful tech tip on brake cleaning. Thanks.

Jon

[DGXSER]

Your Welcome, A couple points to clarify.

First, the tip on not pulling the lever all the way to the grip applies at all times. Not had it happen to me, but it can cause the seal in the master cylinder to invert.

Second, when bleeding, I always put my wrench on the bleeder, then put a piece of tight fitting hose over the bleeder nipple, let the hose go up just a bit then drop it into a small bottle of brake fluid just enough fluid 1/4" or so of the hose is in it. Creates a pocket of fluid on the bleeder nipple so it will only draw fluid and not air back in if you mess up on tightening the bleeder before you release the lever.

[crazy steve]

Here's a pictorial on rebuilding calipers....

http://www.xs11.com/forum/showthread.php?t=39657

This is showing 'standard' calipers, but the same procedure works for the Special calipers, there's only slight differences in the caliper. The Special calipers do require 'special' care when reinstalling them on the bike, look here:

http://www.xs11.com/forum/showthread.php?t=37207

A lot of 'dragging brakes' on the Specials will be caused by the calipers not being aligned right or not being able to pivot freely on that sleeve, so make sure you follow this tip.