How to : Clean your brake caliper(s)

[S21FOLGORE]

I was originally going to include this in "How to : Keep your Monster clean" article.

But, maybe it deserves its own thread. So, here we go ...

Things you will need

Cleaning stuff



Okay, what do we have here ...
Dawn (dish washing soap from the kitchen), water in spray bottle, diluted Dawn in sauce dispenser bottle,
Brake cleaner (DO NOT spray brake cleaner  / parts cleaner onto calipers. Repeated use of these harsh chemical will damage the seals. This is for cleaning pad pins, clips, etc AFTER they are removed from the caliper.) , tooth brush(es),
Permatex disc brake lube (NOT regular grease), Copper grease (anti-seize compound) , and spray polisher / cleaner.

Tools



Socket and ratchet handle ,also torque wrench for caliper retaining bolts, needle nose pliers for pad pins and clips,
small piece of wood, file, caliper piston tool.

I forgot to take photos, but you will also need eye protection, gloves, bucket and paper towels.

Now, put the bike up on the stand, and ...

1) Caliper removal



Undo two caliper retaining screws. Remove the caliper from the fork bottom. Do one caliper at a time. Never try to do both side at the same time.



Look inside. Dirty, but not extremely dirty. ('cause I clean the caliper every once in a while. If you have never cleaned before and kept on riding for years, it would look a lot worse.)

Quick glance at this stage tells me I don't have problem here.

1)Pad wear is even. Both sides pad material have the same thickness.
2)There's no angle to wear front to back

Uneven wear / angled wear is the sign of sticking piston(s) and / or front wheel not aligned properly.

4)Looks dry
Meaning there's no fluid leak here.

... remove the clip ...



... remove the pad pin ...
(I forgot to tell you, you will need  a bungee cord to hang the caliper.)




be careful, when you pull out the second pin, pads will fall off ...



Keep the pads the way they came out. (so that you can put them back into the same position. Out side pads go back to outside. Inside pad goes back to inside.)

2) Washing

Now it's time for fun. Wear eye protection and gloves. Get a tooth brush and soapy water, and ...



... scrub ...



... scrub ... what you really want to clean is the side of the pistons, so ...

... use this tool, ...



... rotate the piston ...




... attack the side of the piston ...



when you are satisfied, rinse off with water.

Now, ...

3)Check the movement of the pistons

... hold the caliper in hand, while looking at the pistons, gently squeeze the brake lever.The piston(s) should come out from the caliper body. But do all of them come out at the same rate ?
If you have never cleaned the caliper before, you may have one or more stuck piston(s). So, you may actually have 2-pot or 3-pot calipers ...

If you happen to have stuck piston(s),
push back the piston(s) that are moving freely, and use spacer (or use cable tie through pad pin hole) to hold the free-moving piston(s) in place, then squeeze brake lever gently. The offending item should come out. Clean the side of that piston, push it back. Repeat until that piston starts moving freely.



You want all the pistons coming out at the same time, AND retract at the same time.



(All four pistons retracting at the same time is important. If your brake makes farting noise, it could be because of this.)

4)re-install everything



Always clean the thread of the screws. Apply copper grease.
Always clean and check the condition of the pad pin. IF they got groove, or corroded, replace them. Apply thin coat of disc brake lube (or, nothing. If you don't feel like it.)

The pads go back to where it came from. Outside pad goes to outside. Inside pad goes to inside.

If your brake is making noise, you can try chamfer  the leading edge with hand file.





Follow the torque setting of the service manual.



Double check everything (hey, you're working on the brake, you know ...)
Is everything Okay ? Then, move onto the other side.

When you are done with other side,
1)check air gap in reservoir.
2)check if the wheels spins freely.
3)pump the brake lever till you have full pressure. Spin the wheel and make sure it stops right away.





That's it ! Now, your front brake should give you a lot better "feel" !

[Dellikose]

Great write up!

Pay special attention when trying to free a stuck piston. They move surprisingly fast when the others are blocked. You'll loose a good deal of fluid if the piston comes out of the bore (personal experience).

[Slide Panda]

Another nice write up.

Where'd you source the caliper piston tool? - A quick search on that phrase got me a lot of tools, but nothing quite like that one.

[S21FOLGORE]

Here's one ... $26.96
http://stores.sportbiketrackgear.com/Detail.bok?no=17823

Another ...(I bought mine from here) $18.85 right now
http://japan.webike.net/products/20018149.html

Nothing wrong with STG, but japan.webike.net is cheaper, and the shipping is faster (despite the fact that it has to come from the other side of the planet !)

[ChrisK]

Anyone have any other tips for freeing stuck pistons? Mine were/are gummed up real bad and it seems that no amount of scrubbing them I do and working them in and out, I still can't get all four pistons to move at the same rate.

[Slide Panda]

Have you removed them from the caliper?

You may need to. It's a pain, but allows for more inspection.

- Remove the caliper from the bike
- Put a thinnish wood strip in the area the rotor would normally occupy. A paint stirrer or two is perfect for this task.
- Use compressed air to *gently* blow into the brake fluid inlet. Start easy on this and gradually up the pressure. If you blast it with too much air too fast the pistons come flying out of the caliper body. You're just trying to ease them out. The wood is there in case you're too heavy handed - it'll protect the pistons from them marring each other in the event the pistons come out with too much gusto

Once they are free you can clean the whole piston and seals.

- When putting the pistons back in, be sure to give them a dose of brake fluid on the sides as a lubricant.

[ChrisK]

Interesting, so basically drain out all the brake fluid and remove the brake line from the caliper, then blow compressed air through that? There's no risk of ruining the seals or anything? I was kind of under the impression that once those pistons are in the seals, you really don't want to mess around with taking them out.

[seanster]

Interesting, so basically drain out all the brake fluid and remove the brake line from the caliper, then blow compressed air through that? There's no risk of ruining the seals or anything? I was kind of under the impression that once those pistons are in the seals, you really don't want to mess around with taking them out.

I think he meant that you trying to push the pistons out without completely out of the caliper body...far enough for you to clean the side of the pistons.

that piston rotating tool is a must have should have.

you don't have to disconnect the brake line to do this...I did this: all mentioned in the OP

1. put a few of those paint stir sticks from home depot between the pistons
2. pump the brake lever to push the piston out
3. gently clean the side of the piston.  do two at a time (top two piston or bottom two piston)

Use warm soapy water....do not use the brake cleaner bottle, those can damage your seal (I learn the hard way).