Help! Rear Brake Pad Replacement

[pais]

Should/will rear caliper come off for rear pad replacement?

[0leman]

You don't need to take the caliper off to replace the pads.  I just replace the pads on mine while rear end was all together. 

Look a the right side of the caliper, there is a screw/plug, has a regular slotted screw head.  This is a plug.  remove it, then you need a metric hex head wrench or socket, not sure now but think it as a 3 or 4.  remove the bolt. This will allow you to pull the pads out.  Watch how the spring clip is sitting in case it falls out.  I used a screw driver to put the brake pistons back in to make room for the new pads.  You may have to remove the cover of the reservoir to allow you to push the pistons in. New pads slip in, make sure the spring clip is still in position, put the bolt back in.  Some use anti-size on this bolt.  then the plug.  should be good to go. 

Some folks do remove the caliper to do this.  They want to clean up the pistons before putting in new pads.   Not a bad idea.  I did it the last time I put on new pads.

[hubcapsc]

I do just this much to get the caliper off... some people take the caliper
off the mounting plate, I like to remove the whole mounting plate, which
requires pulling the axle out some...



-Mike "I'm one of those always-clean-the-pistons people :-) "

[pais]

  Well as usual, a 30 minute job has turned into a project. This is the way I roll! I took the caliper off the the mounting plate because I was hell bent on cleaning the entire caliper and pistons.
  I started by pulling out #11 and before deciding to take off entire caliper. I destroyed #11 trying to re-install.
  When I tried to remove caliper by removing #12. I found out #12 was rounded and 12mm wrench would not fit nor would any ASE wrench  . I'm guessing PO had it out at one time. As hard as it turned out, I am worried he cross threaded it into the aluminum mounting plate.
  Now that I have caliper off, pistons seem to have some scuffs that I could not get off/clean. Soooo, I decided to order #'s 11, 12, 1 and 9. Figured I may as well rebuild while I have off.
  Big concern now is, 1 piston pushed out and the other is still in caliper about half way out  . I'm guessing that 2nd piston is gonna be a pain to get out?

[hubcapsc]

Big concern now is, 1 piston pushed out and the other is still in caliper about half way out  Undecided. I'm guessing that 2nd piston is gonna be a pain to get out?

Moosh the one that came out back in, and put a 1-by (board) or something similar
in there... where the rotor would be... use compressed air to pop them both out...
The one that came out before will probably pop right out, but it will be stopped
cold by the board (or whatever), and it will effectively plug its bore... continued
application of compressed air will probably pop the other piston loose...

Better (I've done this a couple of times now)... if you haven't bled the hydraulics yet,
you can skip the air and just mash the brake pedal (or pull the lever) to make both
pistons pop out to the board.

-Mike

[Earl43P]

Once the pistons are pushed out, (I use a brake pad)
use a deep well socket that closely fits in the piston bore, and wiggle them right out.
At that point, I polish the pistons bright with 600, then 1000 grit.
I chuck a firearm bronze borebrush into a variable speed drill to clean up the seals channels.
Fill caliper with fluid before remounting.
Bleed at the caliper banjo 1st thing!

[pais]

    Parts showed up Thursday(yesterday), I will work on it Saturday. I have not removed caliper from brake line yet. I can see it will be easier if I do that.
    I will put the one that came out back in and use the board/pad/air trick. My big concern is getting #'s 11 and 12 back in without damage. We shall see. I will certainly keep you guys informed. I'm much better at riding than repairing!

[pais]

   Well, had to work Saturday(yesterday). Just got done getting pistons out of cal housing. This is what I found!

   

     

Bottom of housing does not match. Looks to me as some of the checkerboard broke off? Edges of same seem to be worn? Or is this how it's supposed to be? Coincidentally this is the side that piston was hard to remove. I do not believe piston was extending out properly. It would push in but only come out half way when I applied air pressure to get out. Other one came out easily. Wondering if I need to buy new caliper housing?

[Ricky-D]

I think that how the bottom of the bores look is inconsequential.

What matters is:

1) The quality of the bores.

2) The passages for the fluid.

3) The condition of the pistons.

4) The condition of the piston seals.

***

[pais]

After staring at this for awhile. The bore that I think has damage is actually a channel for fluid flow into other piston bore. In the process of re-assembling.

[pais]

I think that how the bottom of the bores look is inconsequential.

What matters is:

1) The quality of the bores.

2) The passages for the fluid.

3) The condition of the pistons.

4) The condition of the piston seals.



Bores are clean and smooth

Passages are clear

New pistons

New seals

   Well, had to work Saturday(yesterday). Just got done getting pistons out of cal housing. This is what I found!

   

     

Bottom of housing does not match. Looks to me as some of the checkerboard broke off? Edges of same seem to be worn? Or is this how it's supposed to be? Coincidentally this is the side that piston was hard to remove. I do not believe piston was extending out properly. It would push in but only come out half way when I applied air pressure to get out. Other one came out easily. Wondering if I need to buy new caliper housing?

***

Lower photo is the bore on the caliper closest to where fluid enters caliper. The channel in said bore is for fluid flow into second bore. Passages line up perfectly. I got nervous when I first saw it. Was sure something was wrong. Brakes all back together and enjoyed ride to and from work today. Thanks for the input on this issue!