Rear brake pad installation

[Splicer]

Replacing my brake pads myself for the first time, so please forgive the newb questions. I'm replacing the pads of my rear Brembos of my Nero Corsa.

 

(I had a lot of fun getting the old pads off: http://splicer.com/2012/07/09/pin-brembo )

 

First thing: the old pads came off and are worn quite unevenly. The right pad was worn pretty much down to nothing. The left pad has 2mm of material left on it. Is that a symptom I should be concerned about? Maybe in combination with the next thing I'm going to mention?

 

Second thing: I'm having a dickens of a time getting in to add the new pads. I've seen the suggestion to get in with a screwdriver (perhaps wrapped in a rag or paper towel) and push the caliper back to make the space to slide in the new pads. Well, I don't know how to get enough space to get the screwdriver in. I tried an (expired) credit card, and it is too thick to jam in between the caliper and the rotor. I thought maybe if I could get two playing cards in I could then slide the credit card between them, then maybe slide the screwdriver between one of the playing cards and the credit card. No dice. With great effort and sliding back and forth I am able to get one playing card in between the caliper and the rotor. I cannot get the second playing card in at all.

 

The left side seems much more open. I still haven't gotten the pad in, but I don't have any trouble getting at least the credit card in between.

 

My thought is that if the caliper is that firmly jammed up against the rotor it accounts for the uneven wear.

 

So: any thoughts about what I could do differently?

[Lucky Phil]

Replacing my brake pads myself for the first time, so please forgive the newb questions. I'm replacing the pads of my rear Brembos of my Nero Corsa.

 

(I had a lot of fun getting the old pads off: http://splicer.com/2012/07/09/pin-brembo )

 

First thing: the old pads came off and are worn quite unevenly. The right pad was worn pretty much down to nothing. The left pad has 2mm of material left on it. Is that a symptom I should be concerned about? Maybe in combination with the next thing I'm going to mention?

 

Second thing: I'm having a dickens of a time getting in to add the new pads. I've seen the suggestion to get in with a screwdriver (perhaps wrapped in a rag or paper towel) and push the caliper back to make the space to slide in the new pads. Well, I don't know how to get enough space to get the screwdriver in. I tried an (expired) credit card, and it is too thick to jam in between the caliper and the rotor. I thought maybe if I could get two playing cards in I could then slide the credit card between them, then maybe slide the screwdriver between one of the playing cards and the credit card. No dice. With great effort and sliding back and forth I am able to get one playing card in between the caliper and the rotor. I cannot get the second playing card in at all.

 

The left side seems much more open. I still haven't gotten the pad in, but I don't have any trouble getting at least the credit card in between.

 

My thought is that if the caliper is that firmly jammed up against the rotor it accounts for the uneven wear.

 

So: any thoughts about what I could do differently?

Just pull the caliper off the mount and with the old pads in place use a big screwdriver between the pads to lever the pistons all the way back into the caliper. Just make sure the oil reservoir isn't totally full or the pistons wont go all the way back in.You may have to remove a little oil from the reservoir.

Fit the new pads and refit the caliper and pump the brakes. Shouldn't take more than about 15 min.

I wouldn't be to concerned about the uneven pad wear unless the side with the remaining material wont go back into the caliper and is seized.

While you have the caliper off it would be a good time to replace the fluid as well.Just crack off the bleeder and nip it up again BEFORE you loosen the caliper fit the new pads put something about 6 mm thick between the pads and hold the bleeder with a tube on it upright and bleed until fresh fluid comes out.

The real question is why you need to replace the rear pads in the first place. Mine never wear out as I only use the rear brake to hold the bike on a hill at the stop lights and sometimes to help it hold a line mid corner. Have never changed out a set of worn rear pads in 40 years of riding.

Ciao

[Splicer]

Just pull the caliper off the mount and with the old pads in place use a big screwdriver between the pads to lever the pistons all the way back into the caliper. Just make sure the oil reservoir isn't totally full or the pistons wont go all the way back in.You may have to remove a little oil from the reservoir.

Fit the new pads and refit the caliper and pump the brakes. Shouldn't take more than about 15 min.

I wouldn't be to concerned about the uneven pad wear unless the side with the remaining material wont go back into the caliper and is seized.

While you have the caliper off it would be a good time to replace the fluid as well.Just crack off the bleeder and nip it up again BEFORE you loosen the caliper fit the new pads put something about 6 mm thick between the pads and hold the bleeder with a tube on it upright and bleed until fresh fluid comes out.

The real question is why you need to replace the rear pads in the first place. Mine never wear out as I only use the rear brake to hold the bike on a hill at the stop lights and sometimes to help it hold a line mid corner. Have never changed out a set of worn rear pads in 40 years of riding.

Ciao

 

Wow, I'd rather not get into the rear brake "never" versus "infrequently" discussion. I'm not one of those who uses the rear brake routinely, but neither do I think it is dead weight. It has a purpose and I use to for hard stops or slippery conditions. Also, living in San Francisco I probably make more hill stops in a week than most riders do in a year. (Many people call a 5% grade a "hill" and a 10% grade a "steep hill". I call a 20% grade a "noticeable incline." That's just where I live.)

 

Also, I'm not the original owner. I don't really know how it was ridden before I got the bike. What I know is that I had metal on metal grinding with no brake pressure applied. It was past time for the pads to be replaced, even if I disconnect the rear brake and never use it again. So the real question is: how do I get these new pads in?

 

It sounds like I've already blown the chances of ever getting the new pads in, because it's too late for me to do anything with the old pads in place. The old pads are already removed; I can't unring that bell.

 

I (perhaps foolishly) followed the instructions (and photo) in the shop manual:

 

http://splicer.com/files/imagepicker/1/IMG_0079.png

 

I pulled off the plastic shield, popped the pin out, removed the spring, then slid out the old pads. That's all. Now I need a way to get the new pads in.

[Baldini]

Sounds like maybe you have a sticking piston? Get the caliper off, clean up & check pistons are moving freely. As Lucky Phil says above, you should be able to easily push the pistons into caliper body til piston outside face is more-or-less flush with caliper body.

 

KB

[dave]

Firstly, clean the whole caliper, especialy around the pistons with brake cleaner and a toothbrush. Debris could cause a piston to stick later when the retract. If you have the space to get a credit card in, find a thin piece of cold finish steel the same size. I will mail you one if you need. The pistons not want to go in evenly when they are near the end of their travel so a screwdriver is likely to cause binding. Slide the shim stock in place and alternately compress each piston in turn until a larger gap in made.

 

Let me know how it goes,

Dave

[Splicer]

Thanks everyone! I unbolted the caliper without disconnecting the fluid line and was then able to stick a rod through and use it to push the pistons back using both thumbs. It was slightly awkward getting the pads in, the caliper back on, and keep everything lined up so I could put the spring and pin back, but it was definitely do-able.

 

My first brake pad replacement was completed in five days. Now that I've done it, the next time will be more like an hour. After that I'll start trying to hit that 15-minute mark Lucky Phil mentioned.

 

Many thanks!

[docc]

Just for emphasis: the rear pistons graze along just above the nasty tarmac getting wet, nasty and ugly. Cleaning those pistons (with brake cleaner), working them in and out, and bleeding that fluid (yearly) is good stuff, along with being certain the foot pedal doesn't drag the brake (there should be a little "play").

 

The same applies to the fronts: the pistons will tend to move differently. Routinely, work the pistons in and out applying brake cleaner watching them to move together more uniformly. The change in brake action is really amazing!