Bicycle Mechanics - Disc Brake update.....

Well I cleaned and sandpapered the rotors. I reseated my wheel making sure it was gootNtight. I pulled the caliper off, removed the pads and sprayed them with brake cleaner. I sandpapered them and sprayed them clean afterwards. I made sure not to touch the important surfaces. I carefully lined up the caliper as per the instructions-making sure that I had 1/3 of the space on the inboard side and 2/3 of the space on the outboard side. I tightened the two bolts (after locktighting them) and then backed off the pads about 2 clicks on the inboard and 2-3 clicks on the outboard. I am happy to say that I now have brakes. :o
They still squeal like no tomorrow... they really do sound bad.
And, of course as my luck goes, there is still an issue. Looking down at the brakes it is easy to see that my pads, while still new, do not line up with the rotor like they should. There is "toe out" and it is impossible to fix this. I don't know why they are like this but they are :(
The brakes look like this:
/|\
Looking from the top. It is of course not this pronounced but there is toe out... the pads first touch the rotor as the rotor leaves the caliper. This, in regular brakes, is notorious for causing squeal. I wonder, off hand, if applying automotive type "anti squeak" compound to the back of the pads would help? What it basically is-is a silicone like compound that adheres or dampens the pad so that it cannont chatter. Make any sense?
D

New disk brakes always squeal. They will continue to squeal until they break in. This took about an hour or two of riding with my avid disk brakes on my mountain bike. Basically, they squeal until the rotor is smooth and any grooves or scratches in in are polished out by the brake pads. This might take longer for you now since you sanded down your rotors with sandpaper. (Why would you do that?)

New disk brakes always squeal. They will continue to squeal until they break in. This took about an hour or two of riding with my avid disk brakes on my mountain bike. Basically, they squeal until the rotor is smooth and any grooves or scratches in in are polished out by the brake pads. This might take longer for you now since you sanded down your rotors with sandpaper. (Why would you do that?)

Because they were contaminated with God know what. I didn't "sand down your rotors" I lightly scuffed them with 320 grit wet/dry paper to prepare them for the the lightly scuffed and cleaned pads. Reference this post:
disk brake dismay (http://www.bikeforums.net/showthread.php?t=96060)
For the full story.
D

Just ride them down the biggest hill you can, dragging them the whole way and make a good hard stop at the bottom.

The brakes look like this:
/|\
Looking from the top. It is of course not this pronounced but there is toe out... the pads first touch the rotor as the rotor leaves the caliper. This, in regular brakes, is notorious for causing squeal. I wonder, off hand, if applying automotive type "anti squeak" compound to the back of the pads would help? What it basically is-is a silicone like compound that adheres or dampens the pad so that it cannont chatter. Make any sense?
DSomething is still wrong. Is your H-spring in the correct position? It should be straddling the pads just outside the friction material

Just ride them down the biggest hill you can, dragging them the whole way and make a good hard stop at the bottom.

I did, twice. They stopped sqeaking when they were hot and then a block later they were howling
D

Something is still wrong. Is your H-spring in the correct position? It should be straddling the pads just outside the friction material
Yeah, I made the sandwich like the instructions say to do and it snapped in nice. I eyeballed it prior to installing it and everything was sitting correctly. I'll take some pics tomorrow. Heck, after the two high speed downhill runs it might have squared itself out... still sqeals though
:D
D

At least it "feels" better know. I can almost lock the front tire with my brand new Conti TT tires. That's good enough for me. In the somewhat distant future I may bump up the diameter of the rotor....
D

What brand is this?
I would not spray anything, even brake clean on the pads. They look like sponges if you magnify them enough and even if you try to wash off something the brake clean, with its very low surface tension, will flush stuff into the matrix. Then it will evaporate leaving the lube in the pad.
So, in conclusion, I would suggest a new set of pads, after cleaning your rotors again. :)

What brand is this?
I would not spray anything, even brake clean on the pads. They look like sponges if you magnify them enough and even if you try to wash off something the brake clean, with its very low surface tension, will flush stuff into the matrix. Then it will evaporate leaving the lube in the pad.
So, in conclusion, I would suggest a new set of pads, after cleaning your rotors again. :)

It's the avid Road discs brakes.....
I was kinda thinking the same thing... this must be why the instructions are pretty adamant about NOT touching the rotor or brake surface with your fingers.
So what gives with all the advice about isoporyl alcohol?????????
I left the pads sit face up in the sun for about 1/2 an hour and they were bone dry when I reinstalled them. I'm gonna ride these damn things for the next 30 days. If they continue to squeal I'll do the new pads. I'm gonna give them 30 days. If they still squeal it's Ebay time and I'll throw some decent V's with the diacompe levers on and be done with it.....
:D
D

I have never tried this: If you have an old pot boil the pads in it this is supposed to get all of the oils out of the braking material.

I have had good luck with the Avid stuff myself.

So what gives with all the advice about isoporyl alcohol?????????

D
It's not isoporyl alcohol you should be using it's DENATURED. Use it to clean the rotors after handling them.

I'll point out that it shouldn't be a big issue if the pads aren't perfectly lined up with the rotor. When you squeeze the lever, they will be.

Raiyn, don't start on me about this. When my Headshok blew up, it leaked oil onto my almost new front brakes. I soaked them a bit with alcohol, and set them on fire to burn
off the oil. It worked, but I'm not sure it's a good idea. If anyone else tries this and has some kind of accident, or burns their house down, don't blame me.

" or burns their house down,"

So you are saying, "Do it outside" :)

Same thing with the boiling trick. It seems like it should work. But I offer no gaurantee.
Brake pad materials get way hotter in use than they would in boiling water or even lighting them on fire for a few seconds, so the heat should not be a problem

I chucked them on the BBQ, Chuck. The grille plate side. They seem to smell a bit like fajitas now...

Raiyn, don't start on me about this. When my Headshok blew up, it leaked oil onto my almost new front brakes. I soaked them a bit with alcohol, and set them on fire to burn
off the oil. It worked, but I'm not sure it's a good idea. If anyone else tries this and has some kind of accident, or burns their house down, don't blame me.
Moi? Start something? :roflmao:
I usually don't recommend cooking / burning the pads because strange things happen when some people play with fire and accelerants

That's why I put them on the BBQ. I can always lower the lid and smother them. Our rear patio is framed in timber, and we have timber floors throughout. I'm extra careful about heat/fire/portable thermo-nuclear reactors.

That's why I put them on the BBQ. I can always lower the lid and smother them. Our rear patio is framed in timber, and we have timber floors throughout. I'm extra careful about heat/fire/portable thermo-nuclear reactors.
There are some people I don't trust with spray paint and / or SAE allen wrenches, let alone fire

People in wood houses shouldn't throw coal. Do you trust them with metric wrenches?