Rejuvenating hardened brake pads by sanding them down?

[sms]

My son was saying that the brakes on the road bike that he expropriated
from my wife were not working well. They are properly adjusted but I
think that the pad material has hardened with age. My cyclist friend
said that when this happens you just have to sand off a little of the
surface which has hardened and the material underneath will be fine.

Has anyone else done this? New pads aren't expensive, but if the old
ones are still okay there's no benefit in buying new ones. The pads are
the original pads from when my wife bought the bicycle, a Raleigh
Technium, in 1986.

[Sir Ridesalot]

If the entire pad has hardened then sanding them wont't do much.

Why gamble that brakes won't work when REALLY needed, due to hardened pads? Put new pads on and be safe and sure.

Cheers

[Doug Landau]

On Thursday, June 15, 2017 at 4:54:48 PM UTC-7, sms wrote:
> My son was saying that the brakes on the road bike that he expropriated
> from my wife were not working well. They are properly adjusted but I
> think that the pad material has hardened with age. My cyclist friend
> said that when this happens you just have to sand off a little of the
> surface which has hardened and the material underneath will be fine.
>
> Has anyone else done this?

Yes

> The pads are 1986.

Tell us how it works out

[sms]

I'll try new pads but I suspect that he's expecting too much from
side-pull caliper brakes from that era, and is comparing them with the
powerful brakes on his mountain bike. My daughter used that same bike
for more than a year and on big hills at UC Santa Cruz, and she never
had an issue with the brakes.

[John B.]

On Thu, 15 Jun 2017 16:51:04 -0700, sms <scharf...@geemail.com>
wrote:

I've done it but more in the nature of removing a surface that is
glazed, probably from grease or oil getting on the pads. In my case it
did improve the braking.

In any event it is cheap to try it.
--
Cheers,

John B.

[Frank Krygowski]

That's what I was going to say. How hard could it be to try it?


--
- Frank Krygowski

[Jeff Liebermann]

On Thu, 15 Jun 2017 16:51:04 -0700, sms <scharf...@geemail.com>
wrote:

I suspect that your son is about to repeat one of my mistakes. I
sanded some brake pads long ago not because they had hardened but
because I had installed them wrong and the pads were wearing at an
angle. To straighten them out, I sandpapered until they were straight
and flat, or so I thought.

After remounting the front pads only, I went for a test ride. No
problem stopping for about a mile. Then, the brakes required more and
more pressure until they appeared to be chattering and slipping.
Thinking that I sanded them wrong, I repeated the sandpaper ceremony,
only to have a repeat performance of the brake failure.

I then took off the front pads and looked at them under a microscope.
There were gouges and rough areas similar to what I would expect to
find if I installed a new set of automobile disc brake pads on a rotor
that had not been turned. There just weren't enough points of contact
between the rim and pad to provide sufficient braking friction.

At this point, a sane person would have tossed the pads and installed
something that was flat. Instead, I pressed some 800 or 1000 grit
aluminum oxide sandpaper onto the aluminum rim while it spun. I then
used a rotary polisher and some polishing compound. On my 3rd try, it
produced a fairly shiny polished rim that appeared to be fairly flat.
I then used some polishing compound on the brake pads to get them
shiny and flat. Hints: Push very lightly when polishing the rubber
pads. It helps to lubricate the sandpaper with water or light oil.

When I replaced the front wheel and brake pads, the brakes now worked
better than they ever had, and did not fade out during subsequent
rides.

I never followed up on this as it was far too much cost and work to
justify saving worn or hardened pads. Still, it was interesting and
somewhat of a surprise.

You might also try softening the rubber. In computahs and hi-fi
repair, the magic elixir is "rubber restorer" which is mostly xylene.
This stuff, mixed with a little mineral oil, causes the rubber to
temporarily swell, allowing the oil to fill the voids. After the
xylene evaporates and pollutes the atmosphere, the rubber shrinks back
to normal, but with the surface properly oiled. It's the oil that
give the rubber the flexibility (and the loss of oil causes the
hardness).

I don't know which brand to suggest. The problem is that xylene is on
the California list of banned VoC (volatile organic chemicals)
products.
<http://www.ebay.com/gds/How-to-Restore-Rubber-/10000000177771171/g.html>
Fedron is probably the most well known product.
<https://www.amazon.com/Fedron-Rejuvenator-Offset-Blanket-Duplicating-Processing/dp/B00PKOUEPC>
<https://www.amazon.com/MG-Chemicals-Rubber-Liquid-Bottle/dp/B008O9X3KS>
Incidentally, they all have a rather foul smell and should be used
outdoors.


--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[avag...@gmail.com]

86 ? Buy new pads

The subject requires more background than 'sanding'

There is restore n tweak for tour or race

https://www.google.com/search?gl=us&site=&source=hp&ei=PVxDWa29KqrajwSrua8Y&q=Cleaning%20brake%20pads%20site%3Ayoutube.com&oq=Cleaning%20brake%20pads&gs_l=navquery-generic.12...2264.34196.0.36018.29.29.0.0.0.0.8259.26613.0j18j7j1j9-3.29.0....0....1j4.64.navquery-generic..2.9.1827...0.j2kucHMRieg&ved=0ahUKEwjtz_GxwcHUAhUq7YMKHavcCwMQ2wEIIA

With drums, remove surface contaminants with ? Gum out ( auto shoes) then remove glaze with fine grit n sanding block.


More grip...no problems but the equipment is antique materials not late 20c bicycle.

The pad shape if extreme suggests new pads n checking the system thereafter.

[avag...@gmail.com]

Cleaning surface is spraying a dolly with solv eg nt, wiping surface, spraying clean dolly area wiping g surface
,spraying clean dolly area wiping surface

NOT soaking the bicycle with solvent

Ztrying to not disturb the pads surface

I assume the manual or blog would give specific advice fir pad types

[cycl...@gmail.com]

On Thursday, June 15, 2017 at 4:54:48 PM UTC-7, sms wrote:

If he has ridden fairly new MTB's with V-brakes or Disks he is simply expecting more violent braking than those old caliper type brakes can give. You can LIGHTLY sand the shoes to restore them if they haven't hardened to the core. Shoes though are cheap and there is high coefficient of friction shoes available - I think they are softer and yellow. They make quite a difference but they also wear pretty fast.