Brake Squeal
 

When you work on a bike for a friend, do you give it to them with squealing brakes and explain that the squeal will go away in a day?. Or do you get rid of the squeal?

I finished servicing a friend's bike. Brakes were almost non functional. Cleaned rims, filed glaze off the old pads (she asked me to re use pads, since she is broke, and they are Kool Stop salmon with plenty of rubber left, just terribly glazed), fixed the cable housing problems, replaced the inner cables, trued rims, adjusted brakes. Now her bike stops great. But the front brake squeals. The pads have no separate holder and no toe adjustment. I knocked off the trailing edge of the pad and tightened the caliper mounting bolt, but it still squeals a little. I know the squeal will go away after a while, but I don't want to ride it myself long enough to make that happen. I don't want to bend the caliper arm, they are newish dual pivots and I'm not sure the arms are designed to be bendable.

Seems kind of amateurish to give her a bike with a brake squeal. I'm sure a professional bike mechanic would not do that. How do you (pro mechanics) deal with it?

I just replied to another thread about brake squeal. I put Kool Stop salmon pads on my MTB commuter awhile ago and they can squawk something awful, even though I have them toed in to the point of the brakes feeling soft or squishy.

BITD, there was a Park tool you used on the period common center pull, and lower cost single pivots
and GENTLY torqued the arm where the pad was mounted, to toe in the pads .

an adjustable wrench may do ..

mafac, plain post pads the post can be flexed a bit without breaking the Swage in the holder,

it probably will un do itself back to square to the rim again, but might quell the squeak initially

chamfer the back, leading, end of the brake pad , A Bit..

I'd rub the pads with some garden dirt. Has worked for me many times. Andy.

Dirt, that is interesting. Thanks!

On a professional level, you should tell your client that the brakes will squeal until broken in.

Knowing that some brakes squeal until they are broken in, I tell my clients to come back if it does not go away in short order.

Just built myself a bike with dual pivot XT brakes and Kool Stops and it only took a few miles in the summer sun to get the front to stop squealing like a cat in heat but then it was gone.

It is rare for well set up brakes with quality pads to squeal continuously unless they are Avid Shorty 4 (cantis) which are notorious for being impossible to correct... it is fun to pass these on to new mechanics and tell them to get them to stop squealing.

Once they are curled up in a ball, drooling, and rocking themselves back and forth we tell them it is the Kobayashi Maru of bike repairs.

Wanna bet?
Seriously, I really like my LBS but their mechanic, though skilled, can get lazy.
A few visits ago I went in for a "tune up". I test rode the bike in the parking lot and the brakes stopped better but squealed.
I brought it back in and he said "There's probably just some dirt on the rim" It was a quick fix, but his response was totally lame.
I think I now have a reputation in the shop as that "pain in the ass customer" I am proud to say that all repairs and adjustments are
done right the first time.

Somehow we have accepted the idea that brake noise is wrong. When a customer comes in with said complaint I quickly ask if the brakes still stop the bike. Then explain that brakes have made noise for decades, even on cars with the best safety reputations (like Volvo) and that noise is somewhat environmentally controlled. Rain, dirt, temp all contribute. I also say that even if we are able to eliminate the noise at the time of pick up it might occur again as things change. I offer to try and ask if the cost of a pad replacement is agreeable. Then joke about whether a wheel change is also OK.

When we do the service we apply all the usual attempts. New pads, sanding old pads, creating a beveled back end (and always removing a Kool Stop scraper ramp), beveling each pad segment, toe in, toe out (surprisingly this works sometimes), cleaning rims with steel wool or sand paper. Then when things still squeal I go outside and rub dirt into the pad. This almost always stops the noise. But as this is so contrary to accepted practice we do this as a last resort. Andy.

I'm glad to see responses on this from experienced folk. I just delivered a couple of bikes with brakes that squeal. Brakes stopped the bikes just fine but were noisy. I did just about everything, save changing pads, which the customer would not go for. I explained all this to the customer and he was ok with it. I hate being presented with problems that I can't solve. I've been told in the past by professionals that some brakes are just noisy and there is little or nothing that can be done. So be it..

I think brake squeal is caused by oil & grease residue. My shade tree method: Flip bike upside down on seat & handlebars. Get cotton balls & rubbing alcohol. Soak cotton ball, apply to rim, rotate rim, continue until no more dark residue appears on cotton ball. Soak a corner of shop rag with alcohol. Squeeze rag between rim & brake pad. Pull rag back & forth across brake pad. Wait till everything dries up. Get some 200 grit sandpaper. Apply to rim, rotate rim, continue until rim has shiny new appearance. Sandpaper the brake pads. Good to go - no more squeal until the rim gets oil on it again.

Brakes always make noise, this is why dogs can hear you coming from a mile away and plan their attack.

Brake noise that you can hear is caused by the vibrations you can hear, oil and grease will stop those vibrations but will also render your brakes useless.

Most brakes will stop squealing once they are bedding in, the same applies to cars when you replace the brakes.

Sanding rims is not a good idea.

Yes and no.

One common theme I see here is the old pads were re-used, and that can cause problems.

Rubber compounds dry out and the rock-hard result is perfect for causing those vibrations.

I have had luck treating old brake pads with WD40, which restores some of the softness and reduces squeal.

Once the excess is wiped off they stop just fine...

That would be yes and yes...

I tell students to avoid spraying WD40 on their rims or brakes while they are working and have had a lot of folks ask, or even come in to to the shop with barely functioning brakes after they lubed them up to get rid of the squealing.

A light sanding can remove the glaze that build up on brake pads, there is a lot of friction and heat that gets created there under hard braking.

I have to stress that sanding rims is not a good practice.

I think the kool-stop salmons are more squealy than other pads. or from a small sample size of one...I have had more squeals from Kool-stops on a set of universal brakes that I have had with any other brake/pad combo. But they do stop really well

The salmon pads don't like our winter cold very much... I run black pads on the winter bikes.

Salmons are the choice for our rainy winters.

{Disclaimer** Shade tree mech {/Disclaimer**

Personally, I wouldn't give it back squealing, but that's partially me being OCD. I found dual-pivot rim brakes squeal in two circumstances:
1) Pad not parallel to rim.
Loosen the adjustment bolt, clamp the brakes, and tighten. Perform a couple of hard stops and the brakes should quiet right down.

2) Contamination on the rim.
Road oil & dirt can cause squealing. Clean with isopropanol as suggested above. This has been by far the most consistent solution for me.

Bed the brakes in and they should be quiet.

I can only assume you have never tried what I suggested...

I know that WD40 has some very limited use in restoring natural rubber, silicone works better although this takes a longer period of time.

It is not general shop practice to use WD40 as a restorative on brakes.

Nor is it general shop practice to send a bike out with brake pads that squeal...

:rolleyes:

I could just ride the customer's bike for a while as long as I stay on the clock and get paid.

I ran salmon Kool Stops when I was in Portland (and have fitted thousands of them) and they are excellent in that wet environment, they are usually the best problem solver when you are re-fitting bicycles with new brake pads as they make a version for nearly everything as well as new inserts for vintage holders.

Our winters get a little colder and the salmon pads can get a little chirpy, the black Kool Stops seem to dampen vibration better at lower temperatures and the multi compound pads have worked well although they don't seem to get quite as much traction as the straight black compound.

Sometimes you just have to play with different pads to suit the conditions and the bike... my 1957 Peugeot does not like salmon inserts mated to the cantis at all, the stock Mafac pads always squealed like a cat in heat, and black Kool Stop pads were the ticket for quiet secure braking.

I also like the brake pads from Mountain Equipment Co-op, their Shimano V brake inserts are actually nicer than OEM... I plan for bikes to be ridden late in the season when it can get much cooler and this is when brakes can get a little chirpy.

I test ride just about every bike as part of the service, nothing goes out the door squealing like a cat in heat but I tell folks that newly serviced brakes might squeal or chirp a little as they bed in or that they might make a little noise under different riding conditions (ie wet or cold).