Brake squeal

[Old-tool-guy]

Ride1Up cafe cruiser, wife & i each have one, about 350 miles. Recently my brakes have started squealing very badly right at the end of a stop. When i brake while riding, there is no noise, it’s only the last few seconds of stopping. And when i take the bike off the hitch rack, i use the brake to keep it from rolling down the ramp too fast, and it squeals badly. What should i check?

 

[Aushiker]

Clean the discs, maybe check or change the type pads (a bit extreme but still sometimes worth a try), maybe brake squeal spray might work ... and the list goes on... nine ways according to Bike Radar

Disc brake squeal is common as. A Google search should come up with a plethora of 'solutions.'

 

[fooferdoggie]

get some rubbing alcohol or such the stronger the better spray it on the rotors and caliper push the bike around with the lever held down a tiny bit then spray it again. thats the first thing to try. then we can move on to others after.

 

[PDoz]

If you get nowhere with the usual clean / bed in / re alighn things, and it's worse after being on the car hitch, it might be worth reviewing the set up - any contamination of disc / pads can contribute to noise, including exhaust fumes ( especially diesel ) . Unfortunately, even a goid clean with metho might not fix the issue if diesel has soaked into the discs - requiring replacing them andvpads AFTER avoiding future contamination

 

[Old-tool-guy]

PD … not a diesel vehicle, and the exhaust is on one side so that should only contaminate one wheel … but both make noise. I have some brake cleaner spray, i will give it a shot.

 

[fooferdoggie]

PD … not a diesel vehicle, and the exhaust is on one side so that should only contaminate one wheel … but both make noise. I have some brake cleaner spray, i will give it a shot.

no that can destroy the seals on your pistons only use alcohol.

 

[Old-tool-guy]

I took a disposable rag, sprayed it with brake cleaner, and thoroughly wiped off the disc. I didn’t spray the cleaner near the bike, and did not get close to the calipers. Rag got very dirty. Went for a ride … it might be a little better but i5 still squeals. I ordered new pads.

 

[Aushiker]

I took a disposable rag, sprayed it with brake cleaner, and thoroughly wiped off the disc. I didn’t spray the cleaner near the bike, and did not get close to the calipers. Rag got very dirty. Went for a ride … it might be a little better but i5 still squeals. I ordered new pads.

I have done similar using CRC Brakleen but have not found it effective, so I am not surprised by your outcome. I will try isopropyl alcohol next time before going to the next step of pad replacements (unless they need replacing anyway).

 

[PDoz]

Sorry if this is telling you how to suck eggs, but this is my approach:
1 clean the disc ( I use metho / alcohol and 2/3 seperate paper towels -it's REALY important to be able to spin the wheel as you clean so you clean evenly)
2 bed the disc in - ie ride for about 5 mins lightly dragging the brake, then do 4/5 progressively harder almost stops - DO NOT stop ( if you stop, you leave an uneven coating on the disc which causes squeal )
3 if it still squeals I check pad / slave cylinder alignment , axle is tight, wheel bearings are good , no loose spokes etc
4 if that doesn't work I try to figure out if the issue is disk or pads. I'm lucky enough to have several bikes so can quickly swap across wheels / usually have a few spare pads etc. NB if the pads have been contaminated, then some of the more porous disks also get contaminated - especially if you have spilt brake fluid / used a cleaning product with residue . Putting new pads onto a contaminated disk will ruin those pads within a few rides.

good luck

 

[TrevorB]

Isopropyl alcohol is industry standard for cleaning brakes as it doesn't leave a residue. Meth will leave a residue ie purple dye.

 

[Old-tool-guy]

PD … thanks for the advice. I may have previously spilled brake fluid on the rear brakes … maybe … but both squeal equally badly.

Is there a need, or reason, to add a dab of grease between back of the pad and the caliper?

When i replace the pads this week, i will wipe the rotors with alcohol before assembly.

 

[fooferdoggie]

I took a disposable rag, sprayed it with brake cleaner, and thoroughly wiped off the disc. I didn’t spray the cleaner near the bike, and did not get close to the calipers. Rag got very dirty. Went for a ride … it might be a little better but i5 still squeals. I ordered new pads.

but the brake cleaner will strip everything off then you have to re bed the pads. so then you have to go through the bedding process all over again.

 

[PDoz]

PD … thanks for the advice. I may have previously spilled brake fluid on the rear brakes … maybe … but both squeal equally badly.

Is there a need, or reason, to add a dab of grease between back of the pad and the caliper?

When i replace the pads this week, i will wipe the rotors with alcohol before assembly.

There is a black powdery compound you can put between the pad and caliper on really difficult brakes . Sorry, I have no idea what it is ( my friendly lbs just put some in a ziplock bag for me) . I've only needed to use it on one bike and I suspect this bike had a faulty shimano mount at the hub. I've never used grease .

do you know what disk and pads you have? Some discs don't play well with some pads - eg the lower spec shimano discs can't tolerate sintered pads

 

[Old-tool-guy]

No idea, they are original equipment from the seller.

 

[PedalUma]

We are using 90% isopropyl.

 

[m@Robertson]

Cleaning the discs will un-bed the rotors. Actually the worst thing for getting rid of most forms of brake squeal.

Disc brake rotors have an invisible coating of brake pad material on them. This coating silences the brakes when in use. If you lose this coating, the brakes tend to squeal like banshees. In particular if you ride in the rain, or hose off the bike with pressurized water, you'll get abominable squealing and vibration until more pad material gets deposited. If you live where there are hills, the brakes will re-bed often by the time you get to the bottom of your first steep hill. If on flat ground, it can take quite a while, because pad material isn't deposited until the pads and rotors reach a certain level of high temperature.

Brake bedding is something high performance car owners know all about, but thats not so in the bicycling world.

Before you do anything, just bed your brakes and see what happens. This is just one of many tutorials online on how to do it. The cooldown phase is super-important to keep from warping a rotor.

How Do I Bed My Brakes?

Brake bedding is something almost nobody does and everybody should. Its a requirement on performance cars taken to the race track. Its the same procedure for any type of vehicle.

talesontwowheels.com

 

[Old-tool-guy]

Have not washed the bikes, mine or wifes, have not ridden in the rain. Neighborhood has some nice gentle hills, plenty of opportunity to ride the brakes going downhill.

 

[PedalUma]

Sometimes brakes get some road dirt that gets baked in. I like to clean that off and re-bed them.