Squealing brakes

[alan_sh]

My front disk brakes squeal. Not when I apply them hard, but a but less than that. Any cure? What do I look for?

The bike is a Rockrider EST-520.

Any advice gratefully received.

Alan

 

[EME]

Disk Brake cleaner ( or the cheaper acid I can’t spell ) is inevitably you friend AFTER you’ve bedded in your brakes properly imho. No need to change anything else Afaics.

 

[Mikerb]

Assuming these are not new pads not yet properly bedded in, it probably means the pads and/or rotor are contaminated...........typical causes are bike cleaning products especially silicon sprays or spray on lubes, or road contaminants if you carry your bike on a car rack.
Easiest way to try to sort it is to remove the pads and clean up the surfaces with emery paper and clean the rotors with brake cleaner. If that does not work you need new pads.

 

[Beekeeper]

Use resin pads. They may not slow the bike down but they are quiet as a mouse ?

 

[Mikerb]

Use resin pads. They may not slow the bike down but they are quiet as a mouse ?

or just remove the pads.....sorted!!

 

[alan_sh]

I'll try cleaning them. The bike is not that old.

 

[04fuxake]

Use resin pads. They may not slow the bike down but they are quiet as a mouse ?

What you lose in brake squeal you make up for with screaming.

 

[04fuxake]

I'll try cleaning them. The bike is not that old.

I had this recently. I cleaned the pads and rotors with isopropyl alcohol and sanded the pads on sandpaper. Quiet as a mouse now.

 

[steve_sordy]

If all else fails, try the disco inferno.

 

[Bellefield]

My back breaks started squealing on the big descents on Sunday's long ride, so decided to take it easy until I could check them when I got home... not much left of them or the spring clip

Went straight down to the LBS on Monday and bought a couple of new sets of pads, although the front one still has some life in them as they were changed about 6 months ago, so just changed the rear set, took me an age to re-align the calipers though to stop any rubbing against the new pads as they were so thick in comparison to the worn ones.

I know we should check them regularly, but its hard to see in there to gauge the wear, so any tips for checking pads (without removing them) is greatly appreciated.

 

[alan_sh]

Yes, I took mine out the other day. They had enough "tread" but I sanded them down and chamfered the edges. The squeal is now just a very high pitched noise occasionally, so I am obviously doing something right.

 

[Mikerb]

My back breaks started squealing on the big descents on Sunday's long ride, so decided to take it easy until I could check them when I got home... not much left of them or the spring clip

View attachment 56472

Went straight down to the LBS on Monday and bought a couple of new sets of pads, although the front one still has some life in them as they were changed about 6 months ago, so just changed the rear set, took me an age to re-align the calipers though to stop any rubbing against the new pads as they were so thick in comparison to the worn ones.

I know we should check them regularly, but its hard to see in there to gauge the wear, so any tips for checking pads (without removing them) is greatly appreciated.

It literally takes 2 minutes to remove them and best to do that occasionally when you clean the bike so you can clean the calipers as well.
There are a couple of reasons why new pads can cause clearance problems. The first is pistons not being fully pushed back. The second is that there is either air in the system or the (dot) has absorbed moisture. Both effectively increase the volume of fluid and prevent full return of the pistons. So the brake needs bleeding. Or a short term measure is to remove the bleed screw on the lever whilst pressing the pistons back which will force a little fluid out of the system.

 

[steve_sordy]

................... Or a short term measure is to remove the bleed screw on the lever whilst pressing the pistons back which will force a little fluid out of the system.

I once had to do that by the trailside when replacing well worn pads with brand new ones. There was just too much fluid in the system to allow the pistons to go back far enough so that I could get the pads in to the calliper.

 

[alan_sh]

But be careful - if it's like motorcycles, brake fluid can damage paintwork.

 

[Bellefield]

It literally takes 2 minutes to remove them and best to do that occasionally when you clean the bike so you can clean the calipers as well.
There are a couple of reasons why new pads can cause clearance problems. The first is pistons not being fully pushed back. The second is that there is either air in the system or the (dot) has absorbed moisture. Both effectively increase the volume of fluid and prevent full return of the pistons. So the brake needs bleeding. Or a short term measure is to remove the bleed screw on the lever whilst pressing the pistons back which will force a little fluid out of the system.

I appreciate the advice, however while it might take you two minutes, but it took me half and hour of faffing get the back wheel off, getting the old pads out, pushing the pistons back and then trying to putting the new ones back in again, then getting the back wheel on again.... ok, maybe not half an hour but definitely not two minutes (for me anyway) and all the while trying to keep my oilly hands off the pads and the disc!

They are aligned up nicely again, but it took some fettling as every time I thought they were aligned, I'd tighten the bolt a little then check it and that little rub could be heard again ? I think it was the fettling that took the longest time, but finally did it by feel, moving first one end back and forth, then the other end back and forth to find the sweet spot, then tightening (slowly!). I found it hard to check the position visually,

 

[Cb750stu]

I align my brakes by undoing the brake caliper spinning the wheel and applying the brake, hold brake on then tighten up the caliper again always worked for centering the brake disc ?

I clean the pads by dripping some water on one pad then vigorously rub both pads together , surprising how black the water gets , I haven't had squeeky brakes even with sintered pads ?

 

[steve_sordy]

But be careful - if it's like motorcycles, brake fluid can damage paintwork.

Fortunately, I had a mate with me and he held a paper towel to catch the overflow.

 

[steve_sordy]

I align my brakes by undoing the brake caliper spinning the wheel and applying the brake, hold brake on then tighten up the caliper again always worked for centering the brake disc ?
.................

Me too.

 

[leix_toffee]

Emery paper and a light scrub does the job. Add water as well and the gunk will run off

 

[04fuxake]

But be careful - if it's like motorcycles, brake fluid can damage paintwork.

If the brakes use DOT fluid, yes.