Squealing Brakes driving me crazy

[Boopop]

I'll try to make this as quick to read as possible
1. Noticed a saddle rail broken at the start of a charity ride. Briefly showed it to mechanics at the start in case they had a spare saddle. They didn't. He pointed out my brake pads were worn. My Birzman pad checker said otherwise.
2. Nonetheless, my next trip was to the Peak District, so I replaced them anyway. Like for like Gorilla Brakes Semi-Organic pads on my SRAM AXS Force brake calipers
3. I bed them in, no issues seemingly.
4. I ride from Rugely Trent Valley railway station to where my relatives live, about 30 miles. On the very last descent (the Pinch, you might know it, in to Milldale) the pads start squealing.
5. I go on a ride the next day, 50 miles. Super loud squealing, infuriating, both front and rear. Nice ride though other than that.
6. I get some sandpaper and disc brake cleaner. Twice I sand the pads, clean the rotors. Seems like it might have worked when bedding them in again.
7. No, next ride I go on (35~ miles), still in the Peak District, screaming brakes.
8. I decide there's nothing for it, new pads and rotors (switched to Shimano rotors, supposed to be compatible).
9. Bed them both in...front brake starts squealing!
10. I give both calipers/brakesets a full blown service. I floss the pistons as per Calvin Jones (Park Tools) instructions, I then bleed both brakes as I've done before.
11. Bed the brakes in again...seems OK, maybe, oh, no - there we go again, front brake is squealing again.

I'm at my wits end, they were quiet before I changed pads. I've still got the old pads so I'm tempted to switch back to that on the front as a test. Or should I just give up on Gorilla Brakes? They are an odd brand but they've been alright up until now.

What would you do? I'm thinking I might just try some different pads, maybe SwissStop 35 RS.

Cheers for reading all of that.

 

[Ming the Merciless]

Did you realign calliper, did you push pistons back? Is there a small oil leak?

 

[Gwylan]

I'll try to make this as quick to read as possible
1. Noticed a saddle rail broken at the start of a charity ride. Briefly showed it to mechanics at the start in case they had a spare saddle. They didn't. He pointed out my brake pads were worn. My Birzman pad checker said otherwise.
2. Nonetheless, my next trip was to the Peak District, so I replaced them anyway. Like for like Gorilla Brakes Semi-Organic pads on my SRAM AXS Force brake calipers
3. I bed them in, no issues seemingly.
4. I ride from Rugely Trent Valley railway station to where my relatives live, about 30 miles. On the very last descent (the Pinch, you might know it, in to Milldale) the pads start squealing.
5. I go on a ride the next day, 50 miles. Super loud squealing, infuriating, both front and rear. Nice ride though other than that.
6. I get some sandpaper and disc brake cleaner. Twice I sand the pads, clean the rotors. Seems like it might have worked when bedding them in again.
7. No, next ride I go on (35~ miles), still in the Peak District, screaming brakes.
8. I decide there's nothing for it, new pads and rotors (switched to Shimano rotors, supposed to be compatible).
9. Bed them both in...front brake starts squealing!
10. I give both calipers/brakesets a full blown service. I floss the pistons as per Calvin Jones (Park Tools) instructions, I then bleed both brakes as I've done before.
11. Bed the brakes in again...seems OK, maybe, oh, no - there we go again, front brake is squealing again.

I'm at my wits end, they were quiet before I changed pads. I've still got the old pads so I'm tempted to switch back to that on the front as a test. Or should I just give up on Gorilla Brakes? They are an odd brand but they've been alright up until now.

What would you do? I'm thinking I might just try some different pads, maybe SwissStop 35 RS.

Cheers for reading all of that.

Watching with interest and sympathy.
Seeking the magic cure, too

 

[Boopop]

Did you realign calliper, did you push pistons back? Is there a small oil leak?

I did realign the caliper, I've pushed the pistons back several times now. Each time I put new pads in, and after I flossed the sides of the pistons too. No sign of oil leaking.

 

[KuroSan]

Something to check just to remove it as a possible cause, check the mating surface of the rotor mounts and the hub are completely free of any debris, same with the caliper mounting post. You'd be amazed how easily brakes can go out of whack because of a bit of gunk on a mating surface!

 

[Punkawallah]

Don’t work a lot with disc brakes, but have found the spray-can brake (rotor) cleaner to be ‘iffy’. Would not be the first time I had to sluice the rotor with water to stop squealing. YMMV, T&CA, DTTAH.

 

[13 rider]

My friend had a similar problem but with Shimano calipers and eventually found a microscopic leak on the piston ,worth checking although different manufacturer which uses different fluid but sort of makes sense if noise only comes back after a period of riding and using the brakes

 

[BigSid]

Try some copper grease on the back of the pads. Sometimes the sqealing is vibration between the pads and shims.

 

[C R]

Try some copper grease on the back of the pads. Sometimes the sqealing is vibration between the pads and shims.

Wouldn't that risk dangerous contamination of the pads and discs? I would think more along the lines of a thin rubber shim, but that would add some dead travel as the shim is compressed.

 

[Drago]

Wouldn't that risk dangerous contamination of the pads and discs?

No, a moderate amount wont. However, its better to use proper moly brake paste rather than copperslip, although the latter will do the job.

 

[fossyant]

You'd know if you had contamination - the brakes won't stop well. Had a microleak on MrsF's Deore SLX brakes - not enough to see. Nipped up the hose connection and all was OK.

An anchor would help !

 

[Gwylan]

Try some copper grease on the back of the pads. Sometimes the sqealing is vibration between the pads and shims.

Just means taking everything apart and starting a new experiment. Thanks anyway

 

[Boopop]

Someone suggested lubing the pistons with brake fluid on Reddit, I've done that before on the rear caliper and it worked I think. I've spent several hours on this now with little improvement. Lubing the front calipers like that worked briefly and then went back to how it was. Just as I arrived home the rear started squealing too.

I think I might give in, Merlin Cycles has the latest SRAM D2 shifters and calipers for £360. I'm still on D1 the current shifter/caliper setup is 5 years old.

 

[fossyant]

Wow, £360, just like that....

How did the other expensive groupset/component change go some months back ?

 

[Boopop]

How did the other expensive groupset/component change go some months back ?

Sorry, don't know what you're talking about.