Can anyone tell me based on the photos if I need to change my brake pads?

[Sophie777]

Left hand side. On second viewing it looks more off centre rather than bent but to the extent that it appears to be rubbing on the disc rotor. Try loosening both caliper bolts to the point where the caliper can move freely, pull on the brake lever hard and nip the disc caliper bolts up tight while still holding on to the brake lever. This will help centre the caliper with the disc.

The springs may be bent, but if you've never taken the pads out before, I don't see how they would get bent, unless very careless assembly by your bike shop. To me it just looks like the springs are just not centred properly, in both pics they are canted far over to the right, hard up against the right hand pad but not even touching the left. Also not centered on the split pin, so on the left the spring does look like it could be rubbing on the rotor. I would just give the spring a wiggle and see if you can centre it. If it is bent it will be obvious, in that case replacement is best as others have said, but you can bend them back into shape by hand as well if they're not too bad out of shape

Yes, I think I see what you guys mean. At a minimum, the spring looks off-center.
I'll try giving the spring a wiggle; failing that, I'll try re-centering the caliper.

 

[Sophie777]

I did have a look at my rotors, calipers, and springs.
Both up front, and in the rear, I can easily wiggle the spring side to side on the cotter pin.

The rotors and calipers are fixed solid.

I centered both springs as best I could - but I'm sure once I ride over the next pothole, the springs will jiggle off-center once again.

The rotors inside the calipers also look a bit off-center - more so in the rear; but the rear never gave me any problems.

No squealing brakes after a further 22 Km, and I never experienced brake rub.

So I think I'll leave things alone for now; relying on the maxim: "After perfection, comes destruction".

 

[tobster]

I think that they look fine and it is just the angle of the photo

 

[KennyB]

So do I. How do they sound? Any catching, rubbing squeaking as you spin the wheel?

 

[Sophie777]

So do I. How do they sound? Any catching, rubbing squeaking as you spin the wheel?

They sound fine.
No catching, rubbing, and no more squeaking, when spinning the wheel or when riding.

 

[KennyB]

Seems in order then

 

[Sophie777]

The pads are far from worn out.

Show a picture of the rotors, front and rear. I'd like to see the amount of deposit and coloration on the brake track, as I suspect glazing and/or improper bedding-in process.

Replacing the pads and rotor is a quick and inexpensive way to fix squealing, but if the user goes a little too hard with bedding in, it will just happen again.

So I think you guys are correct - there is indeed a problem with my front disc brakes.

Yesterday, they started squealing again, though not nearly as loud as before.
But more concerning, today I felt on 2 occasions, the sound/feel of metal on metal when I applied the front brakes.

I don't know what's wrong, but I'm going to replace the pads.

Varaxis asked for photos of my rotors; there is some streaking - please see photos below:

First 3 photos are the outside face of the front rotor, the last photo is that of the inside face of the rotor.
Do I need to change the rotor?

 

[Philly G]

Over the last week or so I've had trouble with the brakes on my Rail too, still quite a new bike, only been riding it for 3 weeks. Brakes are Shimano MT-520 with 203 rotors, Shimano's budget level 4-piston brakes, and I have found the rotors to be particularly noisy. Rotors were also not running true from brand new, I've done my best to straighten them but I haven't been able to get rid of brake rub entirely. They are often noisy when they get dusty, especially the front, like a goose honking with each rotation of the wheel. I can quieten them by squirting rotor and caliper with water, sometimes this is enough to silence them.

The other problem I have had is I have had to warranty my front caliper. I couldn't get the pistons on one side to fully retract into the caliper, so it was impossible to set the brake up properly with all 4 pistons moving equally and no rotor rub. When I tried to push these two pistons back, using a tyre lever, I heard a crunchy gritty sound. I did a google search and found on another forum a discussion about this issue. The pistons are ceramic and will sometimes break inside the bore. Incorrect assembly perhaps. LBS mechanic said mine were the 6th brake he'd warrantied. The pistons look fine from the outside, but when you take apart the caliper, you find broken-off pieces of the piston, which stops the piston fully retracting and causes the gritty sound.

XT M8000 broken pistons

I recently attempted to fix the long lever throw that had developed in my XT calipers. As is documented in several places here, I did the piston extension/clean/lube thing. With one of the pistons on my front caliper, I could not get it to retract. This is what was causing the lever throw...

forums.mtbr.com

Sophie777, I don't know if you have this issue, but I went back and took a look at the pics of your caliper, and your pistons are further out on the left than the right, so the rotor will be rubbing on one side. I would start by removing the pads, and see if you can push the pistons all the way back. If you can't, and it feels/sounds gritty, you've got the same problem as me. If everything is fine, try centering the caliper over the rotor. Put everything back, and pull the lever. If you can see one side is moving further than the other, hold that side back (carefully, with a screwdriver pressing on the backplate of the pad) and allow the other side to come out. Might need to do this a few times to lubricate the seals. Also check your rotors are straight, spin the wheel slowly and note where the rotor is rubbing. Use an adjustable spanner (clean the jaws first) to bend that part of the rotor to where you want it.

I would add the lines on your rotors is normal, you don't need to replace your rotors. Your bike probably came with sintered (metal compound) pads, as mine did, which are also noisier than resin pads. You could try fitting resin pads.

 

[Sophie777]

Over the last week or so I've had trouble with the brakes on my Rail too, still quite a new bike, only been riding it for 3 weeks. Brakes are Shimano MT-520 with 203 rotors, Shimano's budget level 4-piston brakes, and I have found the rotors to be particularly noisy. Rotors were also not running true from brand new, I've done my best to straighten them but I haven't been able to get rid of brake rub entirely. They are often noisy when they get dusty, especially the front, like a goose honking with each rotation of the wheel. I can quieten them by squirting rotor and caliper with water, sometimes this is enough to silence them.

The other problem I have had is I have had to warranty my front caliper. I couldn't get the pistons on one side to fully retract into the caliper, so it was impossible to set the brake up properly with all 4 pistons moving equally and no rotor rub. When I tried to push these two pistons back, using a tyre lever, I heard a crunchy gritty sound. I did a google search and found on another forum a discussion about this issue. The pistons are ceramic and will sometimes break inside the bore. Incorrect assembly perhaps. LBS mechanic said mine were the 6th brake he'd warrantied. The pistons look fine from the outside, but when you take apart the caliper, you find broken-off pieces of the piston, which stops the piston fully retracting and causes the gritty sound.

XT M8000 broken pistons

I recently attempted to fix the long lever throw that had developed in my XT calipers. As is documented in several places here, I did the piston extension/clean/lube thing. With one of the pistons on my front caliper, I could not get it to retract. This is what was causing the lever throw...

forums.mtbr.com

Sophie777, I don't know if you have this issue, but I went back and took a look at the pics of your caliper, and your pistons are further out on the left than the right, so the rotor will be rubbing on one side. I would start by removing the pads, and see if you can push the pistons all the way back. If you can't, and it feels/sounds gritty, you've got the same problem as me. If everything is fine, try centering the caliper over the rotor. Put everything back, and pull the lever. If you can see one side is moving further than the other, hold that side back (carefully, with a screwdriver pressing on the backplate of the pad) and allow the other side to come out. Might need to do this a few times to lubricate the seals. Also check your rotors are straight, spin the wheel slowly and note where the rotor is rubbing. Use an adjustable spanner (clean the jaws first) to bend that part of the rotor to where you want it.

I would add the lines on your rotors is normal, you don't need to replace your rotors. Your bike probably came with sintered (metal compound) pads, as mine did, which are also noisier than resin pads. You could try fitting resin pads.

Hey, thanks for your response!

I am going to try your suggestions on centering the caliper.
But I also got new brake pads - metal ones from Shimano. You are correct, my bike came with metal pads.
I wanted to try resin ones as you suggested; but none of my 3 local bike shops had any Shimano resin pads in stock.

I am pessimistic about things working out; so I don't want to try another brand, and introduce an unknown variable. I suspect like you, I will have to bring my bike to the shop.
But I will post back on how things go.

 

[Sophie777]

Over the last week or so I've had trouble with the brakes on my Rail too, still quite a new bike, only been riding it for 3 weeks. Brakes are Shimano MT-520 with 203 rotors, Shimano's budget level 4-piston brakes, and I have found the rotors to be particularly noisy. Rotors were also not running true from brand new, I've done my best to straighten them but I haven't been able to get rid of brake rub entirely. They are often noisy when they get dusty, especially the front, like a goose honking with each rotation of the wheel. I can quieten them by squirting rotor and caliper with water, sometimes this is enough to silence them.

The other problem I have had is I have had to warranty my front caliper. I couldn't get the pistons on one side to fully retract into the caliper, so it was impossible to set the brake up properly with all 4 pistons moving equally and no rotor rub. When I tried to push these two pistons back, using a tyre lever, I heard a crunchy gritty sound. I did a google search and found on another forum a discussion about this issue. The pistons are ceramic and will sometimes break inside the bore. Incorrect assembly perhaps. LBS mechanic said mine were the 6th brake he'd warrantied. The pistons look fine from the outside, but when you take apart the caliper, you find broken-off pieces of the piston, which stops the piston fully retracting and causes the gritty sound.

XT M8000 broken pistons

I recently attempted to fix the long lever throw that had developed in my XT calipers. As is documented in several places here, I did the piston extension/clean/lube thing. With one of the pistons on my front caliper, I could not get it to retract. This is what was causing the lever throw...

forums.mtbr.com

Sophie777, I don't know if you have this issue, but I went back and took a look at the pics of your caliper, and your pistons are further out on the left than the right, so the rotor will be rubbing on one side. I would start by removing the pads, and see if you can push the pistons all the way back. If you can't, and it feels/sounds gritty, you've got the same problem as me. If everything is fine, try centering the caliper over the rotor. Put everything back, and pull the lever. If you can see one side is moving further than the other, hold that side back (carefully, with a screwdriver pressing on the backplate of the pad) and allow the other side to come out. Might need to do this a few times to lubricate the seals. Also check your rotors are straight, spin the wheel slowly and note where the rotor is rubbing. Use an adjustable spanner (clean the jaws first) to bend that part of the rotor to where you want it.

I would add the lines on your rotors is normal, you don't need to replace your rotors. Your bike probably came with sintered (metal compound) pads, as mine did, which are also noisier than resin pads. You could try fitting resin pads.

So I yesterday finally installed the new brake pads (Shimano metal).
The hardest part (as you and others have alluded to) was centering the rotor inside the caliper.

The "trick" posted everywhere of loosening the caliper bolts, and re-tightening them while squeezing the brake lever did not work at all for me.
Took multiple attempts at manually positioning the caliper before I could spin the wheel without any rub.

Tested the brakes on a ride out today. For about the first 10 km of a 22km ride, I was quite disappointed to hear a low pitched hum when applying the brakes. Power actually seemed normal.

The last half of the ride, silence!!! Hope this will last and is not temporary.

So I am going to accept things as they are for now.

Thanks for everyone's help!!!