Author Topic: Squeaky brakes (Read 4559 times)

Skippernick · « **on:** 25 July 2016, 04:57:42 pm »

So i have squeaky front brakes, saw a post on the Facebook page about someone buying this goo which goes on the (i assume) back of the pads instead of copper slip.
Did a google search and one of the reasons for squeaky brakes is the vibration of the pad where its not quite touching the piston. I never knew this and is it true, have i really not applied enough copper slip to the back of the pads and that is why they squeak?

Nick

joebloggs · « **Reply #1 on:** 25 July 2016, 05:31:26 pm »

May also be worth looking at the brake pads, if they were not roughed up when fitted they may have small slithers of disc material imbeded in the surface of the pad, can be a pain to sort.

Skippernick · « **Reply #2 on:** 25 July 2016, 06:33:55 pm »

The thing is it was doing it on the old pads which needed changing so i did, and it carried on the brand new pads.

BBROWN1664 · « **Reply #3 on:** 25 July 2016, 07:10:26 pm »

Did the old pads have an anti-squeal shim fitted (like a bent bit of metal) and did you re-fit it?

darrsi · « **Reply #4 on:** 25 July 2016, 07:16:16 pm »

You should only need a very light smear of copper grease on the back of the pads, you don't wanna slap it on.

Are your pistons moving freely enough? If one side is doing more work than the other making pressure on the pads uneven that could cause a squeal.

What type of pads are you using as well? Did you replace the old ones with the same type and brand?
If the pistons are moving okay it might just be a simple pad issue on your discs.

Have a look at the pads and see if they're wearing evenly for starters, if they are give them a quick going over with emery paper, then swap the pads over each side so they need bedding in again.

darrsi · « **Reply #5 on:** 25 July 2016, 07:18:42 pm »

Quote from: BBROWN1664 on 25 July 2016, 07:10:26 pm

Did the old pads have an anti-squeal shim fitted (like a bent bit of metal) and did you re-fit it?

I just had a look for him to see if they were available to buy but couldn't find any.
I have them on the rear but have never really suffered with squealing at all on this bike.

Skippernick · « **Reply #6 on:** 25 July 2016, 08:41:13 pm »

yes it had the shim which i refitted.
Pads are your favourite ones Darrsi, what ever they are called. Pistons seem to move freely but i'll check as the wheel is out and the evenness of the wear on the pads.

darrsi · « **Reply #7 on:** 25 July 2016, 08:47:29 pm »

Quote from: Skippernick on 25 July 2016, 08:41:13 pm

yes it had the shim which i refitted.
Pads are your favourite ones Darrsi, what ever they are called. Pistons seem to move freely but i'll check as the wheel is out and the evenness of the wear on the pads.

Galfer

Grahamm · « **Reply #8 on:** 25 July 2016, 09:58:07 pm »

You could check for warped discs too.

darrsi · « **Reply #9 on:** 25 July 2016, 10:29:09 pm »

If you genuinely have warped discs the low speed vibes will be unbearable.
The squeaking/squealing will be the last of your problems.
In my opinion it's a very over used term which is very rarely the cause, even more so for general everyday riding.
More of a track/maniac rider problem.

Skippernick · « **Reply #10 on:** 25 July 2016, 10:37:39 pm »

I'll check but theres no vibes or anything it just happens as you slowly come off the brakes when coming to a stop.

darrsi · « **Reply #11 on:** 25 July 2016, 11:18:56 pm »

Quote from: Skippernick on 25 July 2016, 10:37:39 pm

I'll check but theres no vibes or anything it just happens as you slowly come off the brakes when coming to a stop.

I would be inclined to slightly push the pistons out, give them a good clean up with a toothbrush and brake cleaner, then cover the exposed parts with red rubber grease and see if that helps.
Something i like to take my time with on a nice sunny day, but always worth the effort eventually.

BBROWN1664 · « **Reply #12 on:** 26 July 2016, 08:19:06 am »

squeaky brakes come from two things normally. Dust on the disk/pads or the pads rattling in the caliper. The spring takes care of the latter one so I would be looking at making sure the disks are clean and make sure the leading edge of the pad is chamfered.

Skippernick · « **Reply #13 on:** 26 July 2016, 06:12:22 pm »

Quote from: BBROWN1664 on 26 July 2016, 08:19:06 am

squeaky brakes come from two things normally. Dust on the disk/pads or the pads rattling in the caliper. The spring takes care of the latter one so I would be looking at making sure the disks are clean and make sure the leading edge of the pad is chamfered.

Do i just file the leading edge?

joebloggs · « **Reply #14 on:** 26 July 2016, 06:39:15 pm »

Quote from: Skippernick on 26 July 2016, 06:12:22 pm

Quote from: BBROWN1664 on 26 July 2016, 08:19:06 am
squeaky brakes come from two things normally. Dust on the disk/pads or the pads rattling in the caliper. The spring takes care of the latter one so I would be looking at making sure the disks are clean and make sure the leading edge of the pad is chamfered.

Do i just file the leading edge?

File the leading edge and emry cloth the face to rough it up

celticdog · « **Reply #15 on:** 26 July 2016, 08:08:42 pm »

Also, check out the condition of the caliper pins, one on each caliper with a R clip at each end. It's worth giving them a very light greasing, if they're even slightly bent or pitted replace them.

darrsi · « **Reply #16 on:** 26 July 2016, 09:14:39 pm »

Quote from: celticdog on 26 July 2016, 08:08:42 pm

Also, check out the condition of the caliper pins, one on each caliper with a R clip at each end. It's worth giving them a very light greasing, if they're even slightly bent or pitted replace them.

Yeah, i forgot about the pins, i have a stainless steel fibre scouring ball to clean my pins with, it works a treat without doing any damage at all.
Again, a very light smear of copper grease on them as well.

joebloggs · « **Reply #17 on:** 26 July 2016, 09:59:06 pm »

Personally I think brakes are overrated, only slow you down....

Rob R · « **Reply #18 on:** 26 July 2016, 10:03:32 pm »

Probably nothing to do with your problem but I noticed some squeaking at low speeds when I fitted some new Galfer pads. I found that the backing plate on one pad had a bit of "flashing" left from the pressing- a quick bit of filing and the squeaking disappeared-it must have been rubbing very slightly against the caliper.
Rob

tommyardin · « **Reply #19 on:** 26 July 2016, 11:58:11 pm »

Be cautious using copper slip on and around hydraulic brake parts, its OK to use it sparingly on the back of the pads and pins,but do not use it on the pistons or anywhere near rubber brake parts as it is mineral based and will rot rubbers, same applies to using copper slip as a sex lube it will rot your rubbers, not convinced it would do much for your knob either. watch this space I will let you know.

darrsi · « **Reply #20 on:** 27 July 2016, 06:31:08 am »

Quote from: Rob R on 26 July 2016, 10:03:32 pm

Probably nothing to do with your problem but I noticed some squeaking at low speeds when I fitted some new Galfer pads. I found that the backing plate on one pad had a bit of "flashing" left from the pressing- a quick bit of filing and the squeaking disappeared-it must have been rubbing very slightly against the caliper.
Rob

I've never had any issues with mine, but i think we worked out i've got an older model of Galfer pads that are a slightly different compound and discontinued now, whereas i remember Nick saying before that his were quite dusty in comparison.
I've never liked organic pads, for example, because of the excess dust, because they clog the pistons up much easier.

Skippernick · « **Reply #21 on:** 28 July 2016, 10:12:48 pm »

So when you say file the leading edge of the pad, this is in fact towards the rear as the wheel goes up through the callipers?

darrsi · « **Reply #22 on:** 28 July 2016, 11:04:32 pm »

Quote from: Skippernick on 28 July 2016, 10:12:48 pm

So when you say file the leading edge of the pad, this is in fact towards the rear as the wheel goes up through the callipers?

Yeah, just take the corners off the rear end at 45 degrees, you don't need to do a lot, but it'll determine whether that might be the cause or not.

Skippernick · « **Reply #23 on:** 29 July 2016, 06:59:58 am »

Thank you.

Stripped them left calliper seems to be fine, right one has uneven wear, although the pistons move freely enough so need to investigate further.
How far out do the piston go before they fall out of the seals?

darrsi · « **Reply #24 on:** 29 July 2016, 07:34:08 am »

Quote from: Skippernick on 29 July 2016, 06:59:58 am

Thank you.

Stripped them left calliper seems to be fine, right one has uneven wear, although the pistons move freely enough so need to investigate further.
How far out do the piston go before they fall out of the seals?

The only safe way to answer that is to hold 3 pistons back at the same time by whatever means you have, i have some small g-clamps that are really handy, SLOWLY pump the lever then as soon as you see a clean shiny part of the piston then that'll be enough, if you're cleaning them up whilst still attached.
With the hardest toothbrush you can find, use ONLY brake cleaner, then slap on the red rubber grease so that every part of the exposed piston has grease on it. Then gently push the piston back in and move on to the next one, clamping the other 3 again. Leave the other caliper on the other disc while all this is going on.
Mine are generally clean and move freely because of the way i do this every time but if you have iffy looking rust spots or they generally look shite then you might have to get a bit more involved, as in a proper strip down and clean up, or maybe even new seals.