197 Brembo calipers rebuild- HELP! :(

This is a 2 minute read so bear with me pls!
I recently got said calipers from a guy, got them powdercoated, brand new pistons and seals, new pad hardware (pins and anti rattle shims), DS2500 pads and new Brembo max 280mm discs.
This is my second attempt to to this job, first time I cheaped out and only bought new pistons on the right caliper (the other ones were looking good) and I got myself with a horrendous brake squeal on the right side- the side with the new pistons oddly (only appears on moderate pedal pressure). This first time I had some cheap Valeo (new though) pads which I got as a package with the calipers.
So now I decided to do the whole job AGAIN, this time everything new as I said, plus I bought the DS2500 pads.
Before taking the calipers apart I took out the pads only and slowly pushed on the brake pedal to see how the pistons came out and to my expectations- on the right side one piston was coming out very easy and the rest were "lazy". So I blamed this imballance for the squeal. OOK
So threw away all the inner seals and re-did it with new ones. I used Frenkit for the pistons and seals on both sides (if that helps)
I took extra care to patiently clean everything, pistons went in no hassle, put special grease(not much) on all pad to caliper contact points, nothing seemed seized or anything else to worry about.
This is by far not my first brake job, and from my experience all went well.
Bled the brakes thoroughly with RBF600 Motul fluid, I also had brand new braided hoses for the calipers.
Went out for a test run and I swear after 500m - you can imagine the brakes were like new basically (beside the discs that I had run for a week with the old pads)- the right side caliper started to squeal AGAIN.
I really really have nothing else up my sleeve and have no idea what to do next (
All of this did cost me some money but that aside- not being able to fix it is really really sad.
I will take it tonight for a proper bedding in of the new pads but I'm skeptical that's gonna fix it.
What am I missing here?
Are these 4 piston calipers with two bleed nipples tricky to bleed? The pedal feels as it should- nice and firm, and the brakes bite decently even if they're not fully bed in at the moment.
Thx! (waiting for some brake guru to come with a solution )

If the brake pedal is decent then assume its bled up right, always bleed outer nipple first then inner. Sometimes the 4 pots take a few goes but the pedal is crap.

Bed the pads in properly and go from there.

My trophy wilwoods were doing all sorts of crazy s**t when i fitted new ds1.11 and reyland discs. It was pulling all over the place so i agressively bedded the pads in, took about 15 moderate to hard braking to get it all to work right. Ive had the same on megane brembos too especially on half used pads and discs, once matched up they were fine.

Wasn’t there a ‘thing’ a while ago about chamfering the edge of the pad to stop squealing?

Only thing that makes sense is there's still a difference in how the pistons slide in and out, thus pressing on a certain pad unequal and creating the squeal. Meaning that if one of the two pistons of a certain pad don't push by the same amount it creates that sound. Maybe there's some tiny air pockets behind one of them pistons and they're lazy coming out?
But the strange thing is- it happened twice on that same side- that I wasn't expecting after I re did the whole job.

Daniel said:

Wasn’t there a ‘thing’ a while ago about chamfering the edge of the pad to stop squealing?

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Oldskool method, little chamfer on the edge of the pad to stop squeal. I do this to cheap stock pads on the povo spec clios.

Daniel said:

Wasn’t there a ‘thing’ a while ago about chamfering the edge of the pad to stop squealing?

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That I think was applied to the std calipers when mounting ds2500 pads that were a very tight fit. On these 197 calipers the pads move freely, so I don't think that's the issue

ripp said:

Only thing that makes sense is there's still a difference in how the pistons slide in and out, thus pressing on a certain pad unequal and creating the squeal. Meaning that if one of the two pistons of a certain pad don't push by the same amount it creates that sound. Maybe there's some tiny air pockets behind one of them pistons and they're lazy coming out?
But the strange thing is- it happened twice on that same side- that I wasn't expecting after I re did the whole job.

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Id give them a bleed and let them settle in.

When you say right hand side i assume you mean o/s/drivers side. This caliper always works harder than the passenger for whatever reason, i always see more brake dust on the o/s front on both of my diesel clio's with calipers working as intended.

Oh wait, you are talking about chamfering the pad material right? Well the Valeo pads were chamfered from factory and it still squealed like a stabbed pig so it's not that

Brigsy said:

Id give them a bleed and let them settle in.

When you say right hand side i assume you mean o/s/drivers side. This caliper always works harder than the passenger for whatever reason, i always see more brake dust on the o/s front on both of my diesel clio's with calipers working as intended.

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I'm saying right hand side as it's simpler to identify as I'm driving an LHD car 🙂

I will try a re-bleed because that's the only thing I could do, I'm out of other ideas

Id just run it if the caliper is not sticking, and no other issues i.e caliper hitting disc or duff wheel bearing causing disc to move.

Get some pad material onto your discs and go from there.

Brigsy said:

Id just run it if the caliper is not sticking, and no other issues i.e caliper hitting disc or duff wheel bearing causing disc to move.

Get some pad material onto your discs and go from there.

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I just came from doing a proper bed in session. Nice blue ish material deposit on both discs, I also had an infrared thermometer and measured temperatures both sides - gradually went up in braking force and ended up to about 200°C on both sides (measured the discs), max difference left to right was about 10°C so that was fine.
The brakes feel good, they bite as they should.
Everything's fine except that horrible squeal that yeah, it's still there. If it were just a little squeak I'd be fine with it but I wake the whole neighborhood with it so not ok
I'm starting to think that the caliper is at fault... Will do a bleed one more time but honestly I have low expectations

Good idea with the infrared thermometer.

'Mintex ceratec anti squeal' paste kit is great. Well worth a go - it worked for my brembo set up, I had squeel and this stopped it.

Are you sure it’s the calliper?

I would make sure the pad slides freely. Ferodo pads are notorious for being too big.
Then I’d go back through the installation of the brackets ensuring all the mating surfaces are clean/free from corrosion, washers are applied (if any are used normally), and torque it up to spec.

The 197 calliper bolts are 105nm

Also check to make sure there’s no play in the wheel bearing and that the hun nut is tightened to spec too (it’s 175nm)

If everything is fitted right and the car performs as expected, then I can’t really think what else to suggest.

Gus said:

Good idea with the infrared thermometer.

'Mintex ceratec anti squeal' paste kit is great. Well worth a go - it worked for my brembo set up, I had squeel and this stopped it.

MINTEX CERA TEC & ANTI-SQUEAL SHIMS STOP THE SQUEAKING BRAKE PADS | eBay

1 x MINTEX CERA TEC 75ml. (4) MINTEX SHIM ADHESIVE PADS. SHIMS ARE USED TO REDUCE / ELIMINATE THE SQUEAKING NOISE FROM BRAKE PADS. NORTHERN AND SOUTHERN IRELAND, ISLE OF MAN AND ISLE OF WIGHT ETC. NOTE:IMAGE FOR ILLUSTRATION O.

www.ebay.co.uk

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Do these hold up to trackday temperatures? Wouldn't want them brakes on fire 😁

RSRowe said:

Are you sure it’s the calliper?

I would make sure the pad slides freely. Ferodo pads are notorious for being too big.
Then I’d go back through the installation of the brackets ensuring all the mating surfaces are clean/free from corrosion, washers are applied (if any are used normally), and torque it up to spec.

The 197 calliper bolts are 105nm

Also check to make sure there’s no play in the wheel bearing and that the hun nut is tightened to spec too (it’s 175nm)

If everything is fitted right and the car performs as expected, then I can’t really think what else to suggest.

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Not so sure it's the caliper but it kinda points there. I used a torque wrench to tighten all down. As far as I last checked the wheel bearing is ok and tight. But will do a re check, thx!

RSRowe said:

Are you sure it’s the calliper?

I would make sure the pad slides freely. Ferodo pads are notorious for being too big.
Then I’d go back through the installation of the brackets ensuring all the mating surfaces are clean/free from corrosion, washers are applied (if any are used normally), and torque it up to spec.

The 197 calliper bolts are 105nm

Also check to make sure there’s no play in the wheel bearing and that the hun nut is tightened to spec too (it’s 175nm)

If everything is fitted right and the car performs as expected, then I can’t really think what else to suggest.

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And yes the pads move freely, I had the experience with ds2500 pads on the old std calipers and I obviously made sure there’s some free movement there

Never had DS2500 squealing, used them on a few cars with single piston, 4 piston and 6 piston callipers. With and without shims.

Have the callipers been machined correctly so that they sit in the correct position on the discs?

Ph1 Tom said:

Never had DS2500 squealing, used them on a few cars with single piston, 4 piston and 6 piston callipers. With and without shims.

Have the callipers been machined correctly so that they sit in the correct position on the discs?

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I have some odd adapters custom made, but the calipers sit ok, but will do a re-check to be sure.
They look like this:

You could try to take the pads out, but leave it on the disc, and have someone slowly press the brake to see if all pistons are moving at the same speed, or if one is sticking. Just don’t let them pop out or you’ll have to start over.

I’ve used the frentech service kit - it was absolutely fine so I wouldn’t worry about that at this stage.

ripp said:

I have some odd adapters custom made, but the calipers sit ok, but will do a re-check to be sure.
They look like this:

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Normally the brackets are one piece to give more stiffness. Maybe yours allow the callipers to flex.

Ph1 Tom said:

Normally the brackets are one piece to give more stiffness. Maybe yours allow the callipers to flex.

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I've thought about that but if the nut that holds the caliper to the adapter is tight and then the adapter is tight to the hub there should be literally no flex as the adapter itself is a long bolt that goes through the caliper and then the bolt that secures it to the hub is close to the mating surfaces between caliper and adapter so very little leverage for flexing. Of course I'd rather have them in one piece but I think it should be fine.
Plus, the other side is totally silent, I imagine if there was a design flaw big enough to create a noise that wakes up the whole neibourhood I'd expect it to be present on both sides.
I also marked the bolts and nuts that hold everything in place with white marker paint to observe if anything comes loose. So far so good

They do look quite crap. I wouldn’t want to run them personally.

Switch them side to side. That’ll prove if it is them

RSRowe said:

They do look quite crap. I wouldn’t want to run them personally.

Switch them side to side. That’ll prove if it is them

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They work with the 280 discs without having to drill the calipers like with the PMS kit. I don't know other brackets that can be used without modding the calipers. If you do then let me know. I'll Switch them and see

sub said:

You could try to take the pads out, but leave it on the disc, and have someone slowly press the brake to see if all pistons are moving at the same speed, or if one is sticking. Just don’t let them pop out or you’ll have to start over.

I’ve used the frentech service kit - it was absolutely fine so I wouldn’t worry about that at this stage.

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I did the piston test and they moved as they should

To sum it up:
1. Get rid of the squeal
2. If these brackets last me this season I'm happy.
I'm gonna switch to 300mm discs next year and probably the pms dedicated brackets.

Back again.
Took out the caliper, Inspected and cleaned all contact points, re checked the pads for free play, wheel bearing seems ok (no play). Put it all back together nice and tight an it still squeaks.
I swear to God I have this car for 18 years, went through engine and gearbox rebuilds plus other clio stuff but this thing puts me into depression.
No fkin idea what to do next

Have you tried swapping the pads side to side? Any videos of said noise?

Did you try swapping the adaptors from left to right like I suggested previously?

RSRowe said:

Did you try swapping the adaptors from left to right like I suggested previously?

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I booked the car at a garrage on thursday to be checked, maybe extra brains will do something. Didn't swap the adaptors because it was late an I had no time left last night, but will surely be doing it on thursday, I'm kinda pissed off because I planned to do it yesterday but as said time only allowed to do only what I described

Matt Cup said:

View attachment 1697624

Have you tried swapping the pads side to side? Any videos of said noise?

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probabably will try that too. plus the ear plugs lol

How many miles have you done on these?

Udder Nonce said:

How many miles have you done on these?

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mhhh not much at all, maybe 100, but I did bed them in properly. I know I was thinking the same- just let them settle even more but trust me- the noise is unbearable

ripp said:

mhhh not much at all, maybe 100, but I did bed them in properly. I know I was thinking the same- just let them settle even more but trust me- the noise is unbearable

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Is it continous?

Udder Nonce said:

Is it continous?

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once the brakes heat up a bit (after the first 10 brake applications from cold let's say) yeah, the noise is high pitched and continuous at moderate to low pedal pressure, when stamping on the brakes hard it goes away most of the times but I can't brake like a hooligan all the time lol. And it does it alt all speeds, high speed, low speed and coming to a stop- which I guess annoys my neibours when entering the hood

Im not keen on the adaptors, caliper might be slightly off centre causing the pads to not hit the disc perfectly square.

Id go for a proper setup like pms personally.

ripp said:

To sum it up:
1. Get rid of the squeal
2. If these brackets last me this season I'm happy.
I'm gonna switch to 300mm discs next year and probably the pms dedicated brackets.

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I've got a set of 300mm pms brackets that I've just taken off my car if you're interested 👍

Brigsy said:

Im not keen on the adaptors, caliper might be slightly off centre causing the pads to not hit the disc perfectly square.

Id go for a proper setup like pms personally.

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I'm not a fan of them brackets also but they came along with the calipers from the guy that sold them. And for now I wanted to run the 280mm disc setup. The PMS kit which is lovely made indeed requires you to drill and take off 5mm from the calipers in order to fit the 280mm brackets which I didn't want to do for two reasons:
1. I can't trust anyone locally to do the job properly (I'm not in the UK where u guys are lucky to find endless places who can do a good job)
2. I'm thinking in going to the 300mm setup maybe next year so altering the calipers was not something I wanted to do, so I'll probably get the 300mm brackets anyway just not this moment
Will do a re-check on the caliper alignment at the garrage appointment on thursday and see if we can find something

MLB said:

I've got a set of 300mm pms brackets that I've just taken off my car if you're interested 👍

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thanks bud but for the moment I'm trying to keep this setup and make it work Maybe next year if you somehow don't let them go

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