New brakes - issues?

safrane

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16,746
Be aware the OEM discs only have 2mm of surface before they are 'worn out' so any skimming will significantly shorten their life.

get them measured before soing this to see how much if any they are warped.
 

P R

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1,382
Be aware the OEM discs only have 2mm of surface before they are 'worn out' so any skimming will significantly shorten their life.

get them measured before soing this to see how much if any they are warped.

Thanks.. does the measuring take into account build up of pad material?

First port of call is still going to be the stripping and cleaning of the pistons / pins on the calipers..
 

MrMickS

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3,951
Thanks for the feedback. My issues started a few thousand miles later.. When are you off to Italy?

Heading off on the August Bank Holiday. So should have put 3k miles on between now and when I get back.

Everything does feel a lot sharper now. Especially with getting the tracking done and the same time. I did have a little wobble beforehand but knew that the tracking was out due to tyre wear which is what prompted all of this work in the first place.

Slightly concerned at a slight lip on the disks, given the reports of how thin the surface is, but don't have the spare cash to replace them at the moment. I'm anticipating these brakes not lasting as long due to that and having to replace the whole lot sometime next year.
 

MrMickS

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3,951
Brakes are still fine after the trip to Brands and back. They are a lot better than they were before I had the pads changed. I hadn't realised how bad they'd got.

One thing though. There are brake sensor wires, that presumably will light up on the dash saying that I need new brakes. If I was so low on the pads and these hadn't been triggered shouldn't they be set higher to prevent disk wear?
 

P R

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My brake warning didn't come on either when the dealer said they should be done. I expect the dealer is playing it safe (or maximizing revenue!) and changing the pads before this happens.
 

MrMickS

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3,951
I got the pads when they were removed. Not much left on the fronts, so I'm putting the lack of warning down to Maserati wanting to sell more disks ;)
 

CatmanV2

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48,539
I'm struggling to see why worn pads will brake less effectively than unworn pads. Until you run out of friction material, you've got the same surface area between the disc and pad, and everything else is equal. You may lose some thermal mass, and there may be some contamination but other than that.

Anyone?

C
 

davy83

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2,809
I'm struggling to see why worn pads will brake less effectively than unworn pads. Until you run out of friction material, you've got the same surface area between the disc and pad, and everything else is equal. You may lose some thermal mass, and there may be some contamination but other than that.

Anyone?

C
I agree worn pads should not brake any worse than new ones, in fact news ones don't brake well until they have bedded in so the shape of the friction material matches the steel they are up against. I think where you might see differences, is brake dust building up (this acts as a lubricant) and also rusty or pitted areas on the discs (or hubs with handbrake) and and also if you remove and re-fit used shoes they never sit quite where they were and the contact area is reduced for some time before they bed in again. So new discs and pads will give ultimately the best performance after the pads have bedded in.
 

CatmanV2

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48,539
All you say makes sense, Davy. I'd have thought the brake dust effect (if there is one) would be pretty minimal, and / or pretty immediate (that is you'd reach a static level pf brake dust pretty much after bed in is complete)?

C
 

P R

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1,382
Bit of an update. Took it in to the garage that fitted the discs, they measured the brake force on their MOT machine which showed uneven pressure on the meter, suggesting warped discs. They measured the run out using a dti gauge, and both discs were warped, with the high "spot" lasting around half of the disc (like they'd been folded in on themselves, obviously only slightly). They also checked the hubs, which were fine. The hub itself looked clean and the disc seemed to sit ok on the hub. I asked about the pads they said they looked fine and no signs they had been sticking.
At a loss now as to why this has happened, but only options are buy a new pair of discs or try the skim in situ route, which I think is worth a try.
I could try and email supplying Maserati dealer in NI but can't see they would be interested in replacing them under warranty.
 

philw696

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25,113
We do a lot of disc machining on the vehicle down here if they are in spec and it works well and New pads bed in nicely.
Maserati wouldn't do it only replace with new.
All about the sell and the bonus $$$$$.
 

P R

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1,382
Quote to skim the discs in situ was around £100 for the pair, and takes around 2 hours. I will book it in and report back...
 

safrane

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If the tech lit for the discs is correct there is only 2mm of hardened surface...hopefully your skim will not need to be too deep.
 

P R

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1,382
If the tech lit for the discs is correct there is only 2mm of hardened surface...hopefully your skim will not need to be too deep.

Yes hopefully so. From what I can see either the discs go in the bin anyway or I try a skim. I will get them to really clean / check pistons and sliders on the calipers as I am still in the dark as to why this has happened.
 

P R

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1,382
So they're done. Plenty of meat left on the discs. The run out was about 0.15mm.
He also stripped and cleaned the calipers. The end of one of the pads looked heat damaged. He also reckoned that they had been fitted dry so could have been binding or touching slightly. He applied brake grease not copaslip. It's obviously solved the issue so let's see how long it lasts....

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P R

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1,382
So they're done. Plenty of meat left on the discs. The run out was about 0.15mm.
He also stripped and cleaned the calipers. The end of one of the pads looked heat damaged. He also reckoned that they had been fitted dry so could have been binding or touching slightly. He applied brake grease not copaslip. It's obviously solved the issue so let's see how long it lasts....

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P R

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1,382
And the answer.. the usual few thousand miles. They aren't too bad but they have deteriorated again.

Fed up now
 

MrMickS

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3,951
After reading this I'm now not sure whether mine have deteriorated after running them for the 3000 mile trip to Italy and back. There is what feels like a slight judder through the foot on initial braking contact. That said I didn't really notice it when I was away and braking ******* the mountain passes so maybe its my imagination. I'll keep an eye, or foot, on it and let you know if it gets any worse.

I'm not driving the Ghibli as much during the week at the moment so maybe I'll notice more when switching between cars.