Discs don't warp under road use. They will be badly fitted, badly machined from new, or have pad deposits on them.
How did the mechanic check them for runout? It's best to get them checked by a competent precision engineer on all 4 faces.
You sound like you know how to change them yourself, so best to diy them.
I'd give Brembo's a chance, after all, they are well known for braking systems. They had those entry level discs, quite affordable and hopefully, more reliable than other aftermarket brands.
Regarding the skimming, I can't see how that would fix the problem for good, unless maybe the discs only warp to a certain extent and then they stop. It would then make sense skimming them, if you would know they won't warp any more. At least, this the only explanation I could imagine. I would try it though, seems less likely, but maybe the guys at the garage know what they're talking about?
pagid are the company that makes bmw original equipment at least they used to dont know if they still do, i have fitted there discs and pads to 3 different cars fo mine and never had a problem, i know this may not be helped but as for town driving if your stopping and staring all the time doing short journeys this will not help as the brake swill never reach a decent temperature which can eventually lead to warped discs. with regards to what you said about the last 4 sets of discs the pads should have been changed each time for a new set on both sides as uneven pads can also cause warped discs over time, if your handy with a socket set and spanners then try fiitning them yourself, just make sure everything is cleaned properly before fitting the new discs and pads making sure the sliders are free and there is no brake dust or corrosion on the carriers
Once again thank you for all the helpful advice.
A little internet research came up with this article.
I found it interesting and it touches on some of the comments here about driving style and bedding in in a second document.
The bedding in procedure mentioned is not a technique I have ever used. I suppose since the days of asbestos in brake pads has been over other materials have had to be found which have their own characteristics. I have copies it here.
1. Drive slowly for a few kilometres, using the brakes gently to bring them up to a moderate operating
2. Perform 6 consecutive brake applications of increasing intensity from 100 km/h down to 30 km/h.
If wheel lock-up (or ABS activation) is referred to as a 100% brake effort then you should be aiming
to build up to a 60 - 70% brake effort for the last 2 applications. The applications should be
performed consecutively, accelerating normally back up to 100 km/h after each application, before
3. If possible, do NOT come to a complete stop throughout the 6 brake applications described above.
Doing so canl result in ‘pad etching’ during which friction material is unevenly deposited onto thebrake disc causing DTV and brake judder. The will be visible as the outline of a brake pad on the
disc surface. (To learn more about pad etching and DTV click here)
4. It is normal to experience a strong smell and even see a small amount of smoke rising from the
brakes from the 4th application onwards. This is not a problem. Be prepared to experience “green
fade” from the 4th application onwards.
5. Drive on, using the brake as little as possible, for a number of kilometres allowing the brakes to cool
substantially in the air-stream before parking the vehicle and allowing the brakes to cool
completely. This cooling cycle is important.
Many thanks for the info about ECP discount "payno". Very useful. BTW did I brake a rule?
Pads pads pads...
What have they been doing during this?
Are the same pads being used?
i assume the calipers are in good condition with the pistons returning to the cylinders on release (i.e. are not partially seized/seized) if the pads are constantly rubbing on the disc this will cause heat build up and potentially warp them??
The pads were left in each time the discs were changed. I was reassured that they were "re-faced" so as not to interfere with the bedding in process.
Also callipers were inspected and again I was reassured all is well with them. The road wheels spin freely when the car is jacked up so I must assume that all is OK.
Just wish I had somewhere undercover to do this job my self. The problem of a gravelled drive is not to be underestimated :-(
Pagid are supposed to be a decent brand, and if you've got warranty on them all the better.
- 20% is prob what eurocar parts sell them for trade price.
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