One of the many discussion points at MoT time has been the state of the rear discs and the marginal pass on the brake tester. Typically the rear discs and pads have lasted about 3 or 4 years on the C8 before needing replacement; they don't get much use unless the car is towing or fully laden and there's enough weight on the rear wheels to open the brake valve which polishes the discs.
This year I thought I'd try and get the discs skimmed and I found out how much the procedure has changed. I had visions of me casually undoing the rear calipers, braying the discs off with a suitably sized hammer (as I've done a few times before) and taking the discs to a local engineers (not done for years and years). There a chap in overalls would take a thou off each side, making the discs look like new, I'd hand over a few modest notes and be on my way. Nowadays, I'm informed, nobody does that any more. There's a franchise operation where you leave the whole car at a garage, they remove the calipers and pads and fit a machine that skims the discs while they are attached to the car. Whatever next?
The money involved for this project makes no sense. I was quoted nearly £100 for caliper removal and disc skimming in situ with a week to wait for an appointment, and find my own pads, but my trusty Ebay seller has delivered me a set of discs and pads for a few coppers less than £40. With costs like that, how does the in-situ disc grinding system ever get any customers? Have any of you had your discs skimmed recently? On the car or off? How much?
Last edited by: smokie on Mon 22 Apr 19 at 00:26
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I didn't think anyone would bother these days with it being, as you've found, are so cheap. I guess there's a market for people who like to do things out of habit or perhaps very specialised brakes that it's worth it do such a thing
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Never had disks skimmed in 45 years of motoring, I have filed off the rusty lip, but thats as far as it goes.
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Discs have a minimum thickness (usually cast in them nowadays) for a reason.
Many years ago I had total brake failure on the A2. Unbeknown to me, a previous owner had the discs skimmed. This resulted in a caliper piston coming out too far and lodging sideways, causing a little pressure to be applied to the pad. The resulting heat boiled the brake fluid. I hit the brakes and the pedal hit the floor!
I now use a micrometer to measure my discs every year.
Modern materials seem to cause the discs to wear as fast as the pads. Both are so cheap, I reckon it's not worth bothering about grinding the discs.
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Saw Ed using one of those machines on WD. It was however a Porsche. Presumably the discs on those are much more expensive than the run of the mill stuff that can be replace for not a lot at your motor factors of choice, thereby making it more cost effective.
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Agree, skimming discs while on the car seem to be acceptable for expensive discs that have a fancy way of attaching them to the hub when you are looking at maybe a grand plus for new discs and pads.
It's just not worth it for normal use, my ATE discs also have a indent machined into them to give a visual indication of when you have reached the minimum thickness as well as a number in mm.
Plus it's one of the satisfying auto DIY jobs still doable by a competent driver.
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Have deglazed pads and discs with emery, but that's it.
Disc skimming is firmly in the Colway remould era.
It's not like they cost that much to replace.
Discs nowadays are pretty much shot after one set of pads has worn down - if the pads are done I replace both.
Pagid and Brembo are my go-to brands.
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'Colway remoulds' Now theres a blast from the past. :)
When Eurocarparts have a 50% offer, which is nearly every other weekend, the brake parts are good value.
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>> 'Colway remoulds' Now theres a blast from the past. :)
Kingpin remoulds are still available, I've a couple in the shed that I used for trialling - once!
The last time I had new tyres they tried to tell me remoulds were illegal.
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I seem to recall Russ Swift used remoulds for his "driving on 2 wheels" record attempts as they had more rubber to wear out.
It seems 4x4 tyres work too..... www.youtube.com/watch?v=cIpBpGQ0XTI
Last edited by: Lygonos on Mon 22 Apr 19 at 23:15
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>> I seem to recall Russ Swift used remoulds for his "driving on 2 wheels" record
>> attempts as they had more rubber to wear out.
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>> It seems 4x4 tyres work too..... www.youtube.com/watch?v=cIpBpGQ0XTI
Pedant Corner
The wheels weren't changed, they were taken off and then put back in the same place.
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Wheel nuts were loose before they started as well.
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Just dropped the Berlingo off for new pads and possibly more.
Mrs B complained yesterday that there was an odd noise from rear, mostly whilst braking. She doesn't usually hear mechanical noises so it had to be something fairly gross. Sure enough a visual inspection through wheel spokes showed outer pad/nearside worn to backing and carrier doing an excellent job of de-lipping the disc!! Corresponding offside pad is probably 80% worn.
My guess is that nearside caliper is not retracting completely so pad has dragged but guess unworn one might have sized off. Latter though I think is unlikely rear pad wear on that car, usually driven solo unless the caravan's attached, is pretty slow and I'm in habit of doing visible wear checks through the spokes on a regular basis.
Drove it to local fast fit emporium very carefully and making minimum use of brakes. Mrs B followed in my Skoda. Everybody but her says she's in habit of braking late/hard...........
EDIT: Guy just phoned back. Disc shot. New ones are integral with bearing and ABS ring so £170 each. Ouch.
Last edited by: Bromptonaut on Mon 29 Apr 19 at 15:08
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Problem is, modern cars use brakes for traction control and Electronic Stability Programme (or whatever 3LA they use).
Daughter managed to wear out her rear discs in 30K miles - before the front ones!
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>> Problem is, modern cars use brakes for traction control and Electronic Stability Programme (or whatever
>> 3LA they use).
>> Daughter managed to wear out her rear discs in 30K miles - before the front
>> ones!
Was talking to manager/senior tech at fast fit place about loads/rear brakes. Recalled BX/Xantia with proportional valve that controlled rear brakes according to load on rear height corrector. He explained as above that these days rear brake application ir controlled by ABS/ESP.
Only time I heard noise on way to fast fit was braking to halt on arrival. Kept load off rear through local villages, while meeting Artic on horse/cart era bridge over River Nene and through suburban traffic.
Quite proud of that.
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My car is currently showing that the rear and front pads need replacing in 3,200 miles. Mind you, it’s said that all year... In my experience cars are remarkably easy on brake pads nowadays - I did 50k miles in an A4 convertible on the original pads, and 40k in the Merc. The e-tron had regenerative braking so not a direct comparison, but that didn’t need pads in our ownership, and the BMW has done 32k miles on its original pads. In fact, the last pads/discs I had fitted were to the 1994 Audi Cabriolet!
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>> .. In my experience cars are remarkably easy
>> on brake pads nowadays - I did 50k miles in an A4 convertible on the
>> original pads, and 40k in the Merc.
The trouble is, unless you have just the right kind of use, if the pads/discs don't wear out, the discs go rusty so you end up braking on narrow shiny band. And the back of the disc is worse than the front face.
I think helps to strip and clean brakes every 6 months. I'm past doing that sort of stuff now and I've asked a couple of garages and they won't do it as it doesn't make financial sense.
Funnily enough on my Merc, which had very rusty but little worn discs as it's only used for occasional long trips, I looked at getting them skimmed - our village garage does it. But he wanted to fit new pads and at the end of the day it wasn't much less than the indie I use was quoting for the whole job. They were quite a bit cheaper than the MB dealer though, so if that was your alternative skimming would make sense.
Last edited by: Bill Payer on Tue 30 Apr 19 at 11:39
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>> EDIT: Guy just phoned back. Disc shot. New ones are integral with bearing and ABS
>> ring so £170 each. Ouch.
>>
You're being diddled - they're only £107 each from the dealer.....
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Citroen C8 MPV - barke disc skimming/grinding - sooty123
