AlanG wrote:
On Thu, 15 Jul 2010 15:02:31 +0100, The Natural Philosopher
wrote:
AlanG wrote:
On Thu, 15 Jul 2010 05:15:53 -0700 (PDT), Jo
wrote:
Hello,
My car was taken to a garage for an unrelated problem. The garage said
my brakes were worn and needed replacing. They charged me £30 for the
parts and £55 for labour (excluding VAT).
The guy seemed shifty - he said if I paid with cash I wouldn't need to
pay VAT!
You don't get a receipt and no proof of work done if anything goes
wrong
http://img197.imageshack.us/img197/8355/brakediscs.jpg
Are these brakes worn and were his charges reasonable? I estimate the
thickness of the abrasive portion of the parts to be 5mm thick.
Replacing pads depends also on the disc thickness. It wears too you
know. Quite possible to need a change at 5 or 6 mm depending on the
mechanical characteristics and wear. But even on a good disc I've been
recommended it should be done at a minimum of 2mm. Safety first.
On the pics they look borderline.
Sorry for my ignorance on the subject, I'm a medical student!
Thanks.
A quick search pulled up this.
Reading it and looking at the pics should give you some idea.
Its rear pads but the principle is close enough.
http://www.alcester-racing-sevens.co...brake_pads.htm
Yes. Two points
- no pad material left is not the point at which the brakes are worn to
the point of needing replacement: as that article points out, less than
half the original thickness is where you start thinking about it. The
same goes for disks, Skimmed discs are no longer accepted, not because
they are not flat, but because most car brakes rely on a big chunk of
steel to absorb heat in a highs speed emergency stop. very few road cars
can do more than one or at most two stops from 100mph, in a row, or
three or four from 70mph.
- that site is a racing car site: see above for why brakes need to be
more than 'MOT specification'
I dug it up as an example because she was uneducated in these matters.
So I say, marginal call. If you drive slow, and not often, and dont use
the brakes much and are a skinflint, they would do a year. If not, they
would have scored the discs within a year. Costing a LOT more.
Yes.
I would have changed them
I just spent 400 quid on replacing two exhaust gaskets. Camper passed
its MOT but was blowing from the manifgold, and I was getting dopey and
a headache after a hundred miles or so.
Every single stud needed drilling, extracting and replacing. They say it
took them two man days. I actually believe them, too. I've done a bit of
that in my time.
I once sat with a spark eroder for 16 hours getting hardened steel
studs out of an aluminium honda cylinder head. Not nice 
Those were the days. Not :-)
I think there is a more fundamental point at work here.
It has to do with a different mindset.
To may people a car is a thing with wheels that gets them from A to B
and that's it. Its 'safe' if it passes an MOT and its 'legal' if it has
the relevant paperwork to prove it, and is driven within a strict set of
guidelines that are nothing more than that. A strict set of guidelines.
Those of us who have been more deeply involved with cars, see things
differently. Its a machine, and engineering compromise, nowhere near as
safe as it could be, and only as safe as it needs to be, or can be, at
the price it's sold at. When we get into a car, we are acutely aware we
are in control of a lethal weapon that kills 3000 people a year, and
that its safety as such is eroded next time, and the only effect the
annual MOT has is that the grosser examples of cars that are not fit to
be on the road, are, by and large, kept off it. Good maintenance will
lift its safety margin considerably above the 'legal minimum'
When I test drove an XKR 'Silverstone', I did an emergency stop on an
empty road from 130mph. That car had what I call proper brakes. Not
racing brakes, but proper brakes for a road car. I believe Porsche has
similar. Brakes that really will stop you from autobahn speeds without
fading, again and again.
The jaguar double wishbone keeps you stable on an bumpy curve. In the
way a McPherson strut never will. Anyone who has driven a Triumph
Herald, vitesse or spitfire knows that whilst the front suspension is
almost best of class, the rear is undoubtedly the worst. Its
comfortable, but alarmingly unstable.
Where do you draw the line? Pads are cheap, and burnt out brakes are
something you wont discover until you really need them, and then its too
late.
I used to maintain my sports cars to a far higher standard than the MOT
required. I could feel wheel bearing play, and suspension play. You may
not normally need to hit a crisp packet in a fast swerve at 70mph, but
perhaps one day you may need to. I don't mess with car maintenance of
the brakes tyres and suspension or seat belts.. That's *all* that keeps
you on the road, finally. What price your life? or a major injury?