accounting for lipped discs

My sqealing brakes I'm told are due to my 'lipped' discs. They have quite a big lip on them after 75k miles, it's a 2002 Corolla. A previous 1994 Corolla had 120k miles on it and virtually no lips. What would account for such a big difference? ... I dont think its the driving style either.

Reply to
John Black
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Its the material which the discs are made, most discs are a throw away item nowadays.

i think that when they introduced asbestos free pads the friction was reduced and now have to be used in conjunction with a softer disc material.

Reply to
Rob

I don't. Asbestos-free materials may be a bit more abrasive. Pad pressures may have gone up to allow for the lower friction, hence more wear.

The extent of the lip will depend on the positioning of the pad: if the pad extends outside the disk, the lip will end up on the pad. A pad which moves around a bit in service may result in their being less lip on the disk.

*Provided* the disk thickness is still within spec, it's not difficult to remove the lip. Jack up one side and take the wheel off. Assuming you don't have a limited slip diff, put it in first gear and start the engine. Using an angle grinder with a grinding disk, manually dress the lip on each side while the disk is spinning. (May be best to set the steering at an angle).

Not a method any manufacturer will recommend, but I can't see anything wrong with it (and I've done it a dozen times).

Reply to
newshound

Not recomended puts the disc out of balance and if your ham fisted you could warp the disc or cause stress cracks through disproportonate heating

Reply to
steve robinson

One reason for spinning the disk is that you can use a very light touch, no risk of overheating. While the removed material is at the periphery, it tends to be pretty symmetrical and its mass is small compared to what has already worn off the disk.

Reply to
newshound

Most people would not be able to tell whether the disc is still within limits in the first place and if it is as worn as it sounds it is knackered.. Nowadays discs are so cheap it is hard to understand why anyone would not just replace them. The OP (I am fairly sure it is the same one) has been grizzling about this problem for months. If the OP can't afford to or is too mean to, then it might be time to stop driving. Brakes that are as good as they can reasonably be are up there at the top of the list for vitally important bits, even above tyres, you don't ignore them.

Reply to
Mrcheerful

IMHO, you've been told wrong.

At 75,000 miles, they're very likely past replacement time. Get the thickness measured - it's likely they are worn beyond the limits. These days it's fairly usual to replace the discs every other pad change.

Reply to
Dave Plowman (News)

+1. I've never had squeal caused by lipped discs.

Manufacturer's tolerances or design might have meant the pads were closer to the edge of the disc, so there would be no discernible lip.

If the OP wants to know the minimum thickness, I'll be happy to post it providing details of exact model are given, including whether it's an 'up to' 2002, or 2002 'on'.

A set of discs and pads can be had for under 50 quid delivered; that's less than the price of a decent angle grinder ;-)

Chris

Reply to
Chris Whelan

You've not found Lidl? Their angle grinders are brilliant. Buy three 4" for the price of a 'good' make - saves having to swap discs.

Also bought a 9" one from them some time ago - cheaper than hiring for a weekend. Soft start too.

Reply to
Dave Plowman (News)

agreed, 99 per cent of the time a cheapy is good enough, the only time you really need an expensive angle grinder is if you need to use it for hours at a go, the cheapies are generally too heavy or fat for long time comfort. Then you buy a Makita.

Reply to
Mrcheerful

Indeed. It's not even worth thinking about these days.

Reply to
Chris Bartram

I'm sure they're very good; the smiley was intended to indicate that I was making a tongue-in-cheek statement.

I'm not any sort of snob; I often buy the very cheapest items at the Supermarket I use. However, although I have both a Lidl and an Aldi locally, I don't like them at all for foodstuffs and household items so I don't get to see the short-lived tool offers very often.

Chris

Reply to
Chris Whelan

But I've got an angle grinder; several, in fact so that I don't have to faff around changing between cutting and grinding disks, a wire brush, and a sanding disk.

How long does it take to swap out a pair of disks, compared to two minutes with a grinder? ONLY after checking thickness, of course.

Reply to
newshound

That is some of the most fuckwitted advice I've seen on here in a long time.

Reply to
SteveH

go to their websites and get the emailed brochures, they generally do two a week each, then you can spot when to go.

Reply to
Mrcheerful

On Fri, 04 May 2012 12:01:46 +0100, newshound ventured forth with:

No, because it's fuckwitted nonsense. If you are that tight you can't or won't buy a new set of discs you shouldn't be on the road.

Reply to
Mike P
[...]

I've never had brake squeal caused by a lipped disc, but if I had, an even easier cure would be to run a file down the side of the pad to remove a tiny bit of pad material.

The only reason I can see to remove the lip would be to 'persuade' an MOT tester that the disc is not 'in such a condition that it is seriously weakened or insecure'.

Chris

Reply to
Chris Whelan

On Fri, 04 May 2012 15:59:45 +0100, newshound ventured forth with:

Depends what sort of PC or server it is.

Oh, you means discs?

Well I changed all 4 on my car a couple of weekends ago put new pads all round and cleaned and lubed the calipers. Less than an hour to do the lot, and I've got new discs and pads all round, rather than a nasty cowboy job.

Reply to
Mike P

Jesus wept.

Reply to
Rob

I bet he did when they used a grinder to cut the nails to get him down!

Reply to
Woodworm

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