Might as well make a start... 14/12/03
Here's a nice example of what happens when the friction material parts company from the backing of a pad during an emergency stop from 25-30 mph!
This was a brand new disc 2500 miles before it was resurfaced courtesy of Lockheed...
(note the axle stand on extreme left and in shadow - ALWAYS support your XM on axle stands of sufficient load rating placed on the sill jacking points. NEVER work under or beside an XM solely supported by a jack. NEVER get under an XM with it's suspension set on 'high' under any circumstances.)
What you see below is exactly what greeted me on removing the wheel. No sign a pad, neither friction material or back plate!
Car stopped perfectly, with a slight graunch! On pulling away there were some strange noises (probably the pad back finding it's way out of the carrier) followed by the most horrifying graunch when the brakes were next (gently) applied. Unfortunately the piston wound up protruding about an inch and was rather difficult to retract. It was found necessary to depressurise the system and open the caliper bleed valve before it would wind back in.
The pads in question were Lockheed and with about 30% of the original material left. Absolutely no excuse for a failure of this kind in my opinion. They have been replaced with the brand I have used for some 30 trouble free years - Ferodo.
In a way the incident above was a lucky break. The tyres on this car were nothing special and I'd been intending to replace them for some months. After sorting out the mess above (and noting the inside edge of the OSF tyre was too well worn for comfort) I then swapped the pads on the other side (NSF) and was horrified to find that the tyre tread, of which there was some 4-5 mil left, was separating from the carcass around about 75% of the perimeter on the inside edge!
Unfortunately the picture doesn't do the state of the tyre justice, so here's a close-up.
Oh, what a coincidence, part of the tyre identification shows up on this... Well I never did like Michelins, and needless to say I'm not replacing these tyres with something from that manufacturer. By the way, it's not wear, the tread is simply parting company with the sidewall, like a cheap remould, not bad for a £80 tyre!
I wasn't happy with the ride comfort (too much thumping and roar) or the handling (soggy), though the grip, both wet and dry was OK, so I'd been keeping an eye on the tyres. But without either jacking the car up and grovelling underneath, or removing the tyres and inspecting the inside edges neither the lack of tread on the inside edge of the OSF (the side the pad auto-destructed on) or the tread separation on the inside edge of the NSF (above) were visible even with the wheels on full lock.
Take heed, you can have extremely unsafe tyres on an XM and be completely unaware of it even with regular visual inspection!
It's been an expensive weekend, and a sobering start to this section. Hopefully the next entry will be a bit more positive.