Front disc rotors on '03 Disco

...and snipped-for-privacy@internet.com spake unto the tribes of Usenet, saying...

Your mechanic was partly right. The wear leaves a ridge which contacts the sides of the brake pads rather than the friction area and makes them rattle and squeal at low speeds. If the disc (rotor) was contacting the calipers you would have a real problem. I cured it on my P38 (similar axles) by replacing the discs - a very easy job. If these have been replaced, were new pads fitted (I should hope so)? If so, taking the pads out and applying a small amount of copper grease to the backs and any areas that might contact the calipers might cure it. Easy or heavy on the brakes should make no difference - correctly set up, they should work and not squeal.

Thanks for your reply. I may have misunderstood what the wear-created ridges on the rotors were contacting, maybe it was the side of the pads -= I was picturing that contact to be to the caliper itself. =20

The pads were not changed. On my next routine visit to the dealer I'll explore changing pads and ask about the use of copper grease.

With my limited mechanical experience I'm still surprised that the pads were fine but the rotors wore out!

Thanks again,

LB

...and snipped-for-privacy@internet.com spake unto the tribes of Usenet, saying...

I'm very surprised the pads were not changed with the new rotors. The pads contact most of the disc/rotor area, but there is a small band on the very outside, perhaps 2mm wide, where they do not. As the disc/rotor wears, it leaves a step on the outside of the disk which will also corrode as it is not swept by the pads. As the pads oscillate slightly, a step is also worn in the side of the pads. It is the interference between these two steps that caused the pads to vibrate and sqeal. There is a similar unswept area on the inner part of the disc, and of course the same on the other side. In effect, the pads and discs wear a pattern into each other, and it is always good practice to replace both if you are replacing the disc.

I doubt if the original pads lasted 38k miles, so they will have been replaced at some point. With a heavy vehicle like a Disco, a very hard pad compound is necessary, which does tend to wear the discs out in time. These days I regard brake discs as consumable items, which will probably need replacing 40-80k miles from new. 38k seems quite soon, but doesn't surprise me.

The copper grease dodge shouldn't, strictly speaking, be necessary if all the parts are fitted back correctly with new anti-rattle shims etc, but in reality it is often the cure for an annoying squeal that won't respond to anything else. Just make sure that only a smear is used, and can't get anywhere near the friction surface.

Yes, that seemed strange to me too but I was assured the pads had very little wear. In fact, the service mgr also asked if I had replaced the pads. I've had the vehicle serviced only at the dealer (free periodic servicing) and unless the dealer did it without telling me (or making a record of it) the pads are original.

=20 Perhaps in a few thousand miles some wear on the rotors and a little more wear on the pads will eliminate the squeal completely. I think it is a little better. I'll wait until the next scheduled maintenance

I appreciate your input. Mainly, I was surprised that the vehicle needed new rotors given the mileage, my driving habits, etc. and wondered if others might be having a similar experience because of a Land Rover deficiency in materials or design. Guess not.

Thanks again.

LB

In message , Margaret and Loren Block writes

I ran a Td5 (diesel) automatic Discovery II from new in 2000 until I part-exchanged it five years later, with 58,000 miles on the clock. It was main-dealer serviced throughout and MoT tested at three, four and five years and brake discs (rotors) and pads were never renewed, or even mentioned.

I believe there was a major change in brake components in the '03 Disco. = We had a '00 Disco (gasoline) that was a bit iffy on high-speed quick stops however when trading the vehicle with 44K miles the brake components did not show sufficient wear to warrant replacement. The '03 Disco has preformed noticeably better on braking. LR appears to have traded rotor life for braking performance.

That's interesting. I part-exchanged my 2000 Discovery for one of the last of the Discovery IIs, a six-months old September 2004 model, and that has much more reassuring braking (and is a noticeably better vehicle overall). Its current mileage is only 15,000, so I have yet to test your theory.

I believe there was a major change in brake components in the '03 Disco. We had a '00 Disco (gasoline) that was a bit iffy on high-speed quick stops however when trading the vehicle with 44K miles the brake components did not show sufficient wear to warrant replacement. The '03 Disco has preformed noticeably better on braking. LR appears to have traded rotor life for braking performance.

I think my discs are original at 225,000 miles. I've driven the car for

TonyB

I understand that some squealing can be caused by glazing on the pads. I tried several consecutive hard stops at high speed to melt the glaze, but the squealing continues. Sounds like it might be working for you.

Very impressive mileage on your discs. What year / model is your Land Rover?

Thanks, LB

Very impressive mileage on your discs. What year / model is your Land Rover?

Thanks, LB

It's a '92 Disco I 200 TDi. The new discs seem to have cured the wheel wobble I've been banging on about for months now. I've spent a fortune on new tyres, balancing, tracking and checks on steering geometry and pre-loads and at last seem to have found the problem.

TonyB

Dammit, I was premature on that last statement. Just driven from Norfolk to Birmingham and back today and the wobble's still there. It's moved up the speed scale a bit and it's not quite as bad, but definitely still there. So it must either be a square tyre ( although I swapped 'em all round with the spare recently, that's how I b*******d the spare wheel carrier) or maybe a bent shaft of some sort.

TonyB

Hi Tony

I'm not familiar with something as new as an '03 Disco (or your previous posts on the wobble) - I had a wobble on a Range Rover that was due to the panhard rod bushes being worn - if an '03 Disco has such a thing - have you checked the bushes?

Graeme