Should discs be changed?

[Dan1502]

My E53 3.0D Sport front discs are at 29.2 mm thickness.

I believe the minimum is 28.4 mm.

I checked them as the MOT guy said the pads are ok but low though to me there seems to be a fair bit of life left in them.

I shall be changing from winter wheels back to summer (which are being refurbed and having new tyres fitted) so am wondering whether the discs and pads should be changed at the same time.

Any thoughts?

[fenj66]

as long as their not warped or causing any other issues like being rusty on the outer brake surfaces, i wouldnt spend money unnecessarily. mot guys always seem to reckon things are low or near the limit, must be some sort of ass covering!

[Dan1502]

They're working fine.  The rears have been changed but the fronts have been on from new I think so about 35,000 miles.  I'm just wondering whether they're pretty close to needing doing as if so they might as well be done whilst changing the wheels over.

[fenj66]

i would say at least double that mileage before expecting discs to need changing.
im surprised the rears needed changing at such low mileage though!

[X5Sport]

Might be a 'demon late braker!!'  That would wear them faster.

Richard

[Raj]

Discs being replaced at 35k miles isn't unheard of tbh. It really depends upon vehicle use. If you spend ya life on the motorway then yes they will last a hell of a long time.

Tbh the way to check discs is if there is at least a 1-2mm lip then they are up for replacement. The ability to warp or crack discs when more than that limit of wear becomes a very high probability.

[Dan1502]

The rears were changed due to a grinding noise as a result of corrosion.  Cleaning them with a wire brush worked for a while then the problem returned so the discs, shoes etc were replaced to solve the problem once and for all.  I'm certainly not a demon late braker.

Pricing things up on bmmini parts it seems to be just over £200 for discs and pads if changing bolts and sensor as well or £295 value fitted deal at the stealers.  Based on what you've said I think it's probably worth leaving them at least another season then.  Whether I then change the discs as well as pads is to decide but part of me thinks if they are likely to need changing during the period we intend to keep it we might as well have the benefit of the new ones.

[Dan1502]

Driving is mixed but I would say probably more of an emphasis on shortish journeys.  My wife has used it to commute a lot since we owned it which is not far but a mixture of motorway and town driving.

I guess part of me is thinking it would be nice to have new brakes all around but there's no point spending money unnecessarily.

The lip isn't particularly deep but I shall measure the difference between the edge and worn part of the discs with the verniers when I get a chance.

[Smeeagain]

Obviously it is down to driving/braking style, but I have 102,000 miles on my front and rear discs since I changed them. I do a lot of motorway driving.

[shadrack]

always change the pads when putting on new discs, also the pads may look like theres alot left on them but if there is a large lip on the disc they may catch before the pads are well down.

also if you cant tell for yourself if they need changing and don't trust the mot mans view get a second opinion, please don't leave on another season from forum advice off people (no offence) that havent seen them in the flesh! brakes are a pretty essential bit of kit