Porsche Enthusiasts Club Forum

This being my first Porsche I was surprised how hard it was to stop when applying the brakes, I mean you have to put a lot of pressure on pedal before it will really slow down, it don't know if this is normal? the pedal is high up in car and hard, does not feel as if it is a fluid issue. The brake discs look nice and shiny:) I have felt the front discs and they have quite a bit of a lip on them, I have ordered a Vernier Caliper from amazon, only £5.54 delivered..I will measure their thickness..
Front new 34mm and Rear new 28mm
If my discs when measured should be below the above specs by approx 2mm I should replace.

If discs need to be replaced?
There are a number of options for replacing ie
original Porsche, £200 each
OE £66.00 each
EurocupGT £78.00 each

or other ???



If discs are to be replaced, need advice on which type of pads too..

BTW I have requested a 2 yr membership from Tipec

The pedal will be harder, most modern cars are overservoed so use very light brake pedal pressure. Porsches luckily don't do this, pre ABS it would have helped resist locking wheels as well.

As for Discs then I've used Sebro & Zimmerman in the past with no issues. So any decent OE disc should be good, talk to Jon at JMG Garage who is on here & also Promax as regards bits. You'll need pads with your new discs as well.

As regards measuring then a quick way to tell is whether there is an large lip on the outer edge of the disc, if there is then there will be some wear. If you use a vernier you may need to remove that lip to get a true thickness.

Porsche disks usually tolerate about 3mm of total disk wear, which is 1.5mm per side.

Interestingly, Porsche disks also have a really interesting feature that all the aftermarket disks (that I have seen) also feature... each face of the disk as a 1.5mm bevel around the outside edge of the disk.. the cool thing is, if you notice that instead of a bevel, you have a lip on the outside of the disk, that side of the disk has worn bellow the specifications and should be replaced.

Often a disk will wear more on one side than the other, and as a disk that is vented in the middle, either side being worn by more than 1.5mm means that side of the disk has worn too far to continue being reliable.

A few times in the past we have warned customers of their car needing new disks, and they have measured the thickness of the entire disk and complained that we have tried to rip them off, so it takes a bit of explaining to show them that as soon as the inner or outer face of the disks have worn to the point that they have a "lip" on the outside edge, we have to under out duty of car warn that the disks need to be replaced.

The other complaint we have had in the past is that after our warning a Porsche has gone on to pass an MOT, which again cannot fail a car on the disk being bellow the manufacturers tolerances, just on the brakes not being as good as the benchmark per tonne as a Morris Minor... Unfortunately a Morris Minor does not need to stop from 160mph, and is unlikely be able to accellorate between corners faster than the brakes can cool down, like a Porsche can.

The only reason I mention the above is that disk wear is a problem which can be potentially dangerous, as can assuming that the overall thickness of the disk is the important factor, as a caliper with sticking pistons on one side, will wear the disk on the opposite face.. 3mm of wear on one face would be a disk that is thinner than the minimum by up to 1.5mm!! which will see the disk cracking, especially if your disks are the drilled variety.

The other reason for saying this is that so many people rely on the MOT to warn them of potential problems, which can be dangerous, as mentioned above.

The disk wearing bellow the wear limits can be dangerous, we have seen some Porsche that have suffered a large part of the disk cracking and breaking away, usually through the brakes getting hot and then one cooling puddle has caused them to quickly cool and shatter or break... the result is often either a locked on brake (nasty at speed) or ripping the caliper clean off the car (even nastier at speed)

One last thing, the brake disks are cast, heat treated and then machined/ground.. on the surface they have a dense material, bellow the surface they have a porous almost crystalline structure.. One of the reasons for the brake disk having a wear limit of 1.5mm per side is so you never wear through into the inner metallic structure of the disk, which is why sometimes on a disk, you might notice the surface looks like it is peeling away, because it is! This is particularly common on the inside of Boxster, Cayman, 996 and 997 brake disks, which wear the inner edge more quickly than the outer.

Forget the measuring devices, use your eyes on the brake with perhaps feeling the edges of your disks with your fingers... any lip, change them.

Zimmerman are fine, they get a lot of stick sometimes on forums, but I think that is because a lot of people used to use them with EBC brake pads, which are seriously hard wearing on any brake disk, so many people ended up blaming the brake disk for wearing too quickly.

Sebro, Euro Car parts own brand, Not OEM as some people will have you know.. Would put them in the same league as Zimmerman, not too much wrong with them.

Pagid, part of the same company as Textar and Mintex, which supply Porsche (Pagid in the past and Textar now), these are OEM - Original Equipment manufacturer, or in other words, the people that supply Porsche themselves.