Brake discs

I recently replaced my front brake discs and pads and will probably replace my rear brake discs over the next couple of weeks. However, whilst lubricating the tonsils at the local, i began expressing my satisfaction about a job well done to a couple of friends who happen to be mechanics. I was a little taken aback when they asked if i had put them on the correct side, followed by the statement that the discs are right and left handed due to the internal webbing. I immediately checked my car and what they said seems to make sense. If the discs (zimmerman) are put on one way the webbing (with the disc rotating) will scoop air into the disc. However, fitted the other way, you would not get the same effect. Is there any truth in what they are saying. Luckily, i think mine are fitted correctly. Would be interested in comments as i am still just a beginner. Oh, and are the rear discs more problematic than the front ones?[&:] David

The discs ARE handed, and are marked L & R on the box. The rears aren't any more difficult to do that the fronts. I'm not sure if the Zimmerman disks are marked with a part number, but on Porsche parts if the third group of numbers in the part number is an odd number, then generally it is a left hand part. Even numbers are right handed.

Thanks Richard.[ ] I honestly can't remember if the boxes were marked etc and don't have anymore to check the part numbers etc. However, i assume that the correct way around would be to have the largest part of the web open when rotating to scoop the air in. Now that you have confirmed that the rear is no harder, i shall go ahead. Thanks again, David[ ]

Sebro or Zimmerman discs do rust easily but I think that is something to do with the actual chemistry of the discs that Porsche specify for their discs. If I remember correctly there is a fairly high % of carbon steel for heat conducting properties. Can't comment on the ones you mentioned as Idon't know them.

It's just surface rust, goes away again the first time you brake. If you want to change to a different brand you should use MORE money, not less, you usually get what you pay for. [ ]

Thanks to both. However, in the 4 years ive had the car i have had to replace brake discs both front and rear twice. I am reluctant to continue with sebro. I hear now that pagid are being promoted as being close to original. I like the idea of the ones quoted as being zinc coated and am looking for something which wont rust as quick. I also believe these to be 28mm thick. Not sure if sebro are considerably less. As far as rust is concerened Alex, if you looked at the ones ive removed you will find that the discs rust from the inside edge considerably. I machined down two discs previously but have turned them into what could be considered expensive clocks. Might re use these. Does anyone know what the minimum thickness should be, is it 20-22 mm? thanks

For a C2/C4 it is 26.6mm front, 22.6mm rear. There is a chart in the Member's Technical Articles section. [ ][ ]

Pagid are part of the tmd friction group and they also make textar pads which is what comes out of the Porsche branded box from the opc

Cheers everyone, will measure the ones i machined earlier. Still not had anyone comment on cheaper versions found!!! Wonder if this is telling me something OR have i stumbled across a new venture?

From personal experience on 2 BMW M3's (3.0 litre E36s), I found various aftermarket discs significantly inferior to the BMW OE parts & had to throw them away prematurely (less than 5,000 miles) due to horrendous brake judder induced by the discs wearing / distorting unequally arround the circumference. With each car I ended up back on OE discs - without the issues & whilst still driving the car hard. The problems may be less / eliminated if the brakes are used less "enthusiastically" & depending on the sensitivity of the car (My brother has fitted many aftermarket discs to Land Rovers with no apparent issues). Paul 2004 996 C2 40th Anniversary

If they are zinc coated surely as soon as the coating is worn away, won't the disc start to rust?

.....those ebay disc's look remarkably like extremely cheap and cheerful EBC's.......step away.

I wondered if these are any good: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150562208223&ssPageName=STRK:MEWAX:IT Seems like a good deal.

Like Minny said "Pagid are OEM" & those are Pagid.

LOL, true, but they're not going to be driven like a 996, if they're anything like our defender, top speed 80mph (with a bit of a run up, and providing there's no hills)

Yep, already clocked those on ebay. Looks like i will go for the pagid ones eventually as i think you get a better deal buying the pads with the discs. Next job lined up once ive sorted the radiators and condensers Thanks again everyone