356A brake drums

[roy mawbey]

Saw this on ABCGT forum. I wonder how much they look nicely machined.

https://www.youtube.com/watch?v=LrFSshR ... e=youtu.be

Roy

[simon james]

Cracking little video that Roy!
Thanks for sharing.

[pauldvern]

Question is........how much?



Paul

[jeremyg]

$8,500 for a set, reports ‘inautonews’.

[Winston Teague]

So are they/were they forged with the iron liner in place or is it shrunk in after machining? W

[roy mawbey]

I reckon shrunk in after. But a really good question Winston. You would need to really get the liner very cold and drum the opposite. But to get an even temp on both items and to the required levels, before before quickly trying then to place them together, using a special fixture? and press is not easy. The liner must surely have a reasonable lead for entry on one side to allow dead square entry. Then the drum must be set up and ground internally relative to the bearing diameter.

Hey the more I think about it the more complicated it gets! I am so pleased my originals work so well.

Maybe because its steel into aluminium the interference fit could take place just by having the lead in diameter and a press. Or heating just the drum?


What's your thoughts Winston or anyone elses?

Roy

[Mike Smith]

`A` --------- Fronts or Rears - £1,133-66 Each + Delivery & VAT

`B` --------- Fronts or Rears - £1,103-12 Each + Delivery & VAT

It is not just the fixing of the lining that needs to be considered it is also the Drive Splines on the Rear Drums

I believe that I am correct in saying that these are the first `A` Drums that Porsche has produced since original production. However, they have been producing `B` versions for a number of years and this is at lease the 3rd production run since the originals. I am not aware of any problems with the previous version of the `B` drums - lets hope that these meet the same specs.

Just for Info.
1) - Some Early Porsche `A` Drums would spin the splines (felt like clutch Slip) Porsche changed the design
2) - `B` Drums get rid of the Heat better than `A` Drums
3) - The alloy that the `B` Drums are manufactured from is different to that of the `A` Drums, `B` drums will corrode if stored for long periods in poor conditions. The corrosion often takes place between the Liner and the Drum producing high spots. (I do not know what the difference in the alloy is)


After Market NEW Drums
1) - We have had the complete Centres break out leaving the Wheel and Drum running on the Brake Linings - (60mm)
2) - Linings that turned and started to work their way out of drum - (60mm )
3) - Out of Round Drums - (40mm)

I am sure that we have had other problems through the door but that will do for now

[roy mawbey]

Mike,

Thanks for all that information. Its interesting and valuable for those who have real problems with drums. These items are so important to have right.

Roy

[vwgillybilly]

On my A I think there is one serviceable rear drum...

The fronts have been changed to B drums, one of which is literally peeling like an onion... The other front maybe ok but I doubt it, one rear is like dust & the other seems ok.

Just ordered CSP front & rear kits with their dual circuit master cylinder. Not purist I know but hard to see the difference through the wheels & more reliable stopping, plus the total cost is significantly less than four drums!

Gill

[john ruston]

Pace Products Haverhill produced 356 GT brakes that I used on both Pre A race car and my S90 Cab.

Tested under competition conditions .