930 floading disks, replacement floating parts

[aseem]

Last time I replaced the front disks on my '80 930, all the bolts that holds together the disk assembly, that is the alu brake flange (930.351.457.01) and the steel ring, snapped. Steel and alu held together with steel bolts corrode badly. The alu brake flange is very expensive to replace, so I drilled and re-threaded the bolt holes. Unfortunately, some of these holes are not centred correctly, so I have experienced increasing unbalance in the brake disks, and a shaking steering wheel during braking as a result.

I have taken the assembly apart to diagnose as I failed the bi-annual inspection, and find that several of the square spacers have come loose. It looks like the alu corrosion has come so far that they just fall off.

So now, I wonder what folks are doing to repair these floating brakes? Any suggestions are welcome

I see five options:

1: Bite the bullet and buy new parts (here in Viking country, the alu brake flange alone is over $700 a piece). Fore a piece of alu less than a pound!
2: Replace parts to update to '81 brakes (expensive).
3: Replace with a Big Red kit from one ove several suppliers. Also expensive, but at least I get better brakes. But, this deletes the use of my original 16" wheels. I do have 17" thou.
4: Have some one machine new parts. I tried this with a machinist I know, but he really didn't want to get involved in car parts involving safety, and I understand.
5: Buy this part from VCI, that I think replace the original part VCI-5500 which is a replacement for the floating assembly of the 78-80 930. VCI - Porsche 911- 930 69-89, 914/6 brake upgrade page (towards the end of the page)



See how the spacers tabs have just ripped out from badly corroded alu


First time I took these brakes apart, i thought that there were some kind of gasket between the alu flange and the break disk, but it was oxidised aluminium that could be scraped off. Look center top.

[Iciclehead]

Interesting, my 930 floaters are steel....I'd be uncomfortable with dogs that were aluminium for the exact same reason as yours failed....

Dennis

[aseem]

Thats weird. Could it be a difference between the US and RoW models? Is your an '80 as well?

[Iciclehead]

I believe that the floating rotors were only on the '78 and '79 Turbo's over here.....mine are '78.

I know that Porsche uses steel now as I had a pair machined using a loaned new part from my friendly Porsche dealer, it was definitely steel.

Dennis

[ELZ's930]

Only seen steel on the 78-79 930

[sundevil64]

My 78 RoW is steel.

[aseem]

It looks like a genuine part, and not like some after marked part... Black anodized.
The inside ring is steel

Her from the other side

[aseem]

I've ordered the VCI parts, and are looking forward to installing them in a week or so.