75 discs on an Alfetta

[Sam]

Hi Everyone

I have a spare set of new front 75 rotors and I'm thinking of using them on my Alfetta.

I've done a search on the forum to see if anyone has re-drilled these to fit the 4 stud pattern, and although there are many posts about using 75 discs on Alfettas,  I can't seem to find one dealing specifically with re-drilling them to suit 4 stud.

I've heard that people had done this, but when I looked into it at least one of the new holes would wind up very close to one of the old ones.

I'm worried about creating a weak spot where the disc may crack.
Any thoughts ?

Sam

[Sheldon McIntosh]

I'm worried about creating a weak spot where the disc may crack.
Any thoughts ?

That worry is called Darwinism, you should listen to it.

[Tristan Atkins]

Hi Sam,

When I swapped out the NORD motor with a TS on my 116 GTV, I also swapped over the front uprights, brakes and rotors.  I was keen to keep my 4 stud Simmons wheels so I purchased a new set of rotors and then had them machined to suit.  You can use one of the existing holes so you only have to drill 3 additional holes. Only one new hole is in close proximity to an original hole, all the others have plenty of material around them. You will also only be able to use one of the countersink screws to affix the rotor to the hub.

I can't promise you that they won't fail as I have not done any type of analysis. However, I can say that for the past 30,000km, including a sprint at Winton, they have given me no trouble. Actually, its the first time the car has pulled up in the straight line without fade for an entire sprint.

I would suggest that if you intend to use the 75 calipers that your also you obtain a set of 75 uprights. My GTV uprights had very little gusseting where the caliper mounts to the upright, the 75 uprights have significantly more material in that area. It would also ensure that all components (caliper, disc and upright) mate up correctly to one another. I would also suggest that you rebuild the front calipers with new pistons and seals, as well as changing the brake lines to braided.

Piston sizing in the Brembo, to my understanding, is the same as the std calipers so it should not alter the brake balance.

Best of luck with the upgrade

Tristan

[BradGTV]

ive done it, no issues and i doubt their will

[Sam]

hey folks ....

thanks for the advice, from most accounts It seems doable.

Despite my Darwiniistic worrys    .... I may just put those 75 discs to good use ...now I just need a set of calipers  ......

Sam

[BradGTV]

i know of some, but he wants $250 just for calipers? i dont understand why their so expensive?

[Duk]

i know of some, but he wants $250 just for calipers? i dont understand why their so expensive?

As they say: "Something is only worth what someone else is willing to pay."
There has been some Alfa stuff on Ebay for years always advertised at the same price. Clearly the seller believes it belongs at that price but no one else does...........