Original Brake Disc Series II needed

[ralphy75]

Hello,

Who can tell me which brake discs I need, for my 1962 SII. The discs are very rusty and I am curious which other car brand is using the exact same rotor discs. I did find original ones for 600$ each, which is ridiculous for a Sunbeam :-( and all Sunbeam specialists just offer S3-5&T discs.

I don't need conversion solutions etc. but only the identical discs, otherwise the current discs have to be straightened.

Thanks a lot!

 

[65sunbeam]

Can yours be turned down to make them true? Are the S2 discs larger in diameter from the later Alpines? I probably have a few early discs if you could let me know the dimensions of yours. They won't cost $600 either-that is crazy! Eric

 

[Barry]

Eric,

IIRC, the early discs are 9.85" diameter versus 10.00" for the later discs.

I recall several posters asking if the later discs can be "shortened" for use on an early series Alpine, but I don't recall seeing a definitive answer.

If you have both early and late discs, a good comparison (overall diameter, hub I.D., hub bolt pattern, offset, etc.) would probably be very useful.

 

[65sunbeam]

Thanks for that Barry!
I will check today and compare the two type discs and share the info here.

 

[DanR]

Certainly seems as if the disc could be put in Lathe and have the diameter turned down from 10" to the 9.85 dimenations Barry provided ? Why not? Could that be the "Shortened" method?

 

[Barry]

Certainly seems as if the disc could be put in Lathe and have the diameter turned down from 10" to the 9.85 dimenations Barry provided ? Why not? Could that be the "Shortened" method?

Could be, IF the hub diameter, hub bolt pattern and rotor offset are the same.

 

[ralphy75]

Thanks for the reply! So there is no existing set of identical disk brakes which is also being used on a Triumph, MG, Austin etc.?

 

[65sunbeam]

Here is a photo of a S2 disc on top of a later Alpine disc. They are lined up at the bottom to show the size difference. Just eyeballing it but the centers and offset look the same to me. I would get later discs turned down to fit.

 

[Alpine 1789]

Thanks for the reply! So there is no existing set of identical disk brakes which is also being used on a Triumph, MG, Austin etc.?

Not that I have ever heard. They are unique.

 

[ralphy75]

Is “shortening” the solution? I.e. Are all other specs the same between S1-II and S3-SV, like bolt pattern, offset, hub diameter etc?

 

[todd reid]

If no one here knows the answer to this, I would ask Rick at Sunbeam Specialties. If he doesn't have replacements for the early series cars, he more than likely has a work around.

 

[DanR]

Maybe someone that has a Series I or II can make contact with the SAOC (UK) and make an inquiry?

I have only SIV & V's.

Tried to measure a couple on my disc to get an idea.... looks like the offset is 3/8". I'll try some more tomorrow.

Sure looks as if this is an important aspect of the Sunbeam community to Keep'em-on-the-road

 

[Toyanvil]

I have some series II rotors that I can measure.

 

[DanR]

That would be great John!

 

[RootesRacer]

Years ago it was said that the SI/II rotors were almost the same as the SIII and later ones but the outer diameter of the rotor was a tad larger.
If this is true, a little lathe work would convert the later to the earlier but I would love to see those dimensions to know for sure.

 

[Toyanvil]

Here you go. I am pretty sure I have newer series hubs on my series II, so the bolt pattern should be the same.

 

[ralphy75]

Thanks a lot to all of you! I already got the discs straightened on a lathe. Much cheaper, fantastic result and still enough meat on the bone!

 

[DanR]

John, I believe these dimensions (thickness of rotor disc) will change if and when they (disc) are turned in a Lathe. I did what you show here with some SIV & SV disc.

 

[George Coleman]

Just a note about turning the rotors, the make up is what is called Ductal Gray Iron so be careful the dust is not to good for you! I had made some with the help of a friend who is a 35 year machinist, it sure was messy! You can get the material from McMaster Carr! Just 2cent worth

 

[Toyanvil]

That rotor is just a hair under .500 and should be fine to check offset to see if it is the same as later series, I would think it would be a go or no go. This is how I turn mine, this way you can turn both sides without re-clamping.