Whose disc brake?

[Ragnars-Frogeye]

Hallo all together,
I#ve just come up to a problem.
I'll convert from drum to disc brakes. I got them an now when it's getting cold I'll start converting.
The disc brakes I got have a disc diameter from (or of?) 210mm and a the thickness is nearly 8mm
I own some wire wheels for a long period and never converted. So on these wire wheels are old discs
240mm and 12mm. I know the car they were coming from an MG Midget!
I tried to read the numbers stamped into the discs
it seems to be 2ca 37730 the only number I can really read is 7730 or 773D.
Can anyone help to get the numbers and parts right?

[Jim Gruber]

Ragnar,

The important thing on the disc brake conversion is making sure you've got the correct steering arm. That also needs to be upgraded otherwise you will get rubbing. Steering arms from I think up to a '72 Sprite or Midget can be used. They changed the steering rack I believe after '72 to a Triumph Rack.Otherwise the drum to disc conversion is pretty much a direct bolt on. Be sure to inspect the wishbones from your donor Midget. I've done an upgrade of the front end twice now and found that many time the wishbones are worn or more importantly cracked and are unsafe to reuse. There are two grades of wishbones available through MOSS. The more expensive grade is a much heavier wishbone designed for rubber bumper cars. If you need to replace, that's the one I'd purchase. Fulcrum pins also wear and need to be replaced. A MOSS Major Suspension Kit has the parts you need. The Kingpins bushings will need to be reamed to proper size but a good machine shop should be able to do that for you or there are sources in the US that can provide. Consider a shock upgrade as well as you complete the front end rebuild. Peter Caldwell at World Wide Imports in Madison, Wisconsin will rebuild your shocks better than new with new internal parts that do not leak. Good luck with your project.

[Ragnars-Frogeye]

Hallo Jim,
thanks for your answer and all you mentioned is right. I've all the parts together to convert. The weather will become heavier now and that's a good time to convert.

The problem I have is the disc from the wire wheels which I bought nearly 30 years ago.
These discs have a diameter of 240 mm 9.4488 in.
Normaly a Spridget has a 210 mm 8.2677 in. disc.

So whose disc is it?
In the meantime I came up to some numbers that I can read now after cleaning and cleaning and ....
20A17730 or 2DA17730 another number seems to be G8050680.
I also measured the disc completely
Diameter 241.82mm = 9.52mm
Thickness 11.75 = 0.4625 in
Height complete 20.39 mm = 0.803 in.
I also measured the width between two opposite bolt holes
outer 94.38 mm = 3.755 in
inner 75.86 mm = 2,987 in
in Addition this is 85.12 mm = 3.3512 in for the centre of the bolt holes
diameter centre hole 66.82 mm= 2.630 in

As it seems that the holes for the4 bolt won't fit to a Spridget I asking me what sort of brakes that MG Midget in the end of the 70s had.

Sitting in a room looking out to very dark afternoon sky with heavy rain no Frogeye weather

[Charlie Tolman]

From 1962 through 1979, Sprites and Midgets had
one part number for brake rotors used with steel wheels, and
a different part number for brake rotors used with wire wheels.

Charlie T.

[Charlie Tolman]

Disk brake assemblies from a Triumph are sometimes used as an upgrade on other BMC or BL cars.
I am not sure if brakes from a TR-7 will fit a Sprite, but one source lists the rotor diameter of 9.4" or 239 mm, and another source at 241 mm. These values are close to your measurements.
This car was chosen as a random example, but the parts might not fit a Sprite. An Internet search of other Triumph models might prove to be fruitful.

I have a friend with an early-to-mid 1960s Turner, and some of the brake parts came from a Triumph model ( I do not know the model. )

Charlie T.

[Asolepius]

Re steering arms. I just finished the drum to disc upgrade on my Mark 1. I didn't change the steering arms, and although there isn't much clearance there is no contact. The 1500 Midget arms that came with the discs could not be fitted without changing the track rod ball joints - the tapers are a different size.

[Ragnars-Frogeye]

Hallo Folks,
all your answers are sounding good. As I was searching through the net I came to the Brembo Site.
There I could look up many discs. The bets thing is you can look up for special the model you want and also the disc itself.

I tried it all and didn't find anything. The TR 7 is listed there with 241 mm. but only 9.6mm
The MG B has 273 mm but all the discs are not so thick (or strong?) only 8.7
What I didn't find was the Sunbeam Alpine.
The Alpine has a front suspension similar to our Spridgets. Whether it would fit I don't know.

The Spridgets disc are all 209 mm and 7.7mm The different between wire wheel and steel wheel is the height Brembo said
The Austin Healey 3000 has 281 mm and 12,7 thickness
But the disc I want to know about is 240 mm and nearly 12 mm thick. I think it must be a car bigger than ours and with much more power. 11.75 is really thick for a normal disc.

http://www.brembo.com/deu/P-k-w/Ersatzt ... ischi.aspx
click on the small car and you are in the (Katalog) catalogue. It's really easy to use!

Next time I can look in will be Friday/Saturday. I hope in the meantime the Sunbeams will answer.

Thanks for thinking
9°C stars in the sky and my November-Frog in the Garage waiting to be driven.

[Jim Gruber]

Ragnar,

Since you are unsure where these rotors come from, skip the drama and order new. Your life is not worth the cost of new rotors and calipers or parts from a known donor..

[Ragnars-Frogeye]

Hallo Jim,
for my Frog the parts are all there - rotors hubs and all
The intention of my question is to come to know whose rotor it is only to identify the hub assembly as it would be a shame to throw them into the garbage.

9°C sometimes sunny with hard wind
dry enough for riding the frog

[Ragnars-Frogeye]

Hallo all together,
I know something new about disc and hub.
They don't fit to an Alpine or other Rootes Group car.
So I start at the beginning - whose brake and hub is in my garage?

12°C and dark as night, getting up to 20° tomorrow the forecast says

[Rod H]

The spitfire rotor is approx 9" (228mm). That is the rotor that is used for the big brake conversions. I'm not sure where the 240mm rotor came from. Seems odd, could it have been a special Girling or otherwise?

[Ragnars-Frogeye]

Hallo again,
sorry for writing so late, but I didn't get any email.
So what happened in the meantime:
I got hold of the vendor who sold the parts many years ago.
He still remembers my Frog an that I bought the wire wheels and all the stuff. The only strange thing is, in his thinking he sees an old red Sunbeam Alpine where he screwed it all off.
The problem is the Sunbeam friends say - no that can't be from our cars.
So I decided to wait until February. There will be veteran fair in Bremen. I'll take the lumps with me and will ask there and hopefully someone says oh fine that's from a ......??

The Triumph Spitfire will not fit to the parts so far I know from brembo.

May be something special, but that would be bad as nobody will be able to recognize the parts then in February.

[Ragnars-Frogeye]

Hello all together,
February is long gone and nobody knows anything and we have June now.
Still trying to get the right answer.

Ragnar

[Ragnars-Frogeye]

Hello all together,
sometimes it takes a long time, but now I know where the rotors and wheels came from.
I've asked around a lot. The Alpine Club Germany said no can't be a Sunbeam.
A friend of mine bought an Sunbeam Alpine - the similar car that james Bond dorve in "Dr. No". He was looking for wire wheels. So I started to search agein.
Now I get the answer form the Rootes Archive Centre.
The numbers didnt't help but my measurements were the same as the ones from an
Sunbeam Alpine Series 1 or 2 from 1959 - 1963.
So the problem is solved

Ragnar