I have a set of sigma disc rotors and am trying to fit them up to the bellett front stub axle. The outer wheel bearing from the sigma fits as its the same as the bellett one, but the inner one does not fit. Has anyone done this swap before and if so do you know what needs to be done to make this swap work?

Thanx in advance

Renegade

it all depends on what model sigma the discs are off, as there are 2 different types that i know of, and they need different things done to make them fit.
my race car has 4 wheel discs, with late model sigma discs and 4 spot toyota calipers on the front, but they needed ALOT of work to make them fit.

while is may be ok for the track, the biggest problem with either sigma conversion is legality for use on public roads... and this is simply because certain critical parts must be machined, which may reduce their strength.
these modifications are illegal in all states of oz, and i highly recommend that they are not attempted...
added to that, a suitable caliper mount/bracket has to be made from scratch. this is ok, but only if it's done in a manor that satifies a vehicle engineering inspector, so that's another problem to think about.

the best conversion i've seen is to use a drum brake hub, and put a slip on brake rotor over the wheel studs (like how the late model commodore and falcon is done). this then doesn't break the "machining" laws, but again, a suitable caliper mount has to be made from scratch and engineered.

sorry to be the bearer of bad news, but this is a common problem with the bellett... nothing fits without modification, unlike the easy things that can be done with datsuns and toyotas.

thats ok thanks for your reply. I guess I will have to get the original drum brakes fixed. Get the slave cylinders resleeved, brake shoes rebonded etc. and hope that does the trick!

Renegade

pr91 makes a good point about legality and safety, my bellet had machined stub axles with galant hubs and calipers with a custom bracket. then one day without warning the stub snap in my drive way! after some investigation machining stub axles is a big no no
i have since then put sigma hubs and calipers
spend the money and get it done proper drums are crap

so your saying get it professionally engineered and use alternative discs and not the original drum brakes

Although having a disc brake front end on a Bellett is fantastic having all round drums is not really that bad. I had drums on my first car for quite a while and they were not to bad. If you go to a good brake place and get them to machine your drums and get them to re-bond your brake shoes with a lining that will suit what you are using the car for you will be surprised how well it will stop.

hi, I agree, I have had drums on several cars including my Stiletto and have never had any problems. Maintenance is required more so than disks but they are quite good. Adding a booster to drums can make them feel like disks also. The last thread is spot on re: setting them up properly.

I have found a brake shop, that are happy to fix the brakes on my bellett and they say they can machine the drums (if needed) resleeve the slave cylinders, rebond the shoes and fit an aftermarket master cylinder (if needed). I also got a brake booster to suit my bellett and they will fit it when they do the brakes, so its in their hands now!

Thanks to all who expressed their views, it was appreciated.

Thanks once again.

Renegade

I can relate to the stub machining. I had my 1970 car turn turtle on me at Philip Island just as I was changing form second to third at 80 mph. It was a bit embarasing as I had an instructor in the passengers seat. Lucky it did not happe on the main straight as we were hitting well over 100 mph. I have GT disca on my sedan and will be going the Dubbo Way and using TP Magna. They use the standard Bellett drum hub. Just a bracket to make up for the caliper.

Just get a Magna 85-92 4-stud disc and its caliper. (Models like TP?)

Remove the 2 Magna caliper bolts and the disc just pulls off.

It will fit on the Bellett drum-brake hub (remove the drum and brakes!).
You'll need to manufacture a caliper mounting bracket.

I'm unsure about suitable backing plate/s, hose threads, and if 13" rims fit. (I may be able to find out...)

FYI - New Magna discs are 24mm with a wear limit of 22mm. (To think the GT Belletts were 10mm with a 7mm limit!)

That would have been handy to know in December of 2007 when I was asking everyone I could find what the disk thickness was supposed to be... I couldn't get an answer, the machinist went with 3/8 inch, which is 9.5 mm, so I have rotors that are already 25% under...

You wouldn't happen to know what the bolts that hold the disk to the hub are supposed to be torqued to?

13" wheels won't fit over this conversion.
minimum of 14" wheels are needed.

14" wheels eh - the Florian market is growing daily, although homologated GT rims would also do.
And Mitsubishi rims - I wonder if they made the GT-R rims in 14" as well?

what about 15" rims lots around in different offsets and styles in the same stud pattern and they would clear the magna rotor/calliper easy, also can get some pretty sticky tyres in 15"... just my 1c worth!

Should be fine. The only constraint is rolling diameter and width (and offset). Though I wonder if the authorities would know anyhow if you were inspected?
Maybe find the rolling diameter of the original 14" GTs. What have I DUN with that info?

Would it be possible for you to post a photo or dimensions shape etc of the caliper mounting bracket for the Magna/Bellett disc brake conversion. Drum brakes used to be OK when good linings were available, but with the new cardboard ones, absolute crap.
What brake hoses fit, do new ones need to be made?
Any other info you could provide would be most appreciated, as I need better brakes for my 64 sedan
Cheers Beetle

A template for the TP conversion is around. I do have one but I am loath to pass it on at present. I am doing this conversion on my Bellett but have a new template that requires a laser cut to get it done. It utilises "ALL" 4 mounting bolts on the stub. I am not really happy with the original with only using 2 bolts. It is better to spread the load across the whole mounting area rather than 1/2 of it.

From the wreckers you will need
TP discs (new is better)
2 Calipers L & R
Both brake hoses and the nut that is on the steel pipe.
Recover "ALL" mounting bolts
Both backing plates (they may need a mod to fit)

I am about 4 weeks away from getting it set up so I will keep informed.

I had to machine the center bore of my disks to fit on the hub properly. (turbo sigma, but same part number as tp magna) Any one else have the same problem?

I'm about to make the mounts this weekend I hope, a template would be good but it looks like I'll just have to dream something up.

Hi guys,
Couldn't help but get a little excited reading about the whole disc brake conversion conversation.
My first bellett was modified somewhat for hillclimb racing (by original owner) and it had a Volvo setup in the front and a Toyota setup in the rear with bias adjustment in a homemade centre consul.
I have no idea how it was all done or how much machining was req. I'm guessing a lot.
Any who, why I was leaving a plug is in regards to the bearing size issue with fitting the Sigma discs to the stub axle. (The outer fitting fine but the inner not fitting)
Whilst a mate was doing a disc conversion to his v8 Bedford van he had a similar issue fitting Ford rotors to the Bedford stub axle. This he was able to overcome by mixing compatable bearing components together to get the req size.
What that involved was buying 8 bearings to make 4. For his inner bearing he used the centre of a Bedford bearing and married it outer of a Ford bearing to fit the stub without any modification. For the outer he used the centre of a Ford bearing and the outer of a Bedford.
The sizes have to be precise to fit each other but this can be sourced through the specs of the bearings from the respective suppliers.
I haven't as yet checked if this would be feasable for the Bellett application but it is definatly worth looking into. Has to be cheaper to throw away 4 bearings then to get components machined or enginered.
Just thinking outside the box a little and thought you would all be interested in a possible safe, easy and cheaper option. (thats if it will work in this case)
Regards Stickman

I have made some progress. I got all the brake parts. $88 from local wrecker. The others including a pick a part type locally wanted $160 plus. The brackets are being made and the machining on the discs at same time. Should have the bits back and on by 8th on this month. Will keep informed of progress. Now to get the tandem master cylinder.