I have started a new thread as the original one was for Galant style conversion which involved (illegal) machining of stub axle, or finding new inner bearings. That thread was here http://www.bellett.net/forums/viewtopic.php?f=35&t=174&start=20

Apprently, somebody has done the TP magna conversion but like always, there seems to be "missing" detail information.

It's interesting, if you Google TP Magna brakes, these rotors are used on many conversions. Most often Nissans, because of the same PCD.

This thread then is going to try to make the process more practical, hopefully. ie. WHAT I HAVE FOUND.

BUT, this has not been fitted on an actual car so is only what I have found on a stub axle assembly. Sedan. THIS MAY NOT BE LEGAL, AS IT HAS NOT BEEN ASSESSED BY AN ENGINEER.

1st off, this only a TRIAL run using parts i have to hand. (NO car) The rotors though can be bought very cheaply on ebay, Around $60 per pair.

In the other thread, i gave the part number for the vented front rotors from TP Magna. The calipers were removed from the same model. I can't swear to this, but think the next later (5 stud) model used the same caliper also.

On Calipers, a rough check of costs, from the wreckers, about $28 each. Re-build kits about $20. Pads ? There are also new PBR calipers available, roughly $180. A quote to get a Pro to rebuild the calipers, was $40 in labour. (each)

## Beware also, the unsprung weight in this conversion will increase dramatically, especially over drum brake originals.


AGAIN, SINCE I HAVE NO CAR, THE INFO HERE IS MAINLY FOR INTEREST ONLY.

Here is a Bellett stub axle assembly of unknown year.

I removed the 4 bolts holding the old drum brake assembly

So, now slip the rotor over the hub as indicated in other posts........

Mmmmm........... does not fit !

The rotor has a 69 mm hole, ......Bellett has a 74mm shoulder area. 5mm needs to be machined from the centre of the rotor.

I should add here that the Bellett hub needs to be absolutely clean. It will have a build up of grime and surface rust. This must be revoved totally so the rotor will (eventually) seat on the hub correctly.

So, first job is to get somebody to machine out the hole.........

more later.

Always good to see a thorough write up on how to do something, not enough exist for these little beasts. Thanks for taking the time to walk us through what your doing trying these brakes. (always good to see the bits you need to modify!)
Hopefully if i ever do anything proper to my bellett i will remember to take alot of pictures to show how i did it, right or wrong!

In this age of digital pics, the more the merrier. In the days of building my previous cars, how I wish i had documented them !

I must stress again that this is my own take on the conversion. Hopefully finding any 'issues' that may arise.

I now have one rotor turned out to correct size. The fun begins...working out the caliper bracket. This is where I will be guessing though as not having a car here, i can only assume the actual position of the caliper. ie front or rear of the axle.

OK, some mysteries here. In the other TP thread, mention is made of a caliper mounting plate. I think 9mm thick.

I have fitted the caliper up with it's old pads which are quiet evenly worn. I have a gap of about 5mm from the face of the caliper to the face of the Bellett upright. I am not an engineer but I think 5mm plate is way too small for this job. Although, the distance between them is relatively small. I mean in a radial sense. Not the spacing.

Any suggestions here? One 'could' mill a little off the caliper face itself to increase the gap, but this is a no-no legally. So I won't go there.

For ref. The original Magna mounting bolt is 30mm long. The thickness of the mounting plate (casting) on the Magna is roughly 11-12mm.

If the 9mm plate is used and that sounds reasonable to me but I am not an engineer. One issue might be that 9mm plate is not s td. thickness?

That would mean extensive machining in a mill to fit these calipers.
If say a 10m plate was used, then there would need to be about 2.5mm taken off each side of the plate, in appropriate areas, to maintain adequete thickness in the area between the upright and caliper. ie. the plate would be full thickness in that area, but milled back in the upright and caliper mounting areas only. Not a cheap part to have made i think.

Fitting a Backing plate would also complicate things. It's probably a good idea though to fit one, to look 'factory' and keep out the crap etc or whatver they are for !

Another observation here... the lip on the hub, normally meant to fit into the wheel for support, is now missing. This maybe a moot point as most if not all mag wheel fitments would not be correct here either.

any inputs here ? I can't do any more now, as I have no steel plate.

glenn

There is something 'strange' about this conversion in these threads.
The gist is to use TP Magna rotors and calipers.

OK, I have found the rotors need to be machined.

AND, from my observations (above) the calipers don't fit with a simple adapter plate.

ie. Looking back at the threads, one picture shows a caliper mounted up with a plate, seemingly not milled etc.

Another picture shows a caliper that requires the plate to be machined. This seems to be same caliper i have.
ie, TP Magna caliper.

The mystery for me now is, what is the other caliper off? It's a totally different style of caliper. It appears the mounting boss area is different (thinner) and the overall style of the caliper is a lot different also.

anybody know?

glenn

Here are the 2 types. One for sure is TP Magna as I removed this from a car. What is the other one from? Maybe a different Magna model?

1st picture is 'my' TP Magna caliper, made by PBR.

What is the other one from ? Perhaps calipers changed as time in the TP model life?

This is why you need "exact" details of "everything" for any proposed mods. or substitutions !

second calliper almost looks like a commodore rear calliper? (vn, vp, vr, vs?) just a thought?
after looking them up on the net they look similar but they are different to what you have shown there.

Can't do much more on the fronts for now as no metal for brackets etc.

So, I took another trip to the wreckers to look at the rears also. The car I took the fronts off, was gone! They had cleared several rows of cars for the crushers. Luckily, another TP was found in the yard.

In a thread here somewhere i read somebody (Brett?) used Mitsubishi rear rotors and Commodore calipers.

I looked again at the rear of the TP Magna, which has disks. The (solid) rotor is also part of the HUB on this model so is not usable for a Bellett. Maybe the calipers are usable BUT, they mount on a cast iron bracket which is then attached to the end of the axle on this car using 4 bolts. I am unsure if this setup is usable on a Bellett though. One would need an appropriate rotor (from what car?) and then offer it all up to the Bellett rear to see what's what. I suspect the bracket won't fit.

So, not much joy here at all. While probably overkill to have 4 wheel disks, it would be 'nice' to have, and also to have a matching set of brakes from one donor car, to hopefully reduce any issues. The proportioning valve from the car would also be needed although it might not suit the lighter Bellett? Aftermarket adjustable ones though are on ebay fairly cheap.
The other thing to look at maybe, is what size bore the master cyclinder is on the Magna. I tried to get the master off the car in the wreckers but not so easy, so left it. Possibly can find this out easily enough anyway.

glenn

Brett said:-
didn't know that they need a skim myself, but i haven't done this conversion either.

personally, if u can find the late sigma stuff, i'd use that.
sure, some hub machining is need, but it's not much and is far far better than the old days of machining stub axles.
i really punish my set in the race car, both in loads and heat, without failure, so they can't be too bad.

mind u, i remember years ago a few guys talking about at making a sleeve that went over the Bellett stub to take up the difference between the bigger sigma inner bearing size and the inner face of the stub.
the outer bearing is exactly the same, and surely a pressed on sleeve would be better again than machining a stub.

think we better now chat on your brake threads!

Glenn..... i don't think i would go with a sleeve. The amount turned off was very small so the sleeve would be very thin.... and i would think, prone to being distorted under loads.

The TP front rotors, while needing to be bored out, is relatively painless to do (if you have a lathe) and you get a a later disk that is vented. Not that vented is really needed, but these TP rotors seem to be very easy and cheap to get, new, as they are used in a lot of other brake upgrades. The caliper mounted is a bit of an issue though. A simple 6mm bracket like the sigma conversions does not apply here. It will be thicker and need some milling also.

I wonder what the minimum accepted mounting plate thickness actually is? We used 6mm before and no apprent issues. Maybe a 6mm plate for the TP calipers is ok, but the caliper would have aslight offset

glenn

the amount you're thinking of is how much is taken off the stub for an early sigma conversion tho...
on the late model sigma, the inner bearing is different again and the difference between the inner size of the inner bearing to that of a bellett is quite a bit (ie: the sigma bearing is a bigger diameter to the bellett), so a sleeve would be fine as it definitly wouldn't be too thin.
from memory, it maybe 4mm all around, but that was years and years ago... and being pressed on would mean it wouldn't distort under load unlike a slip-on sleeve would.

IMHO, 6mm for a mounting plate is too thin, unless it has some sort of reinforcement.
i know the mitsu scorpian had 6mm plates, but it was pressed with ribs and a return all the way around to put strength into it.
i use a minimum of 10mm on flat plates i've made to prevent any distortion or flexing, as that's the last thing u need.

OK Brett, not knowing the difference, makes it hard to judge a sleeve i guess.

Is the bearing somebody found a number for, in these threads, for the early or late sigma ? ie to adapt directly to Bellett stub.

I was thinking 8mm plate might be enough. The caliper is fairly close, radius wise from the hub (see pics above)
However, if it has to be milled then starting from 10mm wouldn't be much more trouble. The trick is keeping the 10mm thickness in a larger area as possible i guess and no sharp edges..

Is welding a stiffener though to a thinner plate 'legal" If a thinner plate was used say 6mm and a piece of thick 10mm wide strap was welded on edge to it that might work. disortion migh be a problem though wehn welding.

there seems to be no simple path to this disk conversion..

your comment above:
"personally, if u can find the late sigma stuff, i'd use that.
sure, some hub machining is need, but it's not much and is far far better than the old days of machining stub axles.
i really punish my set in the race car, both in loads and heat, without failure, so they can't be too bad."

What did you do to the HUB itself ?

im am watching this thread eagerly, would love to convert to discs one day.
question about the rear rotors etc brett used? did you keep the hand brake or not worry being a race car?

It's an interesting topic and one i have 'followed' since trying to stop a Bellett way back, with drum brakes in reverse....... not a nice feeling ! Not long after, i converted it to disks using the Sigma/Galant ones, but using the infamous stub axle mods.

Obviously not keen to go that path again, although i never had trouble with it.

What i am trying to do here is follow some suggestions on the TP magna and other conversions to see just what is involved. That's why I am trying also to get exact info on where the parts come from and what fits and what doesn't !

And exactly what you have to do for a conversion. I doubt it's necessary to do the rear disk conversion also but might as well look into it at the same time i figure. Have plenty of time since no actual Bellett (yet)
As you can see, i am following the TP Magna course, but found problems that need to be sorted out yet. It might well be that I revert to Bretts suggestion to stick with the Sigma parts although i already spent money on some TP parts. I need to investigate the actual difference in inner bearing sizes to see if the sleeve is viable also. Another few hours at the wreckers, pulling things apart ad measuring i think ! Also need to make sure parts are generally available. Magnas and Sigmas are getting thin on the ground these days. Gemini's for example, not seen any at all in local wreckers. All rusted away perhaps ?

I don't think Brett used a handbrake. Commodore calipers don't have inbuilt handbrakes. They use a drum system inside the disk rotor.

glenn

keep at it glenn we all want to know where we go next ....cheers ...great job ..davo

I need some help too !

a race car with a handbrake...
not in my world. that'd be unwanted weight to lug around!

Glenn is rite. Commodore's don't have the handbrake in the caliper. It's a totally separate mechanism that sits inside the hat section of the rotor and works like a normal drum brake.

have you got that hole saw in action yet?

glenn

always on the search with it mate.
u'd just about die if u look really close at it and try to count them now...

have a few new things to do on it soon, but a certain Falcon and it's 351 is keeping me busy.