The other thread was getting Cluttered and I wanted to change the focus of the investigation. We know that an AWD caliper will bolt up with the Ralliart Rotor but with some serious investigations I have uncovered this photo.

Take a look at this picture from a 1993 3000GT 3.0TT VR4 Rear Caliper.

Number on the bracket is 1417 - Same as AWD/Ralliart
Number on the Caliper is AD38 and 20-15 - Same as AWD/Ralliart
Only different number is the 1417 on the caliper near the brake line. AWD and Ralliart is 3803.

Ony visual difference is the casting of connection for the hose to caliper.

Could it be that an AWD/Ralliart calliper will bolt up with a 3000gt Rotor?????

The 3000GT rotor has an offset of 52.8mm (3.7mm less than the Ralliart?)

If we are still going to have an issue with the 3.5-3.7mm offset, then couldn't we just put 3.5-3.7mm spacer rings between the axle stubs and the calliper bracket to correct the alignment and use slightly longer bolts?

To confirm this picture, I'll be getting some pictures of the rear 284mm brake setup of a 3000GT TT shortly. I'll post my findings.

I measured up the caliper axle bolts from a std rear magna brake setup.

Bolt had

14mm Hex Head
M10 thread (~32.5mm long)
Neck (non-threaded section) - roughly 10mm
Threaded length ~ 22.5mm
Thread pitch 1.25

Had a 10 stamped onto the head of the bolt. Is this the Class Rating (10?) or simply a reference to the diameter of the bolt. If it's a metric bolt, should it be rated as 9,9 or 10,9?

Anyway, Can anyone think of a reason why the caliper offset can't be moved to align with a 3000GT Rotor Offset by using longer bolts with spacers (washers) between the axle stubs and the caliper brackets?

I measured up the caliper axle bolts from a std rear magna brake setup.

Bolt had

14mm Hex Head
M10 thread (~32.5mm long)
Neck (non-threaded section) - roughly 10mm
Threaded length ~ 22.5mm
Thread pitch 1.25

Had a 10 stamped onto the head of the bolt. Is this the Class Rating (10?) or simply a reference to the diameter of the bolt. If it's a metric bolt, should it be rated as 9,9 or 10,9?

Anyway, Can anyone think of a reason why the caliper offset can't be moved to align with a 3000GT Rotor Offset by using longer bolts with spacers (washers) between the axle stubs and the caliper brackets?

because i personally wouldnt want to risk it.

if i did i would be checking them almost daily, if not replacing them for fear of stress fractures.

think about how much force is involved with braking.

on my downhill mountain bike. the force they were under was crazy. thats for an 8inch rotor, with a 6 pot brake. although even with 2 pots the force was crazy, you could easily shear a bolt. the bolt would come loose over time jsut from being used.

a car has ALOT more stress than the application i was using them for... dont risk it.

you want a larger surface area to be taking the force, which is what happens when the caliper and axle stubs. when using 'adaptors' which require the use of a longer bolt, this is creating an enormous weak spot...

Wooley's pretty right but it's more due to the shear stresses in the bolt due to the torque. If the caliper is mounted on the bolts, right up close near the hub, a torque is produced on the bolt. Now say you double that distance, remember a doubling in distance is only a few millimetres, the troque produced on the sides of the bolt is doubled:shock:. Not good.

Undoing a bolt is a good example. If you were undoing a bolt and the spanner won't undo it, you get a socket wrench which has a longer handle. Now you aren't putting much extra force into the end of the wrench, but the bolt comes undone easily (or you get a longer bar lol). This is due to the larger amount of torque produced.

Sure the design torque used would have been much higher than what the bolts would nomally ever see, but they are getting on a bit in age and without calculating the stresses I wouldn't wanna do it.

thats pretty much what i mean, the sheer forces on the bolts would be extreme.

hehe do it i wanna see someone have to replace the tabs on their axle, as the bolts have just sheered off from the rotation forces of the caliper trying to pull its self along the rotor:D haha

i think i just explained myself. most people will understand...

Wooley's pretty right but it's more due to the shear stresses in the bolt due to the torque. If the caliper is mounted on the bolts, right up close near the hub, a torque is produced on the bolt. Now say you double that distance, remember a doubling in distance is only a few millimetres, the troque produced on the sides of the bolt is doubled:shock:. Not good.

Undoing a bolt is a good example. If you were undoing a bolt and the spanner won't undo it, you get a socket wrench which has a longer handle. Now you aren't putting much extra force into the end of the wrench, but the bolt comes undone easily (or you get a longer bar lol). This is due to the larger amount of torque produced.

Sure the design torque used would have been much higher than what the bolts would nomally ever see, but they are getting on a bit in age and without calculating the stresses I wouldn't wanna do it.

A rough force diagram indicates the torque on the rear bolts will increase by about 30%. Selection of the bolt grade would need to allow for this. The front brakes use a 10.9MPa bolt but based on my examination of the rear bolts, there is a lot less force on them and hence they are not as high a grade. I think I'll run this scenario past some brake specialists/automotive compliance engineers.

This IMHO is safer than using a spacer plate between the axle and the brake rotor and that design has stood the test on time (well several years to date).

To dig up my old thread I can confirm the following,

I have recieved confirmation that the JF 1991-93 3000GT 284mm Rear Rotor has the same internal diameter as our magna rotors (168mm). So it will physically fit on the hub and the handbrake will work as normal.

It is only a matter of correcting for the offset and it's a goer.

It is only a matter of correcting for the offset and it's a goer. You can use a spacer aslong as it's fixed to the hub.

You can use a spacer aslong as it's fixed to the hub.

The 3000GT rotor has a 3.7mm offset in the opposite direction to the AWD rotor. so I need to fit a shim in between the axle stub and the caliper bracket as shown here.

This is a much safer option that wheel spacers.

That's a 4x4 axle btw

And of course the replacement bolts/spacers will be high grade e.g. 10.9MPa (to match the fronts)

I currently have in the pipeline some new rotors the same specs as the ralliart ones currently in transit to me. They have worked out to a total of $290 incl. shipping for the pair - If you can hold off a week or so ill let you know if they are what ive been promised and I can source them for you guys.

I currently have in the pipeline some new rotors the same specs as the ralliart ones currently in transit to me. They have worked out to a total of $290 incl. shipping for the pair - If you can hold off a week or so ill let you know if they are what ive been promised and I can source them for you guys.

:gtfo: What brand are these??? :)

Ill let you know when they arrive :cool:

Ill let you know when they arrive :cool:
Hope they're not RDA (EBC) cause they only do AWD's

I'm a bit concerned that they might be cheap chinese rotors...But I'm still interested to see what eventuates from this...

they definately arent AWD ones, I have a spare set of AWD ones. I gave the supplier in the states the measurements and he said he had them. 56.5 wide not 60.2 :) I cant wait till they get here ive painted my calipers gold : )

they are the AWD ones again! I am soooo cheezed. :rant: I am reverting to my original plan of cutting back the EVO rotors to fit, my brake guy said this was a better option than shims. The EVO rotors are 300dia 58height and 22thick with the same handbrake setup so if you get 1.5mm machined off the inside you get 56.5mm height then machine .5mm of the outside and you get the 20 thickness then machine the outside down to 284 and your done. Im going to price this tomorrow. Ill let you know what it costs me :) hopefully less than what ive already spent.

they are the AWD ones again! I am soooo cheezed. :rant: I am reverting to my original plan of cutting back the EVO rotors to fit, my brake guy said this was a better option than shims. The EVO rotors are 300dia 58height and 22thick with the same handbrake setup so if you get 1.5mm machined off the inside you get 56.5mm height then machine .5mm of the outside and you get the 20 thickness then machine the outside down to 284 and your done. Im going to price this tomorrow. Ill let you know what it costs me :) hopefully less than what ive already spent.

That's a shame mate. My only concern with machining 2mm of the rotor blade is that you approach or exceed the minimum rotor thickness before you even fit them.

Goodluck and let us know.

I've been on to RDA/EBC today concerning maunufacture of Ralliart rear rotors,and it looks like they aren't going to be making any unless they get some more people asking for them.If you are interested please ring RDA on freecall from any location 1800 880155 and tell them you want rear ralliart magna rotors, and make sure they take your name and number and tell them to ask head office !!!!!

To dig up my old thread I can confirm the following,

I have recieved confirmation that the JF 1991-93 3000GT 284mm Rear Rotor has the same internal diameter as our magna rotors (168mm). So it will physically fit on the hub and the handbrake will work as normal.

It is only a matter of correcting for the offset and it's a goer.

After briefly fitting the rotor on the weekend, I can confirm that the 3000GT rear rotor fits nicely on the rear hub. Parkbrake shoes make full contact with the internal drum and everything looks good. All that's needed now is the 3.7mm spacers for the Rear AWD calipers and it should fit nicely. I've already sourced some longer 10.9 grade (M10 x 40mm length 1.25 fine threaded) bolts which was an effort in itself.

Once I've rebuilt the calipers, it'll be ready to go.

One Question though...
Can anyone get caliper rebuilt kits cheap? Rear AWD kits are like $60 retail each!

did you get the 3000GT calipers that have "MITSUBISHI" embossed on them?

did you get the 3000GT calipers that have "MITSUBISHI" embossed on them?

Nah, I got the 3000GT Rotors, and I'll be fitting AWD Magna Calipers to them. Rotor diameter and thickness is identical. It just a matter of offset. I'm getting some CNC spacers fabricated that will be 3.7mm thick (+/- 0.1mm) so alignment should be spot on.

I'll be rebuilding and spraying the calipers over the weekend (should the opportunity ariselol )

Just a little teaser today as I don't have the pics at work. But I have successfully bolted 284mm 3000GT rear rotors with Magna AWD Calipers to Give Us FWD's hope of Bigger rear brakes.

They look the shizzle and work great!!