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Need confirmation on SC300 rear brake conversion

Old 09-25-18, 11:13 AM
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Dakthuli
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Default Need confirmation on SC300 rear brake conversion

Read here and other places for weeks for LS brake conversion for SC300. Decided to start with LS400 and then perhaps go to Supra TT.
Did not like the idea of only having larger fronts since you have to go larger than 16 to get the fronts to work. Makes the rear look sad.

Bought 18" rims and tires
Bought LS400 front calipers, caliper bolts and rotors
Bought 97+ LS400 rear rotors

Fronts went on without having to grind anything on the caliper.

Put on rear rotor, bracket did not fit. This was expected as I had read a post (which I can no longer find) that mentioned you have to "get the LS400 brackets" to make this work.

Found a 95 LS400 and pulled the rear brackets off. Looking at them they seemed the same size as my 95 SC300. Tried them, same fit. Figured the year was to low.

Got someone in Cali to send me a set of 96 SC400 rear brake brackets as I was having trouble finding any cars in my yards here to get this done. Looking in the forums here the late SC400s and Ls400s have the same rotor, should have the same bracket and all use the same caliper.

SC400 brackets got here, same size as my 95 SC300. Do not line up with bolt holes, sit on top of rotor. I wasn't in the yard when these were pulled, he IS a SERIOUS gear head, but mistakes get made and maybe it was a split year.

Get a message that a 97 LS400 was in the yard yesterday, go there today, pull brackets. Look EXACTLY like my 95 SC300, the 95 LS 400 bracket, AND the 96 SC400 bracket.

Put them side by side, flipped them so the top bolts of one hit the bottom bolts of the other and then used dial calipers. ALL the exact same size.

Figured maybe the rotor was from the wrong car, so measured that. 12" on the dot!

So can someone confirm that they have put a LS400 rotor on the REAR of a SC300 and got it all to bolt up and let me know what witchcraft or animal sacrifice I have to use as I've now tried 4 brackets from 4 different cars and 3 different models and all the brackets measure identically. All of them sit on top of the rotor with the bracket being to short to hit the bolt holes.... which make sense. Since the SC300 is supposed to have smaller rotors... if the bracket is the same size, it could't possible work.

No one has ever mentioned any difficulty with the rear nor any hub changes, just "The LS rears from early LS are the same so they are not an upgrade" and that one post with "you have to get the LS400 brackets to make it work"

Notice no one says anything about bracket swapping for Supra TT rears either...... just get them..... which now makes no sense to me either as the TT rears are LARGER than the SC AND LS 400 so how could the smaller bracket work on those?

Its going to be a pain to turn these at the machine shop to cut the circumference to fit in the bracket since I would have to get on the back side to try to measure the distance from bracket to mount center.
I have seen a picture of the IS bracket...bracket, someone made which was a solid flat bar they drilled into, but do not see how that would exactly work here as there is no horizontal offset, but the need to move the entire bracket up by about 1/4" to clear the edge of the rotor.
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Old 09-25-18, 11:33 AM
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https://www.clublexus.com/forums/sus...fitment-2.html

mentions 99 SC400 rear brackets to make his swap work.

https://www.clublexus.com/forums/sus...rade-info.html

lists model years with rotor sizes.

Shows all SC400 with the bigger rotors, Shows 95+ LS400 with bigger rotors... but I can confirm MY 95 SC300, the 96 SC400 which I now have a picture showing the vin sticker in the door AND the 97 LS400 in the yard ALL have the EXACT same size rear caliper bracket.

The only thing I can see is that the rear hub in my car may be larger/taller than the SC and LS400 rear, the 99+ SC400 specifically comes with a taller bracket to make it work on that car and so putting it on my car will raise the bracket up

The problem is I've spent so much time and money that I probably could have just gotten the TT set up by now and ESPECIALLY so, if I have to buy these remanned 99 SC400 calipers w/bracket as they are the only source i can find FOR 99+ brackets specifically
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Old 09-27-18, 05:05 PM
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I am not sure if this info will help your problem but to my knowledge the brackets shouldn't need to be changed to fit larger calipers to an SC300. I did not even have to do this to my 1993 SC300 when I swapped in 93-98 Supra TT rear calipers and rotors... (however I did not opt to buy the MKIV TT rear brake dust shields for mine-- I cut my SC300 stock dust shields to fit those calipers and rotors).

1992-1997 SC300's should all have the smaller front *and* rear rotors and calipers.

1998-2000 SC300's have the same rotors and calipers front and rear as:
--all 1992-2000 SC400's
--all 1991-2000 JDM Soarer 1JZ & 1UZ vehicles (but probably not JDM Soarers with 2JZ-GE's)
--all 1993.5-1998 MKIV Supra NA's.

But I don't know anything about fitting LS400 rear rotors and calipers though. Just the common front 1995-2000 LS400 calipers/rotors.

Outside of that it's weird that you're noticing inconsistencies in rear bracket/caliper mounting points if you're using any rear MKIV Supra, SC or Soarer rear brake components. As long as you're still in the same SC/MKIV/Soarer Z30 vehicle family with the rear brakes everything should interchange back there
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Old 09-27-18, 09:20 PM
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The LS400 rears don't fit. Only the fronts. That's why most people try to run LS400 fronts with TT rears or evo 8/9 rears.
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Old 10-30-18, 10:13 AM
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The ls400 brake mod is only for the fronts and you need 1 shorter bolt (the ls400 bolt).
No one has bolted on the rears as far as I know.

You can throw on the sc400 rear setup if you have a 92-98 sc300 as it is slightly larger, but most people go for the supra tt rears or just leave them stock and put good pads and rotors on.
unless you have that setup laying around its really not that much better it seems.
With the LS400 setup up front you will have better braking even with the factory rear and you can should be able to lock things up pretty good.
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Old 11-04-18, 10:48 AM
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Originally Posted by Blkexcoupe View Post
The LS400 rears don't fit. Only the fronts. That's why most people try to run LS400 fronts with TT rears or evo 8/9 rears.
Originally Posted by Ali SC3 View Post
The ls400 brake mod is only for the fronts and you need 1 shorter bolt (the ls400 bolt).
No one has bolted on the rears as far as I know.
There hasn't been a follow-up on it, but info from last summer indicates that the LS400 rears do work:

https://www.clublexus.com/forums/sus...ml#post9965195

Worthwhile-ness would appear to come from weight savings not performance.
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Old 11-15-18, 11:40 AM
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Aren't those rears from the earlier year LS's? Doesn't seem worth it unless you are changing pads out and want to save some weight.
Unless its a 2 piston caliper that is close to bolting up it wont be worth it. I want to say they used mostly single piston calipers on the rear except for the supra.
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Old 11-15-18, 10:30 PM
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Originally Posted by Ali SC3 View Post
Aren't those rears from the earlier year LS's?
Beats me. I'm pretty sure the one I confirmed the aluminum rear calipers on was '95+, but I have no idea what the earlier ones ran.

Doesn't seem worth it unless you are changing pads out and want to save some weight.
You say that like it's a bad thing. All else being equal, less weight is a good selling point!

It's just weird that they're supposedly compatible -- only recently discovered -- and it's been gospel for 2+ decades that Supra rears are the only simple upgrade path. Whether or not it's worthwhile is far less significant than making the option be known.
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