mx83 rear brake upgrade

[PlacentaJuan]

here is an easy upgrade to mx83 rear brakes.

it uses the r33 gts-t rear 2 spot calipers, and jzx100 rear discs, which are much thicker, vented, and larger diameter (and can be slotted to match the front)

the jzx100 rotor has the same internal diameter for the handbrake.

edit: jzx100 rotor is 310mm in diameter.





this pictuer is decieving, they nearly look the same thickness, but the jzx100 is quite a bit thicker.


the only problem i have encountered so far is the hub diameter, the jzx100 rotor is 2mm larger diameter, which may require a ring spacer like used for the ba/r33 front brake upgrade.





a guy in america who did thise conversion used some sheet metal and made his own rings.

i have some 0.5mm airfract speed tape (aluminium tape) with which i will use 2 layers to take up the 1mm gap around the hub.

to bolt up the jzx100 rotor to the hub, the dust shield needs to be hammered inboard quite a lot.

it is also interesting to note that there is no air scoop to direct air into the center of the rotor for cooling, as mx83 does not require it since the discs are solid, and not vented.

this should be fixed quite easily in a few minutes with some tin snips.

go make a template bracket i bolted up the new rotor to the hub, and ran some thick cable ties around the outside, which will give it nearly 2mm clearance from touching (about the same as stock rear and the new front calipers.




then i positioned the caliper in between the stock holes, and got my wife to apply the brakes (the new caliper bolts up to the mx83 brakes lines) so as to check clearances.



the thickness of a cable tie worked well, there is a bit of room in the center of the rotors, but since the best braking force is done firther away form the center as possible, the caliper is situated perfectly.



now i know its ready for a templace bracket.

i used some aluminium plate, and first made sure it bolted up to the stock mx83 holes:



once botled to the hub, i used a flapper wheel and angle grinder to get the shape for the caliper to fit, i kept grinding the template down until the caliper was sitting hard up against the cable tie / disc again.

[PlacentaJuan]

once it was in position with the template in place, i could mark the holes for the caliper:

and with washers as spacers, mount the caliper as it will appear with a proper bracket made up:





once i had the exact location of all 4 holes, a much cleaner bracket could be drawn up / designed.

i foudn a metal cutters in adelaide who can cut a shape with just a trace, and 2 brackets from 25mm steel will cost me $50, (much less if ordered in bulk)

here is the final design, with dimensions removed until i can confirm proper fitment.



only issue maye be 2 of the holes are a bit too close together, but ill see how it goes.

[Officer Doofy]

NIce work PJ, subscribes....

[PsyCo]

one day...*dreams*
Awesome work.

[CrUZida]

Look near identical to mine
http://www.toymods.net/forums/showthread.php?t=239

Picked up some of the rear stuff today.

The caliper adaptor



and the spacer





And it installed.




I'll place it all together tomorrow perhaps.

Rear upgrade test fitted today.
All came up well.

[Cuzzo]

The fact that you have done all this work amazes me. Well done.

[PlacentaJuan]

peewee will the dimensions on the caliper bracket be the same for mx83?

if so, are you willing to share the drawing?

your new disc looks like there is a lot of room around the hub (more than my 1mm) or is it just an illusions?


if so it loks like no spacer, what did you do?

looks like your caliper is spaced a lot farther out from the stock brackets than mine, probably because your disc has a larger diameter, ill check the jzx100 diameter, so they probably wont be the same, but yes looks very similar, i need to get it milled in the same spot too!

and did you do anything for directing air into the center of the disc, like the front brake dust shield has?

[CrUZida]

The MA61 caliper has a spacing of 167mm from memory, not sure what MX83 is.

Its a Z32 297mm disc, so centre bore is 68mm
I put spacers on, just not during test fitting.

I had it milled like that to keep the thickness as thick as possible, while making the alignment as good as possible. From memory its 20mm thick, with I think 8mm milled off it. I also have a 6mm spacer under the disc (to space the disc out), so that the disc doesn't rub on the swing arm.

Stock discs are vented anyway, so I didn't need to do any mods. Plus with the spacer under there, the new disc was well clear of the dust shield.

[cambelt]

16 mm thick should suffice 25 mm is a tad overkill . Most factory calliper brackets i have seen are around 15 mm . And for engineering purposes its best to use threaded holes and no nuts.
Dave

[PlacentaJuan]

ahh ok thanks peewee, looks like the brackets are quite different (in terms of hole spacing anyway)

picket up the plates today they lookreally good.

thanks dave i am going to tap 2 of the holes in the bracket, and use helicoils too because it is stronger and gives a better finish thread (than i can go with a hand tap anyway)

got it in 25mm coz i will need to mill off some like peewees bracket to get the spacing right.

i never thought about spacing out the disc or anything, i hope it doesnt cause any problems.

its funny, the guy who i am going to get to do the machining, he is really old school; no copmuter or cnc machines or anything.

his idea was to use 12mm plate and WELD some washers or spacers on there for the caliper spacing! i was like "yes that is a good idea but i need single piece to get it engineered", he still thought i should weld spacers on....

[CrUZida]

My main reason for spacing out the disc was so that the increase in track matched the front (which was increased due to skyline brake upgrade).

It just happened that some spacing was needed to clear the dust shield/etc and it all worked out well in the end.

[PlacentaJuan]

oh i hadnt thought about that, the only thing that would affect track for mx83 brake upgrade would be the thickness of the disc at the hub (where the wheel bolts on to) woulnd it?

[CrUZida]

Yeah, the thickness of the disc.

When you convert the MA61 to Nissan front end, it adds 8mm track per side.
And then the Z32 rear disc is 2mm thicker than the MA61 rear disc, so I used a 6mm spacer to increaes the track to 8mm per side at the rear too.

[cambelt]

Spacing the disk out isnt ideal but ok . Jesse check with a engineer , i think spacers welded on are ok , GT,s hiux calliper brackets are like that.
Dave

[PlacentaJuan]

nah i dont think i need to use a spacer,

here is the bracket i picked up today:



all i need to do is get the bottom 'cirles' cut down to about 12mm, i wonder if i can do this myself with a 32mm end milling bit and a drill press?




(blackwoods p/n: 01025243 in case the pic doesnt load.)

although i dont think a 32mm shank will fit in my press.....

[PlacentaJuan]

ended up getting them done properly, although it cost me 100bucks for the pair!

i reckon that is a bit expensive.



hurry up and order me that disc gavatron!

think ill get some handbrake pads while im at it.

[CrUZida]

For one off pieces, including extra milling, thats cheap.

If you got a dozen done, it would be like $30 each.


Laser cutting one or two pieces is pricey.

[twiztd]

PlacentaJuan - possibility of a group buy of these between here and TC.net? I'd hope there'd be enough interest to get 10 or so made up...

Mike

[PlacentaJuan]

Im going today to get a quote for a batch of 10.

there are some guise on cressida forums who are interested also, i will advertise in both forums, but what is tc.net?

[CrUZida]

tc.net = cressida forums (toyotacressida.net)