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Tutorial: S1 280ZX Rear Disc Brake Conversion for 240/260Z.

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Lurch:
This article is a step-by-step guide to mounting the rear calipers & rotors from a S1 280ZX onto the rear of your 240/260Z.
You should be able to complete this conversion in a weekend PROVIDING you have the required parts & tools.
It is also recommended that you recondition the calipers prior to use, fit new pads & rotors.
Please note, unless you want to go to the HUGE trouble of removing your rear hub, it is easier to simply cut the backing plates off.
Be aware, once you have removed the backing plates it’s very hard to return to drums…
This conversion will also fit under most 14” rims.

Items you’ll need:
Caliper brackets to mount the 280ZX calipers
(available here: http://www.viczcar.com/forum/index.php/topic,1861.0.html )
280ZX Calipers & the original 8 mounting bolts & spring washers.
(or you can buy new M10, 30mm long bolts & washers).
280ZX Disc Rotors.
2 M8 bolts with nuts & washers.
2 handbrake cable mounting brackets (see below)
Old ‘bundy’ brake lines from the 280ZX shortened to suit or,
Custom braided brake lines.

Tools:
Power drill.
Drill bits (various sizes).
Angle grinder with 1mm cutting disc.
Metric spanner set.
Pliers .
Hammer.
Centre punch.
Cold chisel.

PPE:
Goggles or safety glasses
Earplugs or ear muffs.
Gloves.

Before you start:
You need make up 2 brackets for the handbrake cable.
Cut 2 pieces of 50x50x3 angle (Alum or steal) 50mm long.
Drill 8mm hole in each side in the centre (Pic1).
Next, get the old 280ZX bundy brake line shortened to around 100mm long by a brake shop with a 90deg turn at one end (Pic2).

Lurch:
Step 1:
Jack up car. Place car securely on jack stands. Remove roads wheels.
Remove brake drums & then disassemble the rear brakes.
Clamp a rubber brake line ‘pincher’ onto the rubber brake line to prevent any fluid loss.
Also remove the handbrake cable & brake line (pics 3a & 3b).
Withdraw the slave cylinder. (Pic3)
DO NOT THROW ANYTHING AWAY!

Step 2 (the worst part of the conversion):
Undo the 4 14mm headed bolts that secure the backing plate to the hub.
Give the B/P a tap forward with a hammer to ‘pop’ it off its step on the hub (pic4)
Now, with the B/P loose, cut down to the centre of the B/P with the 1mm cutting disc on the angle-grinder. Do this at opposite sides of the B/P.
Cut down as far as you can WITHOUT cutting into the hub or anything else.
Next, with your centre punch, punch a centre pop a few mm below the end of your cut (pic5)
Drill the hole thru the backing plate with an 8mm drill bit (pic6).
Once through, drill ‘downwards’ towards the hub until you’ve got 2 continuous ‘splits’ in the backing plate – TAKE YOUR TIME! (Pic 7 & 8 ).
(The backing plate is about 3mm thick & of fairly soft steel, you shouldn’t have any trouble cutting & drilling the backing plates in halves this way – just be careful).

Lurch:
Cont:

Lurch:
Step 3 (it gets easier from here):
Now you should now have a nice bare hub.
Using the M10 bolts, bolt the Alum. caliper bracket onto the forward edge of the hub.
It is recommended that you ‘Loctite’ the bolts in place (pic9)
Now, slide the 280ZX Disc Rotor over the studs on the hub (the road wheel holds the disc in place).

Step 4 (Getting there):
Unbolt the upper handbrake cable mount (close to the diff, under the floor) (pic10).
Fit the angle bracket to the body, and then bolt the rubber mount that the cable goes through to the top side of the bracket (pic11).
Next, bolt on the caliper with the bleed nipple facing UPWARDS using the other M10 bolts BEHIND the ‘ears’ of the caliper brackets.
Slide the handbrake cable through the outer holder. Using the old spring clip; push this into place to hold the cable. Secure the clip in place with a couple of cable ties OR tech screw the clip to the mount. (I am still working on a better solution to these).
Then fit the end of the cable to the caliper leaver with the old pin & split pin (pic12).
Secure the cable to the lower wishbone with a LOOSELY tied cable tie so as not to distort the cable too much (pic13).
Next, using the shortened bundy brake lines, fit these to the calipers, and then screw them into the original rubber hoses (Pic2).

Lurch:
Step 5 (Nearly done!):
Remove the REAR line on the master cylinder. Undo the large 17mm nut in the M/C & remove. With a small ‘Eazy-out’ remove the flared pipe seat, behind this will be the little plastic 'Residual Pressure Valve' & spring.

Discard the plastic valve & spring.

Refit the flared pipe seat back into the M/C. 
Screw the large nut back in, then screw the line back in.
Then bleed the M/C at the union, followed by the rear calipers.
Bolt the road wheels back on & lower the car back down & take for a test drive!
(Removing the Residual Pressure Valve eliminates the rear calipers locking on when they heat up).
More information & pics here: http://ozdat.com/forum/viewtopic.php?t=1257&start=15

Note: If you have some trouble getting the alum. caliper brackets to bolt up, a light sand with a flap wheel or sanding disc to the bracket should give you enough clearance to have them bolting up nicely.

If you have any more trouble with this conversion, please email me at:
Lurch (at) Ozdat.com – but don’t expect a speedy reply!

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