Fit 1.8 brakes to a 1.6
Upgrading your mk1 1.6’s brakes to those from a 1.8 is a fairly easy job if you follow our guide
The 1.8-litre mk1 and mk2 featured bigger discs front and rear for superior braking performance. The good news is that they will fit your 1.6 and can be installed with relatively little hassle. Changing all four discs isn’t the work of a moment, but it shouldn’t prove too daunting.
Jack up your car and support on axle stands before you remove the wheels. If you’ve been driving your car hard immediately beforehand, give the discs half an hour or so to cool down before setting to work: burning your fingers isn’t fun.
Clamp off the brake fluid flexihoses to prevent the fluid spraying everywhere when you remove the hoses from the calipers: brake fluid is corrosive stuff so best to avoid it splashing on your paintwork, garage floor, or skin. And if it does, clean it up quick.
Mk2 discs are 255mm front and 250mm rear, compared with 235mm front and 231mm rear items that are standard on the mk1 MX-5.
Chances are you will have to use a metal disc cutter on the rear discs’ heat shields – this is why you should give yourself space…
The disc and caliper can now be lifted off as a unit. Remember to clean the protective coating off the new disc before fitting it, and clean up the face of the hub – if the disc and hub don’t mate cleanly, the disc can move about and cause brake judder.
With a 12mm socket, undo the banjo bolt holding the brake fluid flexihose in place, taking care not to lose the two copper washers as you lift it off. Some brake fluid will leak from the caliper so watch for it and mop it up the moment it spills.
Using a 14mm socket, undo the two bolts holding the caliper/carrier in place, remove them and stash them somewhere safe and clean where you won’t misplace them.
With a file and wire brush clean up the recesses in the pads carrier that hold the stainless steel retaining clips – corrosion can make the pads tight in the carrier, which in turn can cause the brakes to bind.
Use one of the wheel bolts to hold the new disc in place while you sort out the pads and calipers – there’s no other retaining mechanism and you want the disc to hold still as you work.
Apply some Loctite or similar to the thread of the carrier’s bolts. If you’re pulling bits off a donor car, always remember that the best bolts are the shiniest ones…
Apply a little grease to the ends of your new pads where they sit in the carrier (but obviously not to the pad surface…). The pads we’re using here are EBC Ultimax, which are standard spec for the mk1. Insert the pads into the carrier.
The two mounting pins for the carrier require different grease. At the front the upper pin slides through a rubber sleeve so needs (red) rubber grease: universal grease or copper grease is fine for the lower pin. Important: for the rear calipers it’s the other way around.
Still got those copper washers? Then anneal them to give them back their original flexibility. This is done by applying a blowtorch flame until they glow cherry red, then quickly immersing them in cold water. Take sensible safety precautions.
Copper grease any surfaces of the caliper that come into contact with other things, expecially where it touches the back of the brake pads – this will help prevent brake squeal.
Now place the caliper casing over the carrier, insert the upper mounting pin, and carefully tighten up both mounting pins using your 14mm socket.
Put in the anti-rattle springs (the thin wire clips) for the brake pads, if you haven’t lost them! They’re not essential but if you’ve got them, stick them in.
The new bigger disc will touch against the lip of the heat/dust shield – cut off the lip with a disc cutter and then file off the razor sharp edges. Wear protective glasses and be aware that sparks will fly a considerable distance, so move any flammable materials.
The process for the rear is mainly a repeat of the front, except for the fact that the handbrake cable requires attention. It’s released via a 14mm bolt that’s next to another 14mm bolt for a blanking plug on the caliper: undo the right one, and unhook the handbrake cable.
Towards the end of reassembly, locate this adjuster on the back of the caliper: once the handbrake cable is hooked back on, use a 4mm Allen key in this adjuster to push the pads onto the disc, then release them a quarter turn. Remember to replace the blanking plug.
With a second person topping up the brake fluid reservoir as it depletes, use your air bleeding equipment to purge the system of air bubbles. That done, and with the engine running, have your partner press hard on the brake pedal as you check for fluid leaks.
As at the front, purge the brake fluid of air bubbles and then check the system for fluid leaks. Put the wheels back on, loosely thread on the wheel nuts, then with the car on the ground, torque up all the nuts to 110Nm.
Ensuring there’s no dirt or grit anywhere near, and using your newly annealed copper washers, thread the bolt on the end of the brake fluid flexihose back into the top of the caliper.