Fit 1.8 brakes to a 1.6

Total MX-5 - - CONTENTS -

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.

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...

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 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…

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...

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 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...

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...

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...

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...

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.

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