Q&A Technical issues solved
Michael Cleverley of Cleverley Repaired Cars, expert on all things MX-5, answers your questions
You ask, we answer. This month: ignition issues, sticky brakes and more
IGNITION SWITCH ANGST
Q Help please: my 1989 mk1 1.6 has a strange electrical fault – driving along, sometimes the heater, wipers and lights stop working and then start again. It’s quite frightening when it happens and I daren’t drive at night. Can you give me an idea of what may be the problem?
A Electrical faults, particularly intermittent ones, can be frustrating. However, in this case with so many systems affected, it’s likely to be the ignition switch itself. We have seen this a few times on early cars and a wiggle of the key often gets things working again temporarily.
Luckily it is easy to remove the switch from the rear of the ignition barrel. Take the lower kick panel off using a Phillips screwdriver, and remove the steering column cowling as well. With the battery disconnected you simply unplug the ignition switch multi-plug. A single screw is all that holds the switch assembly in. Working carefully (springs and balls can drop out…) dismantle the switch – the contacts can then be cleaned using fine abrasive paper. Reassemble and the problem should be fixed.
If you don’t feel confident enough to dismantle the switch, then simply purchase a brand new replacement.
Q A few times in the last weeks my brakes have been stuck first thing in the morning, and can be noisy when I’m driving. What’s up?
A This is a problem usually related to weather conditions or pressure washing! It has been very wet and salty [in the UK] for a while now, so moisture gets onto the discs and pads. Overnight, light surface rust forms on the discs which can be enough to lock the pads to the disc making moving the car tricky.
The fix is to jack the car up and remove the wheel that’s seized; a light tap of the brake caliper with a hammer should unstick it very easily. As soon as you drive you will hear scraping sounds from the wheels – these should lessen and stop with a few applications of the brakes: the pads clean the rusty disc. The noise may alarm you but it’s actually nothing to worry about, assuming the brakes are not worn out! Leaving the handbrake off and engine in gear overnight will reduce the problem (chock the wheels if the car is on a slope).
In cold conditions it is good practice to leave the handbrake off in any car, as moisture in the cables can freeze solid leaving the handbrake stuck on until it thaws. Which is annoying…
Q My otherwise immaculate mk3 is suffering from unsightly rust at the base of the quarter-lights – can you please advise how to solve this?
A This is a relatively common complaint and is caused by slight movement of the quarterlight’s frame, making the plastic weather seal chafe against the metal, removing the paint and allowing rust to take hold. It looks horrible, but is easily repaired.
Mazda sells new quarter-light frames surprisingly cheaply, and if you look closely at them, a small square of protective plastic has been added to the vulnerable area. You can have the originals powder-coated, but this costs a similar amount to new ones.
The door card comes off easily by removing three screws and prising off the clips around the edge. One screw is in the cup-holder, and the silver top of the door pull prises off revealing a second screw: the final screw is behind the door handle (hook out the plastic trim to reveal the screw).
With the three screws removed, work around the edge of the door card with a trim tool or screwdriver to release the clips and the card comes off. As you remove the panel, the door opening cable and wires to the window switches etc must be disconnected. Next remove the window glass by releasing three fixing nuts and two limit stops (note the position of these). The glass lifts out easily.
The quarter-light can now be removed by undoing three bolts. You have to unbolt the quarter-light glass from the frame and swap the rubbers and glass to the new frame. Put back together in reverse order and your car looks as good as new.
Q My supercharged mk2 keeps throwing off belts: I’ve fitted new ones but it keeps happening. What can I do?
A The belt-drive is often the Achilles’ heel of supercharged Mazdas. Both alignment and tension are critical. On most installations I’ve worked on, shimming of the supercharger mounts to ensure that the drive belt is perfectly in line with the crank pulley is possible and very important. Belt length selection must be right to allow the often limited movement of the tensioner to work correctly. Too much tension can wear the rubberbonded crank pulley, making it run out of true, aggravating the situation. Too little tension results in lost boost at higher revs and huge amounts of rubber dust in the engine bay from the rapidly wearing belt.
It doesn’t help that the standard Mazda belt width is less than most superchargers really need. Wider pulleys are available, but being expensive are not often used. A smaller diameter pulley on the supercharger to increase boost also gears the system up and increases the load even more.
So basically, get the belt run dead-straight and the tension tighter than a normal drive belt – but not too tight – and expect to replace the belt more often than on a standard car, and you should have a reasonably reliable boosted car.
WITHOUT A PADDLE…
Q A customer recently complained about the clutch juddering badly on his mk2, spoiling the pleasure of driving the car, particularly in traffic. He asked if we could fix the problem.
A Mk2 MX-5S are well known to suffer this way, particularly when reversing. As long as the engine mounts are in good condition, fitting a new high quality clutch, and possibly having the flywheel refaced, cures the problem. However, on removing the gearbox of this car, we were surprised to see a paddle clutch installed.
These are intended for competition use or highpowered cars. Designed to reduce slip under extreme loads, they can be used on the road but often will be very grabby and have a bit of an on/off action. The torque of highly-boosted cars may make the use of such a clutch necessary, but the drawbacks have to be accepted. Some do work much better than others, but for a normal MX-5 it is complete overkill!
With this car we installed a standard-spec Exedy clutch (as fitted from the factory) and it’s a pleasure to drive again. For boosted cars we tend to install Exedy stage 1 uprated clutches – driven with a degree of sympathy, they do the job well and are smooth in operation.
Even light surface rust can cause your discs and pads to stick together. A hammer helps…
Some electrical problems are caused by a faulty ignition switch – it’s relatively simple to remove and clean, which will hopefully put things right again
Rusting quarter-light frames can spoil the looks of your otherwise tidy car. Replacements from Mazda (above right) are suprisingly cost-effective – or well priced, as we used to say. But you need to remove the door-card to fit them
To prevent your supercharger throwing off its belt, the belt must be perfectly in line with the blower’s pulley, and have just the right tension
Unless your MX-5 has a serious amount of power, a standard-spec Exedy clutch is perfect for the job