Q&A Problems resolved
Michael Cleverley of Cleverley Repaired Cars, expert on all things MX-5, answers your questions
Fried electrics, a sodden boot, and improved heel and toeing keep our MX-5 expert busy this issue
SMELLS LIKE… Q
My mk3 has started to make a lot of noise all of a sudden and smells of fumes. Have you any idea what has happened please?
It sounds to me like a problem with the exhaust system. The mk3 exhaust system is quite heavy, and now that they are getting older we have seen a number of them cracking just on the weld behind the bomb-shaped centre silencer. The cure is to either replace the part (maybe a good time for an upgrade) or it’s quite easy to re-weld the pipe, as the break is usually very clean. To do this I tend to tack weld it whilst on the car (with the battery disconnected) and then lower the system to the ground to weld it completely. It is possible to do in situ but much harder to achieve a neat result.
THE LIGHT STUFF Q
Whilst driving my car at night recently I could smell burning and now my lights don’t flick between main and dip reliably: what’s going on?
This was a customer of ours with a rare problem on an MX-5 – an electrical fault! Generally with MX-5S if I have an electrical fault I check for any non-standard additions to the car first, as the original electrics are very reliable. In this case having removed the headlight stalk and found the terminals melted. I decided to look for the cause, as they are not a problem usually.
It seemed as though the stalk had been subjected to a high electrical load. On these early cars the stalk switches the lights from main to dip without a relay to take the strain. With this in mind I popped the headlamps up and removed the light units. The sealed beams had been replaced with halogen, a conversion, which is normally OK. Looking at the bulbs, they were a very high output type drawing more than standard amperage – too much for the switch contacts to cope with. The cure in this case was a secondhand dip switch triggering a relay that supplies the power to the bulbs. It’s a simple wiring job that any competent DIY enthusiast should be able to carry out.
PLAYING FOOTSIE Q
I’m looking to do some trackdays in my mk3 but am having trouble heel and toeing in it – is there something that can be done with the pedals to make it easier?
One of our customers asked us to do some upgrades on their mk3 2.0 Sport in preparation for trackday use. We fitted uprated coilovers, uprated brake pads and carefully aligned the suspension to a more sporty spec. Also we replaced the manifold with a stainless steel decat unit. A
remap saw 175bhp on the dyno.
She was very pleased with the results. However, she was having trouble heel and toeing, so we looked at improving the pedal setup to suit her. We needed to raise the throttle pad and bring it closer to the brake. The pedal on a mk3 is a moulded plastic item so we couldn’t bend it or weld to it.
So we modified a commercially available aluminium pedal pad using some 6mm-thick rubber sheet glued to its back, trimming the ends to suit the car and finally bonded and screwed the pad to the throttle pedal, moving it slightly closer to the brake pedal at the same time. Remember when doing modifications of this type you must be certain that the work done is safe and secure.
LEAKING ‘FRANKENSTEIN’ BOLTS A PAIN IN THE NECK Q
My mk1 keeps leaking water into the boot. I can’t see where it’s coming from – what should I look for please?
Check the boot seals are in good condition: I would ensure that the aerial is secure and its seal intact. Inspect the drain hole in the petrol flap area to make sure it’s clear and its gasket is in good condition.
The next areas to consider are the bolts (known as ‘Frankenstein’ bolts, for obvious reasons) that secure the rear of the hardtop in place. With these and the plain bolts fitted to standard cars there is an Oring at the base of the bolt and a gasket under the chromium finishing plate. Remove the bolt carefully so as not to break its captive nut free, or strip the crosshead out. Lift the plate up and clean; reseal the gasket using silicone sealant. Refit the bolt with grease on its threads and silicone on the O-ring. Addressing these points should ensure a watertight boot on mk1s and 2s.
STICKY SITUATION Q
If I drive at 60mph or more for a few minutes in my mk2 the power drops off and the car drifts about on the road: there’s some juddering through the steering wheel, too – please can you tell me what on earth is going on?
This customer was driving his mk2 to us for an MOT test from a fair distance away. We received a panicked call from him saying that the car’s engine was playing up. He described loss of power when driving at 60mph for five minutes or more, the car drifting about on the road, and some juddering through the wheel. After stopping for a few minutes all was well again.
He arrived a bit late and said at slower speed the car was OK, so I agreed to carry out the MOT and see what turned up during the process. As it happened, the car sailed through the emission test and passed the MOT. The only thing I could see that wasn’t quite right was a slightly sticking offside front brake – the disc was black and the rust around the edges bright red, a sure sign of trouble!
I discussed the problem with the owner and after a bit of interrogation we ascertained that the car would drift to the left under braking when the juddering was taking place. I concluded that the power loss was not an engine fault, but brakes binding hard after getting hot which eventually overheated and juddered followed by fading, hence the poor braking performance at the time. The funny thing is that they passed the MOT test and only had slight signs of sticking when rotating the wheel, although one disc was obviously getting hot.
The cure was to strip the calipers (always do both), clean the pistons, rubber grease the seals and re-assemble. Fresh brake fluid and the car’s ‘engine fault’ was fixed!
Headlight stalk terminals can melt, but it’s a very rare fault in a mk1
Mk3 exhaust welds are starting to crack with age, but can be re-welded
Disc showing signs of excessive heat Stripping down the brake caliper and lubricating the components with appropriate grease solved an ‘engine’ problem
Modified aftermarket throttle pedal helps heel and toeing in a mk3
Possible site of water ingress