Q&A Tech­ni­cal is­sues solved

Michael Clev­er­ley of Clev­er­ley Re­paired Cars, ex­pert on all things MX-5, an­swers your ques­tions

Total MX-5 - - CONTENTS -

This is­sue: yellowing lights, a power-sap­ping alarm, and a spongy clutch

BRING ON THE NOISE

QThe door speak­ers of my mk1 rattle and sound poor. Is it easy to change them?

ATh­ese cars are get­ting old and things like the speak­ers are start­ing to cause trou­ble – they get damp and the cones soften lead­ing to fail­ure.

Re­move the door card by pris­ing out the blank­ing plugs from the door pull and un­screw­ing the three crosshead screws. There is a crosshead screw be­hind the in­ter­nal door re­lease han­dle – re­move that and take out the plas­tic trim that it re­tains. Cars with man­ual wind­ing win­dows need the han­dle re­mov­ing: do this by re­mov­ing the horse­shoe clip that is be­hind the winder (a strip of cloth looped be­hind the han­dle and pulled down, or fid­dling with a screw­driver will prise the clip off with­out too much difficulty). Now the door card is re­moved by pris­ing the clips out along the sides and bot­tom edge of the door us­ing a trim tool or screw­driver, be­ing care­ful not to scratch the paint.

Lift the card out and up­wards to re­lease it from the door top. Now re­place the speaker. We like to fit up­graded units, such as those made by Alpine, to im­prove sound qual­ity. Gen­er­ally they’re a straight fit, but you may need to change the two wire con­nec­tions to suit. Whilst in there, why not lube the win­dow ca­bles and door locks.

Re­assem­ble once you’ve checked the speaker works.

TOO MEL­LOW YEL­LOW

QI have a mk2 and the head­lamps have failed the MOT test be­cause of poor light out­put. The lenses are yel­low and cloudy. New lights are ex­pen­sive, so is there any­thing I can do?

AThe head­light lenses on most cars are plas­tic – this has the ad­van­tage of be­ing tough, light­weight, safer in an ac­ci­dent and, I pre­sume, cheaper to make. They work well but un­for­tu­nately some will de­grade over time and ‘yel­low’.

Even­tu­ally the bright­ness re­duces and even high-out­put bulbs won’t im­prove night vi­sion. In­ci­den­tally, the bulbs used in these lights are de­signed not to cause this degra­da­tion and us­ing nor­mal bulbs can speed up the yellowing process.

New light units are costly. How­ever, if you’re pre­pared for a bit of ef­fort, Au­to­glym and oth­ers sell ren­o­va­tion kits. These in­volve a se­ries of abra­sive pads that you use with wa­ter. Work­ing from coarse to fine, you buff the wet lens us­ing a cord­less drill, fi­nally pol­ish­ing the lens with the sup­plied com­pound. Sur­pris­ingly good re­sults can be achieved with some el­bow grease.

BABY IT’S COLD IN­SIDE…

QI have a 2.0-litre mk3 and the heater out­put is rather poor – what should I check for this please?

AAs long as the heater fan is blow­ing cor­rectly, look to the cool­ing sys­tem for prob­lems.

First check that the coolant level is not very low: if it is, air locks can stop the heater work­ing. Find and cure the leak then re­fill the sys­tem with the cor­rect FL22 coolant.

Next you need to check the op­er­a­tion of the ther­mo­stat. When the en­gine is cold, the ther­mo­stat should be closed so coolant in the ra­di­a­tor should not be cir­cu­lat­ing when the en­gine is run­ning. This gives a fast warm-up. Check this by feel­ing the tem­per­a­ture of the top hose run­ning to the ra­di­a­tor.

The top ra­di­a­tor hose should stay cool un­til the temp gauge reads about half­way. As the ther­mo­stat then opens, the top hose should heat up quite quickly in­di­cat­ing that coolant is now flow­ing through the ra­di­a­tor. At this point the ther­mo­stat should open and close to main­tain run­ning tem­per­a­ture (just be­low boil­ing point). If the coolant flows through the ra­di­a­tor im­me­di­ately after a cold start – in­di­cated by the top hose slowly warm­ing up soon after the en­gine is started – or be­fore run­ning tem­per­a­ture is reached, you need to re­place the ther­mo­stat.

This is quite an awk­ward task on a mk3. It’s lo­cated on the in­let side of the en­gine un­der the man­i­fold to­wards the front of the en­gine. Re­mov­ing the throt­tle body just about gives enough ac­cess to carry out the task. The cool­ing sys­tem self­bleeds when you run the en­gine. With cor­rect run­ning tem­per­a­ture the heater should be very ef­fec­tive and fuel econ­omy will be im­proved.

In­ci­den­tally a Ford equiv­a­lent from a sim­i­lar aged Du­rate­cengined car is the same as the Mazda’s ther­mo­stat but quite a bit cheaper.

DON’T BE ALARMED

QMy mk1’s bat­tery keeps go­ing flat after a cou­ple of days’ in­ac­tiv­ity. I’ve changed the bat­tery and checked it charges, with no joy – any ideas?

AMazda electrics and bat­ter­ies are very re­li­able: even on old ones we don’t have many prob­lems. With this par­tic­u­lar car we re-checked the charg­ing and the new bat­tery con­di­tion, which seemed fine.

Next we placed an am­me­ter into the pos­i­tive cir­cuit of the bat­tery. No dis­charge was recorded. We noted that the car was fit­ted with an af­ter­mar­ket alarm sys­tem, which when armed caused a cur­rent draw of more than ten amps! Al­though alarm systems do cre­ate a slight dis­charge, this is rather more than nor­mal.

After talk­ing to the cus­tomer we de­cided to re­turn the car to stan­dard. We re­moved a rat’s nest of wires, made good the orig­i­nal wiring and the prob­lem was cured. All alarms draw a small amount of cur­rent that shouldn’t cause a prob­lem, but it is re­ally im­por­tant to in­stall them neatly and with good con­nec­tions or else re­li­a­bil­ity is likely to suf­fer.

GO­ING SOFT

QI’m hav­ing trou­ble en­gag­ing gears, par­tic­u­larly re­verse. The clutch pedal feels softer than it used to. Please can you of­fer some ad­vice as to why?

AAll gen­er­a­tions of MX-5 use an hy­draulic clutch mech­a­nism. It’s re­li­able and as a re­sult is of­ten ig­nored.

Just like the brakes, the fluid used is hy­gro­scopic (ab­sorbs mois­ture from the at­mos­phere) so can de­te­ri­o­rate over time. This causes cor­ro­sion in the mas­ter and slave cylin­ders, lead­ing to a fail­ure. If the fluid in the clutch mas­ter cylin­der is brown or black in colour then it should be changed. If chang­ing the fluid makes no im­prove­ment I sug­gest re­plac­ing the clutch mas­ter and slave cylin­ders.

It’s straight­for­ward. The mas­ter cylin­der is mounted through the scut­tle us­ing two nuts, one reached from the footwell and one from the en­gine bay. The pushrod can be left con­nected to the pedal.

Care­fully re­move the slave cylin­der feed pipe catch­ing any fluid drips (the fluid strips paint). The clutch slave cylin­der bolts to the gearbox us­ing two 12mm-headed bolts: again re­move the feed pipe be­ing care­ful to catch the fluid drips.

Once new mas­ter and slave cylin­ders have been fit­ted, check the mas­ter cylin­der pushrod ad­just­ment at the pedal. There should be slight free-play be­fore the pedal starts to move the pushrod. Bleed out by fill­ing the mas­ter cylin­der with fresh brake fluid.

A helper will be needed to op­er­ate the clutch. Open the bleed nip­ple on the slave cylin­der and ask your helper to fully de­press the clutch. When fully de­pressed, close the nip­ple and ask your helper to re­lease the clutch pedal.

Re­peat un­til air-free fluid flows from the slave cylin­der. After this the clutch hy­draulics should be as good as new, and pedal feel back to nor­mal.

With the door card re­moved, re­plac­ing the speaker is rel­a­tively sim­ple

Bring­ing a mk2 head­light back to life us­ing an Au­to­glym ren­o­va­tion kit: very sat­is­fy­ing

Prob­lems with your cabin heater can be caused by a de­fec­tive ther­mo­stat – if it is faulty, its lo­ca­tion on the en­gine will make fit­ting a re­place­ment an awk­ward task

Af­ter­mar­ket alarm systems, par­tic­u­larly when poorly in­stalled, can sap charge from your bat­tery and drain it within a cou­ple of days: get rid!

Knack­ered clutch mas­ter cylin­der and at­ten­dant pushrod assem­bly – re­place­ment is fairly straight­for­ward, but you’ll need a friend to help

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