ok , question to all , how do i fit my new second hand mudflaps to my mk2.5 ? I tried longer screws they fell back out !! pop rivets are too small for the holes, and i can not get behind the skin to fit nuts and bolts …so mx5 people how did you fit yours as im at my limit of brain power super cold from all day outside and pi**ed off in general over a job whick is probally soooo simple, help
frustrated mx5 man 
Try fitting a plastic Rawlplug first and see if that works. It did on my Mk1. On the Mk1 can fit them using bolts and nuts, preferably stainless steel ones well greased up.
cool , thanks ill try that sunday
Spent most of last Saturday trying to fit the first on mine 
Gave up in the end as my hands were numb with the cold and I hadn’t any screws that would do the job. (Dispite buying some “Mud Guard Screws” from MX5 Parts) Either the holes didn’t line up or the screws were far too loose. 
I’ve subsequently been off work with a heavy cold and done some more searching for a solution.
http://www.mx5oc.co.uk/forum/files/folders/fitting_instructions/entry69221.aspx
This shows it’s a common problem.
http://www.ebay.co.uk/itm/170782855039?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
This is my solution to date. When I get over this stinking cold, I intend to use these and make some dog leg brackets for the bottom fixing. I will also use a small amount of Tiger Seal (panel sealer) to ensure a good flush fit to the body.
Looked like a easy fit at first glance, no problem - Yer right! Will probably take me a good weekend to complete but at least now I’m confident in getting it done, looking good and secure.
Good luck with yours 
David.
ok thanks to all , David when you done can you send me a pic of the stages?one link talked about the idea of sliding the flaps between the car and the shields , i got some longer push clip things from halfords and will try them when we back to dry weather…
Anything any help in this page?
I’ll post some pictures when I get it done. This weekend is possible, but I’ve given up trying to make plans.
I fitted a full set of s/h fronts & rears to my Mk2.5 yesterday & its easy as long as you buy/have the right fixings to start with.
So before you start you need a bag of 8mm x 22mm trim clips (Mazda ones are rubbish & most of them break or have to be drilled out so at least 10 required for full set of mudguards, 3 on each rear flap & 2 on each front flap)), 2 x plastic expanding nuts (if yours are missing from base of wing/sill for front mud flaps), 4 x M5 spring clip fasteners & bolts, 2 x 25mm long self tapping screws suitable for plastic expanding nuts, 2 x M5 x 25mm bolts & nuts (for underside of rear flaps) & 4 x M5 penny washers. Links are just to show you what you need your local motor factors may have everything you need cheaper, the choice is yours.
To make life easier I removed wheel(s) for better access.
Fronts
If you hold the flap against the wheel arch you will see which 2 trim clips have to be removed, so start by removing these (unscrew or prise out center of trim clip depending on what type it is & they should pull out with your finger’s). Then have alook at front underside of sill for the hole that holds expanding plastic nut in & if there isn’t already an epanding nut there pop one in. Another option here (this is how I did mine) is to use an M5 rivnut but you need a special tool to use/insert them but I decided an M5 bolt into a metal threaded insert was going to be better than a self tapper into plastic, again the choice is yours! Now hold the mud flap in place & screw self tapper/bolt + penny washer through flap into fixing on underside of sill, don’t screw it in all the way. At this point mine didn’t look like anything else would line up but flaps are very flexible so bend them carefully into position & pop the 2 x 8mm trim clips in (push in without centers first, then screw centers in which expands them thus holds them in bodywork). Now adjust the bottom screw in or out until everything lines up & there are no gaps (I think there should be a strip of double sided tape for inside of flaps but I haven’t used as my flaps were s/h). Fronts done, see easy :-). Oh nearly forgot might be a good idea to put wheels back on & torque them up.
Rears
Again hold flap roughly in position & you will see which trim clips need to come out (theres 3 & one will be hidden behind flap but it needs to be removed for next step). If you look closley at the splash guard you have just removed clips from you shoul see 2 u shaped sections that you need to cut out, once you have cut them out peel splash guard away enough to get your hands behind it & slot 2 of the M5 spring clip fasteners onto the bumper in line with the 2 u sections you have just cut out. Next fit the hidden trim clip back into the splash guard now hold your mud flap in place & fit the remaining 2 trim clips without centers, then screw the M5 bolts into the M5 spring clip fasteners. Now loosley fit the M5 x 25mm bolt, nut & penny washer to underside fixing (it lines up with a plastic moulding on inside of bumper). If your happy with the position insert the center clips into the trim clips & tighten all the bolts up. Again refit wheel & torque to correct settings.
Don’t forget to use grease on any bolts, screw.s you use. It might be you that has to undo them next 
Stand back & admire
This is how I did it so I am taking no responsibility for anyone else’s attempts.
Hope this helps
Chris H
Well it took me all day Saturday, but finally did it
Screwdriver indicating where the matching hole needs to be. M5 nut clips in place above.
Off set bracket bent from 2mm x 20mm aluminium for bottom fixing.
Bracket loose for final positioning.
Aligning final position before tightening.
Nut clip in place.
Small amount of panel sealer where the original double sided tape would have been.
All tightened up (may paint the stainless steel heads black)
Result!
Rear guards - holes all matched up ok so relatively quick job.