Hi, car is a used 2005 6MT. I found the screw thread in one of the holes in the airbox (where the MAF screws into) to be stripped. There is no tension when I try screwing in the MAF screw nearest to the engine (opposite side of resonance chamber). It is relying on the other good screw. Anyway, besides wasting a few hundred dollars to get a new airbox, is there any cheap and good DIY method to reinstate the stripped thread in the airbox? Thanks in advance for all your helpful suggestions.

 

Use an epoxy resin in the damaged thread,I used a syringe and needle to apply it,let it go off,use a drill size that will leave enough resin in the orifice to use the standard screw. I had the same thing happen.

 

Cool! Will a hobby grade 2 part 30-minute expoxy work? And has it held up well to engine heat and repeated unscrewing? Thanks!

 

You could also use a plastic welder..or a soldering iron and melt in some plastic scrap from the VFAD tab or someplace else...it is a thermoplastic so it melts

 

hmmmm - i would just put a bigger screw in LOL

 

Guess I'm not the only one having problems.

 

Thats just too easy. Yes and Yes, it has held up for more than a year,adjust your wrist powered torque wrench to 5 inch/pound.

 

Well...if I were you I would not do what the suggested epoxy alone method mentioned above. That's just a temporary solution to hold a screw in place where when you take it out next time, you have to do all over again. Not only that, but it's not exactly holding the screw down tight alike to torquing it down to metal threads.

A proper way to do this is either:

A) If enough insert material is available, just go to the next size bigger screw after tapping the insert to the next size
B) Use a drill to completely drill out/remove the insert currently in place and replace it with a new one using epoxy that is meant for plastic/metal combined, not metal on metal and go back to using the same screw.

 

Where do you get a tap for a "self tapping" screw.?

 

IIRC, those screws are not self tapping....for aftermarket intakes, there are threads already made on the aluminum manifolds (AEM/MS) and the stock ones use insert placed in the plastic.

If I don't recall correctly for the stock intake and there is no insert used (which actually would be more ideal), then I would simply added drill the hole bigger and place in a metal insert in there bonded with epoxy and let it cure.

 

The only way to fix it with the original screw is to plastic weld it...easy...then use a small drill for relief and re-thread with the small self tapping screw

A slightly bigger screw works great too....

Epoxy would be my last choice...cause it makes it difficult to clean it up and do it properly when the epoxy comes loose

 

Hrm....I don't recall those screws being self tapping.. oh well. If they are, then what Dan suggested would work fine. I'd prefer metal inserts in place bonded with epoxy to the intake which would never come out and less likely to strip.

 

Maybe the US and EU stock maf tubes different, mine is secured with 2 very very small black metal self tappers.And the screws sit "in" a recessed hole in the maf mounting pad, so using a larger screw would look shitty, but effective. Each to his own, i suppose the op could just purchase an aftermarket CAI and remedy his problem.

 

All this got me curious...went to the garage and pulled out the OEM MAF tube...

It's black plastic with self tapping black screws

 

Yup, it is. I checked myself; the lighter color of the threads on a glance gave me the impression when I first worked on the MAF a while back it was inserts, which would have been a better design but nope, threaded plastic.

 

mines havent stripped, but Im a bit afraid of cleaning the MAF last time I took it out and found how weak the screws are.
I was actually considering RB REVi intake since its metal.

 

Use cellotape

 

They're actually closer to a sheet metal screw than anything. I had the same problem, plastic welded the holes, didn't worry about drilling and tapping, just used the OEM screws and they went in fine. I guess I'll see the next time I remove my intake or clean my MAF.

PS: These screws are NOT meant to be removed and put back in multiple times. If cleaning the MAF is a regular maintenance practice, some permanent solution has to be performed. I was even thinking of helicoils.

 

Thanks for all the suggestions. I'm crap at DIY so I used the simple epoxy solution that fastfreddy mentioned. Seems ok for now. Leejin, I agree these screws are not meant for multiple removal and the next time it happens, I'm gonna go with the plastic welding technique that you and danobre suggested. Would a simple 40W soldering iron and some loose plastic tree scraps from an old airfix/rc car work?

 

Took the MAF out for cleaning.
Noticed that the plastic treads were looking like black springs in the holes... No longer attached.

I used epoxy made for plastic.

left it overnight.

At first I used a smaller drill bit and found out how brittle epoxy is when set.
I switched to a bit almost as big as the MAF screw diameter... I'll check the size... and all was good! Very solid MAF mounting now.
If you're doing this make sure you have a spare rubber o-ring for the MAF! Mine was stretched for some reason

 

You are right, epoxy is brittle. First attempt: epoxy cracked while screwing in. Played around with various proportions of hardener to resin and realized that with less hardener, resin cures with more flexibility. Second attempt: with more "flexible" cured epoxy, screw goes in without epoxy cracking and "feels" like a good thread-lock compound. Hope it stands up to the heat of the engine and at least till the next time I remove the MAF. I'm happy to use epoxy each time as a thread-lock compound.

I didn't have a spare o-ring. I don't remember it being loose.... Damn, should I be taking it out and redoing with a new o-ring? So far, it drives ok.

 

damn it. I stripped mine today. put a bigger screw in and use only finger tight. if you use a screw driver only use fingers holding the end.

 

Bigger wood screw works fine - just make sure it's not any longer than the stock screw, or it will penetrate into the interior of the intake tube.

 

I cant believe how cheap that part is made, I didnt think I over tightened the maf when I put it back in but I guess I did. Stripped mine in an 09 today.

I went the bigger screw method, I couldnt care less how it looks not like anyone is gonna be in my engine bay except me. I really wanted to take it to the dealer and try and get the part replaced under warranty but I couldnt see it happening because they would just say its my fault rather than mazdas for a weak design.