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miata bolt holes

jejones on Sat January 02, 2010 9:12 PM User is offline

Year: 1990
Make: madza
Model: miata

I am installing an aftermarket A/C unit and all was going well until I got to the compressor bracket. The bolt holes are in the engine block and line up however there are not threads in the holes. There doesn't appear to be enough room to get a tap in the block. I was wondering if anyone else had the same problem. Also do you think a self taping bolt would work.
Please respond with suggestions.
Thanks Jonesy

TRB on Sat January 02, 2010 9:34 PM User is offlineView users profile

All the Miata's I've done had the 4 mounting bosses which were threaded with 10mm x 1.25 tread.


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NickD on Mon January 04, 2010 12:19 PM User is offline

In tight spots, plenty of those under the hood, get by with a 1/4" drive ratchet using a square drive socket to fit the tap. Where there is a will, there is a way.

Cussboy on Mon January 04, 2010 1:39 PM User is offline

Wow, I assume that these are not "through holes" so a nut can be used on the other end?

As to self-tapping: I think that a real tap would do a better job. Either way, be careful, use oil/cutting fluid, back off frequently to amke sure you don't crack the block.

JACK ADAMS on Mon January 04, 2010 3:32 PM User is offline

All the ones we have done in the shop have had to chase the holes with a tap. Like said in previous post, be sure to use good cutting oil and DO NOT break the tap…..

jejones on Mon January 04, 2010 10:25 PM User is offline

The holes do not seeem to have any threads and the bolts that came with the unit seem to be too big for the holes. The holes are in the proper place for the bracket and the spacer fits in goood on the one hole however there are no threads in the holes. I stuck a scredriver in the holes and couldn't feel any threads. mi could see threads in a blank hole just above these holes and the bolt fit that hole but the bracket didn't line up with that hole. Thanks for responding. jonesy

JACK ADAMS on Tue January 05, 2010 10:51 AM User is offline

Get your self a good tap 10mm x 1.25 tread and spray the holes with some WD-40 and go to town. These holes are just gummed up with rust, have done plenty of these to know that is all that is wrong..

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