The saga continues. Will it never end?? After installing new water jacket seals and an intake manifold gasket a second time (they leaked the first time) - I tightened the nuts and bolts down to the Mazda shop manual recommended torque settings (14-19 ft/lbs). Actually, I never really reached the recommended torque, because one of the bolts snapped before the torque wrench gave way. I was lucky enough that I was able to remove the broken shaft of the bolt with a pair of vice grips. Unfortunately, I also discovered that I had managed to strip one of the threaded studs and nuts that holds the manifold on. Again, I was fortunate that I didn't strip the threads inside the rotor housing. However, I am at a loss as to where I can find replacement bolts, studs and nuts for an '84 12A. Does anybody have any recommendations out there? Does this mean a trip to the junk yard or a machine shop? Any help is surely appreciated!

 

They're just standard bolts. Take one of the nuts with you to the hardware store. The studs can be removed from the rotor housings if you have a set of good pliers or vise-grips - they just unthread. You can replace it with another stud or go with a bolt - a stud is recommended because aluminum can gall when you thread things in and out of it.

I believe they're 8x1.25 thread diameter/pitch, but take some of the old ones with you to you can check.

edit: Your torque wrench is probably wrong. Just tighten them by hand. We're not talking about rocket science here, the torque spec is just a generic number to keep you from breaking bolts.

 

Peejay - thanks for the info. I am pretty confident I can find a bolt at the hardware store. It is the stud that I am more concerned about. BTW, the stud came out when I tried to back the stripped nut off - so, no problem there. It is not very comforting to think that my brand new torque wrench is wrong - especially if it is going do the opposite of what it was intended to do (i.e. prevent bolts from breaking). That aside, the first time I installed the intake using the hand-tightening method, it leaked...and the seals hadn't shifted position. Now I have a stripped nut & stud, a broken bolt and a mangled gasket. Live and learn. %$&*^#@

 

If you have a click-type torque wrench, it probably *is* wrong.

Good click-type wrenches are expensive (couple hundred bucks), come with a datasheet detailing the accuracy at various levels (like, say, 50, 150, and 250lb-ft). And they need to be sent back for recalibration once a year or so.

Cheap click-type wrenches are a total crapshoot. You're better off not using a torque wrench at all.

 

Good to know. Mine is a cheapo.

 

Ehhh, cheap torque wrenches are not *that* inaccurate. As long as you don't abuse them and use an appropriate one. So, don't use a 300lb max wrench for your oil pan because the accuracy is typically measured as a percentage of the total scale of the wrench, not whatever setting it's at.

 

Yep. 8mm x 1.25 for studs nuts and bolts. I'm not sure on length. I ran out of all my spares when I brought a core engine to life.

 

The broken bolt may have been a result of operator error on the el cheapo torque wrench. I found some M8 - 1.25 x 20mm nuts and bolts at Kragen. The head is slightly smaller. I wonder if I should use a washer? I also found an M8 - 1.25 stud in the proper length at Ace Hardware, but the threads are unequal length on each end. I'm going to try to re-thread the original stud with a die. If that fails, I am going to try to equal out the thread length on the Ace stud with a die. If that fails I've got to find another hardware store somewhere! To be continued...

 

Doesn't anyone have a spare stud for this guy?

I have a couple dead 12A rotor housings. I tried removing a stud yesterday. It messed up the threads. I might try removing the other today with a couple nuts. If it's ok I might send it to you in the mail. what do you think?

 

You can cut a stud, just screw 3 bolts over the middle of the part you want to keep, cut it, then unscrew the top one. Should work.

 

Or you could get a long bolt and chop the head off. Easy stud. Of course it will be missing the shank part, but it's not rocket science to thread it in to the rotor housing a certain amount and then add the nut after installing the manifold.

 

I always see studs in the parts stores and hardware stores. Never bothered to check if they were all too short, since I never needed one for an intake manifold. (Reattaching the turbo to the exhaust manifold on my Isuzu, however...)

Washers are a very good idea. They ensure that the nut is tightening against a "perfect" surface, or at least a better one than bare aluminum.

BTW - you wouldn't believe the trials and tribulations I went through to find the proper bolts for the strut bottoms. I think 12x1.5. When I ended up doing was using a screw-in wheel stud for the short one and one of the accessory studs borrowed from my '80 12A, and some nuts from the accessories. (Mazda used bolts for a good reason, as I discovered when I tried to remove the strut again. The control arm will not clear the caliper bracket if you try to pull the strut straight off. PITA to remove the caliper, rotor, and backing plate just to get the strut assembly off)

 

are u sure it said ft/lbs and not in/lbs? 14-19 ft/lbs is hard to feel, it's not high enough for the wrench to "click". it's really not necessary to torque the intake. i never have.

 

I never did torque the manifolds on my boingers, not the best idea, but it generally works pretty good

 

Yeah, I double checked and the manual said ft/lbs. I tested my el cheapo torque wrench on a few bolts this morning. Low and behold, peejay was right - the thing is absolutely defective. I even managed to break my vice with it - on the lowest setting! The bastard's going back to Kragen tomorrow. Anyway, I was able to re-thread the original stud satisfactorily with a die. It worked like a charm. Murphy and his %#$^&* law was with me every step of the way, but I finally got the manifold on (hand tightened) and everything back together earlier this evening...and it worked...no more leaking coolant! Hint: watch out for a build-up of rock hard gasket/sealer on the left and right ends of the rotor housing where the intake attaches. I finally resorted to a Dremel to remove the crap from mine. Thanks to everyone for the great suggestions!

 

glad to hear u got the leak stopped, good job.