Hey,

I've had a mechanic spend a couple weeks supposedly working on my diff. He just called me claiming that the bearing cap bolts/screws/whatever, when he torqued them down, one of the 4 stripped, the other turned into an hourglass shape.

From what I understand, we're talking 20-30ftlbs of torque on them, there's no way they should be doing this kind of stuff at those torque levels, right?

 

Yes- except that I had it happen on a 1.6 diff I built way back. New bolts bud.

 

Honestly I've found off road shops have a better idea of how to do diffs. They do lockers and ARB's all the time and the run of the mill shop might do it once a year. That said NO it should not do that at that torque.

Also yes I know we aren't doing lockers in Miatas, but they do know how to set up the lash and other things related to diff stuff better than most rednecks with hammers.

 

Where can I get said new bolts?

 

This was over 15 yrs ago- but I'm guessing I got them from Mazda competition parts since it was for my showroom stock car. sry

I agree- they're not supposed to, but I remember explicitly not be able to reach the torque spec. It got to X and stayed there as I turned. I backed it out and it had the hour glass stretch. I tried the second one and it made min. spec, but started stretch as tried to raise it beyond that.

 

Mine stretched too, replaced them with some I had in my tool box. Flanged grade 8 of the right pitch and length.

Wonder if they're randomly torque to yield bolts.

 

I've re-torqued (bending beam type, not click) those bolts 3 or 4 times in the diff I keep taking apart to help the owner adjust the giken in it. Honestly if you're only doing carrier work you should just do it yourself. 7-8" mics and dial indicators are actually pretty cheap, like it should cost you $100 for both for some that should be accurate enough to set pre-load and backlash. And its so friggen easy. I've not done R&P setup but the crush tube scares me. At this point I can practically set backlash and pre-load by feel, at least on this particular diff.