Went to change the thermostat (original I think). Felt to good to be true and broke the back bolt. The stud bolt, flush break, nothing sticking out to grab. Anyone got any ideas, procedure from experience, specs on bolt or tap size? Anything will help before I attempt. Think plenum has to go....dam what a smooth move huh? Thanks

 

305 TBI w/stock intake manifold? Had to drill mine out recently and replaced with helicoil. Been working fine since. Will get the size and dimensions in the morning if someone doesn't get to you by then.

 

Much appreciated

 

TPI motor should be the same.

 

I used the OEM (Autozone) Fix-A-Thread Thread Repair System part number 25606 to fix my broken thermostat housing bolt. It comes with a tap and helicoils and specifies to use a 9.9mm or 25/64 drill bit. The bolts I used were Dorman 3/8" - 16x 1 1/4in part number 960-211. I tried other means prior to this (i.e. freezing/heating/reverse drill) but they did not work. I ended up drilling out the remainder of the bolt, tapped it, and dropped in a helicoil. Was not fun; but, rewarding afterwards. If you plan on doing it yourself get a good drill (mine barely passed), quality bit (broke two), lubricating oil (helped alot), and protective glasses (safety first). Be patient and take your time. You can do a search here and on "youtube". Wealth of info out there. Let me know if you have any specific question. Not an expert but I've been there. Good luck.

http://www.autozone.com/autozone/acc...er=557090_0_0_

 

It most likely goes without saying but you must get a good dent with a center punch or you will be walking the bit all over the place. Its going to want to start the hole next to the bolt because the surrounding metal around it is softer.

 

dent it like was said above, then try to drill it out with a left hand bit, that way if it catches it can spin the bolt out ... unless it is pressed in

 

I drilled and tapped both. Working good. Didn't have to take out the fuel rail thanks to Gatorbite socket on the tap with a 3 foot ratchet.Chaulk one up for the Gatorbite.