Hardware/Bolt Grade for...
 

What grade hardware do you guys suggest if I am replacing my rotted suspension bolts? This is for a purpose built racecar. The bolts to the lower A-arm etc.

Also... While removing my frt. Anti sway bar one of the bolts broke. It's about a quarter inch buried, nothing exposed. Do I drill a hole in the deadcenter of the bolt not quite the diameter of the hole, punch the remains out carefully, chase the threads then tap it clean again or?

I believe the large suspension bolts are metric 10.8 it would be similair to an aircraft type bolt. drill the broken bolt and chasing the threads is the easiest if it can be done. otherwise a "helicoil" can be used to repair the threads. I like the solid insert over the coiled wire type. suspension bolts will likely need to come from Mazda, but you may be able to find a good subsitute.

When I started rebuilding/replacing suspension parts, I was able to find many of them at Ace hardware. They have have a fair selection of 10.8. I also went to NAPA. Most regular parts stores have a very limited selection. I was able to avoid the dreaded dealer markup. Good luck!

Sorry for the double post. The forum won't let me delete.

Grade 8 all the way.

Since these are metric bolts, you will need to use the Metric system of grade identification.

Metric 8.8 is basically equivalent to SAE grade 5; Metric 10.9 is very similar (actually, slightly stronger) than SAE grade 8. I would recommend using (metric) grade 10.9 for the suspension.

As for your other question: yes, you should be able to drill a hole through the center of the bolt. If you are careful about it, the threads in the hole can be cleaned up, and a new bolt can be put in. However, I would actually recommend using an Easy-Out, (or any bolt extractor), as it makes life a little easier.


Rob

Just out of curiosity, what gen RX-7 is this?

I have deleted you! MUHAHAHHHA! ;)

2nd Gen. Thanks for the replies!

I should probably start another thread but... (and have done a search in this forum)...

N/A S4 with a S5 LIM and UIM, light porting... should I pull the 6-port sleeves or not? My rules allow for anything pretty much.

If you have access to a welder you can weld the bolt out. I take a section of 1" or so flat iron and drill a hole about the size of the broken off bolt in it. Hold the bar with the hole over the broken chunk and weld the broken chunk to the flat iron. The heat from the weld normally breaks it loose and you just wiggle it back and forth until you can turn it out. Fast and easy.

-Trent

What grade?

I always use Grade 8 (english) or Grade 10.9 or 12.9 if possible. Fasteners are cheap but critical.