Difference between S4 and S5 rear shock bolt??
 

Hello,

I just finished installing an S5 TII complete sub-frame in to my 86 N/A FC RX-7. The S5 sub-frame did not come with shock lower bolts so I tried to re-use the old S4 shock bolts, but they don't fit. The bolts thread in fine for a turn but then get tight almost like they are too large. I looked through the parts catalog and it looks like all the lower shock bolts are the same part number. Anyone know if there is a different bolt for S4 and S5 or N/A and TII?

Thanks!

Sounds like the wrong pitch thread. Time for a trip to the hardware store. If you have an old bolt box, find one that fits before you go.

Indeed, thanks for the reply TonyD89. I was thinking the same thing. I went to the store last week and got a couple of bolts, even an imperial bolt, none of them fit. Unfortunately I have misplaced my pitch gauge but I believe I've tried both a fine and coarse pitch bolt of the right size, 12 or 14 mm. I'll get pictures of the bolts when I get home.

12 mm has like four different pitches and 10 mm has five.

Basic Metric Thread Chart (M1 - M100) - Fuller Fasteners : Fuller Fasteners

Thanks for the chart TonyD89, much appreciated! I found my pitch gauge, the 86 N/A bolt is 1.5 pitch, the 89 TII is 1.25 pitch. I'll order up some 1.25 12mm bolts and post back with the results.

Get grade 8, which I believe is 10.9 in metric? You might want to verify that. My guess on the number of pitches available was wrong so...

I edited to say alloy socket head cap screws (takes an allen wrench, think McMaster-Carr) are grade 8