Down to the bolts?
Race Director
Joined: Aug 2007
Posts: 10,977
Likes: 19
From: Canboro Ontario
Paragon does have most nuts and bolts for almost every application. They also have a laminated chart of all the bolt heads and use. It is pretty cool, and I think it is free, if you ask nice.
1969/1971/2021 Coupes
Joined: Jan 2008
Posts: 2,212
Likes: 80
From: Port Huron MI
St. Jude Donor '09-'10-'11-'12-'13-'14-'15
Team Owner
Joined: Jul 2004
Posts: 40,239
Likes: 786
From: Redondo Beach, California
Good fasteners to use are generally a grade 8 bolts, nuts, and washers. They are expensive. As for stainless steel(SS) fasteners, generally available SS fasteners are not as strong as grade 8. The SS fasteners stronger than grade 8 are aircraft rated stuff. Grade 8 is expensive enough, but aircraft SS is +$$$$.
There are some suspension fasteners that are grade 5. Grade 5 is not as strong as grade 8, but it's not as hard and a little more flexible. GM knew what they were doing, there's probably some places you need a bolt that can exhibit a little flex. I don't have any guidelines as to what grade 5 bolts should be kept as grade 5.
An IMPORTANT FACT. Some the bolts in your suspension are really not "bolts" per se, they are pins. The shanks of these "bolts" have accurate diameters to match holes through which they are inserted. The trailing arm bolts are pins. They are threaded at the end only to accomodate a nut to hold them in place. The Florida mafia suspension vendors will sell you threaded bolts. The threads mate up to surfaces that were intended for pins. There's a concern the threads will bite into the holes. The story here is that where a suspension bolt is used as a pin, use the ORIGINAL GM BOLT. Trailing arm "bolts", differential forward bracket "bolts", and the "bolts" for the front wheel lower control arm attachment to the frame are "bolts" that are really pins.
........and another. Grade 8,being tough fasteners, is rather corrosion resistant (rust). The hardened surface of these fasteners gives them a good degree of rust resistance. Not as good as SS, but unless (to repeat myself) you go to aircraft SS, the Grade 8's are optimal fasteners for strength and rust resistance.
For trailing arms, you really need "pins" to attach to the frame. If your trailing arm bolts are the replacement bolts, the threaded portions will eat into the frame holes. The trailing arm bolts(often rusted, destroyed in TA removal) are hard to buy. A low hanging fruit replacement it to use the bolts that attach the differential to the front differential bracket. I think they are the same.
Last edited by 68/70Vette; Dec 10, 2009 at 08:53 PM.
