C2 Rear Bumper Bolts

[Alan Drake]

The 64 AIM, page D222, shows two different bolts for the rear bumper and supports.
The first #9 is a 7/16-14 at 1 1/4" long and is used from bumper to supports.

The second #6 is 7/16-14 1 3/4" long and used: 2 at Brace Inner Upper L&RH and
1 at Brace Outer L & RH Now for the question!

The longer bolts (1 3/4), pn 122293, - - what are acceptable head markings??

Mine are all marked RBW on a smooth head. Marking is along the outside radius of the head. Does anyone known the story behind these?

Note; all my smaller bolts are the expected TR in the center.

[Gene M.]

Re: C2 Rear Bumper Bolts

Expect to find various assortment and possible mixed at that. Such as TR, M, C, RBW, and there is possibility of others. GM had many suppliers for such things as bolts and nuts and washer. Each having there own markings. Are the 7/16 nuts on your car a 5/8 or 11/16 hex? Typical todays hardware is a 11/16 hex nut for a 7/16 thread. The 5/8 hex is harder to find.

[Alan Drake]

TR/RBW both 5/8 and nuts 2, Thank Y *NM*