Bolt ID needed

[Peter S.]

My cataloging system has failed me, as I have lost track of one of my bolts. I'm looking for 397-1 (item #5 in the AIM). The part number is gone, so I cannot look up the size. Does anyone know the size of this bolt? Or perhaps the actual part #? This is for a '69 with an M20.

Peter

[Joe L.]

Re: Bold ID needed

My cataloging system has failed me, as I have lost track of one of my bolts. I'm looking for 397-1 (item #5 in the AIM). The part number is gone, so I cannot look up the size. Does anyone know the size of this bolt? Or perhaps the actual part #? This is for a '69 with an M20.

Peter

Peter------


You will note that there are two bolts which are shown as #5 in the diagram. However, the bolts are of completely different size. How can that be? Well, the description of item #5 does not specify a part number. What it says is "part of transmission assembly". So, the bolts are existing bolts and were not installed at St. Louis.

The bolt on the rear of the extension housing flange (handwritten 397-1 in your sheet) is a 3/8-16 X 1-3/4" bolt. It has a trimmed (i.e. "non-indented") head, phosphate-finished, and GM-280M material grade(3 lines SAE grade 5). "RBW" is a common headmark. It may be a GM #9419054.

The bolt on the side cover (handwritten 397-2 on your sheet) is a 5/16-18 X 7/8" bolt. It has a trimmed head. I have seen these bolts both natural steel and zinc plated. I have seen them with no headmarkings, at all, and with 3 lines and "RBW". The zinc plated variety with headmarkings may be GM #179817.

[Peter S.]

Re: Bold ID needed

Peter------


You will note that there are two bolts which are shown as #5 in the diagram. However, the bolts are of completely different size. How can that be? Well, the description of item #5 does not specify a part number. What it says is "part of transmission assembly". So, the bolts are existing bolts and were not installed at St. Louis.

The bolt on the rear of the extension housing flange (handwritten 397-1 in your sheet) is a 3/8-16 X 1-3/4" bolt. It has a trimmed (i.e. "non-indented") head, phosphate-finished, and GM-280M material grade(3 lines SAE grade 5). "RBW" is a common headmark. It may be a GM #9419054.

The bolt on the side cover (handwritten 397-2 on your sheet) is a 5/16-18 X 7/8" bolt. It has a trimmed head. I have seen these bolts both natural steel and zinc plated. I have seen them with no headmarkings, at all, and with 3 lines and "RBW". The zinc plated variety with headmarkings may be GM #179817.

Excellent information - thank you very much Joe! I had actually just finished installing Mr. 397-2 when I noticed 397-1 was missing. I also noticed they were both item #5, but after spending far too much time installing 397-2, I thought I would check here first.

By the way, my 397-2 was zinc plated with RBW.

[Gene M.]

Re: Bold ID needed

Peter------

.................................


The bolt on the side cover (handwritten 397-2 on your sheet) is a 5/16-18 X 7/8" bolt. It has a trimmed head. I have seen these bolts both natural steel and zinc plated. I have seen them with no headmarkings, at all, and with 3 lines and "RBW". The zinc plated variety with headmarkings may be GM #179817.

Also noted this bolt as non graded with SBC head marking and all three letters on on the same side of head.