C2 Fuel line fasteners

[Ed S.]

Need advice regarding the fasteners (I would call the bolts) that secure the fuel line to the frame for a 64.

The AIM shows the part # to be 171109 and calls it a "screw". Can someone provide the correct description of this screw? I know it is a 5/16-24x1/2", with a fine thread and indented hex head, what I don't know for sure is the physical appearance.

A picture of one appears in a thread in this forum and it is black phosphate and has a head mark with an anchor.

One (leading) vendor who claims theirs is "correct" is finished in zinc and the head mark is "LG".

Another (leading) vendor claims its part is "correct" and it is black phosphate and the head mark is a "D".

Please advise what it should be and if it isn't LG or D, can you recommend a source.

For what it is worth the ones on my car have no head marking - but I suspect they are repros.

Thank you

[David B.]

Re: C2 Fuel line fasteners

GM Engineering Standards lists #171109 as a Hexagon Head Tapping Screw Type C 1/2" Length PLAIN 5/16 - 24
From this description it appears both vendors are incorrect. Your screws MAY be correct!

[Ed S.]

Re: C2 Fuel line fasteners

David,
Thank you very much - that is great info. And.... you are the second person to tell me that the bolts have plain heads. A friend, that owns a very original 64 & a 65 send me an e mail and confirmed that the bolts on his car are plain.

That said, I am going with my "original" plain fasteners. So much for vendor supplied "correct" parts. Makes my head hurt.

BTW - David, can you tell me where you found the description of the 171109 screw? I would love to be able to research that type of info myself, if it is possible - are the references on the internet or do you have a pile of old GM parts catalogs sitting by the TV remote?

[David H.]

Re: C2 Fuel line fasteners

Need advice regarding the fasteners (I would call the bolts) that secure the fuel line to the frame for a 64.

The AIM shows ... Thank you

Ed,

What does the 1964 NCRS Technical Information Manual & Judging Guide show? TIM&JG should give some indication about fastener characteristics. Also Flight Judging score sheets will put into perspective how many points (out of 4500 total points) fastener head markings are.

Dave

[Ed S.]

Re: C2 Fuel line fasteners

David,
Good points (no pun intended). I checked the Judging Manual, you're going to love it. It says the fuel line (that is attached to the frame) is secured with "black phosphate recessed hex-head-bolts that are typically head marked "E". This is not consistent with the GM parts manual description or either "vendor's" offerings. Regarding the use of the word, "typically"..... to me that does not mean always or likely. It implies that the bold may or may not be marked with an E. I am going with my original no head mark fasteners.

Equally interesting, in the next paragraph of the judging guide where it discusses the short rubber hose near the fuel tank, it says that the hose is "secured to the frame with a black phosphorous hex head bold." No mention of head markings even though the same bolt is used in both places.

The 171109 fastener is used in a number of locations, including brake lines. I haven't checked the judging guide for descriptions of the bolt in those other areas where it is used but I will. I suspect I will find different descriptions of it in the guide.

[Alan D.]

Re: C2 Fuel line fasteners

Here is an original from a Mar64. Remember that many vendors were used during production so head markings varied depending upon where the nuts & bolts were purchased, multi sources naturally.

[Ed S.]

Re: C2 Fuel line fasteners

Alan, thanks - that is what mine look like. Thanks to all that provided advice, it was all very helpful.

[Gary B.]

Re: C2 Fuel line fasteners

David,
Good points (no pun intended). I checked the Judging Manual, you're going to love it. It says the fuel line (that is attached to the frame) is secured with "black phosphate recessed hex-head-bolts that are typically head marked "E". This is not consistent with the GM parts manual description or either "vendor's" offerings. Regarding the use of the word, "typically"..... to me that does not mean always or likely. It implies that the bold may or may not be marked with an E. I am going with my original no head mark fasteners.

Equally interesting, in the next paragraph of the judging guide where it discusses the short rubber hose near the fuel tank, it says that the hose is "secured to the frame with a black phosphorous hex head bold." No mention of head markings even though the same bolt is used in both places.

The 171109 fastener is used in a number of locations, including brake lines. I haven't checked the judging guide for descriptions of the bolt in those other areas where it is used but I will. I suspect I will find different descriptions of it in the guide.

[David B.]

Re: C2 Fuel line fasteners

To clarify: The word PLAIN refers to the FINISH on #171109 not the vendor mark that may or may not be found on the screw/bolt head. In other words, #171109 has no coated finish. If a cad or zinc (or black phosphate) finish screw was required the part # would be different. The cad/zinc coated screw is #171110. There is no black phosphate 5/16 -24 x 1/2 screw listed.

[Ed S.]

Re: C2 Fuel line fasteners

To clarify: The word PLAIN refers to the FINISH on #171109 not the vendor mark that may or may not be found on the screw/bolt head. In other words, #171109 has no coated finish. If a cad or zinc (or black phosphate) finish screw was required the part # would be different. The cad/zinc coated screw is #171110. There is no black phosphate 5/16 -24 x 1/2 screw listed.

David, you're killing me. So in essence, "plain" in GM terminology actually means "natural iron oxide", because that is what the part would be in a short time, a naturally rusted fastener. I am not questioning you on this but I am just surprised that these fasteners would not have some kind of protective coating on them especially since they the 171109 "screw" is used extensively for brake and fuel components.

[Edward J.]

Re: C2 Fuel line fasteners

Ed, My take on any fasteners used by GM, could of had any coatings used depending on the suppliers, that's maybe why when reading the JM'S they sometimes say Cad or Zinc plating. black phosphate is a common plating on chassis parts. another thing is Judges rarely deduct for plating problems for hardware, Lets face it these are cars we are restoring, and plating of nuts and bolts is just a guess if you cannot identify what the plating was originally, and then like its been said many times here GM had many venders.

[Alan D.]

Re: C2 Fuel line fasteners

Typically the various GM Parts Cat list the finish required of a vendor, here is a typical page. So a finish is often requirement of the part. These parts also had an individual blue print where a finished was listed.

As mentioned the head markings vary due to the vendor selected to furnish the part (many of those)

[Gary B.]

Re: C2 Fuel line fasteners

All,

Another thing to note is that nuts, bolts and washers with a "plain" finish can look quite different depending on other manufacturing aspects. For example, the 103328 washer (a "hi-collar" lock washer used at a number of chassis/bumper locations during the C2/C3 eras) that Alan highlighted in his posting was heat treated to achieve a certain hardness and the heat treating caused that washer, like others in the 1033xx part number grouping, to have an appearance that is quite dark. Almost like black phosphate treated.

Gary

[David B.]

Re: C2 Fuel line fasteners

[QUOTE=Edward Johnson (49497);814563]Ed, My take on any fasteners used by GM, could of had any coatings used depending on the suppliers, that's maybe why when reading the JM'S they sometimes say Cad or Zinc plating. black phosphate is a common plating on chassis parts. another thing is Judges rarely deduct for plating problems for hardware, Lets face it these are cars we are restoring, and plating of nuts and bolts is just a guess if you cannot identify what the plating was originally, and then like its been said many times here GM had many venders.[/QUOTE

You might want to reconsider your thought process. Alan is right on with regards to vendors providing the exact finish GM ordered. EVERY single nut, bolt, screw, washer etc. etc. has a part # with a diagram, print & description. If a vendor supplied anything other than the part ordered they probably would not be around very long. I suspect JM'S are off/wrong simply because they do not have documented info.