Fuel and brake line clamps

[Michael L.]

I have read the articles in the forum archives on brake and fuel clamp finishes and it has been very helpful. Chuck Sangerhausen's info was great. I just have a couple of questions. For those clamps on the brake line center section that are plated (the three in the front and the one center in the rear), am I correct that the bolts are still black? Also, Chuck's info was for a 70, but the clamps he noted as plated are listed as having the same part number as the two outer clamps on the rear crossmember. Does this mean that (at least according to the 69 AIM and other additional info), ALL the front crossmember AND rear crossmember clamps were plated on the 69? Also, the replacement clamps I have seen all look the same, but the AIM for 69 shows two different fuel line clamp PN and four different brake line clamp PN. Some of these part number differences may be just the finish, but that can't be the only difference, can it? I can't tell if the kits sold for this have different style clamps or not.

Any advice would be appreciated.

Mike

[Joe L.]

Re: Fuel and brake line clamps

I have read the articles in the forum archives on brake and fuel clamp finishes and it has been very helpful. Chuck Sangerhausen's info was great. I just have a couple of questions. For those clamps on the brake line center section that are plated (the three in the front and the one center in the rear), am I correct that the bolts are still black? Also, Chuck's info was for a 70, but the clamps he noted as plated are listed as having the same part number as the two outer clamps on the rear crossmember. Does this mean that (at least according to the 69 AIM and other additional info), ALL the front crossmember AND rear crossmember clamps were plated on the 69? Also, the replacement clamps I have seen all look the same, but the AIM for 69 shows two different fuel line clamp PN and four different brake line clamp PN. Some of these part number differences may be just the finish, but that can't be the only difference, can it? I can't tell if the kits sold for this have different style clamps or not.

Any advice would be appreciated.

Mike

Michael-----


The clamps are all finished in the same way. There are 2 different size clamps for the fuel lines because there are 2 different size fuel lines---the 3/8" supply line and the 1/4" return line.

I've forgotten why there were different clamps used for the brake lines.

[Chuck S.]

Re: Fuel and brake line clamps

I have read the articles in the forum archives on brake and fuel clamp finishes and it has been very helpful. Chuck Sangerhausen's info was great. I just have a couple of questions. For those clamps on the brake line center section that are plated (the three in the front and the one center in the rear), am I correct that the bolts are still black? Also, Chuck's info was for a 70, but the clamps he noted as plated are listed as having the same part number as the two outer clamps on the rear crossmember. Does this mean that (at least according to the 69 AIM and other additional info), ALL the front crossmember AND rear crossmember clamps were plated on the 69? Also, the replacement clamps I have seen all look the same, but the AIM for 69 shows two different fuel line clamp PN and four different brake line clamp PN. Some of these part number differences may be just the finish, but that can't be the only difference, can it? I can't tell if the kits sold for this have different style clamps or not.

Any advice would be appreciated.

Mike

On a 70, the brake line clips are all black phosphate, except for the center clip on the rear cross-over line, and possibly some of the front cross over clips (I can find no information in my files on the front cross over clips).

The rear center clip is a different clip than the end clips on a 70...it is a simple clamp plate with one end formed to fit the brake cross-over line. It is zinc plated, but it is attached with a black phosphate finished, pointed, self-tapping metal screw (#12 or 1/4"), as are all the other brake line clips.

Vendors will invariably supply all fuel line and brake line clamps in C3 kits as zinc plated. If you assume vendors are always correct, you'll be toast at judging.

[Michael L.]

Re: Fuel and brake line clamps

Thanks, Joe. I think I understand the fuel line clamps, but I'm wondering why the four different part numbers for the brake line clamps. Two of the PN differ only in a single digit and likely represent the difference in finish. But the other PNs are totally different. I'm just wondering, is there a big difference in the appearance of these clamps and do the kits from the vendors have all the needed styles?

Mike

[Michael L.]

Re: Fuel and brake line clamps

Chuck,

Thanks for your input. My 69 AIM lists the same part number for all of the front crossover clamps and both the lateral rear crossover clamps. I guess this means that they were likely the same finish, no? If I assume this, then the final question is, what is that finish on the 69? If we assume that the finish on the front center clips for the 69 is the same as for the 70, then maybe all five of these clamps, at least for the 69, should be plated. What do you think?

Mike

[Chuck S.]

Re: Fuel and brake line clamps

Chuck,

Thanks for your input. My 69 AIM lists the same part number for all of the front crossover clamps and both the lateral rear crossover clamps. I guess this means that they were likely the same finish, no? If I assume this, then the final question is, what is that finish on the 69? If we assume that the finish on the front center clips for the 69 is the same as for the 70, then maybe all five of these clamps, at least for the 69, should be plated. What do you think?

Mike

If the part number is the same, then the finish will be the same; not to mention the total configuration being identical.

I am handicapped in that my 70 AIM is not available at the moment for comparison. I would have thought the configuration of the clips were the same as on 69s. My computer data base has no information on the cross over line clips, only on the fasteners which are black phosphate.

My memory is probably faulty...any earlier posts of mine are likely to be more accurate, than information I could supply now from memory. If what I have said today is at variance with the 69 AIM, then I have no thoughts...a 69 specialist can provide better info.

[Joe L.]

Re: Fuel and brake line clamps

If the part number is the same, then the finish will be the same;

Chuck-----


Not necessarily. The specifications for any particular part may provide for alternate finishes (e.g. black phosphate OR zinc). These things were being used by the "jillions" across all GM car lines and it's very likely that many manufacturing sources were used. If alternate finishes were specified, each of these sources may have been different as far as finish is concerned.

[Joe L.]

Re: Fuel and brake line clamps

Chuck,

Thanks for your input. My 69 AIM lists the same part number for all of the front crossover clamps and both the lateral rear crossover clamps. I guess this means that they were likely the same finish, no? If I assume this, then the final question is, what is that finish on the 69? If we assume that the finish on the front center clips for the 69 is the same as for the 70, then maybe all five of these clamps, at least for the 69, should be plated. What do you think?

Mike

Mike-----


A 1 digit difference in the part number will rarely result for a difference in finish alone. Much more likely FOR PARTS LIKE THESE, the 1 digit difference will indicate a difference in SIZE.

By the way, based on a quick look, for 1969 I can find only 3 different clips used for the various brake line clip locations. These were GM #140566, GM #140569, and GM #125912. Of these, I can find that only the GM #125912 was ever available in SERVICE and I can't find any spec information on it.

As far as the fuel lines go, I can find only one clip that was used-----GM #3923695. This clip was used to clamp BOTH the 3/8" and 1/4" fuel lines to the frame and was specially configured for this purpose. It was first used for the 1968 model year when the dual lines began. However, this clamp was used only for Rochester-equipped cars which also used the fuel and return lines. Holley-equipped cars would have used a different fuel line clip. I believe the clip was the GM #140659, but I'm not sure of that.

[Michael G.]

Re: Fuel and brake line clamps

I hate to argue, but, I served on both the fastener technical and finish committees at GM for many years and it would have been extremely rare for any GM clamp drawing to allow an option between a zinc phosphate finish and any plated finish. These finishes are very different animals, with completely different appearance and performance characteristics. Two such clamps would have had different part numbers.

[Michael L.]

Re: Fuel and brake line clamps

Joe,

In my 69 AIM there is a single clip #125921 (not the 125912 brake clip) that appears to have secured the solitary rubber fuel line (but not the vapor line) under the tank before the two lines linked up.

As for the brake lines, my AIM has the three you mentioned, but also has PN 3945439, the brake line clamp for the center of the rear crossover. As Chuck has pointed out in an earlier post, this clamp is different from the others in that it doesn't wrap around the line, but instead just covers over it and keeps it pressed up against the rear crossmember.

For my resto, I think I will be keeping it to three different clamps: the standard double clamp for the fuel line, the standard single clamp for the brake line (and the one spot at the start of the fuel line) and the one special clamp in the center of the rear brake line crossover. I just find it curious that there would ever be different PN for items that were so similar. It makes me wonder what the difference really was.

Not to beat a dead horse, but on page j190 of the 69 AIM, right next to each other, there are two different PN, one for the first clamp on the brake line and another for the rest of the clamps on the brake line. Yet, the PN for the bolts that hold these clamps and all the rest of the brake and fuel line clamps on, are preserved across pages and pages of the AIM. No doubt there is a difference in the clamps, but why?

Thanks to all who for your assistance. I apologize for my OCD and promise to start taking my medication again!

Mike

[Joe L.]

Re: Fuel and brake line clamps

I hate to argue, but, I served on both the fastener technical and finish committees at GM for many years and it would have been extremely rare for any GM clamp drawing to allow an option between a zinc phosphate finish and any plated finish. These finishes are very different animals, with completely different appearance and performance characteristics. Two such clamps would have had different part numbers.

Michael-----


That's excellent information. And, there's no argument, at all; I did not state that the specifications for these clamps definitely provided for either a zinc or phosphate finish, only that it was a possibility based on what I've seen for other parts. For example, many waterpump and crankshaft pullies could have been either painted or black phosphate.

Also, I agree that virtually all fasteners have a single specified finish, although there are a few exceptions. However, some fasteners have had finish changes over time although the part number did not change. I always assumed that this was due to a change in the specifications for the part.

I don't think I've ever seen a situation in which a 1 digit difference (e.g. 3853322 versus 3853323) in a part number represented a difference in finish only, but there very well may have been such cases. Generally, as I mentioned, a 1 digit difference represents a difference in size. For example, GM #181617 is 5/16-24 zinc plated, grade 5 cap screw of 1-5/8" length. GM #181618 is an identical cap screw except it's 1-3/4" long. GM #9439513 is a 7/16" lockwasher and GM #9439514 is a 1/2" lockwasher.

Finish differences for an otherwise identical part seem to have a 3 or more digit difference in part numbers. For example, a 1/4-20 hex nut of GM-288M material and of GM #123800 has a "plain" finish. The same nut with a cadmium or zinc finish is GM #123803, with a chrome finish is GM #123806, with a nickel finish is GM #123809, and with a phosphate finish is GM #123811.

I don't have many specs or information on clamps so my comments regarding them are pretty much "extrapolations" from what I have observed regarding other types of fasteners. Any information that you could provide on ANY fasteners, either now or in the future, would be most welcome and appreciated.

[Ian G.]

Re: Fuel and brake line clamps

How about on a C1? Is cad plating appropriate for fuel and brake line clips on a C1, or were those also black phosphate, or perhaps unplated as many of the underbody nut-plates?

[Michael G.]

Re: Fuel and brake line clamps

Joe,

Thanks, I'll try to help when I can. You are correct about the single digit part number difference usually being size related. Many GM Standards pages were essentially charts of part numbers in sequential order. An example might be for 5/16 hex head bolts, where the incrementally increasing lengths were listed in one column and the part numbers were listed in sequential order next to them. The 1.00" long part was listed above the 1.125" long part and their numbers differed by 1 digit, and so on. Therefore, for parts shown in the standards book (and many weren't), you could usually expect a one digit difference to be size related.

Notably, there usually was a separate page, with a different chart of part numbers, for the identical parts with a different finish. Ie: Zinc plating would be on one page, zinc-phosphate coating on another. Those part numbers would differ significantly from the ones with the other finish. Mike

[Michael L.]

Re: Fuel and brake line clamps

On a 70, the brake line clips are all black phosphate, except for the center clip on the rear cross-over line, and possibly some of the front cross over clips (I can find no information in my files on the front cross over clips).

The rear center clip is a different clip than the end clips on a 70...it is a simple clamp plate with one end formed to fit the brake cross-over line. It is zinc plated, but it is attached with a black phosphate finished, pointed, self-tapping metal screw (#12 or 1/4"), as are all the other brake line clips.

Vendors will invariably supply all fuel line and brake line clamps in C3 kits as zinc plated. If you assume vendors are always correct, you'll be toast at judging.

Chuck,

I am ready to re-install the brake line clips after getting them back from the plater. I'm not sure if the brake line clips came out the way I need them. Although the specified finish was supposed to be black phosphate, these clips don't look anything like the other items that were done in that finish. I don't know of it is just how this alloy of metal reacts to the phospate or what. Can you look at the attached pic and tell me if you think these clips look like your clips after you had them done? For reference, the bolts on the left are black phosphate finished, the clips on the right are cad plated, and the clips in the middle are the ones in question.

Thanks,
Mike