Brake & Fuel Line Detail

[Tom L.]

Regarding a '70, I understand, primarily from information that I've picked up on this forum, that the fuel line clips & bolts and the front brake cross over line clips and bolts should be zinc. I also understand that the clips and bolts for the brake lines that run down the left frame rail and across the 3th cross member are to be zinc oxide (black), but for the different style zinc center clip in the 3rd cross member.

My first question is whether I have it correct. My second question is what vendor carries the black oxide brake clips and bolts. I've bought two sets already and they're all bright zinc. I have the home black oxide plating kit, but the stuff won't stick to this hardware.

As always, thanks in advance for your help.

[Patrick H.]

Re: Brake & Fuel Line Detail

Tom,

On my 72, the brake line clips all appear to be silver zinc. I suspect that the bolts were black, but after 35 years....
I'll attach a picture so you understand.

How to make silver bolts black? Muriatic acid will remove the zinc, and then you can blacken them. Else...a shot of flat black paint works well too.

Patrick

[Chuck S.]

Re: Brake & Fuel Line Detail

In my previous answer to this question (November 7, 2007; see first line in archive search at bottom of page), I said the brake line clips in 70 were black PHOSPHATE...I never said anything about zinc oxide. If your vendor clips are made out of steel, manganese phosphate will stick to them

As Patrick says, you can't expect to apply either oxide or phosphate directly onto the existing bright zinc; the clips will have to be stripped to bare steel first. Both of these processes require a chemical reaction with the steel to get the black color.

I also told you that vendors WOULD SELL YOU BRIGHT ZINC...it appears that you have at least confirmed that part of the answer.

[Tom L.]

Re: Brake & Fuel Line Detail

Thanks Chuck. I have your November response saved on my hard drive. You are correct, you did say phosphate, not zinc oxide. I thought they were the same thing.

I listed this post because I opened up some of my old brake line clips to find areas that are not dirty or rusty to look at the original finish. The front crossmember brake line clips look to be bright zinc, while the other brake line clips look to have been black. Moreover, the TIM doesn't address the issue. Do you believe that all of the brake line clips were black, or just the side and rear ones?

Regarding the bolts, it loooks like I need to find some muriatic acid. Thanks Patrick.

[Tom L.]

Re: Brake & Fuel Line Detail

Patrick,

I just tried the muriatic acid. Wow, that's some mean stuff. I dropped a clip in the container and smoke came out. Two minutes later the zinc, or whatever it was, was completely gone. My home plating kit then worked like a charm. Thanks.

[Patrick H.]

Re: Brake & Fuel Line Detail

Patrick,

I just tried the muriatic acid. Wow, that's some mean stuff. I dropped a clip in the container and smoke came out. Two minutes later the zinc, or whatever it was, was completely gone. My home plating kit then worked like a charm. Thanks.

No problem.
Middle school chemistry at its finest.

Did you catch the hydrogen as it came off?

Patrick

[Chuck S.]

Re: Brake & Fuel Line Detail

Patrick,

I just tried the muriatic acid. Wow, that's some mean stuff. I dropped a clip in the container and smoke came out. Two minutes later the zinc, or whatever it was, was completely gone. My home plating kit then worked like a charm. Thanks.

I think we should have told you to dilute the muriatic acid...dilute with water 4 H2O : 1 Acid. No wonder smoke came off; leave your clips in there very long and you won't have any clips.

My previous post erroneously only considered the front to rear clips. To expand that answer, Yes, the front crossover line clamps are zinc plated. These clips weren't in my notes because I intended to replace them with new. On the rear crossover line, I only remember the center clip being zinc plated, and have nothing in my notes indicating otherwise.

Always go with the car when you can see remnants of the original finish. Of course, zinc will be the most durable finish on chassis parts and fasteners; zinc may still show some evidence of the original finish after everything else is RUST colored.