Stainless brake shoes on zinc plate corrosion

[Steve L.]

Anyone have problems with SS brake shoes on the zinc splash shield.

I have a sticker on the new splash shield saying not to use stainless shoes.
The zinc is sacrificial and must corrode. If this is true, it must also apply to the rest of the PB SS hardware.

Steve L
73 coupe since new

[Joe L.]

Re: Stainless brake shoes on zinc plate corrosion

Anyone have problems with SS brake shoes on the zinc splash shield.

I have a sticker on the new splash shield saying not to use stainless shoes.
The zinc is sacrificial and must corrode. If this is true, it must also apply to the rest of the PB SS hardware.

Steve L
73 coupe since new

Steve-----


That's the first I've heard of that problem. It sounds strange to me. While I don't have the numbers at hand, I wouldn't think there would be much difference in electronegativity between carbon steel and stainless steel. Therefore, I wouldn't think that stainless steel shoes would have any more propensity to induce corrosion than the standard ones. Even if there is a difference, I would expect it to be small and, essentially, inconsequential.

[Steve L.]

Re: Stainless brake shoes on zinc plate corrosion

Joe,
Zinc plate 1.2V
SS 18% 0.5
Cheap steel 0.85

For limited corrosion, suggested differance should be no more than 0.15V

Both cheap steel and SS against zinc is a lot greater than this so the zinc would corrode. The SS will corrode the zinc faster than the plain steel, But I suspect it would take years since the shoes are not clamped very tightly against the splash plate.

Steve L
73 coupe since new

[Joe L.]

Re: Stainless brake shoes on zinc plate corrosion

Joe,
Zinc plate 1.2V
SS 18% 0.5
Cheap steel 0.85

For limited corrosion, suggested differance should be no more than 0.15V

Both cheap steel and SS against zinc is a lot greater than this so the zinc would corrode. The SS will corrode the zinc faster than the plain steel, But I suspect it would take years since the shoes are not clamped very tightly against the splash plate.

Steve L
73 coupe since new

Steve-----


I don't think you'll live long enough to see and significant damage to the backing plates or the plating thereof at that difference. However, keep in mind that standard shoes are fine for most driving situations. The exception would be if one drove a lot in areas with salted roads. In that case, the benefit of the corrosion protection of the SS shoes would more than offset any negative consequences of the SS shoes. The best thing would be if someone manufactured the backing plates in stainless steel (of the same gauge as the standard plates). I'd buy those in a SECOND if they were available, even though I have absolutely no need for them living in California. I LOVE stainless steel ANYTHING. I like it better than gold.

The 8.1L big block (RPO L18) used until fairly recently in some light trucks was equipped with CAST STAINLESS STEEL exhaust manifolds. These should bolt up to a Mark IV big block head but I think that there would be significant fitment problems in a Corvette chassis and they would not flow as well as original Corvette cast iron big block manifolds. Also, these things cost about $600/each, so they're not cheap. Still, I wish they were retrofittable to a Corvette.

[John H.]

Re: Stainless brake shoes on zinc plate corrosion

The 8.1L big block (RPO L18) used until fairly recently in some light trucks was equipped with CAST STAINLESS STEEL exhaust manifolds.

Joe -

When we developed the Prowler as an aluminum-intensive learning exercise (and then built 11,000 of them), one of the basic guidelines was that nothing on the car must rust or corrode. About the only iron or steel parts on the car were the crank, rods, and cams, plus the transmission internals, none of which were visible. That left the exhaust manifolds, and we took the same route - cast stainless steel manifolds, manufactured by Intermet; they weren't cheap, but they'd never rust.

[Gary R.]

Re: Stainless brake shoes on zinc plate corrosion

I use both the SS and steel shoes never had a problem with either. Check the fit of the shoes and the star wheel ends. I use a spot of grease on each plate pad as well. I face the star wheels down as some are too long and cause the shoes to drag fully collapsed.
Check the shoes over the originals to be sure the radius is the same.

[Steve L.]

Re: Stainless brake shoes on zinc plate corrosion

Thanks Gary
I'll check these points out

Steve L
73 coupe since new