Calipers

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Conrad Carter
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Re: Calipers

#16 Post by Conrad Carter »

FWIW,
I sent my calipers to PMB. It is not inexpensive but VERY WELL DONE! They are beautiful!! Too pretty to put on my car actually!
Conrad

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Greg Bryan
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Re: Calipers

#17 Post by Greg Bryan »

PMB replates calipers with zinc dichromate, according to their ad ...
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Bill Lawless
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Re: Calipers

#18 Post by Bill Lawless »

Greg Bryan wrote:PMB replates calipers with zinc dichromate, according to their ad ...
Hi Greg, Not knowing anything about the chemistry of plating, is that a good thing or a bad thing?
A very quick google the 2 methods seam to be interchangeable ??

Bill
 Thanks,
Bill
65' 356 SC Cab Irish Green :D
82' SC Targa
81 VW Westfalia with 2015 Forester Engine
BMW 64'-R50/2, 75'-BMW R90/6, 74' BMW R90/6, Yamaha BW350

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Greg Bryan
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Re: Calipers

#19 Post by Greg Bryan »

Bill - Good, I suppose - according to the ad, that's the original coating or plating - not sure what the process is for zinc dichromate - whether it is a plating process or a dip chemical. I just did a set of 912 calipers and had them Cad II plated not knowing any better. They are visually very similar as far as I know but I don't know the durability of one process over the other. I did my SC calipers a number of years ago, also with CAD if memory serves and after 8500 miles of driving, they are pretty stained but don't appear to have anything growing under the plating.
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Ron LaDow
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Re: Calipers

#20 Post by Ron LaDow »

Bill,
"Chromate conversion coating is a type of conversion coating used to passivate steel, aluminium, zinc, cadmium, copper, silver, magnesium, and tin alloys.[1] It is primarily used as a corrosion inhibitor, primer, decorative finish, or to retain electrical conductivity"
Wiki "Chromate conversion coating"
Those things are subject to high heat, so the factory probably didn't want rusty chunks visible after a year or so of use.
Ron LaDow
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Wil Mittelbach
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Re: Calipers

#21 Post by Wil Mittelbach »

Greg Bryan wrote:PMB replates calipers with zinc dichromate, according to their ad ...
Similar to my 65C cab's original silver calipers - not gold!
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Greg Bryan
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Re: Calipers

#22 Post by Greg Bryan »

Well, I wish I had read the how-to blurbs on the PMB site before I did my calipers. It is very informative.
Wil - they talk about the color of old calipers, and I remember a raging controversy on the list about whether they were originally silver or gold. According to the PMB site, they are all zinc plated then dipped in a dichromate bath which gives them a yellow appearance. With age, the dichromate wears off and the underlying zinc is exposed, giving them a silver color. They claim that when you split the haves, you will see the gold color in the unexposed areas. Jim Brazeale (sp) also swore they were gold color and he rebuilt many calipers.
Now I have two cars with the wrong finish - what a maroon!
Are all the 'gold' colored bits and pieces on late C's and early 911/912s actually zinc dichromate and not CAD II?
I bet, yes ...
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Eric McKinley
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Re: Calipers

#23 Post by Eric McKinley »

I understand that this will not be much use to anyone in the States however I sent my calipers to a company called Classic Brakes in Macclesfield, UK.

Great company to deal with, the persons name was Lee.
He has restored countless 356 calipers in the past and was able to advise on the correct finish.

The price was extremely good also.

Here are the calipers when they were returned and on the car.
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Bill Lawless
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Re: Calipers

#24 Post by Bill Lawless »

EricMcKinley wrote:I understand that this will not be much use to anyone in the States however I sent my calipers to a company called Classic Brakes in Macclesfield, UK.

Great company to deal with, the persons name was Lee.
He has restored countless 356 calipers in the past and was able to advise on the correct finish.

The price was extremely good also.

Here are the calipers when they were returned and on the car.
I'm curious is that a PAINT finish or Yellow Zinc plated? Color is so even...?
Last edited by Bill Lawless on Fri Mar 16, 2018 10:33 am, edited 2 times in total.
 Thanks,
Bill
65' 356 SC Cab Irish Green :D
82' SC Targa
81 VW Westfalia with 2015 Forester Engine
BMW 64'-R50/2, 75'-BMW R90/6, 74' BMW R90/6, Yamaha BW350

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Wil Mittelbach
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Re: Calipers

#25 Post by Wil Mittelbach »

Greg Bryan wrote: Wil - they talk about the color of old calipers, and I remember a raging controversy on the list about whether they were originally silver or gold. According to the PMB site, they are all zinc plated then dipped in a dichromate bath which gives them a yellow appearance. With age, the dichromate wears off and the underlying zinc is exposed, giving them a silver color. They claim that when you split the haves, you will see the gold color in the unexposed areas. Jim Brazeale (sp) also swore they were gold color and he rebuilt many calipers.. .
Greg -
Per the preceding foto of my car's original silver calipers, herewith a counter to the notion that "all" original calipers had a yellow/gold finish as had been adamantly indicated by Jim at Easy.

When doing a tire rotation upon the `67 acquisition of my low mileage 2-yr old late model `65C cab, I noticed the silver calipers which at that time I mistakenly assumed were typical of all `64/`65 disc brake 356s.

Subsequently, upon recently overhauling and dissembling the calipers, I found no traces whatsoever of any yellow/gold plating overcoat in the calipers' crevices or under their bolts and washers, indicating they truly never had a yellow/gold overcoat.

My car's original silver calipers apparently are not an anomaly. In discussions with other late `65 car owners at 356 events that owned their cars since new, some indeed indicated their car also originally had silver non-yellow/gold calipers.

In summary, this may all be somewhat trivial since it was not unusual to have minor component differences/variances in a particular model year during the course of 356 factory production runs - thereby creating controversies decades later amongst 356 enthusiasts/purists as to what is, or is not, original.
- Wil

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Ron LaDow
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Re: Calipers

#26 Post by Ron LaDow »

Wil Mittelbach wrote: Greg -
[...]
In summary, this may all be somewhat trivial since it was not unusual to have minor component differences/variances in a particular model year during the course of 356 factory production runs - thereby creating controversies decades later amongst 356 enthusiasts/purists as to what is, or is not, original.
- Wil
Will, as I've mentioned, your maintenance of your car is more than appreciated, but by all evidence, what you see is not what you got.
That chromate is fugitive. It helps with weathering, but the tech at the time was no better than a lot of the plating tech at the time. And while my eye might be biased, I spy a bit of yellow in that image of your caliper.
More importantly, that part is not a 'minor' part; those were produced by the thousands and I promise no one said "Oh, gee, let's keep these four fronts and these four rears out of the chromate bath!"
Didn't happen
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Wil Mittelbach
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Re: Calipers

#27 Post by Wil Mittelbach »

Ron LaDow wrote:
Wil Mittelbach wrote: Greg -
[...]
In summary, this may all be somewhat trivial since it was not unusual to have minor component differences/variances in a particular model year during the course of 356 factory production runs - thereby creating controversies decades later amongst 356 enthusiasts/purists as to what is, or is not, original.
- Wil
Will, as I've mentioned, your maintenance of your car is more than appreciated, but by all evidence, what you see is not what you got.
That chromate is fugitive. It helps with weathering, but the tech at the time was no better than a lot of the plating tech at the time. And while my eye might be biased, I spy a bit of yellow in that image of your caliper.
More importantly, that part is not a 'minor' part; those were produced by the thousands and I promise no one said "Oh, gee, let's keep these four fronts and these four rears out of the chromate bath!"
Didn't happen
Thanks Ron -
However I disagree. There is, or has been, no trace of gold chromate overcoat whatsoever even when my car was only 2-yrs old and relatively new, which would precede an overcoat wear-off if it did indeed originally had one.

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Bill Lawless
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Re: Calipers

#28 Post by Bill Lawless »

I just got back the re-plated calipers.. Much nicer: although looks like there could of been 2 air pockets when in the bath on lower right caliper..
image1.jpeg
image2.jpeg
 Thanks,
Bill
65' 356 SC Cab Irish Green :D
82' SC Targa
81 VW Westfalia with 2015 Forester Engine
BMW 64'-R50/2, 75'-BMW R90/6, 74' BMW R90/6, Yamaha BW350

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