Author Topic: What gets silver Cad rather than yellow? (Read 17175 times)

johnk · « **on:** January 30, 2018, 18:12:22 »

Gents,
I'm just about ready to send my buckets of parts in for cadmium plating from a complete car tear down, however I am realizing I may be dumping too much in the Yellow Cad bucket. What should I make sure gets silver Cad rather than yellow so they don't get added to the "I should have" list later? Of course I know the aluminum parts are excluded entirely. Right now I am aware of the following but I'm guessing there is much more:

Silver Cad:
radiator expansion tank cap and straps
power steering reservoir clamp
soft top compartment latch
steel oil lines to and from the oil filter

What about:
trunk latch
gas lines under body
brake lines
brake calipers
anything else that's I haven't identified?

Any help is greatly appreciated!

Thanks

John k

mdsalemi · « **Reply #1 on:** January 30, 2018, 18:33:26 »

John,

I believe the radiator expansion cap I have is gold. It was purchased new.
The straps for the tank are silver. New they were $4 each a couple of years ago FROM Mercedes-Benz.
Trunk latch is silver.
I don't think the calipers were plated--raw cast iron.

Couple of points of interest--typically the parts must be stripped down, thus the radiator cap is a curiousity unless you've taken it all apart. Ditto, big time, on the brake calipers.

I don't know about the other things you asked about.

Benz Dr. · « **Reply #2 on:** January 30, 2018, 21:46:44 »

I've plated rad caps many times as well as lines that contain rubber parts and I've had no problems with anything. It appears that the plating process has no effect on rubber parts. I would keep away from hollow components or anything electrical though.

450sl · « **Reply #3 on:** January 30, 2018, 22:34:14 »

Oilfillercap and several hoseclamps silver

johnk · « **Reply #4 on:** January 31, 2018, 00:28:00 »

Thats a great point about the compression fitting or lines compressed to a rubber hose. I was wondering how to deal with them. They are too expensive to replace if still good just to make the metal parts look better. Thanks doc!

johnk · « **Reply #5 on:** January 31, 2018, 00:42:59 »

I think the calipers would look better natural or black anyways. I just have a 2012 motoring investments picture showing they did them in yellow cad. I do have a brake rotor cut-out pic from a 1969 sales brochure which shows the calipers as black. Not sure if its a real pic or artist rendering though.

johnk · « **Reply #6 on:** January 31, 2018, 02:03:08 »

the attached picture from an unknown source makes me thing the lines are silver, but then this engine has a black oil filter cover which is wrong

johnk · « **Reply #7 on:** January 31, 2018, 02:04:16 »

sorry missed the attachment

doitwright · « **Reply #8 on:** January 31, 2018, 04:03:59 »

PMBPerformance.com will rebuild and refinish your calipers and the brake pressure balance valve that is mounted near the rear axle. They insist all ATE calipers were gold zinc plated (I don’t agree) and their site has several good videos that show what they can do for you. They rebuilt my brake pressure balance valve and the cost was reasonable. I believe MotoringInvestments may use them on their restoration cars based on the photos on their site.

The clamps for the heat shield between the intake/exhaust manifolds are silver Cad as are all virtually all hose clamps. The heavy gauge clamps such as on the steering wheel and ignition to steering wheel are gold. Some wiring support clips are silver and some are gold cad.

66andBlue · « **Reply #9 on:** January 31, 2018, 04:50:46 »

As Yogi Berra said deja vu all over again.

https://www.sl113.org/forums/index.php?topic=13688.0

https://www.sl113.org/forums/index.php?topic=17477.

mercakungen · « **Reply #10 on:** January 31, 2018, 05:39:01 »

What I have found of my 280 SL (built 9/69):

Brake lines are silver, nuts of them are yellow
Fuel lines are silver.
Brake calipers were black painted, under the paint is yellow zinc/CAD.
Oil lines are yellow.
Radiator cap (BEHR) is yellow.

Rubber itself does not cause problem for plating process. High strength steels as springs, spring washers and "hard bolts" may crack caused by hydrogen.

66andBlue · « **Reply #11 on:** January 31, 2018, 06:30:34 »

John,
here are some photos of some pipes in my three cars that I am pretty sure were originally Cad-yellow plated.
I have indicated them with yellow arrows.
The transmission oil pipes fur sure were yellow.
When Joe had the 280 SL engine apart we decided to CAD plate all of them as you can see in the last photo.
I would not worry too much whether to go Cad-yellow or Cad-silver, in 10 years they'll be grey anyway.

Garry · « **Reply #12 on:** January 31, 2018, 08:09:28 »

This may help.

wwheeler · « **Reply #13 on:** January 31, 2018, 16:26:10 »

Quote from: Benz Dr. on January 30, 2018, 21:46:44

I've plated rad caps many times as well as lines that contain rubber parts and I've had no problems with anything. It appears that the plating process has no effect on rubber parts. I would keep away from hollow components or anything electrical though.

Yes, that is true and I have done it many times with my home zinc plating kit. Rubber and plastic are ok, but don't be surprised if they get discolored or wrecked in the plating process . They are exposed to strong acid and the plating solution. Not all rubber and plastic parts are created equal.

You also have to make sure those "foreign" parts are perfectly clean. It could spoil the plating solution and why some companies won't accept items with non-metal parts. It is a gamble and you have to weigh the risks.

Benz Dr. · « **Reply #14 on:** January 31, 2018, 20:49:13 »

All things to consider. My plating guy has never asked me not to bring anything with rubber on it. I assume he knows what to do and his work comes back looking nice.

We prepare all of the parts here at the shop by cleaning in solvent, drying, sandblasting most of them, and then hand polishing each piece before plating. Metal parts have to be perfectly clean and polished to take a nicely finished appearance.

Shvegel · « **Reply #15 on:** January 31, 2018, 22:09:15 »

John,
The engine picture you are using is off by 10 miles. I have used that same photo as an example of a bad job. The oil cooler lines are indeed yellow cad. The oil filler cap if your’s is steel is also silver as well. Brake calipers were originally yellow cad but since Mercedes now supplies them in plain Zinc that means either is correct. If you do decide to pull your calipers apart I have extra sealing o-rings for the 2 halves that are very hard to find(I am just up in Cleveland Heights)I bought all the kits and had the calipers replated then decided to just buy 4 brand new Ate calipers. If you are completly swinging for the fences you will find the new oil cooler hoses are off from original by a mile. The original yellow anodized aluminum ends are reusable. I have a source for the correct fabric wrapped hose.

doitwright · « **Reply #16 on:** February 01, 2018, 03:07:58 »

PMB Performance will sell you the small o-rings for between the caliper halves. Their videos also give the torque settings for when you bolt the halves back together. I think it was 15 ft-lbs.

johnk · « **Reply #17 on:** February 01, 2018, 03:59:04 »

Thanks everyone. This is extremely helpful! Unfortunatly as Alfred stated this will all turn the same color in a few years anyways. I have to believe the calipers are plated at first before they were painted, or at least partially. My original front calipers look almost black with rust coming through like they were never coated, but the rears look like they were plated and are currently silver.

I cleaned all of the parts using a Harbor Freight parts washer with water based Purple Power Cleaner. I heat the cleaner up to 110 degrease using a $25 bucket heater from Tractor supply. That works great. Listening to Dr. Benz's comment again I am going to treat all of the visible parts with the wire wheel on my bench grinder. I was only using the wire wheel for some of them originally.

Shvegel · « **Reply #18 on:** February 01, 2018, 08:49:52 »

Calipers were most definatly plated as the bore of the caliper needs the plating for corrosion protection. I also bought an NOS Ate caliper in a very old box that was yellow cad plated.

There are a very few parts that should be black oxide treated as well. The caliper bolts and crankshaft hub bolt are black oxide along with the pivot bolt for the brakes behind the brake booster, the 2 bolts that mount the compensating spring mount on the right, the center pivot shoulder bolt for the upper alternator bracket and one other shoulder bolt that escapes me right now.

Caliper bolts are supplied new from Mercedes in plain Zinc now but as mercakungen pointed out replating hardened bolts can be a worry due to Hydrogen Enbrittlement. I know the shop John is taking his parts to and they are well aware of how to deal with baking the parts etc to prevent this so not a worry there.

One more silver part is the exhaust heat shield screwed to the firewall.

Shvegel · « **Reply #19 on:** February 01, 2018, 09:01:46 »

Here is some factory photos of an early 280 engine(Large Aluminum oil cap) for reference. Unfortunately in black and white but other than the few parts mentioned all else is yellow cad plated. Notice on the exhaust side the water jacket covers are painted black and the throttle pivot cover is not. Also the guides for the positive battery cable are painted black.

johnk · « **Reply #20 on:** February 01, 2018, 18:39:13 »

Pat,
Great pictures thanks. Good point on the heat shields. I wasn't sure how they were finished but I might as well throw them in the buckets rather than messing with a heat-resistant paint that needs to be baked.

John

mdsalemi · « **Reply #21 on:** February 01, 2018, 21:32:58 »

Quote from: johnk on February 01, 2018, 03:59:04

...I am going to treat all of the visible parts with the wire wheel...

Now THAT'S a lot of work. Get yourself a vibratory tumbler and spend your time on other things! You'll get more consistent results with a tumbler.

johnk · « **Reply #22 on:** February 02, 2018, 04:18:35 »

Mike,
where do i get one of those tumblers? I haven't done all of the small stuff yet.

mdsalemi · « **Reply #23 on:** February 02, 2018, 15:29:58 »

For the smaller stuff, there are smaller ones from Harbor Freight, etc.

https://www.harborfreight.com/5-lb-metal-vibrator-tumbler-67617.html

They also have an 18 lb version.

For faster results, but perhaps a bit more invasive, a rotary tumbler. Just search for those...these tend to be a bit smaller.
If you want a large capacity, a small cement mixer (yes, you heard that right) works fine too--provided it's new. Harbor Freight and others have ones just larger than a cubic foot capacity that work well. In those, just plain fine sand works well.

wwheeler · « **Reply #24 on:** February 02, 2018, 15:51:26 »

Quote from: mdsalemi on February 01, 2018, 21:32:58

Now THAT'S a lot of work. Get yourself a vibratory tumbler and spend your time on other things! You'll get more consistent results with a tumbler.

Using a small tumbler, what sort of media would you use to avoid rounding off sharp corners like on hex nuts and such?

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Author Topic: What gets silver Cad rather than yellow? (Read 17175 times)