I just purchased the correct master cylinder for my 63. I sent it to White Rock Restorations and had it rebuilt. It looks great. Now the problem. The lid seems to weep a little bit of break fluid at the rear. The gasket seems to be in good condition and I try to center the cap and finger tighten the lid down. Is there any secret way to adjust the cap? Thanks for any assistance.
-
-
Re: 1963 master cylinder
There's no secret, however 'finger tight' is maybe a loose term--the thumbscrew fastener was short lived and under tension may be one of the reasons. You have to put some elbow grease into tightening the top but you shouldn't need to put a set of tools on it. If 'restored' top isn't flat & true along with top of reservoir and gasket fresh, then you've got a topic of discussion for your restorer. BTW the natural gold cad of the lid is pretty fragile so watch handling proceedures with it (presuming the restorer did the correct plating job).... -
I never saw a 63 MC cap plated gold cad
except for Z06 but that was more like a Copper plate. All 63 except Z06 I have seen were cadmium (silvery when fresh, dull grayed when oxidized).
Did they make Gold ones?
JessComment
-
Re: 1963 master cylinder
If you indeed have the proper cap assembly for a 63 (except Z06), it has 5 pieces when unscrewed. This includes in order: the flat multi-perforated flat gasket, main domed cap, flat washer, mini cap and finally the thumb screw or hex screw. All these caps will leak if the bowl is overfilled. Accelerating and braking causes the fluid to slosh around and these caps are all vented, not as well sealed like today.
Getting the gasket to seal evenly is troublesome on 1963, and 1964-82 up models with rubber cap gaskets employ a wider seal area that bears several ribs for a crush and seal zone. 1963 is just a thin flat gasket, not as high tech.Comment
-
Re: I never saw a 63 MC cap plated gold cad
I agree - standard type one "silver" cad (or maybe it was zinc) on '63 non-Z06 master cylinder covers.
DukeComment
-
There Is No Such Thing As Gold Cadmium
Cadmium is cadmium. It's white. PERIOD. There is a dye called zinc dichromate into which plated parts may be dipped in order to extend shelf life. The result is a golden irridescent appearance monikered "Gold Cad" by tyros.
Cadmium was an avoided plating process by most suppliers because of toxic risks involved in the plating process. Chances are very great that the MC cap is zinc plated.
Dale PearmanComment
-
I agree
I received the following private email on this subject. I cannot understand why it was not presented to the board to support his view.
Ole Jess
BEGIN QUOTE:
Subj: I never saw a 63 MC cap plated gold cad
Date: 9/28/2002 2:26:41 PM Eastern Daylight Time
From: JackHumphreyH@cs.com
To: Docrebuild
Have pulled many used/original thumb-screw caps out of Corvair front compartments (protected from the elements). Finish is NOT gold dichromate (rainbow) but has very subtile/light gold undertone (like the upper riveted plate on SA Trico Coordinated washer pump). Just rubbing with your hand has a high likelihood of the yellowish finish going bye bye and traditional silver cad showing.
I can duplicate this in my home plating tank (when I run cad vs. zinc) by boosting current and using aged electrolyte solution laiden with impurities. Yep, comes out slightly yellow and any form of secondary buff operation causes it to shine stark raving silver.
--------------------------------------------------------------
Had a fellow chapter member who did a '63. They paid through the nose for an NOS, in-box, 7/8-inch master cylinder. Wife read the NCRS JG (cap should be silver cad) and took it to the sink to buff with Brillo to get 'er shining brite & silver.
At one NCRS Regional meet, a master judge commented (didn't deduct points) that many of the original, untouced caps he'd seen had a smooth, uniform, yellowish undertone. The wife 'freaked' remembering how she'd diligently polished all of that away!
My hunch is there were variations in finish due to supplier plating practice. Was this cap run through a fresh tank of chemistry or was it 'cooked' toward the end of a chemical replacment cycle....
Best Regards,
Jack Humphrey
END QUOTEComment
-
Re: I agree
Cadmium is an ELEMENT.......White........... according to dictionaries and chemical reference books........Impurities will cause discoloration. The caumium adheres to the base metal in elecroplating and the impurities don't.
Dale PearmanComment
-
Re: I agree
Gentlemen - As mentioned most parts were most likely zinc plated, not cadmium plated for various reason, one being cost. Zinc and cadmium are in the same groups or families in the Periodic Table (you know the one proposed by Mendelyeev in the 1800s), so they have similar properties; so the dichromate dip or treatment on zinc or cadmium plating should have the same appearance. PeteComment
-
Re: There Is No Such Thing As Gold Cadmium
Dale-----
The term "gold cadmium" is a term used in the VERNACULAR to describe the finish produced when a cadmium substrate plating is "overplated" with a dichromate solution. The dichromate "dip" produces a "gold-colored" finish. The exact same finish is produced when a zinc plated part is "over-plated" with the dichromate solution. Incidentally, the reason for the "rainbow-colored" and "greenish" hues often seen in parts so-finished is due to partial reduction in solution of the dichromate (+6) ion to the chromate (+3) ion. The dichromate valence state is "goldish"; the chromate valence state is "greenish".In Appreciation of John HinckleyComment
-
That's Exactly The Point
You have it correct!
Dale.Comment
Comment