The Official 356Talk Forum

So, after searching the books and asking members, it's unclear what reservoir would be original to our 1963 s90 Coupe, built March of 1963. Everyone has agreed that the cap should be black with a blue insert, but we just get shoulder shrugging on whether the reservoir should be aluminum or plastic. Below are pics of what i have, are any of them correct?

I thought the plastic reservoirs were post-production.

Yes, defnitely a post production master cylinder and reservoir. We have the original master cylinder, but the original bottle was replaced with what looked like a gerbil's water bottle. If I hadn't already thrown it away, I'd taken a picture.

So........aluminum then? And which one? The one on the left or right, as they differ on the top. Thx.

Mario, my 62 had the one on the right; I've recently replaced it but used the plastic replacement, as the original had corrosion creating a hole in the side.
Bob

Thanks Vic and Bob. The one on the right matches what you're saying and the parts book.

All 356s had alum reservoirs -- FTM, all 550 Spyders had alum ones too .

All `64/`65 Cs I've seen have plastic brake fluid reservoir bottles, per the accompanying photo of the original bottle in my unrestored `65C cab.

The PET listing for the '65 356s shows the plastic reservoir, but calls it an "expansion tank". Mine looks just like Wil's.

Wil, Thank you for your correction -- I forgot about the C reservoir being plastic.

I recall a couple of years ago Jim B. telling me that the factory used a larger diameter reservoir for about a year. I believe he said the "fat" reservoir was used around 1955. I believe I have seen some of these and they had an all black ATE cap and perhaps were steel rather than aluminum, but I am unsure of these details. Perhaps Jim can add some more information.

Alan Hall wrote:I recall a couple of years ago Jim B. telling me that the factory used a larger diameter reservoir for about a year. I believe he said the "fat" reservoir was used around 1955. I believe I have seen some of these and they had an all black ATE cap and perhaps were steel rather than aluminum, but I am unsure of these details. Perhaps Jim can add some more information.

Yes, 1955 (there may be exceptions, of course) has a larger steel reservoir. All the rest of the drum brake master cylinders came with aluminum reservoirs. I seen hundreds of examples (most of them rotten and unusable) and I believe the one on the right to be the latest type and the one on the left was pre A and maybe a bit beyond that.

Regards

Jim

Seems like the consensus is aluminum cans are, or soon will be, rotten and unusable.

Does the brake fluid eat holes into the aluminum? Yep, it could if left long enough.
Should you change your brake fluid often? Yep.
Change the fluid, clean out the can, and guess what...... The can will last longer.
How much longer? Quite a bit me thinks. I like the originality of the cans and have had good luck with them.

Just an opinion from a guy that likes to take care of the equipment.

Like Rich, I spend a lot of time taking care of my "stuff". BUT....the years take their toll. My '63 came with the aluminum can but just last week I decided safety was more important....corrosion eventually appeared along with a slight leak. So I replaced the aging master cylinder with the one with the plastic reservoir. Here's a pic of the aluminum reservoir in better days...RIP

Here is one that I removed from a car many decades ago. Necessity, or just being a total tightass, is the mother of invention.

Ciao

Jim