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Discussion Starter · #1 ·
I have a mess on my hands trying to restore the brake fluid reservoir on my 1948 6C 2500SS Touring coupe. I have to disassemble the unit in order to install the fluid level piston assembly inside. Everything came apart surprisingly well except for the fitting that threads into the bottom of the can. It looks like a formed thread similar to that on a light bulb. Lots of area to stick. After trying conventional ways of trying remove this stuck thread I am baffled. The can is very thin, fragile and hard to grip. Does anyone have any experience with this problem? Does anyone have a spare unit I could buy/trade for?
 

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Discussion Starter · #2 ·
Success! I machined a tool to grip the can tightly without collapsing the thin wall. It worked with the tool clamped in a big vise and a huge torque on the fitting.

The next step is to make the reservoir cap. Does anyone have a filler cap for sale or a photo of what an original one looks like?
 

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Discussion Starter · #3 ·
New cap for 6C2500 brake fluid reservoir

Now that I have made adequate tooling I am into restoring the brake fluid reservoir for my 1948 6C2500. My reservoir cap was missing so I am making a new one. I managed to borrow an original cap so I know what it should look like. If anyone needs a new cap please let me know immediately and I will make extras. I cannot define the cost until the job is done, so I will not expect anyone to commit to a purchase at this time. Just let me know if there is a need. I will start machining this Sunday. You can decide if you want to buy one when they are complete and priced.
 

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Discussion Starter · #5 ·
Alfa 6C2500 brake fluid reservoir

Thanks for the diagram. It helps because there seems to be a thin o-ring seal for the bottom fitting where it threads into the can. I can now go looking for that.
 

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Hi Fred,
Are you the same guy who wrote "How to make your car handle"? If so, I am in awe of your knowledge. That is a great book.
 

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Discussion Starter · #7 ·
Ed,
Yes I did write How to Make your Car Handle and another book, now out of print, the Brake Handbook. Thanks for your kind words. I am slowly gathering material for an update of the handling book, but I cannot put a huge effort into it while I am still working a day job. I plan to retire some time between now and 2014, depending on how the economy treats our company. Updating the handling book is a slow process alongside restoring my 1948 Alfa 6C2500SS.
 

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The brake fluid reservoir is similar if not identical to those used in various Lancias and other Italian cars of the era, with variations of cap and pullrod end. You've done the right thing in making a clamp for disassembly.

One thing to keep in mind as you work on the can is that, at least on the ones I've seen, the top is not soldered, rather it's crimped with a rubber seal between pieces. Heat and solvents should be used discreetly. Assuming that the dimensions of the cylinder seal are the same (mine use a 32mm seal), I source rebuild kits from Mike K., below. Similar seals are available in other sizes if needed.
-Steve Katzman

Michael Kristick
155 Mockingbird Rd.
Wellsville, Pa 17365

717-292-2962
[email protected]
 

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Discussion Starter · #9 ·
Now that I have the reservoir restored in metal I am ready to paint it before I screw it together. Does anyone know of black paint that will resist attack from brake fluid? I am willing to pay for high quality paint if it exists.
 

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Fluid Resistant Paint

Hello Fred

I am glad to hear you are finishing your brake fluid reservoir. I believe powder coat finishes will resist brake fluid damage. But I doubt if it would be a good idea given the heat involved. Also the dimensional changes would be a problem if you coated the parts before re-assembling the canister.

Did you find the inside had been zinc coated? There is probably an epoxy paint that can resist the fluid attack.

I repainted mine with synthetic enamel. Like all fluid reservoirs you just have to be very careful handling the stuff. Wrapping everything below in clean rags and using a small funnel has worked for me. But if the worst should happen you need plenty of water on had to wash the fluid away as completely as you can, all the way to the ground.

Make sure you leak test with some pressure.

Does your engine bay have the "floor" panels installed? These were louvered alloy panels, which fitted between the sump sides (with felt seal strips) and the bottom of chassis rails and controlled the airflow through the bottom of the engine bay.

They were probably the first thing to be dis-guarded by owners and mechanics in pursuit of cooler running.

Jim R
 

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Discussion Starter · #11 ·
My brake fluid reservoir will be painted with "caliper paint." It is supposed to be heat resistant and tough, but no mention of brake fluid resistance. I suppose I will just be careful and will not put fluid in it until the paint is well cured. A small funnel for filling will be a big help too.

My Alfa Touring coupe does not have any pans in the engine compartment. I do remember them on the Farina convertible I owned in the late 50s. The oil and gunk from the engine coated the aluminum pans and they looked horrible. One day I decided to clean them so I got a small can of gasoline and a paint brush to do the job. As I bent over the fender and wetted the pans I bumped the metal band around the paint brush against the battery cable terminal on the starter. This metal shorted between the battery terminal and the grounded starter case. The short circuit resulted in a flash, but for some reason the gas fumes did not ignite in my face! I think God wanted me to live on for some reason. I learned a lot that day.

I agree that these pans probably impeded flow of air out from the engine compartment, although my old Alfa never seemed to overheat.
 

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Discussion Starter · #13 ·
I finally collected all the remaining parts for assembly of the brake fluid reservoir. Now I see that AFRA has the complete reservoir for sale in Italy but when I started this job they did not.

Today I am purchasing brake fluid to use in lubricating the parts in the reservoir when I put it together. I bought some Lucas DOT3 fluid in the local auto parts store, with the assumption that Lucas might also be good for use in my Morris Minor. Does anyone have a better suggestion for the brake fluid to use in a restored Alfa 6C2500SS? All the seals and hoses were replaced during the restoration but I do not know anything about the materials.
 

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The main difference between DOT 3, 4 and 5.1 (but not DOT 5) seems to be the boiling point (which seems to be a function of how much Borate Ester is added to the Glycol Ether base fluid).

DOT 3 seems to be a good choice and seems to be still widely used in modern cars (but this page says DOT 4 is gaining market share because its lower viscosity is better suited to ABS and traction control systems). Should you happen to drive the car hard (say, down a steep mountain pass) and get the sense that the brakes become spongy and soft when hot, I'd upgrade from DOT 3 to 4 and drive the same road again ( ;-> ) and see if it makes a difference.
 

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Discussion Starter · #15 ·
Thanks for the input. The fluid boiling points are written on the can. I am mostly concerned that the material in the seals is not attacked by the fluid, causing leaks. There were some stories from years ago that old fashioned seals were not compatible with all brake fluids. I have been working on this alfa for over 20 years and I have no idea what materials were used by the several shops and their suppliers. Maybe that is not a concern any more.
 
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