'40 Wheel cylinders/brake fluid

[russcc]

Rebuilding the original '40 wheel cylinders, honed by machine shop, replacement parts are USA, No foreign parts for me. Couple questions. Is there a paint or protective coating for the outside of the wheel cylinders that the brake fluid doesn't attack. Can you lube the outside rubber boots with silicone, without contaminating the brake fluid. Any sense in using synthetic brake fluid. Heard some negative issues here on Fordbarn. Thank you Fordbarners.

[mrtexas]

I don't like the silicone fluid. Prone to leaks and greasy.

[russcc]

Thank you Mr Tex, that's what I thought I heard also. I appreciate your response.

[V12Bill]

Dot 5 or silicone brake fluid gets a bad name because of leaks caused by bad double flares and loose connections. Dot 5 is of lighter viscosity than Dot 3 and will migrate through small openings. Make the flares correctly and tighten the connections and there will be no problems. There will also be no problem with removing paint from spilled Dot 3 .There will be no problems fdom the Dot 3 absorbing moisture from the air and requiring fluid changes every 3 years. There will be no problem with rusted out brake lines that fail because of moisture in the fluid. If brake failure doesn't bother you , continue to use Dot 3.

[mrtexas]

Make sure your MC and wheel cylinders are OK with DOT 5 at the minimum. If you don't drive your car DOT 3 will cause problems. My everyday driver's have never had a problem with DOT 3.

[deuce lover]

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Use Dot 4

[oldford2]

Originally Posted by V12Bill

Dot 5 or silicone brake fluid gets a bad name because of leaks caused by bad double flares and loose connections. Dot 5 is of lighter viscosity than Dot 3 and will migrate through small openings. Make the flares correctly and tighten the connections and there will be no problems. There will also be no problem with removing paint from spilled Dot 3 .There will be no problems from the Dot 3 absorbing moisture from the air and requiring fluid changes every 3 years. There will be no problem with rusted out brake lines that fail because of moisture in the fluid. If brake failure doesn't bother you , continue to use Dot 3.

Why does everyone make a big deal about bleeding the brake system. I bleed our 46 EVERY year as part of my maintenance for putting her away for the winter. My wife does the "pump and release". Takes 30 minutes max. This year I put speedbleeders on all 4 wheels so can do it alone now. DOT 3
John

[Russ/40]

Originally Posted by V12Bill

Dot 5 or silicone brake fluid gets a bad name because of leaks caused by bad double flares and loose connections. Dot 5 is of lighter viscosity than Dot 3 and will migrate through small openings. Make the flares correctly and tighten the connections and there will be no problems. There will also be no problem with removing paint from spilled Dot 3 .There will be no problems fdom the Dot 3 absorbing moisture from the air and requiring fluid changes every 3 years. There will be no problem with rusted out brake lines that fail because of moisture in the fluid. If brake failure doesn't bother you , continue to use Dot 3.

Amen to all the above! The '40 in my avatar has all the same hydraulic components and fluid, I put in there in 1982. All DOT5. It would be insane to use DOT3

[Mart]

If you're looking for a non silicon fluid (ie not dot 5) then if there is a dot 4 fluid on the shelf, pick that over a dot 3. I had to test clutch cylinders years ago and they lasted better with dot4 than dot3.

Mart.

[oldbugger]

I have had DOT 5 silicone in my 64 TBird for 10 yrs no problem. No problem with sticking wheel cyl and no leaks.

[oldford2]

Originally Posted by Russ/40

Amen to all the above! The '40 in my avatar has all the same hydraulic components and fluid, I put in there in 1982. All DOT5. It would be insane to use DOT3

Insane! I am not sure you understand the meaning of that word. Maybe you will come out and explain. People that use DOT are "insane"?
John

[Russ/40]

Originally Posted by oldford2

Insane! I am not sure you understand the meaning of that word. Maybe you will come out and explain. People that use DOT are "insane"?
John

If you had the terrific results I have experienced, would you want to change things? If I went to DOT3, I would have to be flushing fluid on a regular basis, and within a few years would be replacing all the components.

Well, what I meant to say is, ( I ) would be insane to change to DOT3.

[OldDad]

Russ/40, I have had the same experience with DOT 5, mine done in 1985. I won't use anything else. It is true that you will have leaks if you have any questionable connections. I fixed those, and have had no further problems. I have had no problems with spongy pedal and so forth. This stuff works, and is used by the military for vehicles which will be stored for long periods. These are not race cars with high-temperature disk brakes we're talking about here. I am only reporting my personal experience, FOR THE LAST 28 YEARS. Your experience may vary, and if it does, feel free to spew it out here -- it won't change my opinion!

[larrys40]

I totally agree with Russ and others that if all your connections are good.. and they should be anyway, that Silicone Dot 5 is the way to go.... I've used it in many over the last 10 years and have only had one problem... which was a connection issue. Issue fixed, and no leaks. You don't have to purge and clean the entire system, wheel cylinders and all periodically as you do with Dot3. The silicone keeps everything clean and lubricated as well. I will never go back to Dot 3 on a entire system resto .
Larry S.

[russcc]

Thanks Fordbarner's. I see the advantages of using DOT 5. Now how do you purge all the DOT 3 from the entire system, or are they compatible ?

[L78CHEVELLE]

If you have the regular brake fluid in the system you will have to clean it out of the system. I put silicon fluid in all the 1940 Fords I own and sell. Never a problem with anything even after some of them have had the silicon fluid for over 15 years and driven on a regular bases. I pump all the regular fluid out of the system that will come out. Then I spray a major brand of brake cleaner in a cup and pour it in the master cylinder. I pump all of this out that will come out of the system. Then I take the brake lines lose from the master cylinder and open up all the bleeders. Then I put the air hose to the lines and master cylinder. Blow the entire system dry and clean. Close the bleeders, and connect the lines back to the master cylinder. Put the silicon fluid in and pump the brakes. No more problems for the cars I did this to.

[Ken Bull]

Ditto to all the DOT 5 likers. Once you check the fittings with a paper towel and tighten a little more your forever almost maintainance free!

[woodypecker]

I prefer 5 but I have only used it in a new system that is clean

[Clem Clement]

I replaced my entire system. I had some trouble with leaks. I had to slightly loosen the fitting, wiggle it to remove any minute burs and tighten again.