Just be careful that the old brake cylinders do not have rust holes inside. Why not install new cylinders and play it safe. Norm Blackmer has new cylinders, he is in the WTN. Make sure you flush all brake fluid lines really good. Walt.

Use DOT 5 silicone brake fluid. Rebuild them right the first time, and this fluid will prevent pitting, rusting, leaking in the future.

Tim,
I could send you some of that special sauce if you'd like. Mmmmmmmmmmm. Tasty!
F

Here we go again............

Frank,

Thanks for that offer of the special sauce, but I have plenty! I take it you don't want any Dot-5 with that? Many do use DOT 3 brake fluid because it's cheaper. But of course, they don't figure the cost of having to replace/repair brake components or the labor for such -- if they would, the real costs are more expensive. Never had to fix any of my vehicles once I rebuilt and used Dot 5 -- some of them 20 years now. Have always had to repair leaky wheel cylinders eventually after using the old alcohol based stuff unless the car was a daily driver. Some folks just can't get away from the low tech stuff I guess. DOT 5 is the way to go if you go through your entire brake system and rebuild it properly. You won't be doing it again in the time you own the car. My suggestion: get off the alcohol (the DOT 3/4 alcohol that is).

Tim,
Tim
I don't have any idea how my comment about the BBQ sauce ended up being posted as a reply to the brake fluid thing.

Don't read me wrong, I'm a DOT 5 fan from the git-go. I have it in most, but not all vehicles here......the truck has air brakes. My comment was a prediction of the onslaught of nay-sayers regarding DOT 5. It shouldn't be used in a vehicle with an anti-lock system, though. The slight compressibility of the silicone fluid confuses the A/L system. Our Hudson aren't in that group.
I used 5.1 in the '47 at fluid change time simply because I was too lazy to flush the system of all DOT 3 in order to make a proper change-over to Silicone. They claim it has a lesser propensity for water attraction than the 3 or 4 so I went for it. It's difficult to find a parts joint that even knows what it is. Orielly came through with Wagner brand 5.1 at a good price.
F

Moved to "Hudson" category

When I rebuilt the brake system about 1986 for the previous owner of my 51 Pacemaker I used Dot 5 (Silcone) brake fluid and to date I have had no problems with the hydralic part of the system. I have owned the car since 1988.

Frank (and Jim),

OK, thanks, now I get Frank's comment. Certainly so far, the ones that have responded have been DOT 5 users. The Moderator is staying out of this one! I had seen some of the pressure transducers that operate the stoplights fail, but that was the old ones and it seems to not be a problem these days. That was the only issue I had noted. So suggest you go through your entire brake system, clean up all the lines, replace wheel/master cylinders, check your brake drums and have them turned if necessary, replace brake shoes, and use DOT 5 brake fluid. You want your big heavy car to stop properly when you apply the brakes!

BTW Frank, you better lay off that special sauce for a while!

I'm wondering where all the folks are who used to say that the silicone stuff tended to leak at cylinders and connections. Scared a lot of folks away from the silicone. I'm still running Dot 3 in my Hornet; had it since 1998 and driven it over 40,000 miles without a problem. I have no issue with the silicone, just haven't had the urge to change over. Probably should have done when I went through the brakes earlier this year!

Kevin:

Any reputable brake fluid (Dot3, 4, 5 of 5.1) will be safe to use.

I personally have used Dot 5 (silicone) in my 1937 for over 20 years because it's supposed NOT to attract water (which would corrode the system). Haven't needed to repair any of the hydraulics in that time (though a couple brake linings needed replacement!)

Dot 5 also has the advantage of not destroying your paint, should you spill it.

Dot 5 MAY however, get past the seals in your StepDown stoplight switch and mess it up, or so I've heard. My 1937, on the other hand, uses a mechanical stoplight switch, not connected with the hydraulic lines, so this is not a problem.

But, to repeat: in my opinion you can use any good brake fluid, keeping in mind the advantages / disadvantages of each type.

Thank you all. I will hunt for DOT5, and return the 3 jug. Wheel cylinders were supposedly done professionally before it was shipped from Colorado last Year.

Kevin,

One important point. You must not mix the DOT 3 and DOT 5 brake fluids. If your system already has DOT 3, you need to flush it out completely, then put int he DOT 5 fluid. It's easiest to do all that when the brakes are apart for repair. Don't know the status of your system, but wanted to be sure you understood that. Reasonable flush job with the DOT 5 fluid and you'll be fine. See if you can figure out the status of your brake fluid before you do anything else. Do you know if it is DOT 3 or DOT 5 fluid anyway?

FYI
New Wheel Cyl's and Silicone Brake Fluid are the way to go for any vehicle that sets awhile....... Wheel Cyls are available at NAPA and other Auto Stores. Bleed out all the old brake Fluid until you see the silicone color.