Brake Cylinder Question

I'm getting the brake cylinders sleeved on my 1932 Dodge DL. I'd like to use silicon brake fluid in the finished system, but all the resleevers won't guarantee the work as they say the silicon MAY swell the rubber and cause problems. I'm tired of Dot 3 eating off the paint on my backing plates and frame when/if a leak occurs. It was suggested I use a high end silicon fluid rather than something cheap from NAPA, but they still don't like me using silicon. Any suggestions, experiences or horror stories to confirm/deny this problem? Does anyone make a rebuilding kit that is designed for silicon use, like modern fuel lines designed for ethanol?

You may find that the synthetic dot 3-4 from Napa will work fine. The problem with silicone is that it will NOT swell the rubber cups and this is actually part of the sealing process. I have used the synthetic fluid and found that it does not take away the paint or discolor if removed in a timely fashion. It certainly will remove paint but not like traditional brake fluid. Some folks have used the silicone and have great success, I unfortunately am not one of them and have found this alternative to work well and produce results that are needed and not remove paint like the standard fluid does.

Rob

hattiesgarage@comcast.net

Whoever did the brakes on this wagon used silicone fluid as there is a label taped to the floor near the M/C. No problems since I have owned it.

I've had DOT 5 in my 39 Chevy for at least 15 years. Never change it, no leaks, no problems. The problem is if you wish to switch to DOT 5 you will also have to change all the rubber in the master cylinder and flush the lines really well.............Bob

I put Dot 5 brake fluid in my '35 Auburn 20 years ago when I rebuilt the brakes. Not only have I never had any trouble; I've never even needed to add fluid. I am only now about to redo the master and wheel cylinders now after all these years, because of the age of the rubber components and a rusty appearance to the fluid.

I put silicone fluid in my Austin Healey. It sat, undriven for almost 10 years. I finally dragged it out to sell it. The brakes and clutch still worked perfectly

I have DOT 5 in all of the cars, never had a problem. My 60 Chevy was doneover 20 years ago. I do suggest replacing everything! steel lines, rubber hoses, the only time I heard of anyone having a problem was when they were using existing components If you have to open up the system you might as well just do it once.

I do recall reading that there were problems with DOT 5 on cars that have a hydraulic brake switch if that applies I would look into it before using it. I did the conversion to DOT 5 for the paint reason also, my master is difficult to see the level on and is up against the firewall and was hard to fill with out spilling. I never ad to top any of them off since converting. Downside to DOT 5 is it is harder to bleed, air bubbles tend to stay suspended, so that process is a little slower.

Someone also recommended years ago to use brass sleeves because it is softer rather then stainless, which I did

When rebuilding the brakes on my all-original 1958 Bel-air in 1979, I went with Dot-5 and kept it that way for 21 years until selling the car in April of 2000 - NO PROBLEMS AT ALL !!!

I did the same for the 1963 Impala convertible with the same positive results from restoration to ultimate sale after recovering from Katrina flooding.

I would go the same way with Dot-5 today if rebuilding a brake system

I have DOT5 in my '33 and have had no issue with it in the 15 or so years since I rebuilt the system from scratch with all new tubing, hoses, cylinders. It is harder to bleed but that should be a one time event.

It is my understanding that brake component manufacturers are geared toward what is new. And it is my understanding that modern anti-lock brake systems cannot use DOT5 for some reason. So component manufacturers design and test toward a DOT3/4 brake system and since they haven’t designed for or tested tested DOT5 they don’t really know for sure how they will work so they recommend against it.

I've had Silicon in my 32 Ford hot rod since I built in 96. I've had it in my 56 Olds since 93. I put it in every old car I do the brakes in. No problem with it in any of them.

When DOT 5 fluid was first introduced It did cause swelling of Wagner brake cups. Wagner has long since corrected this problem. The swelling of rubber has stayed with DOT 5 ever since. As mentioned above I have had problems with some NOS pressure actuated brake light switches. New replacements work like a champ. I run DOT 5 in all of our collector cars.

I use DOT 5 in all my cars. No problems.

I will never use DOT 3 or 4 in my old cars that sit a lot.

Thanks, everyone, for your timely answers. Sounds like Dot5 is the way to go.