I will be doing some testing with different coatings to see which ones would be the most resistant to brake fluid and battery acid.. I know that brake fluid as it ages becomes more corrosive. Can anyone tell me what brake fluid is the most corrosive
I think you'll find that brake fluid is not corrosive, but it will absorb moisture...and that moisture is corrosive. Silicone brake fluid will not absorb moisture, so you might say it's less corrosive. But it will let droplets of water form, and they're corrosive.
Thanks Jim. I didn't realize it was the moisture in the brake fluid that wrinkles up the paint . Does not look like there's any interest in this .
Brake fluid attacks paint. Corrosive usually means something that attacks metal, which brake fluid does not. Sent from my iPad using The H.A.M.B. mobile app
The Internet states that DOT3 is very corrosive. I guess that's the wrong terminology.I'll also be testing resistance to battery acid and solvent resistance on various One and 2 component type coatings. It does not seem to be a lot of interest on his board so maybe I'll create a YouTube video
Powdercoating is the best I've found for holding up to brake fluid and battery corrosion. If you're doing a battery tray, do at least two heavy coats, three is better.
I like to research terminology & its proper application , I'll see what I can find ... Edit : you are absolutely correct in your use of the term corrosive , caustic mainly applies to a reaction with living or organic tissue !
Silicone brake fluid was developed because it didn't eat the plastic on Fierios and the paint on Corvettes or at least that was the story I got back years ago from the NAPA brake rep when he would come by the shop and give my students classes on brakes. Street rodders fell in love with it not long after it came out but it has since been noted for being one reason for spongy brakes. You can't just put silicone fluid in though you have to completely flush the system first. It used to be that they flushed it with alcohol then flushed the alcohol with the silicone fluid but It's been 35 years since I listened to those talks by that rep. Personally I'd just be careful and have water available to flush it right off if I spilled it and call it good unless the car is a show only trailer queen.
I am a former Datsun line mechanic. It was in the manuals for routine brake fluid replacement and flushing the system. This was in the late 70's before they became Nissan. I have seen cars come in and you take the top off the master cylinder and the fluid would be black as ink. It would eat the metal in the master cylinder . These were 3 and 4 year old cars and trucks with less than 100K on the odometer. Most were cars from in the mountains of Az. and New Mexico. We figured it was from the fluid getting hotter than a flat land car.
I've noticed that non catalyzed paint was far more susceptible to being "eaten" by brake fluid, than catalyzed paint. Another thing about old cars...they had vented master cylinders until some time in the 1960s, when they went to the rubber diaphragm under the filler cap. This change makes a big difference in how much moisture is absorbed. Japanese car makers suggested a lot of overkill maintenance in the 70s, partly because of the laws in Japan that required it for cars in service there. We could get away with far less maintenance here in the US, because we're not quite as nanny as they are.
It’s not the spill you see that I’d be concerned about. It’s the leak that happens, and drips somewhere you don’t notice for a while. I’ve seen otherwise nicely painted cars where a brake line pressure switch starts to drip. It’s under the hood, dripping down the back of an inner fender. Change the switch, that’s easy, but now the paint is screwed up too. Sent from my iPad using The H.A.M.B. mobile app
From what I've read , DOT 5 was , at least in part, a military development ,it did not absorb water, making it useful in sub zero as well tropical climates , also , it did not corrode parts in storage , was developed in the 70's & military spec'd in the late 70's .
Nope. Imron is a polyester acrylic blend. It is rated at good chemical resistance . Not excellent I recently was presented with a blend and within 10 minutes in urethane reducer it blisters. A full polyester has excellent chemical and acid resistance. For instance 90 days immersion in acetone without softening the paint film.
When I built my roadster 15 years ago, I used silicone brake fluid. I have not had any problems with it since I built the car. One needs to keep the fluid level slightly lower because silicone fluid will expand from higher heat. My brakes and hydraulic clutch are both silicone. Only thing that ever happened was a wheel cylinder failure because I chose the wrong size. That happened in the first year of driving it. I didn't change fluid but started with new master, wheel cylinders, slave cylinder lines and hoses. Right about 38k miles on it.
I think brake fluid can handle heat way better than hyd. fluid. I just got a recall notice for my 2009 Ford because the DOT 3 brake fluid may corrode a ABS module, the fix is inspect/replace the module and change to DOT 4 brake fluid. So I guess DOT 4 is less corrosive than DOT 3? Or it could be DOT 4 just absorbs less moisture than DOT 3 and it is the water that causes the problem. I would bet it is the moisture.
Thank you for that info. I have a 5-year-old bottle of brake fluid of dot 3 that came with the house.This bottle was still sealed so what I will use is brake fluid from the 55 that ate through the floor coat of my garage. Now preparing panels and will need a week to cure
Once the paint has been contaminated by brake fluid and done its damage the most effective way to recoat that area is to grind away the damaged paint wipe it off with a wax and grease remover then take a propane torch and gently pass a flame over the contaminated area before recoating
Unwritten rule that was followed at the body shops I new of was , Before you do anything else to ba panel to be repaired , wash it with soapy water , rinse , dry , then clean with wax &grease remover , then begin repair . Reason given was grinding , sanding etc. Could imbed any contaminant into the metal....really cut down on finishing problems....
To answer the original posters question about which brake fluid is going to be the most "corrosive", in other words which one will damage paint the most, definitely test with dot 3. If dot 3 brake fluid won't eat your coating, none of the others will either.
Soap and water and wax and grease remover is good for body panels. On a porous casting a flame or an oven is used to bleed out the oil. Ceramic high heat applications on manifolds , the manifolds replaced in an oven at 500 degrees for an hour to bleed oil out. If there is smoke there's oil. if you don't have an oven use a propane torch. I hope this helps
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