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texbears3
02-27-2014, 01:20 PM
Last year I replaced my brake master cylinder and clutch cylinders. Since I had it part, I decided to cleanup the mounting bracket and bodyshelf, because the paint was peeling. I removed the old paint and washed the area down with paint thiner then soap, thinking this would remove any residule hydraulic fluid. Then, I painted the surfaces with Rustolium Black for the bracket and Red for the body (Rustolium Red matches very well). About 6mos later I noted the painted areas became severly wrinkled and the paint is soft to the touch. A redo is a must.

At this point I am unsure how to make paint stick to the metal with out peeling. I have used Rustolium on many car parts in the past, but think they may have changed there formulation.
I seek advice:
1. Proper way to clean a metal surface, possible contminated with hydraulic fluid
2. Prefered brand of paint: aersol can or air brush
3. Other?

TR3driver
02-27-2014, 02:15 PM
My opinion, you've had more fluid leakage (or spillage). If it was something left behind on the metal, I think you would have had problems much sooner than 6 months.

However, there are a couple of surface prep products that seem to work well for me. I use DOT 5 brake fluid, which is darn near impossible to remove from metal surfaces and causes "fish eyes" in the paint if not thoroughly removed. A PPG product, DX330 "Acryli-Clean" works wonders for getting it off. It also helps remove other contaminants, so might help with your problem (which I assume is DOT 3/4/5.1 fluid as DOT 5 won't attack paint).

The other product is more for rusty surfaces, but also acts to etch and improve adhesion : DX 579 "Metal Cleaner".

To find these, call around to local paint shops that cater to automotive body shops. I find that, if you ask nicely and make it clear you aren't cutting into their regular customer's business, even paint wholesalers will sell to hobbyists. FLAPS won't have them. Come to think of it, I've been told that DX330 has been outlawed in CA (due to VOC content), so it may be harder to find. I'm still using up several quarts that a friend brought me from AZ some years ago :)

texbears3
02-27-2014, 03:17 PM
In the past I used Dot 3 and 4. Tried Dot 5 Silicone and did not like it...water pooled at the bottom of the calipers. But this time I used Dot 5.1, thinking it would not effect the paint?
Will try the solvents you recommend, if I can find them. Thanks for your reply.

Geo Hahn
02-27-2014, 03:57 PM
...But this time I used Dot 5.1, thinking it would not effect the paint?...

I believe 5.1 will eat paint the same as 3 & 4. The numbering convention is confusing as 5.1 is a continuation of the 3-4 line whereas 5 (silicone) is a whole different thing.

I have had great brakes with 5.0 and no paint worries, but I realize that has not been everyone's experience.

Randall makes a good point that you may still have a leak. A small seepage may present very little visible evidence but will soften the paint for sure.

2long
02-27-2014, 04:33 PM
Hi Randall

How effective is that DX330 with dot5? I was a bit discouraged when I learned that dot5 was virtually impossible to remove and would lead to paint problems when the car is redone. Of course, taking panels back to bare metal must avoid this result? Someday before too long I want to go back to my original color and I would love to avoid any issues with the dot5 contamination if I can.

Dan

dklawson
02-27-2014, 04:55 PM
Tried Dot 5 Silicone and did not like it...water pooled at the bottom of the calipers.

Can you elaborate on how that happened and how you found it? I know water doesn't mix with DOT-5 but it should take a long time for enough water to condense in the system to pool and settle. How long had you run the DOT-5? When you changed fluid types did you replace all the seals and old rubber lines and flush out the metal ones with isopropyl alcohol?

I agree with Randall that your new paint damage is likely to be from new leakage. The Rustoleum would have lifted very early after the touch-up if there was residual fluid on the panel. You may find better results going to an epoxy primer and if you can find it... an epoxy color coat. The only other option I can see is periodic washing of the area around the master cylinders.

TR3driver
02-27-2014, 05:57 PM
How effective is that DX330 with dot5? I was a bit discouraged when I learned that dot5 was virtually impossible to remove and would lead to paint problems when the car is redone. Of course, taking panels back to bare metal must avoid this result?
In my experience, even going to bare metal won't remove all of the DOT 5. I sanded and wire brushed long after any paint was gone, even washed with detergent, and still had fisheyes. A simple "wax on, wax off" with the DX330 and no fisheyes. You have to get the surface wet with it, and wipe it off while it's still wet, but otherwise it seems to work great. I've also noticed that no matter how much I sand, the DX330 always picks up some more dirt and/or rust as well, so I think it's probably good to use even if you don't use DOT 5. (There is also silicone in many other car products, like waxes.)

The only time it hasn't worked for me, I think I probably had tiny droplets of DOT 5 in the air that were contaminating the surface again between the DX330 and paint. I had been using an air gun earlier to clean up the engine compartment a bit and there was probably some spilled DOT 5 mixed with the dirt I was blowing off. After 3 tries inside the garage, I finally walked outside to wipe and paint, and that one came out nice.

That probably says something about the wisdom of using an air gun inside the garage, too. Breathing that stuff can't be good for your lungs.

texbears3
02-27-2014, 06:55 PM
I don't recall the exact year (maybe 8 years ago) I used the Dot 5.0 Silicone....probably mixed with what ever was being used. Shortly after my front calipers started leaking...never rebuilt them prior. When I opened the calipers, small pool of water was there and the piston had rust on it. I had to replace the seals and pistons. Not sure how the water got in, but Houston is a humid place.
Note: Certain seal materials will swell or become soft using Silicones. Sorry I don't have list of those materials.

dklawson
02-27-2014, 08:42 PM
I don't recall the exact year (maybe 8 years ago) I used the Dot 5.0 Silicone....probably mixed with what ever was being used. Shortly after my front calipers started leaking...never rebuilt them prior.

Note: Certain seal materials will swell or become soft using Silicones. Sorry I don't have list of those materials.

I do not know if it is specified anywhere as "required" but I was instructed when I made the DOT-5 switch to replace all the rubber bits that had ever been wetted by DOT-3 or DOT-4 and to flush the metal lines out with alcohol. I know for sure that you are not supposed to pour DOT-5 into a system that still has other fluid in it as it won't mix with anything.

DOT-5 is sometimes described as having "less lubricity" compared to glycol based fluids but I am not familiar with it causing swelling of seal materials other than silicone seals. If you find that list of materials, please post it. I'd be interested in seeing what is on the list. In the old days the big problem was having a garage pour DOT-3 in your British car's brake reservoir. That would damage the seals very quickly.

For reference, Moss has some tech articles on the different brake fluids. They discuss the need for all to be changed periodically and why you might choose one type over the other. In the conclusions section of the article they specifically mention water pooling in DOT-5 if water is introduced or left in the system. However, they comment that it won't be water absorbed from the atmosphere and they do mention the best practice is to replace all the seals at the time the switch is made.
https://www.mossmotors.com/SiteGraphics/Pages/Brake_Fluid/page6.html#Conclusions

Sorry for the thread hijack. Back to the OP's topic.

PatGalvin
02-27-2014, 09:44 PM
There are several rattle can epoxy paints on the market now. They don't last long in the can, after activated. But, if you wanted to paint over bare metal, that might be a good solution for you, assuming you don't have a paint spray setup and a quart of epoxy on hand. Not cheap, but epoxy is typically bullet proof stuff. I would clean with strong solution of dish wash detergent, then wax/grease remover (or maybe substitute acetone). Then, sand it, clean again, and paint.

Or you can search for the PPG cleaners, which I'm sure are fabulous stuff.

I painted my car with Southern Polyurethanes Clear Coat, which is resistant to brake fluid. I don't intend to test that claim, but the manufacturer does claim this is the case.

Pat

JKB1957
03-03-2014, 12:24 AM
About 5 years ago I rebuilt my hydraulic system on my TR3A. I had the hydraulic reservoir powder coated. I've had no problems with peeling or the coating going soft. If you go this route remember to pull out the rubber sealing ring in the cap, it will melt when they cook the powder coat.