Brake fluid proof paint?

[ichthos]

I haven't driven my TR6 in a few days, and unfortunately the brake master cylinder pretty much emptied itself. Of course it ran down the inside and ate at the paint. I plan on painting may car some day if I ever finish the rest of the car. The area below the brake master cylinder and battery were eaten at over the years. The metal is still sound for now, and I would like it to stay that way. Is there a paint or other product I can apply to these areas that is impervious to brake fluid or battery acid? Is there something I can apply to these small areas now that will protect the metal for now? I am not happy at the damage this incident casued, but it could have been far worse has I just painted the car. What are other measures people use to protect the paint?

 

[DrEntropy]

The epoxy primers with a polyurethane topcoat are more "resistant" to brake fluid but about the only way I know of to be safe from the problem is to go with silicone based fluids... or monitor the condition of the hydraulics closely and repair/replace whichever component showing signs of leak or failure before the damage occurs.

I prefer the latter.

 

[PAUL161]

I use silicone brake fluid. It's not supposed to damage the paint if any gets on it. The system should be flushed before using though.

 

[dklawson]

As stated above, rather than change paint, change brake fluid. I have DOT-5 silicone fluid in the Mini and GT6. The Spitfire is too recent an acquisition for me to decide what it will use but it will likely stay on DOT-4 LMA as this car will be a driver.

 

[angelfj1]

Paul: can you provide some details regarding the flushing process. For example, I currently have Castrol in the 250 and I want to convert to silicone. I have a brand new master and rear wheel cylinders. What would I use to flush the lines?

thanks

 

[dklawson]

When I have flushed brake lines I have pumped them dry, then filled the system with isopropyl alcohol. Run a good volume of that through and let it sit "full" for a short while. Then drain the isopropyl. Once drained, I ran low pressure compressed air through for a couple of hours to evaporate anything left behind.

 

[TR3driver]

I've read somewhere that methanol (wood alcohol) should be used for flushing rather than isopropyl (rubbing alcohol). My local pharmacy had it available over the counter, once I explained to the pharmacist why I wanted it.

But since then, I've been just filling with silicone and bleeding it through until clear purple comes out the bleed valve. Seems to work fine for me.

One other point, while silicone will not harm cured paint, it WILL cause fisheyes in new paint. And ordinary cleaning will not remove it. So the last step before spraying new paint should be to wipe down with a solvent that specifically removes silicone, like Acryli-clean.

 

[TR6oldtimer]

... I've heard that DOT 3/4 will even eat "epoxy" paints, although not as quickly as some others.

I tried some Castrol GT LMA brake fluid on a test patch of PPG two part epoxy primer. Yep, at least with this primer, it took a couple hours to dissolve through.

I also put some on a test piece sprayed with PPG Concept DCU2042 Clear coat. After 4 hours, I wiped it off, and you could not tell it was ever covered with brake fluid. I will test this again over night. Hopefully I will remember to look at it.

This is from an earlier thread on the subject.
I did the over night and a final test of 48 hours, no trace there ever was brake fluid on it.

 

[71tr]

I've often thought that if someone could develop a "plastic tray" that would fit cleanly in the area beneath the master cylinder this would be a good workaround for those not wishing to convert to silicone. Perhaps a vacuum formed plastic insert that sits down in the little valley that takes all of the abuse.

 

[TR6oldtimer]

Ah, a dribble bib, maybe like the Saturday Night Live "Stay Tree Peenie Pads"?

 

[DrEntropy]

An old sock works in a pinch.

Stuff it up around th' master cylinders' pedal pushrods. Just don't LEAVE it there!

 

[eschneider]

An old sock works in a pinch.

Stuff it up around th' master cylinders' pedal pushrods. Just don't LEAVE it there!

well, DUH!!!! not like I'm gonna walk around the rest of the day wearing only 1 sock!!!!!

 

[PAUL161]

Paul: can you provide some details regarding the flushing process. For example, I currently have Castrol in the 250 and I want to convert to silicone. I have a brand new master and rear wheel cylinders. What would I use to flush the lines?

thanks

As Randall stated, use alcohol. I used wood alcohol. It evaporates fast. I think and I'm not a chemist, that isopropyl alcohol retains some moisture. Remove all bleeders and blow air through the system for a while. I'd let it set overnight before adding the new fluid. I put all new rubbers in mine before filling, so my wheel cylinders were fully open while flushing.

 

[DrEntropy]

I'll "Third th' motion" with this difference:
<span style="font-style: italic">Denatured alcohol</span>. Followed by blowing 'em thru with air, and all rubber seals renewed.