Repairing brake fluid damage to subframe?

[Joe Frickin' Friday]

2009 R1200RT, 47K miles.  After ten years of ownership and maintenance, brake fluid has seeped out of the rear-brake reservoir (or more likely, I spilled/splashed a bit while bleeding the brakes), and the paint has been rotting off of the subframe in that area:

 

 

Most of the grunge in that area is a mix of swollen, displaced paint and road grime; a quick swipe with a shop rag seems to indicate that most of the rust is just surface rust.  

 

I expect to keep this bike for quite a while longer, so what's the best way to clean this up and protect it from further corrosion?  This is the subframe, hidden from view when everything's fully assembled, so it doesn't have to be pretty; I just want to prevent rust from compromising the subframe's structural integrity over the long haul.  

 

Can I strap a sacrificial zinc anode to it? Is there a coating available that will stand up to brake fluid?

[Calvin (no socks)]

Hit it with brake cleaner and then WD 40.... it'll last another 10 years. 

[szurszewski]

Can you not move enough stuff (reservoir, wiring, etc) to get it cleaned up and then spray it with some matching rustoleum?

[Joe Frickin' Friday]

45 minutes ago, szurszewski said:

Can you not move enough stuff (reservoir, wiring, etc) to get it cleaned up and then spray it with some matching rustoleum?

 

I haven't started this yet, but I can see that cleaning might be a challenge.  The bracket for the saddle boss and the bracket for the brake fluid reservoir look like they create tight spaces that might be impossible to clean with a wire brush.

 

Will Rustoleum stand up to future attacks from brake fluid?  

[dirtrider]

4 hours ago, Joe Frickin' Friday said:

2009 R1200RT, 47K miles.  After ten years of ownership and maintenance, brake fluid has seeped out of the rear-brake reservoir (or more likely, I spilled/splashed a bit while bleeding the brakes), and the paint has been rotting off of the subframe in that area:

 

 

 

Most of the grunge in that area is a mix of swollen, displaced paint and road grime; a quick swipe with a shop rag seems to indicate that most of the rust is just surface rust.  

 

I expect to keep this bike for quite a while longer, so what's the best way to clean this up and protect it from further corrosion?  This is the subframe, hidden from view when everything's fully assembled, so it doesn't have to be pretty; I just want to prevent rust from compromising the subframe's structural integrity over the long haul.  

 

Can I strap a sacrificial zinc anode to it? Is there a coating available that will stand up to brake fluid?

 

Morning JFF

 

Remove as many things that are in the way as you can to get total access to the area, then wire brush, Scotch Pad, tooth brush, etc to get as much paint & scale removed. Then use brake clean, paint thinner (anything that will clean & dry oil free).

 

Then mask off back to clean decent paint, THEN treat with a rust converter. Something like     Permatex 81849-12PK Rust Treatment, or even "The Destroyer"  from "The Shop" (if they are still around).   

 

'The Destroyer' (or similar products turn the rust & corrosion into an oxide (I think zinc oxide) that oxide makes a great under paint primer. (I used to use a lot of this on old rusted equipment & it worked great with no corrosion return).

 

The newer products like   Permatex 81849-12PK Rust Treatment  I believe turns the corrosion into some sort of a polymer that is easily painted over. (I am not very familiar with this product as I am still old school & use  'The Destroyer' & that is more  acid based.

 

If you convert the rust to a suitable (stable) under substrate, then properly paint over it, then you should not have any future issues.

 

Link___    https://www.theshopproducts.com/products_rust-destroyer.html

 

[szurszewski]

44 minutes ago, Joe Frickin' Friday said:

 

I haven't started this yet, but I can see that cleaning might be a challenge.  The bracket for the saddle boss and the bracket for the brake fluid reservoir look like they create tight spaces that might be impossible to clean with a wire brush.

 

Will Rustoleum stand up to future attacks from brake fluid?  

 

Probably not any better than the OEM paint on the frame, but it will be better than unpainted. There's not really any reason for there to be future brake fluid though - I am always perfect when adding fluid, but if I did spill a little I'd make sure to flush with clean water, then Simple Green and then more water and some compressed air for drying the tight spaces... You know, if it ever happened - not that I've had to do that before. Repeatedly

 

If it were me I'd clean up as best I could, shoot some brake parts cleaner in there, flush with water and then compressed air, get it as dry and grit free as possible, then mask the area and shoot in some Rustoleum - I'd look for one that specifically said it could be sprayed directly onto rusty metal just in case you've got some corrosion you can't get to, and I apply a few coats following the directions for multiple coats.

 

Also, I wouldn't worry about it too much - if you haven't had enough corrosion take place to eat through the spring steel holding the reservoir you probably haven't done more than slight surface damage to the frame.

 

EDIT TO ADD: 

As always, what DR said would probably work too. You know, maybe - I mean, he seems to sort of have some idea what he's talking about.

 

 

[Skywagon]

after you clean it, spray with zinc chromate...it will never corrode again.

[aggieengineer]

Absolutely right. Just don't breathe it!