New guy here, just got my first Harley 2006 street bob (new to me) and it is in need of a few small repairs. The main problem is the brake master cylinder cap has been leaking and the paint is pealing. Got two question for you guys.

1. Can you powdercoat the master cylinder and will it hold up to the dot 4 brake fluid?

2. Can you convert over to dot 5 (less corrosive) without having to replace everything?

thanks guys.

 

Mine does not leak but i have the same peeling issue. Tagging along.

 

same peeling issue here

 

I have a master cylinder off my 2010 you can have for postage, it will need a cap but is otherwise in good shape, the only thing you might need to do is clean it as its been sitting without the cap for a while now. I think the main cause of the pealing is over tightening the cap which causes the seal to swell and leak.

 

Thanks P51, I may hit you up for the master cylinder.

 

Mine started to leak so I got a new gasket and also switched over to the DOT 5 silicone fluid.

 

That stupid gasket I hear you, Dot 4 eats paint, Dot 5 is ok.

 

Ok.

If you have paint peeling, then you have a leak. These master cylinder caps like to weep even though they have a good rubber gasket beneath them. Replacing the gasket (as I did under warranty) may very well not help.

The fix for this issue is to take a flat file, 10 inch etc, and plane-off the master cylinder portion of the mating surface. Just gently lay the file across the rim surface and carefully file back and forth. You don't need much. Just enough to remove any irregular paint, casting or powder coat. After doing this, mine sealed just fine. Don't overfill it, though.

Before doing this filing operation, remove the cap and the fluid and pack in some tissues to catch the filings. Don't file-off too much !

Now, you can re-paint your master cylinder just fine. If it stops leaking, the new paint will be just fine.

Dot 5 silicone fluid is what H-D used years ago. It will not damage paint but it will also not work as well as Dot 4 since it's flow specs etc afre are not as good. Your brake feel will not be as crisp. The Dot 4 will be just fine if you stop the drippy cap.

 

Thanks for the info guys. Think I will try to clean it up like leafman said and try a repaint. Will try to post some pic of the process.

 

The fluid eats away at it, i also installed a new cap and it seems to be okay now.