I came out to my car one morning after it was sitting for two days, and noticed a small amount of brake fluid which trickled out if the bottom of the drum, dripped on the rim, and ran down the tire sidewall onto the ground. Okay - annoying but no bid deal…I need to replace the slave cylinder.
I have another car so since I discovered the leak I have not driven it other than 70 feet just to move into my garage in my backyard.
The brake layout is…
- shoe on each side (at 3:00 and 9:00)
- slave cyl. on bottom (at 6:00)
…so any fluid leaking while the car was parked didn’t ever get on the shoes.
My last trip was a 15 minute drive home, and the brakes were fine. I checked the reservoir, and whatever fluid was “lost” was very minimal (maybe 1 or 2 cc’s at most).
This morning before work I took off the wheel and the drum and I felt and looked around. No centrifugal “sling” marks from fluid flying out while the wheel/drum was spinning, no gummy brake dust anywhere, a regular amount of dry powdery brake dust from normal shoe wear, so I really don’t think the brake shoes got “soaked” in fluid.
The shoes are almost new (not much wear at all), so I’d like to keep/reuse them. Is just cleaning them, the drum, and other interior surfaces with brake parts cleaner good enough, or should I replace the shoes with new ones because I’m sure at least some brake fluid touched the surface of the shoes?
Scrub them with soap and water and you should be good to go…You might as well rebuild/replace the other side while you are at it…
Take a propane torch and apply the flame to the friction material on the brake shoes. This will sweat away any brake fluid that may have contaminated the brake shoes.
Tester
Just how much do new shoes cost. deduct the cost of making what you have safe and consider that you will end up paying again when it needs new shoes, I just don’t see the advantage of trying to clean them and reuse them.
I don’t think he wants the hassle of replacing them. A can of brake clean …etc…etc.
This isn’t a “you’ll shoot your eye out, kid” situation where it’s be fluid logged for months and the thing is null and void.
I don’t think you are going to get a straight, knowledgable answer to this perfectly reasonable question. A quick check on the internet will get you a wide variety of answers including many assertions that brake fluid doesn’t evaporate. Since any third grader could figure out how to test whether brake fluid evaporates (it does, albeit not very quickly), you can safely conclude that many “experts” on this subject don’t have the slightest idea what they are talking about.
One thought if you decide not to replace the shoes is to pull the parking brake on and drive around the block. The engine will almost certainly deliver enough power to overcome the parking brake. If it doesn’t, loosen the brake one notch and try again. If the two sides warm up by roughly the same amount, any fluid present isn’t significantly affecting the brakes. Be careful not to burn your fingers. Brakes get really hot. If the “contaminated” brake doesn’t warm up equally, you might want to rethink not replacing the shoe.
Thanks for all the responses!
I do have a new set of brake shoes I already bought when I picked up a replacement slave cylinder, but since the old shoes still have plenty of wear and there’s no evidence of soaking, and the amount of fluid which leaked was very minimal, I’ll try simply cleaning the shoes with brake cleaner whether they need it or not. I’m a bit afraid of the propane idea, since I’d likely be burning the brake fluid, and I also don’t know if it’s the type of fluid that would evaporate clean leaving nothing behind (even water leaves minerals behind unless it’s distilled).
I will pay attention to if the car pulls to the right (the shoes in question are on the left and would not stop as well if fluid soaked) when braking hard after the re-install.
A perfectly sensible “well informed” position.
Replace the shoes!
No!! Don’t!! You won’t regret it!! 
Don’t replace the shoes providing the oil can be removed by lightly sanding them with, say, an 80 grit sandpaper. I would not wash them. The drum can be cleaned as you say with a brake parts cleaner.
This is no more serious than getting a spot of grease on the shoes during installation, and the solution is the same. But did you fix the leak?
I put the new slave cylinder back on, I did my typical general brake cleaner-soaked paper towel rub down to get rid of the majority of accumulated loose brake dust, sprayed and cleaned the old shoes and drum surface with brake cleaner / paper towels (oh man am I glad I put in an attic fan in my garage!!!), and employed my wife to have her fun listening to me say “pump it, hold it” while she pumped the brake pedal umpteen times to help me bleed the new fluid. Yeah she hates it whenever I work on brakes or my clutch!
The result - absolutely no difference (except now the leak is gone of course). The car tracks straight under braking, and still slows down/stops just as well.
So it looks like briefly wetted pads/shoes are okay to clean and reuse…only soaked ones need replacement. Anywhere in between is your call.
If this is the rear brake, also check the rear axle seals (I’m assuming your Datsun 510 is a rear drive car). The last time I had something like this, my rear axle seals on a Caprice needed replacing.
How expensive can these shoes be?? If you’re worried about them…then replace them…Last shoes I bought for my 98 Pathfinder was $30…The ones for my wifes 96 Accord was less then $30.
Personally I don’t think there’s much of a problem…But if you think there is…then replace them.