Using spray brake cleaner

My '92 Legacy needs new brake discs. My question is about the use of spray brake cleaners. The area around the disc is a bit dirty. I've never used spray cleaners before so I'm unsure about how to keep the toxic spray (and toxic dust) contained and not contaminate the whole garage, not to mention my body. Is there a trick to using this safely?

Thanks, Wayne

Reply to
wayne
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Are you removing the discs to clean them? Why? Did grease or oil somehow get on them? Spraying cleaner spray on the discs while they are still mounted pretty much means you'll be removing the lubrication on the slider pins which is not good. Unless the discs got contaminated, you shouldn't be spraying cleaner all over the brake assembly.

Reply to
VanguardLH

I think that overall these cleaners have gotten a lot less toxic over the years, as have brake pad compounds. Never the less, you still want to avoid contact as much as possible. Go down to the hardware store and get some disposable Nitrile gloves (usually blue). Use it outside, or at least have the garage door open. Put down some scrap cardboard or paper towels to catch the run-off. Put out your cigar ;-)

Another option would be to use clean stoddard solvent (basically kerosene) and a small paint brush to clean the caliper/rotor. Place a plastic tray to catch the contaminated solvent. I don't think clean solvent will affect the pads much, but to be on the safe side clean everything before (re)installing them.

Finally, unless things are _really_ dirty, you might consider just wiping everything down with a dry shop rag as needed, thus avoiding the issue entirely.

While you are at it, it's always worthwhile to check the "floating" mechanism of the calipers. If you can move the caliper back and forth smoothly, all's well, but if things seem tight, or bind at all, clean and lubricate the pins and guides. Also check the dust boots on the caliper pistons before you compress them.

Hope this helps a bit.

ByeBye! S. Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101

Reply to
S

I have to replace both front discs (and pads) because they're worn. The shop manual that I'm using says to clean the area with brake cleaner before I start. It's supposed to remove the grime and toxic dust better than using a blower. However, it doesn't say how to properly use the cleaner; much less how to dispose of the byproducts.

Wayne

Reply to
wayne

Thank you for the advice. I've changed brake pads before but not discs. I've been mulling whether to take it down to a shop and have them dirty up their garage or do it myself and mess up my garage. If this were some other part of the car, I wouldn't mind too much but, being that this car is older, I'm not sure whether my brakes pads have asbestos in them or not; or whether brake pads in the past had them and the dust is still around the brake area.

In the past, when changing pads, I would be very careful and try not to disturb any non-vital part that could scatter dust.

Thanks, Wayne

Reply to
wayne

Asbestos was banned in the US back in 2003 or so. If your pads are more than 5 years old...

YOU NEED TO CHANGE THEM MORE OFTEN!!! ;)

Reply to
Hachiroku

Personally, if I were to use the spray cleaner, and which means the parts are out of the car, and because you are talking about the caliper and not the discs, I'd use a soaked rag to clean the piston but cover the piston to protect the rubber gasket. Since the caliper is unmounted, hitting the slider pins won't be problem if you plan on relubing them. Some disc pad kits come with lube but I've seen many that don't (seems they want to save the few cents) so make sure you pick up a squeeze tube of lube when you pick up the pads set. If you're trying to spray the cleaner on the caliper while still mounted, you're going to get it all over, like on the piston gasket, slider pins, brake hose, underside of the fender, etc. I suppose you could provide cover for those items while spraying.

The brake cleaner spray evaporates very, very quickly. The residue left behind won't be the cleaner but what got cleaned off. So make sure to spread newspapers or cardboard underneath. Fact is, you can spray the stuff on your hands as a cleaner but have some grit soap nearby to finish the cleanup (the cleaner will soon evaporate).

The main ingredients in brake spray cleaner are methanol, methyl acetate, and acetone. Methanol is rubbing alcohol. Acetone will eat through plastics hence the need to protect the caliper's piston gasket, brake hose, plastic fender underliner, etc, plus it will dull the finish on paint. Methyl acetate is another dissolver. It has 25% solubility in water but considering how fast brake spray cleaner evaporates means you'll have to do the degreaser or soapy cleanup immediately after cleaning the surface. Different brands use different ingredients. Some use ethyl benzene, heptane, xylene, They are dissolvers so be sure you only hit the surfaces from which you want to dissolve something. That means covering everything other than the target from the splash from the spray. There's a reason why car shops just air blast the caliper and rebuild shops might use cleaner (after air blasting): car shops don't want to go through all the cover protection that, say, when spray painting a door to prevent contamination elsewhere.

Besides, whose going to see the dirty caliper? Do you actually see it through your wheels? If so, how does black on black become noticeable?

Reply to
VanguardLH

Thanks for the detailed information. I feel better about the situation now. I probably won't use the spray after all.

Wayne

Reply to
wayne

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