Honda Accord/Civic Brake Master Cylinder Cap 46662-S9A-003

Honda Fit/06-15 Civic Brake Master Cylinder Cap - 46662-S9A-003

Your brake master cylinder cap covered in oil and looking nasty? This is the OEM cap that sits on top of your brake fluid reservoir. Part number 46662-S9A-003. It's the black cap with the white plastic diaphragm inside that keeps your brake fluid sealed. After 15 years under the hood, the cap's stained and it looks terrible. The plastic diaphragm gets hard and crusty from heat. If you're detailing your engine bay or restoring your car, this cap's one of those cheap parts that makes everything look way cleaner. Scrubbing the old one doesn't work, the oil's soaked into the plastic. 

Here's Why This Cap Always Looks Terrible

The brake cap sits right on top of your master cylinder where it catches every oil drip, every bit of road grime, and every heat cycle your engine throws at it. Oil from your valve cover drips down and stains the black plastic. You try to clean it and it still looks dirty because the oil's absorbed into the porous plastic. After a decade, there's no amount of degreaser that'll make it look new again. The white diaphragm inside turns yellow and gets brittle. You're either living with a grimy cap or you're replacing it. Most people doing engine bay cleanups just swap it out. Way easier than scrubbing for an hour trying to make a 15-year-old cap look decent.

Cheap Fix for Engine Bay Detailing

If you're cleaning up your engine bay, car show prep, taking photos to sell your car, or you just want it to look good, replace this cap. People see dirty brake caps and think "this person doesn't maintain their car." A fresh cap says "I care about my car." It's visible, it's cheap, and it makes a difference. Way better return than buying some fancy engine dressing that'll just attract more dirt.

Comes Complete with the Diaphragm

You're getting the cap with the white plastic diaphragm already installed inside. You're not hunting down the diaphragm separately or reusing your old crusty one. Everything's there. Unscrew your old cap, screw the new one on. Takes 10 seconds.

What You Get

• Honda OEM brake master cylinder cap (part number 46662-S9A-003)
• Black cap with white plastic diaphragm pre-installed
• Seals brake fluid reservoir
• Keeps moisture out of your brake fluid
• Same cap your car came with from the factory

Fits Your Car

• 2013-2015 Acura ILX
• 2014-2020 Acura MDX
• 2009-2014 Acura TL
• 2015-2020 Acura TLX
• 2009-2014 Acura TSX
• 2008-2017 Honda Accord
• 2006-2015 Honda Civic DX/EX/LX/Si
• 2016-2021 Honda Civic LX/EX/Touring/Si
• 2005-2016 Honda CR-V
• 2010-2015 Honda Crosstour
• 2007-2013 Honda Fit
• 2010-2014 Honda Insight
• 2019-2021 Honda Passport
• 2009-2022 Honda Pilot
• 2017-2023 Honda Ridgeline
• 2006-2009 Honda S2000

Note: Unscrew the old cap, wipe the reservoir opening so you don't drop dirt in your brake fluid, screw the new cap on. Don't crank down on it like you're torquing lug nuts. It just needs to be snug. Overtighten it and you'll crack your plastic reservoir. While you've got the cap off, check your brake fluid level. Top it off if it's low. If your fluid's dark brown instead of clear amber, flush your brake system. This cap's mostly cosmetic. If your old diaphragm's torn or missing, then yeah, moisture's getting in your brake fluid and you need to flush the system. But 99% of people buying this just want their engine bay to look clean.