Can I fill my anti-lock brake fluid reservoir?


Hi all. I have a 96 Acura RL. The brake light came on a few weeks ago, so I took it to the dealer. They said the anti-lock brake reservoir was low and topped it off. The brake light has come on again. I looked under the hood and found where the fluid has been leeking from, but I don’t know how to fill the reservoir. Do you need a special tool? I may have to take back to the dealer to get my $90 worth from the first service. Thanks in advance. J.


Yes, you certainly can fill it yourself. Buy a can of brake fluid at any auto parts store. Unscrew the cap on the reservoir and top up. No tools required. This maintenance will shut off the brake light for a few weeks but eventually some fluid will leak out and the light will come on again.

If you ever want a permanent fix you will have to replace the leaking part. You need not go to a dealership. This job can be handled by any independent shop, typically for less money.



Yes, technically you can refill it. But, from a safety and mechanic’s “good practice” it is the WRONG thing to do. In fact, Tom and Ray mention this on their show constantly-- FIX SAFETY ISSUES!

If the brake system is leaking, it is not safe. If it is leaking on the non-pressurized side, it can cause fluid contamination- death to sophisticated ABS units. If it is leaking on the pressurized side-- good luck-- you’ll have braking failure.

Take it to the dealer, or a qualified shop that can inspect, repair, and bleed the system. Note- this car may require a computer “reset” or interface to bleed the brakes properly-- usually a dealer item only.



I am pretty much in agreement with Matt here. If your brake system is leaking, sudden brake failure is a likely consequence. What I don’t understand is why Americans still use glycol based brake fluids in cars instead of hydraulic oils. Glycol absorbs water from the air and corrodes the whole brake system. This is increasingly bad with ABS and other complexified systems designed to keep nitwits from killing themselves or others by their lack of driving skills. If you keep filling it, it may work for a while but one day you’re going to have the brake pedal go to the floor and whatever or whomever is in front of you is what you’re going to hit. The main reason glycols were adopted as brake fluids was that brake cylinders contain rubber parts. With the invention of advanced polymers or even teflon and steel piston rings and seals, there is no reason to continue to use glycol brake fluids. Indeed, even filling the brake reservoir on a humid day can drop the boiling point of your brake fluid by hundreds of degrees as well as insuring that the moisture will be eating away at the brake parts which are usually made of cheap materials like cast iron instead of stainless steel. If you watch a NASCAR race at a short track that requires a lot of braking you will see what happens when brake fluid boils. It’s a sad fact that it costs a fortune to maintain modern cars, but simply filling the brake reservoir instead of fixing the problem is likely to get you killed. Take Matt’s advice and also make sure the entire system is properly inspected and repaired, not just what you think is wrong at the moment. Brake system leaks are often hidden, and when one part of the system starts to leak, it usually means other parts of the system are about to fail due to wear or corrosion. If your brake fluid reservoir is going down it means something is seriously wrong. Coolant loss is often a simple consequence of evaporation or overflow unless it’s severe, but hydraulic fluid loss indicates a serious problem.

I also agree with Matt.  Fix the problem before you have a much bigger problem.  Note: before adding any fluid to your car make sure it is the RIGHT kind of fluid.  Don't just top it off with any fluid, check before you refill and don't refill for any reason that to bring it to the shop to have it repaired.  BTW if that fluid has been in there for more than 2 years, this would be a good time to have the system flushed to replace all the existing fluid.