# Two brake fluid resevoirs? **URL:** \ **Category:** Factual Questions\ **Created:** [April 7, 2005, 3:48pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230 "2005-04-07T15:48:25Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![dauerbach](https://avatars.discourse-cdn.com/v4/letter/d/c2a13f/32.png) [@dauerbach](https://boards.straightdope.com/u/dauerbach)\ **Post date:** [April 7, 2005, 3:48pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/1 "2005-04-07T15:48:25Z")
My 1990 Acura Integra has the ABS Brake light on the dash lit up. Before when this happened I just added brake fluid and it went out. Now it doesn’t, and when I was looking under the hood I noticed that there is a second brake fluid resevoir. The one I usually play with is on the drivers side. This is on the passenger side and has a big warning something along the lines of “Contents under pressure. If you don’t know what you are doing do not touch this.” Can I safely open and check this second resevoir. Might I totally screw up the brakes? ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [April 7, 2005, 5:59pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/2 "2005-04-07T17:59:23Z")
So what part of > [@](#): > > “Contents under pressure. If you don’t know what you are doing do not touch this.” wasn’t clear? Is it the _If you don’t know what you are doing_ part, or the _do not touch this part_? Or is there a grey area in that wording that I am not aware of? First off I doubt that the item you are discussing is an additional brake fluid resevoir, I donb’t recall ever seeing a remote resevoir located way the hell over on the other side of the car from the brake master cylinder. Also I can’t think of any car where the brake master cylinder **resevoir** is under pressure. FWIW the ABS warning light can also be illuminated due to a fault in the ABS system. Adding brake fluid is generally considered the best way to fix an electrical fault. My suggestion would be take it to a competent repair shop for a proper diagnosis. ---
**Author:** ![dauerbach](https://avatars.discourse-cdn.com/v4/letter/d/c2a13f/32.png) [@dauerbach](https://boards.straightdope.com/u/dauerbach)\ **Post date:** [April 7, 2005, 6:06pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/3 "2005-04-07T18:06:59Z")
Well, in these days of suing over everything I wondered just how seriously to take the warning. I once got a recall because the catalytic converter had the wrong sticker on it and they wanted me to waste a few hours while they got around to slapping on the correct one. I assume it was a second brake fluid resevervoir because a) it looked like the other one, and 2) the cap was identical, telling you to clean it off before removing and using only DOT 3 fluid, etc. The other information was on a sticker. And yes, I will gladly take a car in for work that I can’t do myself, but lets face it, it is inconvenient, expensive, and can often be done by oneself. ---
**Author:** ![dauerbach](https://avatars.discourse-cdn.com/v4/letter/d/c2a13f/32.png) [@dauerbach](https://boards.straightdope.com/u/dauerbach)\ **Post date:** [April 7, 2005, 6:09pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/4 "2005-04-07T18:09:36Z")
Oh yeah, and the very first time the light came on I was on my way to the garage to have the timing belt replaced, and when the checked the light told me “Good news, it just needed some brake fluid.” It has been happening for a few years, this is the first time adding a little fluid (usually 1/4 bottle every 9 months or so) did NOT fix the problem. ---
**Author:** ![Berkut](https://avatars.discourse-cdn.com/v4/letter/b/a88e57/32.png) [@Berkut](https://boards.straightdope.com/u/Berkut)\ **Post date:** [April 7, 2005, 9:31pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/5 "2005-04-07T21:31:02Z")
> [@Rick](#): > > First off I doubt that the item you are discussing is an additional brake fluid resevoir, I donb’t recall ever seeing a remote resevoir located way the hell over on the other side of the car from the brake master cylinder. It is a brake fluid reservoir. That year Integra has an ABS reservoir in addition to the main brake master cylinder. **dauerbach** , you can service that reservoir yourself at home but there is more involved than simply filling it. I would recommend picking up a repair manual. Do you hear any buzzing from under the hood? ---
**Author:** ![dauerbach](https://avatars.discourse-cdn.com/v4/letter/d/c2a13f/32.png) [@dauerbach](https://boards.straightdope.com/u/dauerbach)\ **Post date:** [April 9, 2005, 1:56pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/6 "2005-04-09T13:56:50Z")
No, I get no buzzing sound. There is a “tick-tick-tick” after it warms up and then I turn it off, but I have had other cars do that before. The car has 202K on it, and I was hoping to reassure myself that it is still safe to drive–it stops just fine despite the ABS light on the dash, and I don’t want to put a lot of money in it. It is really used just as a backup car for when another is in the shop (like right now). ---
**Author:** ![voltaire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voltaire/32/313_2.png) [@voltaire](https://boards.straightdope.com/u/voltaire)\ **Post date:** [April 9, 2005, 3:20pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/7 "2005-04-09T15:20:30Z")
The “tick tick tick” sound is probably just your exhaust and/or the heat shields around it cooling off after you turn off the car. Thats perfectly normal and nothing to worry about. Your brakes on the other hand are something you _should_ worry about. Get thee to a qualified mechanic. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [April 9, 2005, 4:01pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/8 "2005-04-09T16:01:52Z")
Do you have a standard transmission? If so, that second one might possibly be a reservoir for a hydraulic clutch. Most of them take DOT 3 fluid and look vaguely like a master cylinder. ---
**Author:** ![dauerbach](https://avatars.discourse-cdn.com/v4/letter/d/c2a13f/32.png) [@dauerbach](https://boards.straightdope.com/u/dauerbach)\ **Post date:** [April 9, 2005, 11:03pm UTC](https://boards.straightdope.com/t/two-brake-fluid-resevoirs/298230/9 "2005-04-09T23:03:25Z")
Indeed, I do have a manual transmission. As much as I hate to spend the money, I guess I will have to take it in. As soon as I get the other car back.