TROGDOR! Posted October 29, 2007 Share Posted October 29, 2007 Well now... seems I've got another little glitch. 94 Legacy AWD wagon. When I drive it to work on a cold morning, the BRAKE light comes on and stays on. When I leave work at 5, the light doesn't come on. It's happened a few times now. Seems to only happen when it's under 40 degrees or so. Even if the engine is totally warmed up, even if I turn the car off and restart it, the light still stays on... until I let it 100% cool down and start it again in warmer temps. Brake fluid is fine, doesn't seem to be any leaking brake lines, emergency brake is definitely off, all brake lights are working, etc. Far as I can see everything checks out. Not like it really affects the drivability of the car, it's just annoying to see on the dash. Anyone know what it could be? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted October 29, 2007 Share Posted October 29, 2007 Does messing with the parking brake handle make any difference? What's your voltage when the brake light is on? Sometimes the brake light can indicate an alternator getting ready to crater, since the brake and other warning lights get their ground through the alternator field circuit. Quote Link to comment Share on other sites More sharing options...
Manarius Posted October 29, 2007 Share Posted October 29, 2007 I bet it has to do with the brake fluid. Did you look at the level and the cap? Quote Link to comment Share on other sites More sharing options...
Turbone Posted October 29, 2007 Share Posted October 29, 2007 Well now... seems I've got another little glitch. 94 Legacy AWD wagon. When I drive it to work on a cold morning, the BRAKE light comes on and stays on. When I leave work at 5, the light doesn't come on. It's happened a few times now. Seems to only happen when it's under 40 degrees or so. Even if the engine is totally warmed up, even if I turn the car off and restart it, the light still stays on... until I let it 100% cool down and start it again in warmer temps. Brake fluid is fine, doesn't seem to be any leaking brake lines, emergency brake is definitely off, all brake lights are working, etc. Far as I can see everything checks out. Not like it really affects the drivability of the car, it's just annoying to see on the dash. Anyone know what it could be? My 89 RX does the same thing. I believe its just moisture in the connection. Maybe spray some WD40 or other "stuff" in and on the connection and it should be ok. I have yet to do that Quote Link to comment Share on other sites More sharing options...
TROGDOR! Posted October 30, 2007 Author Share Posted October 30, 2007 OK... Fiddling with the parking brake does nothing (did that this morning). The brake fluid is full (first thing I checked every time) and the cap looks fine. It's been on nice and tight every time this happened. This car doesn't have a voltage gauge, so I don't know the voltage reading when it's on. I just had the charging system checked last week and it checked out good... maybe I should do it again when it's cold. Which connection is this that I should try spraying? Quote Link to comment Share on other sites More sharing options...
Turbone Posted October 30, 2007 Share Posted October 30, 2007 The wire that comes off the cap goes to a harnees connection (I believe). I have one on my RX, dont know what yours looks like. Quote Link to comment Share on other sites More sharing options...
gbhrps Posted October 30, 2007 Share Posted October 30, 2007 I had a similar experience recently with one of my antique cars. Occasionally the brake lights would be on while it was parked in the garage. Stomp on the brake pedal and let off and the brake lights went out, only to go back on an hour or so later. After a month of this shenanigans and having to disconnect the battery after each run, I replaced the pressure operated brake switch, with $10 and 5 minutes work, and solved the problem. I don't know whether Subies have mechanical or pressure activated brake light switches (never had the need to check one) but if they use the pressure version, you might check it out if nothing else is evidently the problem. Quote Link to comment Share on other sites More sharing options...
jamal Posted October 30, 2007 Share Posted October 30, 2007 The problem is not the brake lights themselves it's the warning lamp on the dash. My car does the same thing. I think it's related to the sensor in the MC. I thought it was an old/low fluid moisture problem but I have fresh fluid and now it's on all the time now for some reason. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 30, 2007 Share Posted October 30, 2007 Could be the float sensor inside the reservoir. They are in a pretty hostile evironment. Test the leads coming off it and see if it's got continuity. Should just be a simple on or off type of deal. Also could be the connector as Rob sugested. GD Quote Link to comment Share on other sites More sharing options...
OB99W Posted October 30, 2007 Share Posted October 30, 2007 I'd start by just pulling off the connector at the master cylinder and see what happens. If the problem goes away, it's related to the sensor. If not, look elsewhere (emergency/parking brake switch, chafed wiring, etc.). Quote Link to comment Share on other sites More sharing options...
Virrdog Posted October 30, 2007 Share Posted October 30, 2007 Could be the float sensor inside the reservoir. Ding ding ding! This is the issue the overwhelming majority of the time on the BBS. I have experienced it several times, also. Check to make sure the brake fluid is not a fraction of an inch below the full mark when it does this. Generally, you do not want to keep adding brake fluid as the light is usually an indicator your brake pads are low and the extra volume needed to push the pads lowers the resevoir. But in this case its ok as long as you check your pads on occasion. :cool: Also try jiggling the float inside the resevoir and make sure it moves smoothly. Quote Link to comment Share on other sites More sharing options...
DerFahrer Posted October 30, 2007 Share Posted October 30, 2007 You need new brake fluid. I can almost guarantee it. The old fluid has moisture in it, and on cold mornings the moisture condenses. This makes your fluid level sensor mad, and it illuminates the parking brake light to tell you the fluid is 'low.' Change your brake fluid and I'm positive it will go away. Quote Link to comment Share on other sites More sharing options...
danbennett2u Posted October 31, 2007 Share Posted October 31, 2007 We have the same issue... it started one really cold morning when it felt like one side cable of the parking brake snapped or something. The parking brake still works, just not as well, and there was no effect on the normal hydraulic circuit.... never had any issue with the light before this, so at least on ours it doesn't seem to be the fluid or a sensor in the MC. I haven't done much troubleshooting yet but definitely let us know what fixes it for your case! Quote Link to comment Share on other sites More sharing options...
nipper Posted October 31, 2007 Share Posted October 31, 2007 My other halfs Honda CRV with 220,000 miles on it does the same thing. Both float switches are made by the same company. If it has never been done, flush the brake fluid (never a bad thing) and if it still does it, replace the switch. Otherwise it's just an old car quirk. nipper Quote Link to comment Share on other sites More sharing options...
montana105 Posted October 31, 2007 Share Posted October 31, 2007 In hindsight I can't pinpoint this for you,but my 93 Wagon had the same problem last winter,it was in need of brakes and a new hand brake lever due to the mother in law driving the car( she managed to break the push button on the e-brake lever and tried to cover it up by throwing all the internals away,namely the spring) so I did all four corners,put all new fluid in and replaced the e-brake contraption.The dang light went out and haven't seen it in a year.This leaves two scenarios.The brake pads weren't exactly due for replacing,quite a bit of service left actually,and the fluid looked pretty good with only 5 years on it,which to me rules out the pads and water in the fluid.My thinking is the e-brake lever and the spring,but wouldn't rule out the fluid and linings because wierder things have been known to happen. Quote Link to comment Share on other sites More sharing options...
TROGDOR! Posted November 1, 2007 Author Share Posted November 1, 2007 Thanks for the tips everyone. Unfortunately it'll be a few days before I can do anything, as I'm in the middle of getting ready for a move to another state- heading out on Saturday. With the car still running fine, it's low on the priority list right now. Car's getting towed to the new place (driveshaft's already in the trunk, FWD fuse is in), so no worries about breaking down on the way there. On another note, this apparently has nothing to do with the brake pad levels or pressing the brake pedal. This morning when I started the car I made sure to not even touch the brake pedal. As we all know the brake light comes on when you first turn the key, and in this case, it just never went off. I may try the complete brake fluid flush. The car needs a new ABS assembly (been dead for a year, nothing new there) and of course, replacing that thing invovles almost a complete evacuation of the braking system- might as well totally flush it while I'm in there. Ah, the joys of having a car on the verge of 200K miles! I do have to say, everything *important* is working GREAT! Just another testament to the durabilityof a Subaru. Quote Link to comment Share on other sites More sharing options...
gbrand Posted November 1, 2007 Share Posted November 1, 2007 On every vehicle i have diagnosed wih this problem, it has been low brake fluid. Contracts in the cold, and then heats up to turn out light. subes and non subes. Just a RCH down will do it. Not saying this is your problem, but put plsah of brake fluid in (dont over fill) and see what happens Quote Link to comment Share on other sites More sharing options...
JohnnyB Posted November 1, 2007 Share Posted November 1, 2007 I have had this happen several times on my soob. Open the brake fluid reservoir and check the top of the lid to see if the rubber bladder is pushed out. If so, just push it back in. Quote Link to comment Share on other sites More sharing options...
Hocrest Posted November 1, 2007 Share Posted November 1, 2007 I have had this happen several times on my soob. Open the brake fluid reservoir and check the top of the lid to see if the rubber bladder is pushed out. If so, just push it back in. We have a winner!!!! Amasing that it took 17 replies to get to the quickest thing to check and simplist thing to fix.... The bladder should be recessed up into the lid, if not it will push the fluid to the side and push the sensor down, activating the light. Quote Link to comment Share on other sites More sharing options...
jamal Posted November 1, 2007 Share Posted November 1, 2007 hahaha wow. Pretty sure that's my problem too. Edit: The brake light turned off but I'm not sure if that's how it's supposed to be. It doesn't fit right all jammed up in the cap and I thought the bladder dealie was to keep the fluid from sloshing around. Quote Link to comment Share on other sites More sharing options...
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