Leaderboard

There’s always a good reason to open the hood now and then!

Bennie has a point here....maybe second sensor to auto trans pan or a body housing bolt? Somewhere to monitor trans temp guts. Once you monitor and test it's temp range can set a higher temp for alert? If I had auto this would be my move. Thinking cars with oil temp monitors have sensor on tin or alloy sump close the oil. I'd go side of pan myself

The computer has no control over the battery light. From the 2pin connector, one wire goes to the battery lamp -> fusebox -> positive rail. The other wire goes battery positive as directly as possible. If the voltage the alternator puts out is too high or too low compared to the positive rail at the fuse block , the light comes on from differential voltage. One wire should have some resistance to the positive battery. The other should have very little resistance.

Earlier cars charged at 13.8 V. Some of the newer ones are around 14.4 V. I have a Remy alternator right now that I have to return because it put out too much voltage. It melted the plastic on the coil for the clutch on the A/C Compressor among other things. After I saw that plastic slung all over the place, I did not want to start it just to see what the voltage really was. Subaru's price for the A/C Compressor on our 95 RHD Legacy Wagon is around $1000.00. I looked at a WRX two years ago for a friend that was blowing an 80 AMP fuse. The alternator was putting out over 20 Volts and it was the original that came on the car.

Check and clean the 2pin connector carefully. Replace if needed. That connector is the sense circuit, one wire runs as directly to the battery as possible, the other goes through fuses, dash circuit, through the dash battery lamp. Oldschool subarus have a light bulb for the battery for resistance and the charging circuit depends on that. The alternator uses the voltage differential between two wires to regulate power. If the connector is dirty or wires are corroded, the extra resistance will force more voltage. Yeah and unplugging it completely disables the charging so the lights turn off. No computer involved. The light turns on if there's a big enough voltage differential. No idea how newer ones work, they have leds and digital gauges.

*** Are the old and new alternator symptoms identical, different, or don’t know? If identical, then #3 below is more likely. 1. Clean up, tighten, and verify battery terminal connections and wiring. Check voltage at alternator and battery and make sure they’re the same. 2. Aftermarket alternators aren’t high percentage. zero zero zero surprise if the alt is garbage. 3. Check for crank pulley separation. If it’s bad you can see it. Or draw a line across the face of the crank pulley. Run the engine. If the line “breaks” your crank pulley is separated and you need a new one. You can tack weld it or use through bolts to hold it together temporarily or permanently.

If there is a leak the fluid level will drop. If the fluid level does not drop, the master cylinder is bad. I have seen a few new and reman ones that were bad. This "could" have happened to the original master cylinder. During normal use the piston will only travel 1/4 to 1/2 of an inch and you have a full petal. The seals are working in that area for years. When initially pumping the brake pedal, if you push it to the floor the piston seals are moving into an area that could be rusty or coated with crud and that would mess up the seals. If they leak the fluid seeps past them and goes into the reservoir.

Did the piston return all the way when you bench bled it. Only other thing I can think of is to check the length of the push rod from the booster to the new master cylinder. If the piston in the master cylinder does not return far enough it can not take in fluid from the reservoir. Make sure the brake pedal comes up all the way.