my 1987 2wd pickup is losing brake fluid, down to minimum in reservoir (brake warning light comes on) about every month or so and i only drive the truck on the weekends. I've looked around booster, wheels (obvious places) and see no signs of leakage.....my brake pedal is GREAT! ..no problem stopping. I replaced the passenger side caliper several months back...but again brakes are working great. Any ideas??

 

Also check around any fittings along the frame. Leaking brake fluid is a huge safety concern, one second they work then the next you hit a buss full of nuns and burst into flames.

 

Is hitting a bus fully of nun really that bad? Think of all the kids they hit with rulers.

 

lol

the standard brake check is to pull the drums in the rear, and lift up the rubber boots around the slave cylinders... if they are wet at all, it needs to be fixed.

also look for a rear proportioning valve, i think it's called, above the rear axle, see if that thing is leaking somewhere.

 

I finally got around to pulling all the wheels off to look for the leak and of course it was the last one(passenger rear) wheel cylinder. I still don't know why it wasn't easier to see

 

I had the exact same issue in my '88. There is a lot of room for the fluid to deep inside the drums, making the leak hard to find. Good on 'ya!

 

Well. After fixing/replacing the leaking wheel cylinder, bleeding the brakes and putting everything back. I took the truck for a test drive and everything was good for a couple mile then the truck started pulling to the new cylinder side and eventually, I could tell the brake was dragging. So, I figured I over adjusted the brake out when putting it back. So I took back off and adjusted in on that side. Took it back out for a test drive and all was good. Then next time I took it out it did it again. After a few hours I drove again and it was fine again.
Any ideas why this would be erratic?? Seems odd. At least I'm not losing anymore fluid

 

Check for tension from the E-brake cable. Maybe wire brush and spray all the tension, pivot, and adjustment points down with a penetrant like PB Blaster to help keep it freed up.

Might need to disassemble, clean, and lube (grease) the adjuster near the wheel cylinder. Then again it might need replaced.

Of course keep the penetrant away from the drums & shoes.