Jigglypuff

Not literally, but I can't seem to find the source of the leak anywhere.

Background:
- '91 Civic HB, standard model
- Some cheap, old DOT3 brake fluid

Symptoms:
- Breake fluid resevoir needs to be refilled every few weeks
- Brake pedal goes to the floor when I'm stopped. It'd probably do the same if I were still moving, but I'm not going to test it. Pumping the pedal results in a stiffer, proper pedal stiffness

Inspection:
- No brake fluid seems to be leaking anywhere. I've checked the master cylinder and booster, by the brake pedal, the two front calipers, and the exterior of the right-rear drum (I didn't think drum brakes were prone to leaking, so I didn't bother with the LR drum). No fluid was on the inside of the wheels, and I don't have any brake fluid drops where I park

Proposed solution:
- Replace master cylinder
- Replace fluid with some synthetic DOT4
- Bleed the brakes

Question:
- Where is my fluid going? I bought the car for $500, and I don't feel like spending more money than necessary to keep it running, so I'd like to make sure that a minor brake overhaul will solve my problem.

VPUPPY

Sounds like some type of internal leak in the master cylinder. I would attempt to bleed the brakes first and go from there. This is based on the fact you have thoroughly checked all the lines. Your calipers may be leaking around the piston boot so i would check that also.

Kai

Wheel cylinders do often leak in older cars. Pull the rear wheels, pop the drums off, and have a look.

95civiclx

definetly^^^ check the wheel cylinders.

RedlineBoyzCRX

I have the SAME EXACT PROBLEM! I dont know where it is leaking, the only thing I can think of is I need to change the piston things in the rear drums, casue i noticed the had a little spare leakage when I changed my brake shoes. ITs weird, cause i like always pump my breaks like 3 times without noticing it, and my brakes work and I just refill it. I had a leaky caliper on the drivers side, and I changed that, also on a side note it killed my rim. SO I fixed that and it doesnt need to be filled as often, but it still does need to be filled, so IDK what it could be.

ChrisS

If it's the master cylinder leaking, look for bubbled up paint on the vacuum booster right under where the master cylinder attaches. (the mechanic who did my alignment said none of my brake caliper seals were leaking. But, the bubbled up paint on the booster points to a failing master cylinder.)

My car's brakes occasionaly fade while waiting at a dead stop.

I have a new master cylinder. (Haven't put it in yet. I have to see if I can borrow or rent the adjustment tool because of the close tolerance between the booster's push rod and the cup of the master cylinder.)

Jigglypuff

There's no bubbling paint on the booster, so I doubt it's an external MC leak. I guess I'll have to check the rear drums, or more thourougly check the front calipers. Those drums are rusted, though. As I tried to pull one off during my initial inspection, it started crumbling apart :lmao:

warren91

dude please stop driving your car untill you get this fixed, i dont want anyone getting hit because you have no brakes, its no fun ive had that happen to me when i got rear ended, so just replace your drums if you need to, then check all wheel cylanders and it should be ok.

shorty_boy

the car in between betsie and that a-hole had failing brakes... porr betsie now instead of having a phat a$$, she now has a flat wide a$$ (lol)

Jigglypuff

Update: I found the leak - the one wheel cylinder I didn't check. It's good to know my friend Murphy is still around. It looks like it'll be a straight-forward repair, provided I can find a repair kit.

Edit: Even cooler, a complete replacement cylinder from Napa is only $16.