Brakes going out...

[gijoe985]

So I feel a bit foolish since I should really know the answer to this, but I haven't worked on brakes in the last few years and my diagnosis skills are getting rusty. My buddies 95 awd legacy is having braking problems. He feel slike the peddle goes way too far down to the floor before braking. I sat in and I agreed that it felt like the brakes started catching up high, but they really didn't stop much until the peddle hit the floor. I bled his brakes for him and that didn't seem to help at all.

 

Now, with the car off I can pump up the brakes and they feel super hard. It doesn't feel like air in the lines. But with the car on, and power booster working, the peddle just seems to go right to the floor.

 

How does that sound to you guys? I feel like if the master cylinder was going out, it would slowly lose pressure as I held it down while the vehicle was not running. Could there be a booster problem? I did take off the check valve hose and tested that air only went through on way, just for good measure.

 

Any thoughts? It still stops, but it just feels like by having to push to the floor, that it won't be stopping for long...

[4x4brat]

master cylinder?.....

[Fuzpile]

It may be the m cyl eventually if you go to the floor when bleeding. There was thread just recently which is worth reading and mentions that (as grandad knew) you don't scrunch out every mm of an old m cyl because the cups can get cut on rust/debris.

[salve7]

Have a cinder block and rope ready just in case...

[Fuzpile]

The main thing is the pattern ; RF LR LF RR which is odd to me. I leave the cap on loosely and slow push and release. Mine actually improved even tho I did them myself. One bleeder broke so I used the banjo bolt

3 of them were done with a hand vacuum pump(sealing threads with certain grease). The banjo boy required a 2X4 wedged against the pedal and seat cushion lip -Very tight. Then loosened the banjo and it spit and was tightened.

 

A better way was to use an old liftback strut fixed a similar way because it has a long stroke.

[naru]

Rear shoes(if equipped) not adjusting.

Bad proportioning valve.

Leaky master.

Air.

Ballooning flex line(unlikely)

 

The bleed procedure sounds shakey to me.Could clamp off the flex lines to eliminate effects of air in the wheel cyl./calipers(but not elsewhere).

Booster seems fine.

My money is on the master.Could test by plugging the output ports,but,for all the trouble,I would just change it after checking rear shoe clearance and perhaps rebleeding.

[idosubaru]

make sure you're getting a good bleed for sure.

 

did you check for leaks? the caliper pistons can leak but the fluid gets retained behind the dust boot around the piston. that's the rubber boot surrounding the top of the piston as it sits in the caliper. under that boot can be wet and leaking and it won't come out on a very slow leak when it first starts.

 

i guess you don't have any rust at all in the PNW do you? if there's any rust in the back then the brake lines running across the top of the crossmember tend to leak first if there's anywhere to leak due to rust.

 

subaru MC's and PB's rarely have issues so proceed cautiously. every time i've guessed those i've been wrong so far!

[Caboobaroo]

If for some reason you end up not being able to figure it out, I'm at a Brake and Alignment shop over in Kirkland off of 405. Bring it by and I can take a look as well.