Hard to diagnose brake problem

[Damkid]

Hard to diagnose brake problem

How's your wheel bearings?

Might seem like a random question but I once had a front wheel bearing so bad the wheel was wobbling bad enough that the rotor moved enough to push the caliper piston in, so when braking i'd need to pump up the brakes before they would feel normal again

But having bearings that bad, you'd know it right away lol

[Bert]

Have a go at all this methodically and one corner at a time. The furthest corner away from the master brake cylinder is a good place to start (ie right rear) if you figure on bleeding the brake lines while you're at it. For instance if the rear brake adjusters (via the e-brake) are frozen or stripped the wheel cylinder pistons will gradually have to travel too far. If on top of that the shoes are worn 'right down to the rivets' your brake pedal is going to be down near the floor or maybe spongy (if the tension springs manage to keep retracting the shoes and cylinders). Cylinders can leak, without you ever noticing spots on the ground, for quite awhile too.

[Fester's Quest]

How's your wheel bearings?

Might seem like a random question but I once had a front wheel bearing so bad the wheel was wobbling bad enough that the rotor moved enough to push the caliper piston in, so when braking i'd need to pump up the brakes before they would feel normal again

But having bearings that bad, you'd know it right away lol

Thats exactly what happened to this car, lol. I replaced the driver front wheel bearing and didn't notice how bad the rotor was until yesterday. I've never seen brake rotors so warped in my life, about 0.25 inches to 0.35 inch wobble.

So i'm replacing the front rotors tomorrow along with the wheel cylinders, brake drums, brake shoes, brake pads. The whole brake system will be new from the master cylinder down ( - brake lines of course ) & i can't wait to see how it stops. especially since it's had a pretty extensive weight reduction.

I can't believe how cheap all the parts were. 195 for a whole new brake system ... too bad there's no junk aspires around here for 200

[denguy]

One of the rubber brake lines that goes to the caliper was plugged up on mine. You could dis connect the banjo fitting from the caliper and see if you are getting full flow. Rockauto carries them.
NAPA has madeup metal brake lines with the end fittings in different lengths. You can bend them with your hands and they don't kink unless you try too sharp a curve.

[David88]

Sounds like you got it figured out. I had some problems similar to what you described. I just replaced every single component on the brake system on my protege, but not all at the same time. I started with just replacing the metal lines as they were rusted out. Several things to note here. 1)Then I tried bleeding and getting by with just that but very little brake fluid came to the front calipers during bleeding. 2)Also the calipers would clamp uneven and drag after the pedal was released. 3) The pedal you fade to the floor sometimes until you pumped it again. I tried a better(less rusty) used set of calipers and bleeding again. No luck. Same thing happened. I replaced the master thinking it was bad and not pushing fluid right. Still difficult to bleed. Pedal fade was better but not gone and still calipers still dragging and slow release after letting off of the pedal. New calipers next! Bleed again not much fluid flowing. Still dragging and whats left? After all this Have I learned nothing? Consult the manual. Hmmmm... Symptom.. brakes sticking or dragging: clogged or restricted lines. What lines? It all came down to the four rubber flex lines. Over time the rubber breaks down and swells. Even if they look OK and not cracked or leaking they end up acting like a check valve. Like a one way valve. Pressure from your foot through the master cylinder is much greater than return springs on the brake shoes or in the case of disc brakes rotor flex is what moves the pads from the rotor. I replaced those and its great. Lots of fluid draw when bleeding. Great pedal, no fade. Stops on a dime.

[Fester's Quest]

Sounds like you got it figured out. I had some problems similar to what you described. I just replaced every single component on the brake system on my protege, but not all at the same time. I started with just replacing the metal lines as they were rusted out. Several things to note here. 1)Then I tried bleeding and getting by with just that but very little brake fluid came to the front calipers during bleeding. 2)Also the calipers would clamp uneven and drag after the pedal was released. 3) The pedal you fade to the floor sometimes until you pumped it again. I tried a better(less rusty) used set of calipers and bleeding again. No luck. Same thing happened. I replaced the master thinking it was bad and not pushing fluid right. Still difficult to bleed. Pedal fade was better but not gone and still calipers still dragging and slow release after letting off of the pedal. New calipers next! Bleed again not much fluid flowing. Still dragging and whats left? After all this Have I learned nothing? Consult the manual. Hmmmm... Symptom.. brakes sticking or dragging: clogged or restricted lines. What lines? It all came down to the four rubber flex lines. Over time the rubber breaks down and swells. Even if they look OK and not cracked or leaking they end up acting like a check valve. Like a one way valve. Pressure from your foot through the master cylinder is much greater than return springs on the brake shoes or in the case of disc brakes rotor flex is what moves the pads from the rotor. I replaced those and its great. Lots of fluid draw when bleeding. Great pedal, no fade. Stops on a dime.

We have a BINGO !!!

It ended up being disc brake rotor flex combined with decently worn pads on the passenger side.. Thats so weird how that can feel just like air in the lines. Whats even more weird is that the whole car had no vibration when the pedal had pressure, even though the rotor was warped almost half an inch

I saved lots of monies in returned parts since i didn't need to do the rear brakes.

I have to use my toes to stop now :eeeeeek: These cars stop amazing with new rotors, pads + weight reduction.

[Fester's Quest]

I owe a BINGO to Damkid as well... DO-DOU-DOUB DOUBLE BINGO !!!!

[Damkid]

Hard to diagnose brake problem

Woot woot!! damn im good :lol: