First, note that while I have some mechanical knowledge, I seldom do my own work. Yes I'm a wuss. I've got a local mechanic I like, but I'm getting a bit of a runaround on this braking issue and I'm fishing for opinions. Sorry for the longish post. I'll keep things simple and in point form.
Equipment:
- 1997 Cavalier 2.2 OHV
- Off-brand drilled/slotted front brake rotors, clean with good remaining thickness
- "Posi-quiet" ceramic front pads, 4 mils thickness remaining
- brand new rear drums and shoes
- Off-brand stainless braided flex lines
- 18" Motegi wheels
Problem:
- Spongy pedal, late and unimpressive brake activation
Symptoms:
- It takes nearly the whole pedal stroke to achieve significant braking force. Not much reserve.
- It's annoyingly easy to find the bottom of the pedal.
- There is SOME braking immediately near the top of the pedal stroke, but it doesn't develop into something useful without pushing much further.
- Pedal effort soft through most of the stoke, but becomes extra-heavy by the time the brakes finally work.
- The problem is worse when the car is first started. I regularly run the brake to the floor at the first stop sign. It gets tolerable after about 5 miles. At their best, the brakes are still low but get crazy grabby at the last moment, keeping the pedal from quite reaching the floor.
History / What's been done?:
- Fluid is topped up.
- The brakes first became somewhat softer when I originally installed the "performance" rotors and pads up front over a year ago. The fluid was flushed at the time. After I complained, they were re-bled with no improvement. I chalked it up as a side effect of the parts, and thought perhaps the ceramic pads were less grabby.
- Just recently I took the car in with "soft pedal" as the complaint. I ended up with new drums and shoes in the back. They were just about toast, no lie. The drums were unmachinable and the shoes were bare, one of them cracked.
- The pedal was actually lower after the brake work. I've jabbed the brakes while in reverse to adjust them. This seems to help slightly, but not much. I took the car back in, and they readjusted the new rears. This didn't make any difference.
- I got my mechanic to drive the car, and he acknowledged what I was seeing, but said "if he had just hopped in this car, without being told about it, he probably wouldn't have noticed". (This was when the car was warm, and the brakes were working somewhat well as mentioned above).
- He suggested if I wanted something more done about it, he could take the car in later this week and make sure the front calipers where freed up, sliders lubed, etc. I thought this might be a good measure, but I'm still considering other options. Wouldn't there be more of a visual indication if they were hanging up? My rotor wear seems pretty even.
My thoughts on possible causes:
- Normal nature of the beast: BS
- Ceramic pad material, wear: Might account for some of the soft pedal, but I don't believe it is the only cause.
- Heavier boat anchor 18" wheels: As above. Also, my winter steelies don't make the problem go away.
- Fluid: Is full, and was thoroughly bled a year ago. Contamination seems unlikely, but might explain a lot.
- Brake balance: It does kind of feel like the rear brakes engage early, and the front brakes are slacking. Maybe getting the fronts inspected further would lead to the root of this.
- Master cylinder, booster: I'm beginning to wonder if these guys are involved. I don't seem to have any leakage at the booster; the pedal "pumps", firms up, and holds pressure with the car off. I'm not sure how else to diagnose them.
Sorry for the short novel. Thanks for any advice.
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