pitted brake disc

Post by **abscate** » 10 Feb 2019, 17:42

I always push 250 ml brake fluid through the caliper on a pad change , and usually replace bleeder screw , too.

enotslim · Post by **enotslim** » 23 Feb 2019, 19:55

Installed rear Akebono Euro pads and ATE rotors today. Haven't driven yet (well, ~100 yards slowly just to be sure I didn't forget something, like the lug bolts). Akebono claims bedding in is not required. Is this true? I will at least be "careful" regardless but just curious what people here think about this claim. Front pads/rotors are a long way from replacement and seem fine.

Post by **abscate** » 24 Feb 2019, 00:37

A week of driving in a Boston will bed in the brakes on any car. Probably one day if you commute during the regular hours. Drive it conservatively for that time as you might not get full stopping power until after 100-200 miles

I’ve replaced my rear brakes once and my fronts 5x, and the fronts have twice the area. I think that means the fronts are doing 5x the braking work of the rears,roughly

enotslim · Post by **enotslim** » 24 Feb 2019, 02:58

The rear rotors were long overdue, which probably explains why I had to wrestle them over the e-brake shoes, damaging the left rear shoe in the process. Even with maximally loose e-brake cable and star adjuster the left shoe wouldn't clear the thick collar of rotor rust.

Just did 5 x 40mph > 5mph w/o cooling > 5 x 40mph > 5mph with cooling. It's easy at 4am even on commuter roads. I want to avoid those panic stops. Now some panic (normal) commuting and I should be all set.

Post by **abscate** » 24 Feb 2019, 05:20

I think they used to say “ avoid heavy braking for first 150 miles” so I would tell the kids to hit the car in front rather than use the brakes. I had all girls though, I would not say that to teenage boys.

Twin run in the Mass Pike for me this week, Tuesday and Thursday

Post by **Eddystone** » 25 Feb 2019, 14:38

Brake rotors might "groove" (Ah, the 70's...) from bad quality pads, but they wouldn't cause pitting. That's just very bad steel making up the rotors. Poorly made rotors show pitting (voids) and hard spots where the rotor doesn't wear evenly and grooves the pad.

Re upscale brake pads or "competition" pads, sometimes our little P80s just want good quality "general" pads. I've read stories about people putting competition pads on cars that don't even start to get up to operating temperature before a couple of laps or high speed stops. Before that, they perform poorly. I have not yet inspected the pads and rotors on my 99 S70 T5 other than looking through the wheels. Previous owner boasted of some sort of Brembo upgrade in the front with larger than normal pads. That's what he said. All I know is that my front wheels are constantly full of black brake dust. Thes may be upscale pads, butI wil swap them out at the first opportunity.

Post by **oragex** » 25 Feb 2019, 16:02

About breaking in the brakes... I think this is rather a myth used by some shady car dealers to explain the customer why their recently installed brake discs already cause brake vibration.. "You didn't break in the brakes.." The correct reason being as mentioned above cheap quality discs or some other problem with the calipers

Think of it this way: how many owners 'break in' the brakes on their new cars ? Not even 1 in 1000, still the genuine discs on new cars look and work perfect for several thousands miles. Also, as mentioned as well, one may jump with force on the pedal to break in a new disc, causing rather more problems that good.

Post by **Rattnalle** » 25 Feb 2019, 23:46

oragex wrote: ↑25 Feb 2019, 16:02 About breaking in the brakes... I think this is rather a myth used by some shady car dealers to explain the customer why their recently installed brake discs already cause brake vibration.. "You didn't break in the brakes.." The correct reason being as mentioned above cheap quality discs or some other problem with the calipers

Think of it this way: how many owners 'break in' the brakes on their new cars ? Not even 1 in 1000, still the genuine discs on new cars look and work perfect for several thousands miles. Also, as mentioned as well, one may jump with force on the pedal to break in a new disc, causing rather more problems that good.

Zimmermann sends a long break in instruction with their discs. It'd have to be done at three in the morning to avoid anyone being near when doing it. Or having an airstrip.

Bosch just says "drive carefully for 300 km".

I've only managed to warp the Zimmermans. Twice. Boschs and cheap noname have been fine with my (initial) driving so I'll still to those.

Post by **Rattnalle** » 25 Feb 2019, 23:48

I'll stick to a good standard set of pads as well. They're good for a 200 kph hard braking at least once which is enough for me. I won't be doing it twice in a short space of time anyway. I'd much rather they bite properly straight away around town.

enotslim · Post by **enotslim** » 01 Mar 2019, 13:35

And after such a nice set of new rear pads and rotors ... sudden bad noise and I discovered the broken e brake pad shown in the image. The fragment is placed on the inner liner (whatever it's called). Must have been damaged when removing the old rotor that did have a very large rust lip and took a lot of "coaxing". Not surprising given what I went through to get it off. Should have examined more carefully for cracked e brake pad, obviously.

So ... can you recommend a good set of replacement e brake shoes/pads? I don't know if there is much to choose between or if it matters much as long as they fit. Or maybe it does matter. The e brake mechanism seems OK and functioned fine before the pad broke. The e brake cable could use some work but that's another story.

: brokenEbrakepad.jpg (95.88 KiB) Viewed 605 times

pitted brake disc

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