Jobro

iTrader: (2)

OK so I've stepped my 12A NA + T build up a notch. I'm running 18psi midrange 13.5psi @ 7300-7400RPM. It goes like stink. The brakes the car had when I got it were like worn down to 20%. Finally the rears were on metal on metal for the last 6months so I finally bought 4x new rotors (cheapies), 4x wheel bearing kits (decent ones) and 4x epic most aggressive as it gets street strip brake pads.

I think this material would be more aggressive than the Hawk HP+ model. But basically can anyone who has used Porterfield R4-S, Hawk HPS or Hawk HP+ comment on the initial bite of the brakes. I'm talking during normal street driving but doing un-naturally hard stops.

Basically what I'm feeling is that I can do 0-60 or 80kph and then brake hard to stop or say 20kph and then accelerate back to 60 or 80 quite a few times. What I'm feeling in the car is that its not making much difference on the intial bite no matter how many times I try to do it.

I'm wondering if this sounds hydralics related because my rear calipers are weepy. I'm yet to have a hand with a 100 '**** OCD' spec brake bleed where I get the new fluid out all the bleed points.

I guess I want people to comment on how the initial bite is and I guess I want input on all cars even those using good factory replacement parts.

Jobro

iTrader: (2)

OK I'll give a comparison.

My Mum's car is a 2002 Model Mazda 323 Protege (non ABS model and owned since new by my family). If you push the brake pedal down with the same pedal effort as my 7 your head goes through the windscreen.

The weird thing is that my car stops VERY hard in the end of a hard brake but not the initial slow down bit.

theNeanderthol

iTrader: (1)

I'm thinking you might have a failing brake booster. If you've ever driven a car without power brakes, or with a bad booster, it feels a bit like you're describing to me. I may be wrong, but it's worth consideration. Without the initial umph from the booster during the initial stepping on the pedal, the pedal seems to not press down as quick as it would with the booster.

rotor-motor

iTrader: (7)

did you "break in" the new brake pads?

Jobro

iTrader: (2)

I bedded in the fronts 2 days ago. I just did a serious and I mean serious brake bleed. I'm talking flush every last drop of the old fluid out and then 100% get all the air out. The new fluid is super dot4 which is rated to 287degC when not contaminated by water. The A1RM's are now installed in the rear too. The pedal effort seems really dull still. I guess I should give them a few hundred kms to transfer the pad material onto the new rotor. Past this all I can do is recondition the weepy rear calipers and install braided lines. The car is so nice with new wheel bearings all round.

I can confirm the engine pulls good vacuum on the vacuum brake booster and the brake booster is holding the engine vacuum for hours on end without decay. I'm still going to work on the other parts of the hydraulic system but if that doesn't fix it I guess I went 1 grade too serious for my road cars brakes.

Keith13b

iTrader: (6)

I haven't used the brakes you mention, but could you have bought perfomance brakes for racing that need to be warmed up to work right? I've seen people do that before......alot.

But more importantly, like rotor-motor said, did you break-in the pads properly?

Sure sounds like you didn't. I'd look to see if you glazed the brakes.

t_g_farrell

iTrader: (1)

Agree with other posters. Sounds like you have race pads on there and they won't
really grab good until they get hot, which means after a few laps. Not good for
street use as they tend to go for long periods and cool back down. Also they have
to be bedded correctly according to whatever the pad manufacturer says.

j9fd3s

iTrader: (3)

you should try a different brand of pad, or maybe put the old ones back in an see if it changes things.