damian

iTrader: (2)

Did your rears wear faster than your fronts?

silver0ckt

Yes mine did.

Fd3BOOST

iTrader: (7)

Mine did not

damian

iTrader: (2)

hmmm, one yes, one no...dam not very conclusive...

jimlab

No. There's your tie-breaker.

damian

iTrader: (2)

hehe, thanks jim...well hmm, since my rears are wearing faster, i think my PBV is not working properly and not giving more force to the front brakes.... man this is a PIA!!! lol

maxcooper

My fronts wear faster. Perhaps your parking brake is hanging up or you have a stuck caliper or something. I did come off the track once and one of my rear brakes was smoking like mad. I suspect the caliper got stuck, but I didn't have any trouble with it after that (pad wear was even -- unstuck itself, I guess). Do you have the little spreader V-springs on the leading side of the rear pads? If those are missing, it might cause uneven and accelerated wear. "Warped" rear rotors might also increase the wear rate. Do you get some pulsing (feeling on the handle) when you lightly apply the parking brake when cruising slowly?

-Max

Alien7

iTrader: (1)

I just noticed this too...it seems my rear pads are wearing a lot faster than my fronts.

These cars don't have adjustable brake proportioning valves do they?

jimlab

Nope.

My front pads wore a bit faster than my rear pads also.

TailHappy

With HPSs, my fronts were worn out and I couldn't tell that the backs had ANY wear at all. They still looked brand new.

Alien7

iTrader: (1)

I'm concerned that my stopping power is compromised...

Ideas?

Alien7

iTrader: (1)

Mods...maybe this thread will get more replies in the suspension section?

Thanks!

redrotorR1

As Jim said, no, they don't. I thought about adjusting that when I noticed how much dive my car has under hard braking ... only to realize that there's no adjustability to begin with.

Your front pads should wear faster than the rears. The front brakes probably do at least 75% of the stopping of your car. Your rear pads early wear is a sign of something wrong. Possibly your e-brake not fully disengaging or maybe those v-springs are worn out and the pads are dragging all the time. Or maybe you should lay off the WRC-style E-brake slides....

DamonB

I go through 2 sets of fronts to 1 set of rears. I could probably even stretch it to 3 but have not bothered to try.

Alien7

iTrader: (1)

hrm....i'll have to tear into it this weekend. I hope it's not a frozen piston or anything...

rx7will

iTrader: (6)

On the fds that i've had the fronts wear out faster than the rear. I can tell because when i wash my car i need to scrub the front wheels while the rear wheels barely need to be cleaned. On a side note some new cars were out the rear first or at the same time as the front. I just did a 4 wheel brake job on a 2000 accord with 23k on it. Make sure your rear brake are not sticking and that the pins are clean and lubed.

rynberg

The fronts wore faster on my Hawk HP+ pads and now on my current set of Hawk HPS pads, as it should be. There is definitely something wrong if your rears are wearing out first.

damian

iTrader: (2)

thanks for a ll the great info guys, ....here is my scenerio... there is no brake dragging, no e-brake hanging, clips are in place, all that stuff is normal.... so there is somthing wrong with the PBV or somthing (not master cylinder as i already replaced that)..... i compared to another fd at teh track today and first of all, my pedal travels much deeper than his, his feels like I remember mine used to be, taking less force to stop than mine, also, mine is definetly not putting as much force as it should on the fronts, my car does not 'dive' like it used to when braking hard, ..... only think i can think of is PBV or maybe the brake booster is not 'boosting' as much as it should be....

redrotorR1

The brake booster is likely not the problem if your rear brake pads are wearing faster. The pedal travel is most likely air in the lines. Bleed and/or flush all your brakes lines and see if that improves it at all.

damian

iTrader: (2)

I did that, many times, before and after the master cylinder change.... no difference. :-(

there is some adjust ment to the brake booster and master cylinder rod, could these have gotten out of adjustment causing the deep pedal travel?

maxpesce

It can be the Master Cylnder - The MC uses a Floating piston design and internal leakage past the floating piston will change brake bias and (if iirc) it is a rearward bias change that occurs - in other words the MC can be BAD with out any external leakage. Also air in the FRONT calipers will cause a REARWORD shift in brake bias - Blead the Fronts and see if that helps. Or the Front pads may be glazed - remove the pads and inspect them, If the face looks glossy an very smooth sand them w/ 60-80 grit sand paper wntly all the gloss is removed, also sand the Rotors to a dull finish and then Re-Bed the pads as if the were new.
Booster failure usually causes the pedeal to get HARDER so that it takes LOTS more effort to slow the car and REDUCES pedal travel. To test the booster first with the engine off pump the pedal quick 2-3 times to get pressure in the system then while holding firm pressure on the pedal, start the engine , as the vacuum builds the booster should pull the pedal down another 1/4- 1/2"

damian

iTrader: (2)

err, so are you saying my new one might be bad, I replaced the MC already (i mentioned it up there somewhere)

I bled the calipers to death, no change.

I though that the PBV sees all teh pressure from the MC and it does the distribution, so a bad MC would just cause weaker brakes but not change bias if the PBV was working correctly?

maxpesce

Sorry I missed the part about a NEW MC btw New from MAZDA? or Rebuild/Aftermarket? NEW= 99% probability its good - Rebuild (in my experiance) 40% chance it is bad. also I edited my prev post while you were replying and added some info about the booster
I am not too familiar w/ the PBV on an FD I will have to read up on it in my FSM tonight.

damian

iTrader: (2)

heheeh, no prob max, we were posting at the same time... it is a new MC from mazda, the new part number too.

according to the manual the PBV (proportioning bypass valve) does the job of dispersing more force to the front and less to the rear, it even has the numbers for testing, and I want to test mine but it takes a bunch of pressure testing equipment that i do not have access to.

damian

iTrader: (2)

ahh more good info, i did do the booster tests as layed out in teh manual, and it passed all those tests.... so its probably not the booster.