Stillen pads noisy? (1994 Q45)

[artandscience]

Since I put in my Stillen pads I hear what sounds like a metallic contact noise while driving. Application of the brakes removes the noise.

I'm wondering if not having damping material on the back of the pads (betweenpiston and pad) is causing the noise.

Anyone have any ideas?

Between the brake sensors and the noise I'm beginning to think I should have just stuck with the stock pads.

thanks, S.

[DAEDALUS]

The shims missing could definitely be a factor. Did you clean the pins really well and grease them up? Make sure the calipers float easily.

[911/Q45]

That's why I went back to factory pads.

[artandscience]

Yeah.. I used to race so I know quite a bit about prepping brakes.Everything fits nicely and properly lubed with high-temp brake compound.

Probably was that the stock shims had the rubber coating nearly worn offthem. So, as far as I know, all the stock shims are still there, just not 100%.

I fear that the pads could have a very high metal content and that couldbe the noise I hear.

Way annoying.

[Q45tech]

Unfortunately the metal masters [clones and copies] make grinding noises and later moaning 'rump' noises just before stops.....comes with the territory for high metal pads.

The oem U91 pads have high metal just not as much as MM, the U93/U95 are more ceramic and quietest of the oem group.

[jamesmost]

had the same issues w/stillen pads the worst of it was poor mfg. which gouged my cross drilled brembos in the center of the pad, stillen offered me pads at cost, and would not do anything on the rotors: I switched to akibono pro/act pads.

[artandscience]

Totally true. I think I'm going back to stock pads. What's the point of having a luxury car that sounds like crap?

[Q45tech]

The oem U91 front pads have more metal [thus a higher fade point] than the U93 both are very very quiet......there is probably another even quieter pad for 94-96......forgot the U number. Wish I could find the old U90 pad compound.........dustier but more initial bite.

Since the brake are the same 90-96 you can use any pad [correcting for worn sensor].

The U85 rear pad is the only one available so the friction vs. temp graph of the various front pads must be close or they would need more rear pad options.

The bean counters don't usually over ride the brake pad engineers after a design is in place.........[before production sure but not after].

Anyway at the manufacturers level brake pads [composition] from best to worst don't vary in cost by 50 cents.

How a $80 retail pad set that cost dealers $40, that cost Nissan $10 [in Japan] in mass quanties is an interesting lesson in economics.........the sensor and wire and connector is the most expensive part.

Making $30 on a replacement set is necessary to pay for the $1,000,000 engineering load of the initial testing/design of the pad compounds and brake system.......50,000 set of replacement pads x $30= $1.5 million.

Brake pads, oil filter, air filters, fuel filters, belts, thermostats, hoses are the only Nissan components likely to be used in replacement at least once on every car sold.

[Q45tech]

Most drivers never operate in the above 600F pad range where the oem pads start to lose friction at a faster rate.

On a 100F day that would take 4 back to back full panic stops from 60 mph within a few minutes. Or a single 150 mph stop.

Brake fluid boil is much more common than oem pad fade.

Careful about low light color dust ceramics thay may be worse on hot pad fade than oem or semimetallics............oem is a special mixture of ceramic and metal to try to balance cold and hot.........to work at 30F and 600F......well work well at least to 400F before the start of the slow roll off in friction. By the time the pads are at 400F the typical used brake fluid starts to boil.........some time delay as the heat migrates thru the pad material to the backing plate to the shims to the piston to the fluid.

Obviously pad thickness [9 mm new to 2mm worn] has a material effect on the TIME delay to reach fluid...........why boiling starts AFTER you stop.

[jamesmost]

Qtech u are a mad man, should have been a quantum physics professorback to pads i have on my car now Akebono pro act ceramics on brembo rotors and i like them efinitely quiet and clean but i used to hane cross drilled stillens which they claimed were brembos w/ their metal matrix pads i think the car stopped better when the pads were heated up but again they destroyed the rotors.

[Q45tech]

To create friction either the pads or the rotors must wear. Ideally you want the pads to wear 7 times faster than rotors.........7mm useful thickness on pads 1mm to replacement per side on rotor.

But considering the need to true rotor runout [0.005" per trueing] 5 times is more reasonable from an optimum friction stand point for the pads to wear out every 20,000 miles and rotors to be replaced every 40,000 miles.

MM pads will last longer but the rotors suffer. There is no free lunch.

Human perception of braking prowness is not very accurate without accurate measured comparisons..........most critical time is the first 0.5 second when brakes are fully applied. That's when very dusty pads excel!......the extreme fast friction ramp up while pedal pressure is low till the leg muscles get going.