High-speed braking problem

[modifiede30]

Upgrade the pads to something that can handle the speeds you're driving at. Standard pads don't usually do well with the sort of heat you're generating.

[Mike P.]

I bet it's the...

I bet it's the calipers that are needing replaced. Sounds like you have some play in them...mine does the same thing. My buddy's was also doing it until he picked up a new pair of fronts, and the problem went away. There's more than likely some issues with the sliding pins in the pad carrier (The half of the caliper that is bolted to the knuckle.) I'm not sure if you can buy *just* new pad carriers without buying the entire caliper assembly, but that would solve the problem.

[Mike P.]

Upgrade the pads to something that can handle the speeds you're driving at. Standard pads don't usually do well with the sort of heat you're generating.

I think you're totally incorrect on that one. Crappy pads might overheat and you might get pad fade (which will render the pads useless) from those speeds I hope nobody's irresponsible enough to do on public roads, but they shouldn't cause any added sounds or sensations. Even still, crappy pads should be able to do at least one or two good hard stops before crapping out. I just put in some Axxis Ultimates today and it didn't fix any problems. The fact is, the calipers are still screwed up, no matter what pads are in there.

[modifiede30]

While street pads should be able to handle a couple hard brakes without fading, he mentioned that he was slowing from about 110mph down very rapidly. That's much more intensive than what most street pads can handle. Your points on the calipers are valid but I wouldn't try using street pads at the speeds he mentioned. I'm not sure what rotors he has, but if slotted or drilled, it would explain the noise, and some pads make noise without these types of rotors. Without vibrations though, it doesn't sound like a caliper problem to me.

[Matto]

On the warped rotor topic, my old warped rotors caused a rubbing noise when driving that you could hear. When I braked my car wouldn't go in a streight line. Now those were some warped rotors.

[getfast]

Re: I bet it's the...

I bet it's the calipers that are needing replaced. Sounds like you have some play in them...mine does the same thing. My buddy's was also doing it until he picked up a new pair of fronts, and the problem went away. There's more than likely some issues with the sliding pins in the pad carrier (The half of the caliper that is bolted to the knuckle.) I'm not sure if you can buy *just* new pad carriers without buying the entire caliper assembly, but that would solve the problem.

I'm the "buddy" mentioned above... after a track day at Summit Point, that's pretty much what mine was doing (as per the original description atop page 1.) It couldn't have been anything else, since everything else in the front end was new (pads, rotors, bearings, struts, mounts, control arms, bushings, tie rods, etc.)

Two beautiful rebuilt calipers from work, two new front hoses, and a fresh bleed with Ate Super Blue = no more problem. The caliper was sticking/dragging so badly that the right front inside pad was twice as worn as the other three pads!

Not saying this is your problem, but it does sound a lot like the problem I just had.

Hope it helps-

Jon

[JeffBij]

Pad choice and calipers

Definitely go with a pad designed to handle the heat your generating with those stops. EBC Greens are nice, but they are designed as a high performance STREET pad. Their temperature range is not high enough for the track. I've used EBC Red, but they wear fast. Hawk HP Plus work well and you can still drive them on the street. (They are a bit noisy though.) Use Hawk HP Street in fhe back if you go with the Plus's in the front. (The Plus's aren't available for the rears.)

On the calipers, there is a brass bushing available to replace the rubber that surrounds the two pins holding the caliper together. It is a worthwhile upgrade if you're running the car hard. The brass bushing keeps the caliper from twisting when braking. It will also keep the pads wearing evenly. They will work for the ATE calipers (both front and rear) and some of the Girling ones. You can get them at Bimmerworld, Turner Motorsport and Bavarian Autosport for $50-60 and axel.

Still keep an eye on the rotors. It doesn't take much to warp them. I've also seen brand new ones have a slight warp right out of the box. What brand are you using?

Jeff B.
Roanoke, VA
'89 325i SpecE30 prepared

[Mystikal]

Thanks guys. I'm running Brembo replacements, as I posted originally.

I'm already pretty set on EBC Greens or Hawk HPS, if I want something for the track I'll get something for the track. To me it's like tires, if you're running something between the requirements of each venue (whether that be track/street, winter/summer, etc.), you're just compromising 100% of the time.

[Julien]

sorry, didn't read the last 2 pages, but i had the same problem w/ my 88is... it was the motor mounts, they where so shot the fan would hit the radiator... just a guess for your problem- check your rad for marks



Ju

[getfast]

I'm already pretty set on EBC Greens or Hawk HPS, if I want something for the track I'll get something for the track. To me it's like tires, if you're running something between the requirements of each venue (whether that be track/street, winter/summer, etc.), you're just compromising 100% of the time.

Excellent point. I run the Axxis Ultimates because they're significantly cheaper than those choices - and the only compromise is the insane amount of brake dust! Not to mention the occasional squeek...

Best of luck-

Jon
90 325is track whore now, Spec E30 for '05

[Rob]

My ultimates dont dust anymore than stock *shrug*

[getfast]

My ultimates dont dust anymore than stock *shrug*

This car had Axxis Deluxe Organic on it when I got it from its previous owner - no dust at all. These Ultimates will dust my wheels in 20 miles (and will make the wheels black in a week.) So I have no idea how dusty a stock or stock-type metallic pad would be on this car... but they're certainly a lot dustier than what was on it before :?