They should be delivered tonight.

I have a show and tell schedualed for tomorrow at work with these... Lol

Macro pictures to follow.

 

What are you, an elementary school teacher?

 

lol,

Body designer at Honda R&D.

We run Brembo brakes on the Enduro TL Race car and are very curious to have a look at these seals.

 

I'm very interested to see what these seals do!!

I experienced what may have been "knock back" as well during my last HPDE at VIR. It was on a G35 coupe, all stock except for HP+ pads and ATE Blue fluid. I ended up having to do the left foot brake tap just before every brake zone, to make sure the brakes were "there"

 

And pretty common. God bless floating calipers.

...Until your flagged down because the right rear piston boot caught fire and you find that the caliper had so much flex that your rear Porterfield R4 pads broke in half. But hey, at least there's no knockback, right?
Will

 

There's no way a "special" pressure seal is going to cure knockback on a car with extreme bearing deflection, like the 350Z Track, WRX STi, or 3rd Gen RX-7. Think of the force generated by high lateral Gs with sticky track tires and then try to imagine a rubber piston seal fighting those forces to keep the piston from moving in. It's not going to happen.

I will be very surprised if someone installs these, makes no other changes and discovers their knockback issues are suddenly cured. We need fresh (or redesigned) wheel bearings to reduce knockback on the 350Z. Or anti-knockback springs behind the caliper pistons.

Here's a link to an article on the subject: http://www.stoptech.com/tech_info/wp_knockback.shtml

 

I've seen these seals used in the past for the exact opposite reason.....making sure the pad doesn't drag on the rotor. The seal basically has a chamfer cut on the sealing side that wants to pull the puck back (or push it out) I doubt that it will cure the knockback as good as springs, but I'm interested to hear if it helps.

mike

 

Who said anything about curing pad knock back with these ?

I'd be happy just to minimise it. It's not really a problem with the OEM Brembo. Pad knockback is a fact of life on fixed caliper. It's up to the driver to work around the phenomenon.

So far, they are black and round. Haven't had time to compare them with the regular seals. More to come next week. I'm 720 miles away for now...

 

Actually, it's very much a problem with the 350Z Track Model OEM Brembos if you're at the instructor or pro level and running fast laps with R-compound tires. I have plenty of customers who have to tap the brake pedal with their left foot, before the main braking zone, after coming off a series of left/right turns.

This is a platform issue, not a "fact of life" with any vehicle using fixed calipers. There are lots of platforms with more robust wheel bearings that don't exhibit knockback. Here's an interesting example: I had the chance to drive all the Brembo-equipped SRT8 vehicles at Lime Rock, including the 300C, Magnum, Charger, and Jeep SRT8. All the LX platforms exhibited strong knockback, requiring a quick jab of the brakes, while still on the back straight, to avoid the pedal sinking nearly to the floor while braking for the Uphill corner. The Jeep SRT8, with the exact same Brembo 4-piston calipers, did not exhibit a hint of knockback, no matter how hard it was pushed. The difference was in the wheel bearings and knuckles.


OEM Brembo-equipped SRT8 Dodge Chargers at Lime Rock

 

A Jeep ?!? How much cornering load can that thing take before rolling over compared with a 300C or a Charger or a 350Z ?

Call me slow at the track or stupid. But I'm not going to throw money on a revised bearing assembly when I can simply jab the brakes (Like any other pro racer) before my brake zone to compensate for pad knockback.

These seals are marketed as reducing pad knock back. For someone like me who's not too keen on mounting full anti-knock back springs on his part time track car, these might be a viable alternative. I'm changing the seals anyways, I might as well try it.

 

You would be amazed. I was amazed! I took the first lap easy, figuring it would be top heavy and a pig. By the next lap, I was sliding it through turns like a sports car. They've really sorted that thing out. I could take it to an open track day and run it in the advanced run group and not be a moving chicane. I never would have believed it before experiencing it first hand. I would NOT want to venture off-road with that particular Jeep, though.Many of the pro drivers racing the WRX will install new bearings after each race. (It's nice being sponsored!) Knock-back gets noticeably worse as the bearings wear out. That being said, it's easy to get used to stabbing the brakes with the left foot while approaching the braking zone and much cheaper than replacing parts every weekend.
There's probably no harm in trying these. If they do work as advertised, however, you may end up with some residual brake drag under street driving conditions. I'll be interested in your observations.

 

Keep us posted how these work. I'm still very happy with my knockback springs on my street/track car. Going to Laguna tomorrow to test them out. Last time I was there, my pedal was to the floor after the corkscrew.

 

Well, they're in now.

I took some pictures where we can't see much... Lol

The only visible difference with the regular seals is the inner race. The regular ones are smooth and shiny (still rubber) while the anti knock back ones are rougher.

I'm headed to Putnam Park next weekend.

 

Well, first impression is this.

They don't make a world of difference, but the front brakes are a bit noisier while driving around. Suggesting that the pads are being kept a bit closer than usuall.

Not the upgrade of the century, but if you're swapping your seals, it can't hurt to get those instead.

 

When you say they "don't make a world of difference", can you describe what sort of difference they did make? Did you notice any reduction in knockback at all? Were you able to compare knockback at the same track under the same conditions and with the same brake pads? In other words, you didn't just install brand new race pads, right? Knockback is greatly reduced when new pads are installed, simply because there's not as much room in the caliper for them to be pushed back.

What sort of noise did the front brakes make and under what conditions?

 

The pads are dragging while driving. More so after I've touched the brakes.

So basically, the seals will hold the pads in place under light load. I'm guessing the the small vibrations are countered with the seal's flexing and spring back.

But under prolonged lateral loading, the pads/pistons will still be pushed back.

This is not a mod to replace a set of springs in the pistons. If you have to change the seals, I'd say use these.

As far as repeatbility, it's impossible to say since the car's setup is different and I'm lowering my lap times ~2 seconds each time I go to an event. I still need to check the brakes before the big braking zones. But that's something I always do for obvious safety reasons.