Okay, just so I have the list correct, here are the people who have noticed offset and/or crookedness issues in the revised-spec kit:

* hyperion (me)
* dclin
* reawolfe
* adax
* azn akira

I'm going to reference this thread in my conversation. As near as I can tell, there isn't anyone who has installed the revised kit and not seen issues with fitment.

Please correct me if I'm wrong.

-ch

 

azn akira, why won't the RPF1s fit over the calipers? where is there interference?

 

Hmm. The info I went on was from the site here during the ordering process:

From: http://www.racingbrake.com/RB_4_pist...s110-35-02.htm

That's very different that what you're saying above. Clearly, they say 'street to track' and 'light track event', and 'similar to Hawk Blues'.

It was based on this that I chose them. But they are clearly not even close to Hawk Blues.

I will try the ET800 next time around.

If I can fix the other issues first...

-ch

 

I would think that would more or less throw the "light track event" part completely out of the equation. 430whp on 10" wide race tires will be hard on brakes no matter how you look at it.

 

Let me put it another way: Hawk Blues are a track pad. There are several people on this forum that run high-HP race-tire-shod FDs on the track with Blues. The ET500s are no where near as durable or grippy. Even the comparison to HP+ is stretching it.

-ch

 

FWIW, I test fitted my 18" RPF1 and I have about 3/8" clearance. 18x9.5+45

 

Old kit or revised kit? The revised kit would fit less wheels, as that it is offset outwards more to clear the mounting points for the brakes.

 

After seeing the wear on your pads, I have to agree that they don't even compare to Hawk HP+ pads. I have run several track events with my BBK front and rear on HP+ pads and I am still on the same set of pads. It looks like those ET 500's wouldn't last more then one day at the track.

 

Version 1.0 aka old kit

 

OK, I think I've got it figured out; the bolt holes (to mount the calipers to the brackets) on the caliper are off. In the case of my set, the driver side is a little more off than the passenger side. I'll get to this in a second.

First, what I measured today:

Stock Brakes, Rotor To Caliper Body Clearance
* Passenger side
- Inboard .048"
- Outboard .087"
* Driver side
- Inboard .069"
- Outboard .067"

Interestingly, the driver side stock caliper was nicely centered with the rotors, while the passenger side was off a bit.

RB BBK, revised/2nd gen kit, Rotor To Caliper Body Clearance
* Passenger side
- Inboard .088"
- Outboard .050"
* Driver Side
- Inboard .035"
- Outboard .100"

In my case, my driver side is a bit more off than the passenger side, opposite of what hyperion and others are experiencing. There was no really notable difference in measurements between the top of the caliper and the bottom of the caliper, so I believe my calipers and rotors are basically on the same plane.

Taking a look at the calipers themselves, I noticed that the brackets for the calipers are not flush with the caliper body, and in the case of the driver side, protruded out more than the passenger side. They aren't even. Thinking that the brackets were drilled differently, I took them off and measured with a caliper, but they're even. To be absolutely sure, I swapped sides, but the driver side bracket still protuded out more. This tells me that it's the holes in the calipers that are drilled incorrectly.

My guess? The orginal design called for the brackets to be FLUSH with the caliper body, but somehow the calipers were drilled incorrectly. If they were, the rotors would be more or less centered in the caliper body. The amount protruding on each side is almost exactly what is needed.

Sorry for the slightly different angles, but the difference is apparent irregardless:

Driver side caliper:



Passenger side caliper:



I'm willing to bet there was some quality control issue during the manufacturing of the calipers - at least during drilling the bracket mounting holes.

Is it a deal killer? I don't think so. The stock passenger side caliper shows a bit of offset, and I haven't seen any adnormal wear (though, admittedly, no real serious track time with the stock brakes).

I would like to see an adjustment to my driver side bracket to compensate though, the outboard side is a tiny bit to close for comfort. Some slight milling should get it closer to centered of course. I'm fine with the passenger side offset.

 

Pics of wheel clearance. Again, my brake set is the REVISED KIT/2ND GEN. The Orginal/1st gen/v1.0 kit would likely have a bit more clearance.

SSR 18x10.5 +43
1.75" at the closest point. The spokes are concave, so there is more clearance at the outer portion of the spokes.





Enkei RP01 18x9 +42
Just under 1.25" at the closest point. The spokes are convex, so there is more clearance towards the inner portion of the spokes.

 

Wow, dclin, that's pretty crazy. So it would appear that the L/R variation is at least in part due to the factory uprights. But the caliper/bracket variation is very, very wierd.

You can see that RB uses the same caliper for both sides of the car. It's simply assembled with the crossover tube and bleed screws on different ends. So there are three possibilities:

1) there is a variation in the bolt holes between two calipers
2) there is a variation in the tapped holes between the two brackets
3) there is enough slop between the bolts and calipers that the caliper can wind up in different positions

Rick's work with the dead blow hammer seemed to suggest #3. If you still have the calipers off the car, you should try that experiment: gently tighten the bolts and then tap the caliper to see if you can get it to move.

It would also be interesting to directly measure the caliper bolt holes to see if the caliper shows them to be in different locations. Because it would seem that RB would want to keep the design of the caliper static across all their applications, changing only the bracket...

-ch

 

While the forging/casting of the caliper may be the same, the left and right sides would have to be machined at different times, since the caliper pistons are machined asymmetrical.

This is what I just measured:





The driver side definitely moves the bracket over a bit. While .018" (or .5mm) doesn't sound much, this is almost exactly the difference in between the caliper offsets in my post, the 2nd above.

If my driver side was moved back that .018" difference, I probably wouldn't be concerned and left it be. As it is now, I have less than 1mm clearance between the caliper and rotor on the inboard, drivers side. Is this an issue? Don't know.

I could measure only about .005" difference between the two brackets, which I would guess is within tolerence.

My guess is that the brackets could be both off, just that they are both consistent with each other. If the holes had been machined a .020" over a bit, that would have helped center the caliper.

Sorry, I forgot to mention that these measurements were with the calipers moved as far over as possible. I figure there is about .010" slop.

In either case, not sure what to do at this point. That less-than-1mm clearance on the driver, inboard side may not make a difference at all, but don't want to be guinea pig #3.

 

Wow, great work and great pics. I will pull my calipers off today to get the same data and verify. Guess we're still in beta test, eh?

-ch

 

here are some pics of the interference

 

Okay, so I measured the caliper holes in the same manner as dciln above, but I got the following measurements:

Driver side top: 0.156"
Driver side bottom: 0.138"
(the fastener wore some threads into the bore on the top which may account for the issue)

Passenger side top: 0.139"
Passenger side bottom: 0.141"

So I may or may not be seeing the same thing.

Also, I measured the caliper while taping it around like Rick described and didn't see more than 0.010" of movement.

I've bench bled the MC and flushed the entire system again. I'll be road testing it later today. More to come.

-ch

 

Here are my modified brackets (0.040" off machined surfaces) as per previous post and hyperion's recommendations. I've got them on the car and to the naked eye, they look almost perfectly centered so I probably won't measure them again. Track test in about two weeks.



Alan

 

This seems like a bunch of bs to me! It's interesting, out of 150 cars running at road america this weekend, the only guy I could find using rb's stuff (et800 pads, c6 zo6) went home after a couple laps when the pads faded badly and allegedly caught on fire! Granted, he probably should have went with the 900's, but the track was cold and moist yesterday morning and I highly doubt he was going full tilt.

Chris's fuel tank surge cover worked and fit great btw and sadly seems to have more r&d, quality control behind it than this $2k+ brake kit!

I hope rb steps up to take care of their customers here.....

 

I'd argue we haven't made it out of alpha yet.

Wild guess, but I'm guessing your passenger caliper and my driver side caliper bolt holes were drilled in the same batch (and vice versa). The numbers are way too coincidental.

What was the cost for milling the brackets for those that have done so?

My only concern so far for machining is I don't currently have an uneven plane issue, and it'd be my luck that the machinist is off a few degrees. In the end, I'll probably just go this route to be done with it.

 

I switched to HPS for my street pads, and I'll see what others find they like for the track. I gave up on the idea of having one pad for street and track.

 

fwiw, i haven't received my revised kit yet.

 

More testing...

Even after a complete bench bleed of the MC and flush of the system, the pedal is still very long and mushy. I have to push like crazy just to get the ABS to engage. I'm going to re-bleed one more time and then try swapping the MC.

However, on the last ABS engagement I heard a really loud POP from the front right corner. It sounded like a cork from a 6-foot-tall champagne bottle. I'm going to jack the car up later and inspect. The brakes didn't lose pressure, so I'm not sure what it could be.

-ch

 

I haven't been on the track yet but I have done the bed-in procedure for the ET900's and I did not have the mushy pedal you describe. They smoked like crazy but ABS engaged at >80 mph without much pedal pressure. Does the pedal get firm when the car is parked, engine on and engine off?

 

The pedal is firm-er with the engine off. It does not 'bleed down' like an MC with busted seals, nor does it appear to leak anywhere. But when the car is on and the vacuum assist engaged, if I push hard enough I can feel the MC bottoming out. And I need to get to there in order to engage the ABS.

Pumping doesn't seem to make things much better, either.

I'm still investigating. I noticed a bit of fluid around the bleed screws on the caliper, but I'm 99% sure that it's just the bit of fluid in the screw working its way out. After the next bleed I'm going to clear the excess fluid with the shop air and test again.

And now there's that issue of the big 'BANG' from the suspension...

Sigh.

-ch

 

hyperion, sounds familiar?

http://forums.corvetteforum.com/show...p?p=1562292669

Before you go and competely tear apart everything else, maybe try switching pads? RB does recommend Hawk pads with their rotors. Sounds really bizarre, but....