Rick,

Thanks for taking a look at this. What's funny is that visually pictures #1 and #2 make it look like there is a significant offset inboard (like on my and other cars) but the measurement you took from above in pictures #3 and #4 looks less so. If you have a chance to put a feeler gauge in between the rotor surface and the caliper body (what you're looking at in pics #1 and #2) I'd be interested to see if you get the same result.

Hmm, that's exactly what I saw too! It was the passenger side that bound badly; the driver's side was much easier.

In case you go with the machining approach, I took 0.040" off the inside face of the bracket (the part that mates to the upright) and I also took 0.020" off the part of the bracket that's right against the rotor face because I was worried about interference.

But the left-to-right difference is very weird. I'm going to take a closer look at the factory shims. I'm wondering if there are any asymmetries there.

-ch

 

did either of you call racing brake?

 

Called twice, left message. Hoping to hear from them tomorrow.

In the meantime, I've ordered a Motive power bleeder (thanks, Azn Akira for the part number!) and a bench bleeding kit. I'm going to make sure that my MC is air-free before I change it out.

But back to the offset issue...it looks like we've learned two things so far:

1) In every case, there is a noticeable difference in offset between the driver and passenger's side of the car.
2) In some cases, the passenger side is far enough off that it may cause binding with new brake pads.

I started to do some measurements of the stock calipers to see if they, for some reason, are asymmetrical. But I've decided to leave that to the RB guys--I think they need to get a complete car in their shop for some additional development work.

-ch

 

hmm this is interesting because if you note my earlier posts I had issues with the pads binding when using shims and this created surface cracking on the rotor rings (which RB kindly replaced) however it seemed to be localized on only the passenger side.

 

I'll try the passenger side Wed or Thur to see if I see the same binding. It would be good to at least figure out if it's a Mazda build thing. The other thing I was thinking it could be; could the caliper mounting holes be off themselves?

The RB guys must really be tearing out their hair at this point. I don't suppose now is the time to request an inquiry into a 6 pot front/4 pot rear/rear spot e-brake kit now, would it?

 

[QUOTE=hyperion;7399066]Rick,

Thanks for taking a look at this. What's funny is that visually pictures #1 and #2 make it look like there is a significant offset inboard (like on my and other cars) but the measurement you took from above in pictures #3 and #4 looks less so. If you have a chance to put a feeler gauge in between the rotor surface and the caliper body (what you're looking at in pics #1 and #2) I'd be interested to see if you get the same result.

Chris,

Pictures 1 & 2 are from the passenger side. 3 & 4 are from the driver's side, where there was essentially no offset. Per your request I used a feeler gauge to check the gaps indicated in pictures 1&2 and got: .112" I / .050" O on the passenger side and .118" I / .053" O on the driver's side. This is from the disk to the actual caliper. I re-checked the measurement on the back side of the caliper (like in my pictures 3&4) and found that there was as much as a .050" difference between the top of the caliper and the bottom indicating that the caliper was not completely lined up with the plane of the disk. I had previously measured only at the bottoms. I loosened the caliper bolts (the allen head ones) and tapped the caliper with a dead blow hammer and was able to move things around as much as .050". Seems like there may be a bit of slop in the bolt holes? Its curious that the offset appears to be different at the front side of the caliper vs. the back side. It almost seems like the mounting surfaces of the caliper bracket are not at exactly 90 degrees. I'm still not terribly worried about this as the hydraulics and pad wear should compensate.

I think that if RB is going to effect any change to correct the offset, it should be to move the location of the caliper mounting holes outboard by about .030" and verify that the mounting surfaces are exactly at 90 degrees. Otherwise, I do not believe that the mounting bracket needs any other modifications. Do you agree?

 

Exchanged emails with Steve at RB last week. He told me they are investigating and offered to replace the calipers. I asked him to hold off until I finished investigating.

 

i just recieved my bbk from racing kit. hopefully i'll install it this weekend and take some measurements. im not sure if ill have time though because i need to finish prepping my 24 hours of LeMons car

 

I can't believe you guys actually took cars on track like that. I don't even like to go out with old (but functioning) fluid.

Hope you get it straightened out.

 

Okay, so I finally had time to tear down the brake system for a closer inspection. Without going into great detail, here's what I found:

1) The ET500 pads wore considerably despite the fact that a) I only did about 15 laps on them and b) I wasn't even close to threshold braking. So unless they were a bad set, the ET500's are totally unsuited to track use on the FD.

2) The wear was uneven. The outside pads on both sides of the car wore more than the inside pads. See below:

Passenger side:


Driver side:


You can see clearly in the pictures that the cylinders are sticking out about 3-4mm. I'm going to measure the pads carefully tonight to get actual wear measurements.

You can also see that there was sufficient heat on the rotor to cook off the paint that RB puts on the vanes.

I also clearly noticed what Rick had pointed out, namely that the caliper does not sit in the same radial plane as the rotor. I'm going to try to duplicate his dead-blow experiment later.

I bled passenger's side caliper to see if any air came out. Nothing at all.

Hopefully by tonight I will have eliminated the MC as a potential cause of the mushy pedal issue.

-ch

 

I finally had the opportunity to try out the ET800’s at the track. It was certainly a unique experience.
Earlier feedback on the 700’s here: https://www.rx7club.com/showpost.php...&postcount=967

First session I took it easy (maybe 7/10ths effort) and everything felt great. The pedal was consistent and the pads were grabbing like a track worthy pad should.

The second and third sessions got interesting when I starting pushing it harder. The pedal started out feeling great then started losing consistency after 5-6 hard laps. By the tenth or so lap the car became very squirrelly under hard braking. There was still enough brake torque to engage ABS if I wanted, but the car was darting all over the place. Both sessions I was black-flagged because the car was smoking under decell/braking. They thought I was dumping fluid based on the volume of smoke coming from the car. Inspections revealed nothing out of the ordinary.

By the fourth session the sun set and it was getting dark. Again, the pedal started out great. By the 5th or so hard lap I noticed a spark or two flying by the window under heavy braking. Not something terribly alarming as I’ve seen Hawk Blues do the same thing. The following lap I hit the brakes at the end of the front straight and holy Fourth of July. Literally a shower of sparks came pouring out. That was my 3rd and final black flag. The tech guy and corner worker claimed they never seen anything like that.

Strangely enough, the brakes weren’t particularly hot when I came into the pits. I could touch the caliper immediately after pitting!
I pulled the drivers side wheel and everything looked fine. The rotor face hardly looks used. Zero surface cracks. There is no interference with the uprights or any other part. The pad measured .5-.53 thick. So, about 1/3 of the actual pad material was used up. Not sure how much on track time I actually got with all the flagging and time between sessions wasted inspecting the car. Maybe 45mins?

I’ve killed dozens of pads over the years and I’ve never had one act like this. I expected the ET800’s would at least perform better then the stockers with N-tech competition pads. I guess there are still the ET900’s… but it’s getting to that time of the year. Not sure if I’ll have the opportunity to try them.
Any other feedback on the 800’s? Their behavior was just absolutely bizarre to me.

 

This is a bit out in left field, but are you sure it wasn't metal-on-metal contact as a result of the rotors and calipers swelling up? I notice Chris' pictures above show a pretty tight gap that could conceivably disappeared under hard braking.

 

^^^^

I doubt they'd swell (or even flex) that much.

I've waited a while to say something, because I didn't want seem like a troll, but this all seems like a real cluster****, honestly.

Somebody needs to do some actual R&D on these things, and make sure they bloody-well fit and work before shipping them off to consumers. Seriously, we're not talking about carbon fiber sunshades here, they're brakes!

 

I was thinking more along the lines of a combination of the two (flex and swell). Though I agree, it does seem unlikely.

 

I'm starting to wonder about these as I haven't put it on my car yet.. I'm also been waiting to see what Howard has to say about this or even the guys from RB... Or if this is isolated incident with possible installation issues and such or slightly difference between FD's. Either case, I hate to read negative things about brakes that I'm ready to put on..

 

I got in there with the feeler gauge this afternoon and found similar numbers to yours.

L - outboard: 0.050
L - inboard: 0.130
R - outboard: 0.040
R - inboard: 0.110

For a difference of 0.80 on the left and 0.70 on the right so taking 0.040 off the bracket surface should correct it almost perfectly. I'll take some off the other side as well as it is closer to the rotor than the caliper. Personally I don't think it will affect performance but if I don't fix it now it will bug me every time I put new pads in. The top to bottom difference was minimal and I could correct most of it by adjusting with the slight amount of play between the bracket and caliper as others have mentioned.

 

Looks like almost identical info. Thanks for the detailed measurements.

Well, I do expect RB to send out revised brackets. I have yet to hear back from them but will be calling them again tomorrow.

Here's some additional data on my pad wear. I'd be interested to hear from Adax and Rick to see if it's similar. I measured the thickness of the friction material at all four corners of each pad looking for taper, and also comparing the average thickness of the inboard and outboard pads.

Passenger side outboard: 0.025" variation, leading edge taper
Passenger side inboard: 0.025" variation, trailing edge taper
(This backs up Rick's idea that slop in the caliper fastener holes can allow the caliper to mount out of the plane with the rotor)
Overall: about 0.030" more wear on the outboard pad

Driver side outboard: 0.015" variation, tapered towards the top of the pad
Driver side inboard: 0.007" variation, very slight leading edge taper
(I have no idea how to explain this one)
Overall: about 0.015" more wear on the outboard pad

So it would appear that the Passenger side caliper is crooked, either by the fasteners or the bracket. The outboard pad wears faster than the inboard for some reason, and there is significant taper on the pads although not always leading edge as you might expect.

Overall thickness of the ET500's friction material after 1.5 moderately-paced sessions was about 0.267". It should also be noted that the passenger side pads averaged 0.256" while the driver side was 0.277", so the side-to-side wear was also uneven. However, this may be due to the fact that Laguna is a counter-clockwise track and the three hardest braking zones (2, 5, and 11) are all followed by left-hand turns.

For kicks I visually inspected the stock calipers that I had taken off. Running Hawk HPS, the pad wear was almost perfect in terms of taper and inboard/outboard comparison.

-ch

 

Really weird. Sounds all the world like metal/metal contact to me, but I understand there was no evidence of such. I don't think Rick had the same issues with the 800's but I'm also not sure he was able to push them as hard with the hydraulic issues he and I both had.

-ch

 

With regards to the sparking I think the pad is just super tough and its taking out some of the rotor, I had a lot of this with my Hawk Blues on the stock brakes.

http://www.youtube.com/watch?v=PHq8fasQSSQ

 

If you read the pad info from the RB site about ET500s, you should not have tried them on the track. Only good for 100mph and 1000F. They are an aggressive street pad, not a track pad. Have to give you a .

 

I noticed in my first couple of sessions at Laguna that there was a pretty strong smell of brakes cooking and it felt like they might be fading. Later sessions I did not notice it. It could be because I was over-using the rears early on until I figured out a technique for pumping up the fronts before a corner. I never really pushed the brakes though out of fear for my life. My best times that day were only in the high 1:40's.

I noticed a lot of metal dust collected in the rim when I removed the wheel. More than I have noticed before when using racing pads. The ET800s that I was using may just have a high metallic content which could account for the sparks (I don’t know about the smoking). Since I was driving in the daytime, I would not have noticed the lightshow if it was happening… too bad! The rotors did not seem particularly warn and still show some of the original cross hatching.

I measured the front pads to be around .250 remaining +/- .005 for all and they appear to have warn pretty uniformly top to bottom (though I only did a visual). That seems pretty fair as I did about six 20 minute sessions. Because of the hydraulic problems I was having I really can't pass a firm judgment either way though.

I don’t really mind doing some evaluation and R&D for RB. In fact I find it a bit amusing as opposed to a turn-key solution. I just wished they would have told me first! I do appreciate RB taking this on as the idea of a reasonably priced, balanced 4-wheel system is a welcome offering...especially for a car that has been out of production for 12 years!

BTW, I ordered a 929 MC. We’ll see if that remedies the hydraulic issues.

Rick

 

QFT

Im wishing I had gone with ap racing calipers like I had originally wanted to...

i just got an email from them and they said they only have had one complaint (im guessing thats you) and at this time have no plans on making a revised bracket. im going to install my kit and send them what i find, and if anyone else has this problem call or email rb so we can get this problem fixed.

 

i mounted the passenger side caliper and rotor and i took some measurements.

from the caliper body to the rotor:

inboard top: .085''
inboard bottom: .068''
outboard top: .020''
outboard bottom: .037''

variation side to side: .065''
variation top to bottom: .017''

sorry for the bad cell phone pics
outboard:

inboard:


i also found out these will not fit under 17'' enkei rpf1

 

I hadn't had time to call, I'm going to get both sides mounted this weekend and take better pics.

A thought on installation; if there is play in the caliper mounting holes, we could try to torque the calipers down while someone applies brakes. This might help to at least center the calipers, if it doesn't help with the plane issue.

 

Howard- when are you going to BH Farms for a day of lapping?

Anyone else going before it gets wet/snowy?

Mixed feedback on the trackworthiness of them so far. Still waiting from others before I even think about bolting these up for future use.