codrus

Not directly ABS, but I started putting on the rear calipers from FM today.



Goodwin rears coming off:





FM bracket going on:


New sport rear rotors. It turns out the Goodwin rears are the same dimension as the sport rotors, just lighter. Still, I can't reuse the ones I have because of the uneven wear from the smaller factory pads, and I didn't feel like buying more Wilwood rotors and aircraft bolts for attaching them right now.



New rotor on (yes, this is the other side)


Radial mount bolts on the caliper


Threadlocker is good stuff.


Hydraulic line:


The Wilwoods have an NPT thread on the back, so this adapts to AN.


Installed. Doesn't actually look all that different from the one I was using with the Goodwin brakes. I could probably have left the junction block in the car and just replaced the flex line.



Lots more pad coverage:


Now for the parking brake. Hm. This kit is new enough that mine came without instructions. Factory cable on the top, FM on the bottom. This is the end that goes on the parking brake side (I think). Question is, what's the spacer for?



Caliper end of the cable (sorry, lousy picture). I think there ought to be a pin that goes in the clevis on the end of the cable and attaches it to the parking brake lever, but I don't have one.



I need yet more brake fluid to finish flushing it (gone through three quarts in the last month), so it's on hold pending that and some input from Keith @ FM regarding the clevis.

--Ian

codrus

I poked at it some more. I had the cable ends oriented properly, and I managed to get them attached at the parking brake handle end, using the washers on the inside of the sheet metal mount, and the pac-man spacers on the ouside.



Accessing the back of this mount is a pain, but there's a small shield you can loosen (it won't come off without removing the PPF) enough to reach in with fingertips.



FM supplies clamps to hold the parking brake cable out of the way, but the holes are too small to mount them where the factory cables go. Zip ties to the rescue.



And I definitely need some kind of clevis pin here. Zip ties to the rescue again, although I'm not going to use this for more than going up and down the driveway.



My overall impressions so far is that I really need to bleed the system better, and the parking brake is very weak, and won't even hold the car on the driveway. Hopefully proper clevis pins and some adjusting will help that.

--Ian

codrus

I heard from Keith @ FM today, turns out that I had the cables installed wrong (the washers go on the front of the sheet metal, the big pac-man spacer thingeys on the back), and the clevis just uses a 6mm bolt & nut that somehow got left out of my kit.

--Ian

arbinshire

I would definitely like to know more about the parking brake functionality once you get that all done.

codrus

I installed some 6mm bolts & nuts from the hardware store in the clevis, once that was in place and the pads were properly bedded (I substituted some BP-20 pads for the E compound that FM supplied) the parking brake started working a lot better. As FM says, it's definitely weaker than stock and not good for handbrake turns, but it will hold the car on my driveway.

Driving home from work today, the ABS light came on. Cycling power would make it go off again, but after another 30-60 seconds of driving it would come back on. Got home and checked the codes, it flashes "5" <long pause> "5" <long pause> "5", etc. That's different than what it flashed before, but I still have no idea what it means.

The fuses are fine, and it doesn't turn on the brake light along with the ABS light (which is what it does if it's lost power in any of the power lines). That suggests it's either an intermittent internal problem with the hydraulic unit, or a bad connection in one of the ABS sensors. Since I crimped those wires together myself, Occam's Razor suggests the latter is most likely.

Unfortunately, it appears to be an intermittent loose connection, because I couldn't reproduce it in the garage, up on jackstands, with the 'scope looking at the sensor outputs. So I either need to recrimp everything (ugh), wait til it becomes non-intermittent, or hook up that other diagnostic wire to the OBD2 connector and see if I can find a shop with the Mazda scantool who's willing to try to scan my bastardized ABS system for codes.

--Ian

Reverant

iTrader: (10)

Brake switch.

codrus

You mean the signal coming from the brake pedal to say that the brakes are on?

I thought about that one (it's the only other input to the ABS system) but when the intermittent failures happen they don't seem to correlate with whether or not the brakes are active. Sometimes it happens while braking, other times while just driving down the street. It's never happened while stopped, however.

I'm also not sure how the ABS unit would know if it was getting a bad signal from the brake switch vs just a driver who's being spastic on the brake pedal?

--Ian

Reverant

iTrader: (10)

The ABS knows the wheel speeds. If they start slowing down faster than say, coasting would, and its not seeing a brake pedal signal, guess what.

Laur3ns

I dont buy that. Id say a sensor. Not sure on the code tho...

codrus

Well, I drove it to work and back today, 30 miles round trip, and no ABS lights. Since I didn't do anything to the sensors or the wires thereof, I'm thinking maybe the problem was corrosion on the contacts in the ABS connector from sitting on the bench for a year or so. Any suggestions on the best way to clean them?

--Ian

NiklasFalk

iTrader: (1)

Not on cleaning, but a dab of Vaseline on the contacts before putting the cleaned ones together will prevent corrosion close to forever.

GraemeD

iTrader: (1)

Product called "deOxit" , we use it for aviation connectors.
DeoxIT® D-Series

codrus

So in the ongoing quest to try to fix the mushy brake pedal feel after transplanting the ABS, a friend and I did a bunch more poking at it today.

The good news, is that I figured out how to engage the ABS pump in a diagnostic procedure while sitting on the jackstands. If you look in the shop manual PDF that's linked in the sticky links section as a "1999-2001 shop manual" (it's actually a 99-00, not 2001), it calls out a few things.

So the first thing is that the diag procedure won't run if there are codes in the ABS computer. To clear them, you ground the TBS wire and turn the car on without hitting the brake pedal. Let it flash the codes at you on the ABS light, then tap the brake pedal 10 times at a rate of more than once a second. When they clear it will turn the brake light on, and you'll hear the relays in the ABS unit click. Turn it off, then turn it back on, and it shouldn't flash the ABS light at all. This is on page 04-01-4 in the shop manual above.

After that, the diag procedure will run. You keep the TBS wire grounded and key it on with your foot on the brake pedal, and it will engage the pump and cycle the solenoids for each of the three channels in turn. It's not subtle, it's really really obvious when it happens. This is on page 04-13-1.

Once I could reliably do this, I cycled the ABS while bleeding each of the three channels to try to get any bubbles out of the hydraulic unit and into the lines where I could bleed them out. Then I flushed a bunch of fluid through each of the calipers in a standard bleed sequence, and repeated all of this twice. While doing this, the ABS unit would set a code every so often and need to be cleared again. The code was 5 blinks -- perhaps that's 05, which is a "brake switch open or short", according to the code list on 04-01-5.

The bad news is it that all this bleeding still didn't really help the pedal feel, it's still mushy.

--Ian

codrus

A couple updates. The ABS error code was, in fact, indicating a problem with the brake pedal switch. I re-crimped it and the spontaneous error codes have gone away, yay.

I got frustrated with the brake situation and sought professional help, taking it to a local race shop (well known and well regarded for setting up Spec Miatas and various BMWs). They bled it multiple times and concluded that there was no air in the system, but that the pedal was still sucky. They recommended upgrading to a 1" master cylinder, so I bought a 929 master from rock auto:



Installed, the mushiness is largely fixed, although there's still some slack in the top of the pedal travel that probably means I need to adjust the pushrod. The effort is definitely higher, but it's a significant improvement.

So, my takeaway from this is to suggest that if you're going to use Wilwood front & rear, you probably want a 1" master.

--Ian

OGRacing

iTrader: (1)

Not to bring you down after all your hard work... But. oem ABS units are very hard on braking components during track driving. you're getting a rotor up to thermal capacity than playing patty cakes on them. i've seen allot of rotor failures due to OEM ABS systems. The Pros use a bosch ABS system. it regulates line pressure and not no-off-no-off-no-off like you see on a OEM abs unit. just trying to help.

Leafy

iTrader: (1)

But but but, the ABS is so glorious, other miata people freak out when sitting in the right seat because I'm not going to make it, then I just push the pedal as hard as I can and it stops. Aint nobody got 10k for the bosch abs. What is weird is that there's a lot of pedal pressure required after you can hear the front tires abs working where it still slows down harder and I've done just about everything possible besides changing brake component size to fix that. Parts store pads in the front and hp+ in the rear on 1.8 brakes with 01+ MSM abs. Its very odd.

But yeah it seems kind of tough on components. I can get wheel and hub temps way above 212°F at just auto-x at both ends of the car with it. I dont have a real number but I spay the wheel with the tire sprayer to help get more heat out of the tire and on some courses spraying the wheel center creates instant steam. I used to only get this effect on the most hard braking of course and only in the front brakes before ABS.

codrus

First off, the point is not to engage ABS at every corner on the track, it's to provide a safety net to cut down on the number of expensive flatspotted race tires.

Secondly, in my case said flatspotted race tires primarily happen at autox, not on big tracks, because that's where I use Hoosiers (lightweight tires, a lot easier to lock up) and it's where I'm pushing harder to get times (vs "fun", non-competitive track days). Yes, the photo at the start is of RA1s -- I initially flatspotted those tires doing phase 1/2 of the Evo autox school (48 runs over 2 days, which would be close to the entire useful life of a set of A6s if I had run those). Once the flatspot was created, running them at Laguna finished them off.

Thirdly, there's no way that ABS adds substantially more heat to the rotors during a braking event than threshold braking does. It's basic physics -- the heat comes from using friction to turn the kinetic energy of the car into thermal energy in the rotors. You don't magically get more heat by pulsing the brakes on and off. You could potentially deliver more heat cycles (if the ABS system were PWMing the brakes), except that since ABS stopping distances are within a few feet of threshold braking distances the amount of "off" time in any possible PWM cycle is so small that I'd have a hard time believing it's significant.

Finally, even a street ABS system is not binary. It acts by reducing pressure to a lower value, not by cutting it to zero.

Is a race ABS system better than a street one? Absolutely. To start with, it would be 4-channel instead of 3, and would use technology newer than the at-least-15-year-old tech that was in a 2003 Miata. The software is the big difference -- a race ABS system is not going to have ice mode, would be expected to be used with race tire capable of generating much higher braking loads, and probably includes some tuning parameters to set it up for different car configurations.

It would also, as Leafy points out, cost over $10K, vs the few hundred it cost to put this 2003 system in my car.

Please don't crap in my build thread.

--Ian

OGRacing

iTrader: (1)

Ian,
I am sorry for crapping on your thread. that isn't my intent. i was no insisting that ABS introduces more heat. you're absolutely correct on the fact. I was stating that when your rotor is reaching thermal capacity (at the end of a long braking zone when your abs will come on) the rotor is at it's weakest point. At that rotor's thermal capacity introduce a pulse of 100% pressure and alternate that with 0%. that rotor is taking a pounding. Not to mention the pad takes the force too. We at OG have seen many brake failures due to stock ABS systems. Sometimes it's just a cracked rotor, sometimes it's a car that lost its brake pads. Both situations can cause a severe amount of damage or death.

That being said for Auto-X you're not going to find thermal capacity. The runs are so short the rotor doesn't have time to get near the heightened temperatures. Yes it will help you prevent flat spots on those expensive hoosiers. Also at a track in the rain will have similar Experience, and ABS will be a help.

For dry days on track it would behove you to have a Kill switch for the system.

codrus

Have you datalogged the braking gees before/after adding ABS?

--Ian

codrus

And yes, I have the power line for the ABS electronics attached to the cruise control switch (after melting the CC at a track day I didn't bother to reinstall it, so the switch was going spare).

--Ian