Rear disc conversion for 1st Gen F-body: seeking experience with TRS, SSBC, Wilwood..

[stantaur]

Welcoming your wisdom, experiences & ideas for "reversible" rear-disc upgrade (incl parking brake) on our '69 Z/28 which we've taken a few reversible liberties with restoration-wise, including Hotchkis springs, Addco swaybars, Fox double-adjustable dampers, Tremec TKO600 5-speed and .640" 253/259 solid roller LT1 with Eagle reciprocating & AFR 210s.

Don't worry - no fenders were ever rolled, the DZ and M20 are tucked away in storage. We take this car for spirited drives on early weekend mornings, and all deviations from original are bolt-in/remove reversible in case the future owner wants to bring the car back to stock. Although we have 17" CCWs for decent handling, I want to retain the ability to drive our 15" Rally wheels sometimes (incl bolting on some 15" drag radials).Thus, we don't want to permanently alter the rear end.


Reasons for the upgrade vs. stock drums with semi-metallic shoes are
(1) May do some track day / DEs next year and figure some non-outrageous 11x1 discs beat the drums' performance/safety window,
(2) I prefer working on discs over drums,
(3) Having 11" discs front/rear seems more "finished" to me / more aesthetically pleasing
(4) Reasonable tradeoff of going F/R 11s with reliable 1-caliper designs for far less money (and performance, clamping force) than exotic JL8 4-piston setup.


That leaves me with the following options which I welcome inputs on plus extra ideas we may have missed somewhere:


The Right Stuff AFXRD05 kit which uses the calipers from T/A WS6, Caddy Seville/Eldo/etc., D152 pads and solid 11x1" rotors, adjusts calipers via parking brake cycling.
Economical ($370-ish) at first blush, but extra costs based on some reviews include...
Requires buying new pads since many reviews had fitment issues with shipped pads that were resolved by installing newer thinner pads) and likely getting their shortened hard-line kit for the axle.
Some installers have noted issues on backing-plate-to-bracket needing to be ground.
Requires you to adjust e-brake then bleed with caliper unbolted & tilted to put bleeder at utmost top.
Increase in track width (due to rotors being thicker than drums) btwn 1/8 to 1/4 inch per side. 1/8" I could live with, but 1/4" may require new rear wheels to get the offset just right with 275s I run back there.
https://www.summitracing.com/parts/r...rd05/overview/


SSBC A125 or W125 (anyone know the difference?) using '87-'88 T-bird Turbo Coupe calipers, D-347 pads and 10.5x1" rotors (adjusts via conventional brake pedal use)
I like this implementation (more conventional adjustment approach) but haven't seen many people using either one of these.
Unknown if their 10.5" rotor hat's cited 0.24" thickness is thinner than TRS AFXRD05's 11" rotor.
$600-$650 street pricing is higher than TRS kit - is the kit easier to install & is it more day-to-day reliable than the TRS kit? I'm willing to spend the extra money if so, and even willing to give up some rotor torque (10.5 vs. 11) if the brake feel & reliability are better.
https://ssbrakes.com/i-10092154-gm-f...tors-a125.html


SSBC A125-30 or W125-30 using proprietary billet 1-piston calipers and 11.25x1" rotors
$950-ish price is approaching my limit, proprietary caliper, unknown pad availability. If there are some people who have had good / bad experiences regarding installation, brake feel, stopping performance & day-to-day reliability, please chime in.
https://ssbrakes.com/i-10092140-rear...s-w125-30.html


Master Power Brakes Legend kit - hard to tell if it uses same parts as TRS AFXRD05 or SSBC A125 / W125 - any comments? Also open to ideas from similar kits at Matt's Classic Bowties, Pirate Jack's, etc.


Wilwood 140-11398 - 4-piston caliper, internal expanding shoe parking brake, 11" rotor. Beautiful setup, but I lean toward a stock appearance and would feel odd re-painting the calipers to match the front.


Can't afford the Baer kit (which also seems to require 16" wheel minimum), same for Brembo. Not willing to spring for JL-8 kit as I can't even find a price or supply of parts / kit. Not a big fan of CPP's body of work based on neighbor's issues with their suspension & brake parts.


Thanks in advance for additional ideas and for understanding our quirky / reversible scope. Dad bought the Z back in '69, never so much as rolled the fenders, so the next owner will have to decide whether to take it 100% original with our crate of parts, or enjoy driving what's become a very fun-to-drive car similar to the Porsche Outlaw / Petrolicious ethos. Some might consider me a heretic for not replicating yet another Barrett-Jackson garage queen - that's OK. Driving on an early weekend morning is more personally satisfying to me - to each their own.

[Gmachine1911]

Here's what I can tell you from personal experience...STAY AWAY FROM SSBC!! The only thing worse then their product is their customer service. I had their rear disc brake kit on my 68 Camaro and it was junk from day 1. Wouldn't stop, wouldn't stop rubbing, E-brake cables and brakets weren't right, etc. It got to the point where I couldn't/wouldn't drive the car out of frustration and no matter what I did, it never got better...not until I put Baer Brakes on it! Not saying you have to spend a fortune to get good brakes but shop wisely and read what others say on here and other trusted sites to be sure you get a system that's proven. Good Luck, you've got a great looking car!

[oleyeller]

I've always been happy with Right Stuff products, systems are well sorted out. Never any issues or problems.

[csouth]

I don't have direct experience, but my friend used SSBC on his 65 Impala and had to replace 2 different calipers in less than 5k. He just pulled it for some C5/6 replacements.

[JustJohn]

Have you looked at a KORE3 kit?

[F-Body International]

The WS6 backing plates can be used with a D154 Wilwood or standard G-Body caliper. This would eliminate the problematic parking brake.

Just another option...

[stantaur]

Thanks for your wisdom & guidance. I did some more digging, called TRS today and found another kit that might work. Sharing details so far & waiting on Tech dept to reply.

AFXRD13 kit fits staggered axle '69 layout, but it's not marketed on their main rear-disc swap part of the site. It's on a 14" rear disc swap part of the site. Only downside I see so far is the rotor diameter drops from 11" to 10.5" but that's OK for my usage (mostly auto-x, some twisty roads, maybe 3 track/DE events in the next 5 yrs where I'll practice mechanical empathy). OK, and the list price is 650-ish vs. 750-ish for Wilwoods (or 430ish for AFXRD05 which requires wheel changes, plus new pads, plus new axle line).

When I called, the rep said the AFXRD13 does not increase the track width 1/8" per side (as opposed to the AFXRD05 does increase track width 1/8"). That's key for me, as my existing wheel/tire combo is 275 width with no fender rolling and no rubbing. The 1/8" increase per side of the AFXRD05 setup was going to require different rear wheels to maintain my clearance / articulation.

Secondly, the AFXRD13 doesn't use the WS6 / Cadillac calipers (and their somewhat fussy-to-bleed, parking-brake-actuated adjustment approach vs. more normal adjustments done via pumping the brakes on other cars). Instead, the AFXRD13 uses the T-bird caliper. So there's still good parts availability, maybe easier bleeding, likely reduce parking brake issues.

So basically, the AFXRD13 sounds like SSBC's A125 or W125 (I still can't discern the difference btwn the two on their spec sheets), but from a company with a little better / wider reputation for customer support.

I'll report back after my call with Tech Support, re: more details on caliper confirmation, piston area, rotor width, parking brake design, method of adjusting pad-to-rotor clearance through lifecycle, etc.

[toddz69]

I just looked at the Right Stuff website and AFXRD13 shows Cadillac calipers in the picture so I'd double check to make sure that they're truly using T-Bird calipers. The T-Bird calipers (also used on Lincoln Mark VIIs and other cars), made by Varga, have always been a better choice in my mind and I've wondered why the aftermarket gravitated to the Cadillac calipers instead with all their known parking brake issues. I haven't used the Vargas but I have two Bronco friends that have used them with 35" tires and they both felt the parking brake worked pretty well on them. They aren't as common in the yards as they once were, but they can still be found and their supply is plentiful from an availability standpoint. The Master Power Brakes Legend Kit is very intriguing. I've been following their development over the past year and I think they probably are the best in terms of a hydro-mechanical caliper. I'm pretty certain they're using a late-model Mustang caliper but I'm not certain. Mustangs seem to be about the only cars left in modern times that use a caliper with a mechanically actuated parking brake. I'm also not certain what rotor they use (obviously re-drilled) so I worry sometimes about replacement 10-15 years down the road.

I like your thinking on your project - not a high-zoot pro-touring braking system but something that's better than stock with easier maintenance and still some 'cool factor' that still comes with 4 wheel discs on an older car. I'll be following along.

Todd Z.

[79 Camaro]

You might consider the 2000 Fbody rear discs. You may end up buying two sets to get the staggered caliper mounting. The internal e-brake works well.

If yo want to do some fabbing I was cleaning up our 14 Mustang GT and noticed it has a e-brake system the just clamps the rotor. No internal drum.

I have 97 Fbody rear calipers on my 68 C10. Using a Lokar brake lever I really have to lean on it to provide adequate stopping power.

[stantaur]

While I'd like to go with the AFXRD13 setup's T-bird calipers (per sales rep and tech person's calls vs. what's shown on website leveraged from AFXRD05), the $250 extra expense and similarity in track width drove me to order the AFXRD05 after confirming the AFXRD13 had the same track width increase as the '05. Reason is attached below - drums tend to be 2 to 2.5 / 16ths of an inch thick at the flange, and both setups rotors were said to be 4/16ths (1/4") of an inch. I tweaked the lighting of these pics that another person had posted elsewhere. Consistent with that the tech support and forums say about disc rotor hats being 1/4" thick.

Went with Summit with their 90 day return policy having treated me well in the past, and ordered the shortened disc brake stainless line too.

Will try installing the AFXRD05 kit and post pics this winter. If tire/fender clearance gets too tight, I may get a machine shop mill down the hat area 1/16" (leaving total of 3/16", still more than drums' 1/8").

[CarlC]

This. Tobin is great guy and has helped a ton on various projects I've worked on.

Have you looked at a KORE3 kit?

[stantaur]

Kore3's a great-looking site, but I didn't see options that allow a 15" diameter rear wheel which I use for drag radials.

Pls let me know if I've missed an Easter egg though. Here's the link I looked through: http://www.kore3.com/categories.php?cat=7