I probably didn't articulate it very well in my post but I've just seen Alum caliper brackets fail at the threaded interface and bolts/brackets were coated to fight corrosion. If you have room to put a nut and bolt then great. Yes the easy to get 3 series SS are 1/2 the strenght of most aircraft grade T6 or T7 aluminium but 17-4 and 15-5 SS are over twice the strength of the nicest alum and do well in corrosive enviroments. Yes it will cost more but it also eliminates any possibility of failure.
17-4 and 15-5 PH are both nice alloys, but they're an order of magnitude more expensive than aluminum. And the important point is that all this stuff is bolted to a lightly painted cast steel upright. It's just overkill beyond overkill, and few people will pay for that level of overkill. For reference, the cost of the brackets would go from somewhere in the ~$150ish range to ~$350ish when made out of 17-4 PH, because not only is the material way more expensive, but it's much tougher on cutting tools and slower to machine than the usual 2024-T3 I use when I have a choice.
Brembo calipers and stock Audi calipers use pins that are threaded at one end to hold the pads in and nearly every Alum caliper I've seen has a steel bleeder bolt. Anything that i've touched with 5 years or more on them have given me problems with removing threads during dissassembly. You are correct though I have no experience with Wilwood calipers.
The bridge bolt goes through an anodized aluminum tube that retains the pads, and the pads ride on stainless steel wear shims. The bridge bolt is held with a steel nut, and it's all replaceable, but I don't see how it can ever have a problem.
The bleeder screw is threaded into a brass housing that threads into the caliper, so no corrosion issues whatsoever there. Both of those pieces are user replaceable as well, but the brass essentially kills the potential for galvanic corrosion.
In many ways they're nicer than many OEM calipers, but still affordable.
Pic for reference:
This was directed at a few posts that talked about brake upgrades and how people over look doing this, one even called it a BBK and it had nothing to do with your posts.
I think it's a common term for a brake upgrade, but I'm pretty sure everybody here knows what I'm proposing. The stock rotor diameter is sufficient IMO, and I'd like to make it easy to go between 4th gen and 5th gen rotors for those that feel they need a little more rotor heat capacity.
No need to apologize as I challenged the design based on the limited information given. If anything I hope I helped you with your designs both for the 4runner and any other applications by giving you some of my perspective with some of the failures I've seen with brake upgrades on other applications.
I don't mind some friendly discussion, but I am an engineer as well (worked in aerospace myself for many years), and I do non-linear FEA and structural design for subsea equipment now. So I'm familiar with how to make a successful mechanical design, as well as reasonably prevent corrosion.
Most of your concerns are the very things I don't like about using OEM based calipers, so I agree with you on those points. The Wilwoods solve them all in my experience, and I've never had any issues at all with mine.
