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Discussion Starter · #1 ·
I'm in the process of doing a complete steering, suspension, wheel bearing job on one of the Princesses. It currently has "Bubba's brakes" custom "disc brake conversion" which abuses and misuses 1990(ish) Chevy K1500 front brake calipers and pins. The brackets are horrible, held on by only two 3/8" bolts. All of the braking force is carried from the caliper to the bracket through the slider pins (loading them in sheer), and to the knuckle through sheer loads on those two 3/8" mounting bolts. We're constantly stripping the threads or breaking the slider pins off on these cars. We need something much safer.

Pictured is one of the two cars that need these new brakes.

The parameters are a bit weird on this one. It has six lug wheels, so a six lug rotor would be preferred. I'm probably going to have to re-drill anything and open the center bore on the rotors. This one is 6x6-1/2" lug pattern, with a huge center bore (over 4-3/4", I need to get an exact measurement).

We have 16" steel wheels, and we're not changing wheels under any circumstances. So the brakes have to clear a 16" wheel.

Oh, and this rig weighs in at 6,000 pounds or so fully loaded, so we need something "truck-ish" for the weight.

I'm looking at the 2005 and up (through 2022 at least) Tacoma 6 lug front brakes. The rotors are ~320mm+/- depending on which brand you get, and the early Tacomas with these 6 lug setups had factory 16" alloy wheels. The calipers are 4 piston fixed calipers (not floaters), with 1.78" pistons. It looks like the caliper frame itself is the "pad stop" that transfers braking force to the suspension. I'll have to look at one in the local pull it yourself yard to see exactly how the caliper itself is "captive" in it's mounting system to transfer braking force without loading the mounting bolts in sheer. This is my biggest concern with a lot of "disc brake conversion kits," especially the ones that use GM calipers designed for vehicles with pad stop features not part of the caliper itself (like the early full size truck ones, and the S10/Blazer "metric" calipers). All to often, these retrofit kits designed to fit GM stuff on non-GM cars abuse the slider pins and do not provide a safe path for the braking forces from the pads to the suspension.

It also looks like some "Severe duty ceramic" pad choices are available for these calipers as well, which is a positive for this setup.

My only concern is our master cylinder. I think we have 1-1/8" in there now. The Toyota Tacoma uses 1-3/8", and I think these may need an upgrade to at least 1-1/4" or maybe 1-5/16" master cylinder. I'm going to be checking on that.

Has anyone ever used these brakes on a "hot rod" project or for a "disc brake conversion" on an older all drum car?

Any input and ideas welcome.

Oh, and other brakes I'm somewhat considering are the Hummer H3 front brakes, and some of the Nissan truck (and SUV) front brakes which fit under 16" wheels. Nothing looks as widely available and as good a fit as the Tacoma setup so far.
 

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Discussion Starter · #3 ·
Don't forget second-gen Dodge Dakotas (96+) have 6 lug discs...

Russ
Thanks. I wasn't aware of those. For this application, those rotors are tiny. I'm not sure the hat will even clear our hubs. And I really want the rotor to be over 12" in diameter.

Plus, those Dodge calipers look similar to the GM ones, and look like they require special bracketry to hold the caliper in place against the braking forces. I really don't want to be making brackets that extend past the outer edge of the rotor and back out past the rotor center line for a "caliper stop" feature. And I don't want to abuse the slider pins by using them for the braking forces.
 

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Not knowing of or ever having seen the front-end on one of these, it might be easier to adapt the entire front spindle onto your existing a-arms.

Russ
 

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Just because your dealing with the same diameter rim does not mean the calipers will work. I been burnt by this in the past with break swaps. You need to take offset into account or you will find the rim hits the caliper at that last 1/2" from laying flat.

Single piston sliding "GM" calipers are actually very reliable. If your having issues with pins bending the mounting bracket is probally installed wrong crooked or has a lack of bracing letting that bracket be bent. This will cause the pads to hit the rotor unevenly and pull the caliper. It is easy to check (caliper) by looking at the pads and finding them worn at a slight angle instead of flat.

Single piston GM calipers come in several sizes from 2000lb cars all the way up to (some) c50 trucks.

For driving on the street it is no secret drums do a better job. Depending on what axle you have going back to drums may be a better choice. Otherwise I would look at the mounting bracket upgrading the bracket and the gussets. There are some cheap kits out. I am with you on the possible issue with 2 bolts holding on the bracket and would throw down a few welds(after confirming it is straight) or just go with a weld on setup from the start.

Look closer at your brackets and pads before throwing the whole setup out. You may replace it with a a setup that is still crooked via what your bolting it to being crooked.
 

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If your wheel bolt pattern is indeed 6.5" I don't think there is enough room to redrill to a 6.5" pattern on that rotor. You would be better off to use a 6.5" by 8 lug rotor and redrill it. 2007 silverado 2500 HD rotor meets most of you parameters and uses a floating caliper with a solid mounted caliper bracket. The rotor ID is slightly smaller than your hub pilot so one or the other can be machined to match.
 
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