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Index > @ the Pickup Bed (General Topics) > Thread: Anyone looking for a 6-lug big brake kit?
Thread: Anyone looking for a 6-lug big brake kit? [' This thread is 2 pages long: (1) 2 ']
crit


Revvin Up
Finally REPUing
Posts: 90
posted October 14, 2011 11:44 PM

Anyone looking for a 6-lug big brake kit?

I'm in the final stages of fitting my big brake kit on my truck, with some carefully selected front and rear discs and custom front hubs that keep the 6-lug pattern. I was surprised how much the hubs cost me, but the two shops that have spent some good time on it with me both tell me that the price would be much lower in Qty 10 or higher (5 pair or more). I'm not sure if there are 5 guys out there looking for 6-lug brakes or not, since there's just so few of the trucks left. The front brakes will just barely fit under some 15in wheels and clear 16s pretty easily. The hub faces are approx. 1/4" closer to the vehicle centerline, so it tucks the front wheels in a little in an effort to combat the goofy look of having narrower front fender flares than rear.

The front rotors are vented 280mm x 26mm wide. Rears are 265mm x 12mm wide with the parking brake built into the caliper (no inner drum setup)

If you're interested, please post in this thread and indicate if you're curious, window shopping, or seriously interested.

Thanks guys,
Crit
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77 REPU
84 GSL-SE

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dhood


Hauling
Posts: 134
posted October 15, 2011 11:02 AM

I'm pretty much done with the stock brakes, and most of my spares are worn out too, so I am definitely interested. Would like to know the cost and degree of difficulty switching over before committing. Is it all bolt on, or welding required, or body modifications? And what city are you in since I suppose you would be shipping some parts to me here in Sacramento.

       
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Vin


1st Gear
Posts: 17
posted October 15, 2011 12:31 PM

im interested. How much?
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75 repu

       
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spokanerxdude


Hauling
Less cubes... More balls
Posts: 181
posted October 15, 2011 01:16 PM

Everything is dependent on the Price. Last time I called it was $700ish just for the rear.
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Allen Ervin, spokanerxdude@yahoo.com
509-998-9024

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dhood


Hauling
Posts: 134
posted October 15, 2011 06:25 PM

Does that include the group discount, rotors, calipers and hydrualic modifications? I don't think anyone is going to commit unless they get the whole price. Why get started and then find out its 2k to finish?

       
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crit


Revvin Up
Finally REPUing
Posts: 90
posted October 15, 2011 08:24 PM

I'm doing this on my own, and will finish the setup regardless. I just wanted to share with you guys what I've been up to. The front hubs will reuse the inner and outer bearings and wheel seal. The grease cap will be new, as will the custom hub. The front rotors come from a 93+ Isuzu Rodeo - the rear come from a 91-ish Trooper. The front rotors are $12 ea. on clearance at rockauto.com, so I snatched up a pair. The hubs cost me $520 for the pair without any quantity discount, so you then add bearings and seals (if you want new) plus fasteners, studs, etc. The caliper brackets front and rear are neutral offset, so they're just waterjetted flat plate - nothing expensive there.

I'm not done with the fitment, but it looks like I'll need to grind the front side of the two forward bosses on the spindle in order to make room for the big caliper. If anyone would prefer not to grind the spindle, I can push the caliper about 5mm further out so it would be entirely bolt-on, but the tops of the pads would be off the rotor, so they might wear funny.

The rears will be super-cheap, as it's nothing but a caliper, rotor, bracket and hardware on each side, though I still don't have the parking brake cables sorted. That shouldn't be tough, though.

The fronts are where there's some real cost because of the new hubs, but the bracket, caliper and rotor are all pretty cheap as those parts go. The Isuzu hardware is cheap, beefy, and the same hole pattern, which means that the rear is nothing more than a slip-over rotor.

I'll provide you guys more details as I finish, but it looks like I've got a pretty solid workaround for our brakes that were built in a world of 55mph speed limits and wimpy brakes because of it.
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84 GSL-SE

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dhood


Hauling
Posts: 134
posted October 16, 2011 09:18 AM

Ok, sounds good. So all I need is the quantity discount price for the front hubs when you get enough orders. Thanks for all the info and great ideas.

       
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crit


Revvin Up
Finally REPUing
Posts: 90
posted October 16, 2011 11:52 AM
Edited By: crit on 16 Oct 2011 11:57

Once everything's worked out, I think it would make the most sense for me to send hubs, studs, hardware, grease cap and caliper brackets as a kit that can ship in a flat-rate box on the cheap. Everyone could then choose junkyard or reman calipers, pads, regular or fancy slotted/drilled rotors for themselves.

I will also include a Bill of Materials and exploded views of the front and rear, using the SolidWorks models I've built.

The biggest unknown now is the price of the hubs, but I think I'll initially get another batch quoted in quantity of 5 pair for the first lot.

My truck's off for paint, so I can't verify that everything fits and find a solution until it's back in my hands, but I'll post pics once it's ready.











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77 REPU
84 GSL-SE

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paulsrepu


Hauling
Posts: 107
posted October 16, 2011 07:58 PM

I would definately be interested in this setup depending on the total cost of the custom parts. I would think you would need to change the master cylinder since the original one is set up for disk/drum. Then I imagine adaptors will be needed for the brake lines unless the Izuzu parts use the coarse thread pitch fittings. I want to do track day events with this truck again, and previously it was only good for about 5 or 6 laps before brake fade was becoming an issue.

Paul

       
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Brad


Rotorhead
Posts: 1672
posted October 17, 2011 11:10 AM

Thanks for doing the legwork on this Crit. It looks like a great start but I'd like to see it installed and test driven before I can commit. Thanks for keeping it 6 lug. Does each hub tuck in 1/4", making for 1/2" total narrower track width?

I just replaced the front rotors and pads on my 99 Amigo (which use the same front rotors as 93 Rodeo) and can attest how they are beefy and durable. And easy to work on. Porterfield makes a performance pad in R4S compound for it, listed under Honda Passport which is a rebadged Rodeo.

Front rotors, caliper and brackets are the same 93-01 Rodeo, Amigo or Rodeo Sport.

Paul is right, if you change from drum to disc you have to install a disc master cylinder because drum m/c's keep residual pressure in the line when your foot is off the brake pedal. Do that with a caliper and it'll drag the brakes. I've seen late model Rodeo/Amigo brake M/C installed on 1st gen Rx7's with big brake kits so that may be the way to go.

I'd prefer not to grind the spindle boss if possible. The bracket could be milled down if it's thick enough.

Thanks for the drawings!
____________
-brad-
74 REPU Lawn Green
81 Rx-7 racecar. 12a J-
Bridge

       
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Brad


Rotorhead
Posts: 1672
posted October 17, 2011 11:14 AM

rockauto shows REPU and Isuzu use the same inlet and bleeder thread.

       
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dhood


Hauling
Posts: 134
posted October 17, 2011 12:37 PM

Some of those parts databases are not very accurate when it comes to the REPU. My 77 REPU has a different inlet thread than the prior years, so I changed everything over to a 75. If I remember without going out back to look, it is a banjo fitting.

       
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crit


Revvin Up
Finally REPUing
Posts: 90
posted October 17, 2011 05:38 PM

If you look at the second-to-last screenshot you can see that the new aluminum-colored hub in the background is a little over 1/4" inboard (per side) vs the original REPU hub face in the foreground. In order to let the rotor run so close to the spindle, the caliper bracket is moved inboard, which also spaces the steering knuckle in just a hair.

The hub face doesn't have to move, and it wouldn't be any trouble to make some hubs with thicker faces for those that want to keep their front track where it is.

If I keep the pads fully on the rotor, it pushes the blue Isuzu caliper mount into the spindle bosses. The model pictured has the pads off the rotor by 5mm. If we go with the tighter caliper bracket, Brad, you could grind your caliper bracket while I grind my spindle.

Regarding the master, is it not possible to just remove the drum pressure check valve? Aren't they usually just pressed into the bore under the fitting?
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crit


Revvin Up
Finally REPUing
Posts: 90
posted October 17, 2011 11:28 PM

I just got done updating everything and measuring the offset on the hub faces. With the hub flange at its current thickness, I gain 0.406" per side (call it 3/8") for an overall narrower front track of about 3/4".
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84 GSL-SE

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Rotarywall


1st Gear
Posts: 17
posted October 18, 2011 09:06 AM

I would be interested in this setup as i was already looking into it myself. I was told to look at the B2000 for front brakesthat they were a direct bolt on spindle and all, but this setup looks much better. I would prefer not to grind the spindle. Thanks for getting this project goin.

       
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fliboyz6


Revvin Up
great
Posts: 72
posted October 22, 2011 05:20 PM

Absolutely a beautiful piece of R&D I'm down for a set just let me know where and when I need to send the money.... just a couple questions is the front caliper 1 or 2 pistons... and does the factory emergency cable setup still work

       
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crit


Revvin Up
Finally REPUing
Posts: 90
posted October 24, 2011 03:00 AM
Edited By: crit on 24 Oct 2011 03:06

I looked at multi-piston calipers, but it just won't work. Dual single-sided pistons won't fit on the front inboard side because of the intrusion of the top of the spindle. A single piston on each side won't fit because of the offset of the spindle from the ball joints. Our spindles push the rotor face so far outboard that there's no room for both an outboard piston and reasonable wheel fitment. Basically, all the 6-lug donor vehicles I could find are 4WD with wheels that slip over manual hubs, at least as an option. In order to run an outer piston, we'd need a FWD wheel with a ton of offset, which just doesn't exist. I tried everything I could, but single piston is the only setup I could make work.

If one goes 5-lug, they can slip a spacer over the root of the spindle to run a bigger inner bearing and put T2 rotors and calipers up front with a FWD wheel (you CAN get FWD 5 on 4.5" wheels) but I didn't want to go 5-lug, plus we'd have to redrill the axles.

I've sent my hubs back to be remachined (not enough relief under the heads of the studs - oversight on my end) and should have them back this week. I can finish mocking up the front brake and verifying that it all clears the wheel like I expect, but can't mount anything for real until I get my truck back from the body shop.

I'm not sure what the parking brake setup will look like. The Isuzu rear calipers have a fork for the parking brake that requires a shoulder screw to be passed through it as a pin - much different from the REPU stock cable ends. I'll look at different wheelbase options on the P'up, Rodeo and Trooper to see if one of the three is a good donor for cables that are close to the right length.
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Brad


Rotorhead
Posts: 1672
posted October 25, 2011 12:34 PM

quote:
If you look at the second-to-last screenshot you can see that the new aluminum-colored hub in the background is a little over 1/4" inboard (per side) vs the original REPU hub face in the foreground. In order to let the rotor run so close to the spindle, the caliper bracket is moved inboard, which also spaces the steering knuckle in just a hair.

I see what you're saying.

quote:
The hub face doesn't have to move, and it wouldn't be any trouble to make some hubs with thicker faces for those that want to keep their front track where it is.

That's a good idea. My wide tires rub on the front sway bar.

quote:
If I keep the pads fully on the rotor, it pushes the blue Isuzu caliper mount into the spindle bosses. The model pictured has the pads off the rotor by 5mm. If we go with the tighter caliper bracket, Brad, you could grind your caliper bracket while I grind my spindle.

We definitely want the entire pad to be contacting the rotor surface.

quote:
Regarding the master, is it not possible to just remove the drum pressure check valve? Aren't they usually just pressed into the bore under the fitting?

Good point, never tried that. But also keep in mind as pads wear the caliper piston is moved outward which draws more brake fluid from the master. So the fluid reservoir needs to be larger for the rear hydraulics. Wheel cylinder pistons are much smaller.

quote:
I looked at multi-piston calipers, but it just won't work.

In all honesty the single piston slider caliper will work just fine for us. I don't even want or need a multi-piston deal and I autocross and drive it harder than most here. It's a truck, afterall. There are advantages but it's just not worth the effort IMHO. The Isuzu calipers brake hard and get the job done quite nicely. They're for a SUV that weighs 1000lbs more, are cheap and readily available. And easier to put the caliper back on compared to messing with the T2 springs.

Can't wait to see it.
____________
-brad-
74 REPU Lawn Green
81 Rx-7 racecar. 12a J-
Bridge

       
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fliboyz6


Revvin Up
great
Posts: 72
posted October 25, 2011 07:44 PM

I was at the local wrecking yard looking at vehicles that use the same thickness rotors as well as two piston where the pistons are both on the in side and there are several options ... but the one that I've been looking into the most are off late model crown Victoria's and the reasons I was thinking this model was the caliper mounts torwed the front of the vehicle so they wouldn't conflict with the steering... and only run around $70 brand new... it's just a thought regardless. I will be buying a kit cause there just plain awesome

       
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remydrm


Revvin Up
Posts: 92
posted December 22, 2011 01:58 PM


I'm interested. How far are you with this kit?

Any option to replace the rear with a disk kit?

       
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