DIY front brakes

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itawolf
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DIY front brakes

Post by itawolf » Thu Jun 22, 2017 11:54 pm

If I Rem correct s1 did a front brake conv to rx7 calipers

I have cb front disks on my 69 pan
Balljoints

Rear already with golf caliper setup

Hate the small pads
Looking for different setups
As I have access to a junk yard and a Napa store
And have a wreaked 84 rx7

What other setup can I go with

I Rem on some site a list of possible calipers to use


Anyone Rem?

Camper??
Pile?

It's been a few years and now I'm back at it again
Trying to get my Jan 1960 bug up n going

I know I can buy willwood etc etc

Thanks
Semper Fi

Ita
RET Marine 0317 --with VW on the lobe!!
Lots of iron in the fire

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Piledriver
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Re: DIY front brakes

Post by Piledriver » Fri Jun 23, 2017 1:21 am

I have a set of MK2 RX7 turbo calipers, big finned cast aluminum jobs... Collecting dust.
They look badass. Huge. Very heavy, easily twice the weight of equivalent Wilwoods with pads.

Too huge, actually, and I say that while running (used, I rebuilt) Wilwood Superlights on 1.25" rotors up front 80 miles a day in traffic full of idiots. They get tested, frequently.
The RX7 calipers may eventually get used on my 914, as it has far more weigh on the front.

The 914, 924/944 or RX7 probably have close to 50/50 static weight distribution, which translates to ~80% front bias under max braking.
That is not remotely like a T1/T3 or Ghias weight or ideal brake bias distribution, esp. if your car is lowered at all.

With a ACVWs weight distribution you really need about a 50/50 front rear balance at max braking, maybe 55/45 F/R.
(more rear bias the lower you go, plus if you have rear bias adjuster you have to have enough rear brakes to need turning down, which means ~50/50 on a car with a 35/65% weight distribution)

If you are going to run 4 pots up front, keep the piston sizes down to 1.38" or smaller, or the common rears with parking brakes like off a Mk4 golf/jetta (38mmx2 piston effectively) are never going to be large enough to make for a decent brake bias.
Mine are 4x 1.25 front, and I'm using front 944T brakes out back, which are only a little smaller, 32x2+28x2.
With my squareback, the online calculator shows that to be a 54% front bias, which is just about right at 1G braking.
It's just about perfect with a slightly lowered car with fat sticky tires. A bug is lighter up front and overall, but a little taller.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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itawolf
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Re: DIY front brakes

Post by itawolf » Fri Jun 23, 2017 11:24 am

Thanks for quick reply Pile!!

well put...a lot to think about for me
95% of my driving will be hwy---36miles one way to work and I'm 200yards off the exit
the ole z71 sucks gas and I have that excuse to get my bug up an running again
of course its still subie power ---with radiator now going up front
with the old setup(cb disk setup) if I didn't feather the gas and hit any kind of bump or wave in the road the rear would step out some
plus not to sure on tiny pads up front with the added weight nor do I want to be replacing pads more often

Golf setup in the back really helped back in the day

I guess I just really want a bigger pad setup --up front
RET Marine 0317 --with VW on the lobe!!
Lots of iron in the fire

vwo60
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Re: DIY front brakes

Post by vwo60 » Sun Jun 25, 2017 4:10 am

I made the brake conversion using RX7 series 5 calipers, I have the CAD drawing for the hubs and mounting brackets, i used 20 mm thick rotors from a Nissan patrol, machined a complete from hub from billet T6 and made the caliper brackets fro 12mm plate steels, all engineered and approved for road use in Australia by an automotive mechanical engineer, they have now been on the car for 10 years with no issues, On my Ghia i have a set of Kerscher vented front rotors 20 mm thick that appear to have the same dimensions as my billet items, if these were within a small difference they could be use with the Mazda calipers by only making the caliper brackets, I even have a template for the caliper brackets.

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Piledriver
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Re: DIY front brakes

Post by Piledriver » Sun Jun 25, 2017 4:25 am

The pads are huge on the RX7 calipers or Wilwood Superlites, on the SL the pads are 20mm thick each and almost half the final weight of the caliper... Still lighter than the stock units, or break even depending on the exact set you have.

The really light (and cheap) Willwood Dynalites have smaller pads but still probably 2-3X stock size, the smallest set have 1.380" pistons, and can be had to fit VW rotors, with off-the-shelf (commercially made) brackets.

The Wilwood Superlites and a few other flavors have piston options down to 1.1", I just happened to get a nice 1.25" piston almost new pair for $160, so 1.25" rotor... ~Same weight/cost rotor as the .81", or in the noise.
(but Superlights only come in 1.25" or .81", no .380", the Dynalites come in many widths, using different bridge spacers)

Get the "bridge bolt" version if you can, or just buy the kit, makes the calipers stiffer, but takes slightly different pads or mod the std ones to fit.

CB also makes aluminum hub/rotors in 5x130 that directly replace the stock bits.
(part of a kit that has ~stock calipers, but they will sell just the hubs and rotors, BJ or linkpin/combo spindle)

One can also toss the supplied CB rotor and very likely add a few holes to take a Wilwood rotor adapter on the back if you want vented rotors.

Just try to avoid the huge caliper pistons on the front of a Bug, harder to do the F/R bias right.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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