Big Brake upgrade - Dose it matter where the caliper is

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Turbo047
Posts: 93
Joined: Thu Apr 19, 2012 8:45 pm

Big Brake upgrade - Dose it matter where the caliper is

Post by Turbo047 »

Just a question to get my head straight,

I bought a Brake upgrade 3 years ago, but never fitted it. (Holden Commonwhore VT discs and callipers) They are on green struts.

It wasn't until the other day with the standard brakes I nearly rear ended some fool that stopped at a roundabout when he shouldn't have, I hit the brakes and they were lacking!

So I thought it was time to upgrade the brakes. When I fitted them, the calliper fouled on the steering ball joint. So I spun them around 180 so the calliper is at the front of the car.

Do you think that having the calliper facing forward instead of on the rear would make any difference?
"Just remember, if you aren't forced induced, then you aren't SH#T"
GH Sigma Turbo no. 047

Leyland P76 V8 (next for resto)
Jaguar XJ8 Sport (british racing green of course)
Land Rover Discovery II V8 (the daily drive)
geezer101
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Location: adelaide (SA)

Re: Big Brake upgrade - Dose it matter where the caliper is

Post by geezer101 »

It will make a very minor diference. As long as the brake hose doesn't strike anything and the bleeder nipple is facing upwards it will work normally. The only issue with using the commodore brake upgrade may be how the master cylinder reacts with supplying hydraulic load to the front brakes - change in bias, how long it takes to bite the brake disc etc. Post a pic for us if you can so we can see how this set up goes together :)
Scorpma82
Sigma-Galant Police (Global Mod)
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Re: Big Brake upgrade - Dose it matter where the caliper is

Post by Scorpma82 »

geezer is right....(assuming ur running the factory master cylinder)....it's simply not big enough (by a long way)
ur running a 7/8" cylinder where the VT commodores run 31.75mm/28.??mm
the original cylinder is simply not supplying enough fluid to the calipers


Adjustable brake bias wont fix the problem, only mask it...but to help you out, (PBR part no. P10050) will help you out with the biasing issue as it has a far higher crackpoint psi than the sigma version

The best way to solve the problem is to revert back to VP-VS single piston calipers...ur pedal travel will go back to normal (if anything, it will stiffen up a lil bit)

hopefully this helps you out a bit
Built with pride, Driven in anger
Turbo047
Posts: 93
Joined: Thu Apr 19, 2012 8:45 pm

Re: Big Brake upgrade - Dose it matter where the caliper is

Post by Turbo047 »

Yep I know about the master cylinder not being up to the task so I'll be fitting a VT Booster and Master. It will make it so much easier to find parts.

I fitted up the brakes with the calliper at the front and don't like it. I have to buy new hoses and adjust the strut mount from horizontal to vertical. It will be much easier to remake the adapter plate.

One thing I'm happy with is that the original Globe Montego's (turbo wheels) fit over the brakes and callipers just fine with no problem.

As I will be starting from scratch I'll post the whole procedure and measurements using the Sigma green struts.
"Just remember, if you aren't forced induced, then you aren't SH#T"
GH Sigma Turbo no. 047

Leyland P76 V8 (next for resto)
Jaguar XJ8 Sport (british racing green of course)
Land Rover Discovery II V8 (the daily drive)
siggyloverWA
Posts: 92
Joined: Tue Feb 05, 2013 9:44 pm

Re: Big Brake upgrade - Dose it matter where the caliper is

Post by siggyloverWA »

front calipers are mounted trailing so that when you put your foot on the stop pedal the torque reaction creates a load on the wheel bearings in the opposite direction as they normally experience. as you brake the bearing loads are increased from weight transfer so this opposite load cancells this out.or such is my understanding anyway

on a side note I've found VN master cylinders are externally identical to GH ones.. swapping boosters seems like a lot of trouble when the cylinders are interchangeable.. try a V8 or a VL turbo cylinder maybe if vanilla VN is too small for your liking.. I'm not familiar with VT's but they might use an "identical" cylinder too
Scorpma82
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Re: Big Brake upgrade - Dose it matter where the caliper is

Post by Scorpma82 »

Datsun 120Y's, Ford Falcons, Holden Commodores, Mitsubishi Sigma's, Toyota Corona's have all used an identical 'casting'. (all made by PBR)

The cylinder (internally) is hugely different tho, causing much difference in braking performance!!!!

crack point psi's, piston strokes, pushrod length......all sorts of factors come into play
Built with pride, Driven in anger
Turbo047
Posts: 93
Joined: Thu Apr 19, 2012 8:45 pm

Re: Big Brake upgrade - Dose it matter where the caliper is

Post by Turbo047 »

opps
Last edited by Turbo047 on Sun Feb 17, 2013 12:46 pm, edited 1 time in total.
"Just remember, if you aren't forced induced, then you aren't SH#T"
GH Sigma Turbo no. 047

Leyland P76 V8 (next for resto)
Jaguar XJ8 Sport (british racing green of course)
Land Rover Discovery II V8 (the daily drive)
Turbo047
Posts: 93
Joined: Thu Apr 19, 2012 8:45 pm

Re: Big Brake upgrade - Dose it matter where the caliper is

Post by Turbo047 »

I've fitted up the Callipers and I'm pretty happy with how they are sitting.


Strut fitted up
Image


Remade Calliper mounting plate. I had to offset the Callipers up 30deg from the horizontal.
Image


Modified Sigma hub in place
Image


VT disc and Calliper mount fitted. I had to centralise the mount with 6mm spacers.
Image


Calliper and disc fitted up. Doesn't fowl on the ball joint anymore but I wouldn't want to go anymore than 30deg up or it would start to have issues with the strut.
Image


Wheel fitted and the brakes fit inside the wheel very nicely.
Image


Now I have to go get some brake lines made and fit a new 1" Master from a VL or VN V8. My idea of fitting the master and booster from a VY went out the window when I realised with ABS you have 2 outlets from the master cylinder :$



Image
"Just remember, if you aren't forced induced, then you aren't SH#T"
GH Sigma Turbo no. 047

Leyland P76 V8 (next for resto)
Jaguar XJ8 Sport (british racing green of course)
Land Rover Discovery II V8 (the daily drive)
Bmxer54
Posts: 4
Joined: Fri Oct 30, 2015 9:58 pm

Re: Big Brake upgrade - Dose it matter where the caliper is

Post by Bmxer54 »

you dont happen to want to make another set of those caliper brackets do you? or even a cad file with the dimensions, needing some better brakes for the scorpion which is set up to make 300rwkw and have a set of commy calipers ready to go
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