Rear brake upgrade

Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

I'm midway thru a rear disk conversion, and i've found so far that (incase you didnt know) the VK disks are exact same as VL, easy initial bolt up, however a small pipe is required to be welded where the commodore handbrake cable goes into the backing plate, approx 35mm long and you use the original gemini handbrake cable. I'll keep yas updated when i finish and hopefully get some pics too. Does anyone know regulations for brake upgrades, eg engineering/mod certs???

Gene FJ20DET · Posted: Mon Mar 24, 2003 5:28 pm Post subject: Re: Rear brake upgrade

ahhhh, sneeky bastered!!
i tryed the vl cable but its about 2 foot to long, lol. andlooked at the gemini once but there was no way it was gonna work. didnt think of getting a piece of pipe on there!! how close did ya cable come to the rear springs??
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Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

Yeah the VK cables miles long as well, plus the sheathing is different lengths on each side on the gemi one, well i dunno how well its gonna work yet, and its still not done, but holding it in place where it will sit it has a fairly decent curve, shouldnt bind though, soon find out but... Im still gonna use the mounting tab, and i'm gonna use a hose clamp sorta thing and either mount it to the floor, or to the mount for the rear trailing arm as theres already a hole i could use. I'll get back to ya when i've actually got it done, but i'm pretty busy so who knows when thatll be. I'll try to post pics for everyone else too.

Gene FJ20DET · Posted: Tue Mar 25, 2003 6:36 pm Post subject: Re: Rear brake upgrade

i ahve everything on and ready to go. i have th ecable tabs and new bundly lines all one, and the vl cable, but tis to long so i might try the gemini one this weekend
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Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

Why'd you go new bundy lines??? All mine fitted straight up no mods, i even had a flaring tool incase i needed to change things. Have you upgraded your master cylinder to the 1 inch one from a XB Falcon??? That was simple to do. Well if you get yours done and goin first, tell us any other probs you hit, otherwise i'll do the same.

Gene FJ20DET · Posted: Tue Mar 25, 2003 9:42 pm Post subject: Re: Rear brake upgrade

havent done the master yet, thinking of useing a VX one.

i had to get new lines cos.... well it looked better heheh and cos the gemini bits didnt thread into the vl ones.
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Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

I don't know how easy a VX master would hook up, the XB one is piss easy, modify the push rod from the booster and it just hooks straight up. Well to anyone else i'd recommend the VK rear disks, because the gemi lines thread straight into them, however the difference could be in the car model, mines a TE.

Gene FJ20DET · Posted: Wed Mar 26, 2003 3:03 pm Post subject: Re: Rear brake upgrade

the new brake lines only cost me $10, not the end of the world Wink

hehehe
mate of mine did a vx one to his gemini.
what exactly did u have to mod?
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Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

What was involved in the VX Conversion??? All that needed to be modded was the push rod from the booster, extended 5mm from memory, then the mounts line straight up with the booster, also i needed to get new lines from the booster to the proportion valve thingo below it, cant think of its proper name, very simple, only pain in the arse is bending the pipes up.

Gene FJ20DET · Posted: Wed Mar 26, 2003 7:40 pm Post subject: Re: Rear brake upgrade

dunno what was invold in the VX one yet.

how do u mod it 5mm?
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TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

gene can u right me up a good detail on how to fit the VX booster - i'll need it when i go the same root u did

Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

I'd be interested to find out how involved the VX booster is to put in, i know the XB is easy as and not too expensive either, as i've heard a lot of hot rods use the gemi booster as well. As for extending the push rod, easy, weld a tab on the end and the grind it down to the right size and shape, 0.5 hrs work tops. 5mm is the norm, but i have heard of others doin anywhere from 5mm to 7.5mm i think, thats what Hoppers Stoppers recommended, their kits are a few days off being engineered, and they're looking into a kit for the rears as well (VK/VL), i have been talking to Peter and i will keep everyone informed when i get news of the approval. Also i've heard in VIC that a 3/4 chassis isnt required for the V6 upgrade, i'll post when i find out more...

Gene FJ20DET · Posted: Thu Mar 27, 2003 10:56 am Post subject: Re: Rear brake upgrade

whats the difference with 5 and 7.5?? what whould it do to is functionality

i duno whats involved in the VX one yet.

hopper stopers emailed me saying they have a full kit now, (front rear and booster)
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Reddez · tinkerer Joined: 29 Oct 2002 Posts: 353

I don't think you've looked closely at the brake sytem yet, the booster just provides more pressure/movement from the pedal movement, the master cylinder is where the front and rear is separated. I'd guess the difference would be where the pushrods initial position is, maybe quicker/stronger engaging??? Ask hoppers why that length, i know its more hot rodders with the differing lengths. What exactly was in the email, it was a full kit before, they just recommend a 1 inch master cylinder upgrade... Keep us informed on the VX upgrade as i'm interested...

GEMGEM · tinkerer Joined: 09 Oct 2001 Posts: 74

Regarding Pushrod Lenght
Most gems had a pushrod of lenth 72mm which as peter advised lenghtening to 75mm is advisable. To find what the lenth difference made I found other gem pushrod of lengths 73mm and 74.5mm so before adding any extra material, instead i tried all the different lenghths.
Conclusion: The shorter the rod the lower the pedal to the floor and the longer the rod the higher the pedal.
I found that going from 72mm to 74.5mm was a substantial pedal heigth increase! Bear in mind if the rod is too long then the master cylinder will be partially engaged, good test is to play around with lenths and sit "BLU TACK" on the end of the push rod, bolt it up to the master and remove to c how much the blu tack has squished!
Fitting the XA-XB master is very simple and aint worth payin for conversions (NO offence to Peter Koning)the master bolts to a TE Booster, u need to flare the brake lines with ford flare nuts and if u can find a 74.5mm pushrod (I found n a TG)its enough to give it a go!
Oh also dont be fooled, theres two different type XA-XB Masters I found, U want the one with the brake light switch on the left hand side(front view) not underneath as those dont fit up to gem booster studs! Hope this helps and best braking to u all!