Rear disc conversion

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moley
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Rear disc conversion

Post by moley »

Commodore rear disc
To all that is gemini
I'm putting on the vr rear disc setup, does anyone know exactly what the mods are to the handbrake bracket and what needs to be done to the master and/or proportioning valve?
I have VT going on front. Xb falcon master 1inch bore on there now
Coupe rebuild number 6..
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OTD 079
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Re: Rear disc conversion

Post by OTD 079 »

Handbrake mod is just a sleeve welded on the backing plate where the h/b cable runs through to act as a spacer (so you can use gemini h/b cable without mods).
Details will be on the forum page (pictures - probably not anymore).
I can not advise about master cylinder / proportioning valve as my setup is totally different - sorry.
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moley
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Re: Rear disc conversion

Post by moley »

Thanks mate
Coupe rebuild number 6..
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cjcrow
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Re: Rear disc conversion

Post by cjcrow »

Ive done the conversion;

handbrake cable, 10mm ID washer over the end of the hand brake cable
booster/master, 4 bolt booster with isuzu truck 1 inch master. Prop valve I used HZ (I think not entirely sure) 4 wheel disc valve.
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moley
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Re: Rear disc conversion

Post by moley »

Hmm I don't want to change the xb master it's new. I might ring hoppers and ask them what they reckon. With the washer setup are you just using the std Commodore brackets and just putting a washer on the cable?
I'm only asking because I want it sorted before I put the brakes on the diff and I can't dummy it because everything is out of the car.
Thanks Hayden
Coupe rebuild number 6..
viewtopic.php?t=44564
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OTD 079
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Re: Rear disc conversion

Post by OTD 079 »

Look at the longish tubes on the hand brake cable mounts in the picture on this website (just under the disc front and centre)
http://www.turbogemini.com/Rear%20disk%20kit.htm
This is like what I did.
Going from the words in Gene's conversion thread - needs to be 45mm long...
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moley
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Re: Rear disc conversion

Post by moley »

Yea thanks I did read that and wondered if it was 45mm tube that slipped inside the holes on the Commodore backing plate or if it meant 45mm off the front.
Coupe rebuild number 6..
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cjcrow
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Re: Rear disc conversion

Post by cjcrow »

moley wrote:Hmm I don't want to change the xb master it's new. I might ring hoppers and ask them what they reckon. With the washer setup are you just using the std Commodore brackets and just putting a washer on the cable?
I'm only asking because I want it sorted before I put the brakes on the diff and I can't dummy it because everything is out of the car.
Thanks Hayden
Use the xb master then.
Just slip the 10mm id washer over the end of the cable then feed the cable through. Takes all of 15seconds to do.
Or, weld the pipe extension which requires more of a f around.
I used the washer and never had issues.
http://www.gemswa.com/phpBB3/viewtopic.php?f=29&t=2252, down the bottom of the page.
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moley
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Re: Rear disc conversion

Post by moley »

Thanks mate I googled a lot and that page never came up it's spot on.
The LSD is now another week away so the rush has stopped
Coupe rebuild number 6..
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cjcrow
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Re: Rear disc conversion

Post by cjcrow »

Something like this?
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moley
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Re: Rear disc conversion

Post by moley »

Will be altra 9 yea, but with 5 stud axles. Looks good
I found out that the hz proportioning valve is pretty well non existent now.
Found that the Gemini one can be modified with a different spring so I will see if I can do it and report back
Coupe rebuild number 6..
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Turbocoupe75
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Re: Rear disc conversion

Post by Turbocoupe75 »

The Gemini does not have a proportioning valve standard, it's a pressure sustaining valve for the original drum brake. It needs to be removed or hollowed out or replaced with one from a car with a disc brake rear.

It's easier to install an after market proportioning or limiting valve so you can dial in more or less rear brake, for a track car it's essential.
My set up is Volvo 4 spot, bmw disc, VL disc rear and 1" master... It's awesome!!!
#Turbocoupe75
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moley
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Re: Rear disc conversion

Post by moley »

Yea that's what the guy from hoppers said. But a couple of other guys said the hz disc one is a lot better option. I dunno I will try swapping the spring I guess. I won't be track racing it really
Coupe rebuild number 6..
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F3ARED
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Re: Rear disc conversion

Post by F3ARED »

Regarding the HZ prop valve, give Super Stop in VIC a call - 1300 77 7867 and ask for Goce [pronounced Got-se]; tell him Nick Seki sent you. If he tells you he cant find it, it literally does not exist - hes been able to get Piazza discs for a long time even though they have apparently been NLA for 15yrs. Was about to add not to forget the spigot/spacer ring when doing the VL rear disc to locate it onto the axle, but seeing as your doing the Altra9 it wont matter as they already have a larger lip to suit the VL disc.
Turbocoupe75 wrote: It's easier to install an after market proportioning or limiting valve so you can dial in more or less rear brake, for a track car it's essential.
My set up is Volvo 4 spot, bmw disc, VL disc rear and 1" master... It's awesome!!!
Which model disc dude? Everything ive looked at briefly on the BDA catalog for BMW has a hat height thats way too tall, unless your setup as a floating disc?
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

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OTD 079
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Re: Rear disc conversion

Post by OTD 079 »

F3ARED wrote:Was about to add not to forget the spigot/spacer ring when doing the VL rear disc to locate it onto the axle, but seeing as your doing the Altra9 it wont matter as they already have a larger lip to suit the VL disc.
Only if you tell them that is what you are doing... so be sure to mention it on the order form!
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