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vt/x/y/z rear brakes on vr/s solid axle

markovr

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Ive just installed vt rear 289mm 16mm ventilated rotors on my vr solid rear axle that previously had the standard solid 289 11mm ones and you could do the same to any solid rear disc braked commodore borg warner or salisbury or even with a couple of extra parts from a disc braked vn /p/r/s you could find in any wreckers and the necessary rear axle bearings and seals installed on your axles, convert a drum braked one and it works well and it's a platform for higher end brakes too like brembo/harrop or hsv and use 315 or bigger mm discs
This is what I did...bought some good rear hand brake shoes and vt rear calipers secondhand
Got some old vn/p/r/s handbrake shoes and took all the friction material off them and found when assembled on the original backing plate their outside diameter was exactly the same as the inside diameter of the vt hand brake shoes...so the vt handbrake shoes slipped over the top...so I centred them on the vn/p/r/s shoes and welded them to each other in 6 places a side careful not to create too much heat and then cut them off when it was all welded so now they were 2 separate shoes like original.
Got the vr hub backing plate and removed all the rust built up over many years by soaking it overnight in vinegar (backing plate from factory is left bare metal) and slipped the end of a bolt through the original mounting hole welded one side the cut it off and welded the other side so now the original caliper mounting holes were gone and then redrilled 2 new holes 7/16 drill size inboard at 76 mm centres, 4mm closer to the centre of the hub to fit the new vt calipers...found the standard vt caliper mounting bolts were a 12mm x 1.5 mm thread which happens to be the same thread as a wheel nut so I welded a wheelnut over each new hole , bevel side of the nut up and cut the bevel part off of the wheel nut once welded so it is flat with the rest of the nut...(found out later that I didnt need to cut the bevel off as there is plenty of room) and ran a 12 x 1.5 mm tap through the nut to tap out the thickness of metal of the backing plate and trimmed off the corners of the backing plate where the new caliper bracket touched .When i first tried to work out where to weld the new nuts on the hub I tried them the same distance as the old vr caliper mounting bolt holes but found the vt pbr caliper was too far out from the centre and the very outside edge of the pad was not contacting the 290mm disc so i had to move the mounting of the nuts inboard 4mm and it worked out perfect and everything now simply just bolts up and the handbrake works properly .Cleaned up my welds and smoothed out any sharp edges and painted it black.In time after I had a few dramas getting the nut centres in exactly the right place that if I got a longer wheelnut and ran a shoulder on it the same thickness as the backing plate and then made the hole in the plate bigger now so the barrel part of the nut was a interference fit so now I could have the caliper bolted up tight before I welded it so now the positioning was perfect everytime and it still had thread all the way through.
When fitting up to the car I found I had to trim the dust shield a little where it made slight contact with the new caliper. I used slightly longer caliper bolts that had captured washers that originally came from front standard vz calipers to use more of the thread in the nut just to be on the safe side but the old ones would have been fine. This mod would have worked on any pre vt disc braked commodore salisbury or borg warner. Handbrake actually locks the rear wheels if you are moving (only for test purposes )and travel on the handbrake at the console is only 3-5 clicks now.




















 
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VPRob

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This looks like a beautiful mod. I think VP rears are exactly the same as VRs so I am thinking that this would be exactly the same process on my VP (should I ever get around to fitting an upgrade to the front).
 

markovr

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This looks like a beautiful mod. I think VP rears are exactly the same as VRs so I am thinking that this would be exactly the same process on my VP (should I ever get around to fitting an upgrade to the front).
Yes they are..actually goes right back to very early disc rear commos and the 76mm stud pattern is the norm bolt up for higher end caliper/disc combinations brembo/harrop even hsv stuff...and the handbrake part is bigger and more positive...Im using a ventilated moly carbide disc as well
 
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VPRob

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this is so simple and clever I reckon there's a whole lot of commo drivers wondering why they didn't think of it first........
 

markovr

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Got a mod for the front too? (Or have I missed that one?)
New fronts for my car are coming .....322 ve rda discs and ve calipers and rda extreme pads (they are a semimetallic full pad with a insulating anti squeal shim on the backing standard) with ve 18 inch wheels and just waiting for my 16s to wear out(vt calipers) qfm hpx pads
 
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Immortality

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Should probably get moved into the "how to" section.

Fairly sure the rear brakes are the same right through the Commodore range up until VS (right back to the early disk brake models).

Got a mod for the front too? (Or have I missed that one?)

There are already bolt on kits to suit. VT style that really require a MC/Booster upgrade due to the larger displacement of the pistons of the VT style callipers or the later VE kits that have slightly smaller pistons in the callipers and seem to work fine with the earlier style master cylinders.

Both styles are available with small and larger diameter rotors.
 

Jxfwsf

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Got a mod for the front too? (Or have I missed that one?)

VT fronts onto a VR/VS is simple if it hasn't got ABS (live axle or irs) or has irs abs, change the hub/bearing assembly to a VT one, put on rotor and bolt on caliper.
Need to either buy an adapter for the brake line fitting or change the flare nut to the later one and reflare it with a double flare and you're done.
 

nes138

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VT fronts onto a VR/VS is simple if it hasn't got ABS (live axle or irs) or has irs abs, change the hub/bearing assembly to a VT one, put on rotor and bolt on caliper.
Need to either buy an adapter for the brake line fitting or change the flare nut to the later one and reflare it with a double flare and you're done.

Well I have HR drum stubs with VN V8 rotors with VS calipers....
Was hoping for a VN conversion
 

markovr

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RDA have some pretty good pads nowdays in their extreme range so I thought I'd give them a try as they are quite reasonably priced and qfm are getting exy in comparison...especially rears
I made up a second set of shoes/hubs as per dimensions/welding above..... my car was the guinea pig and it works so well ...I drive with this setup on my car everyday...... the caliper bolt up dimensions mean you can bolt up any vt/y/z rear upgrade to fit hsv harrop or brembo with the right adapter brackets ....the whole setup is bullet proof and totally over engineered and its pretty well boltup...is anyone interested in buying the combo from me?...I can do a deal if you send me your old shoes/hubs.
The actual setup is the same as one i saw on ebay and i have through trial and error got the positioning right and the selling point is that you can boltup brembos/hsv/ upgraded 315 discs / or harrops.
 
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