Hi all,
I've been doing a bit of research into rear brake setups at the moment and have noticed that the VN rear disc brake conversion seems a popular one.
From what I understand, the LH and RH backing plates are swapped over so that the caliper is front mounted which eliminates the clearance issue with the shock absorbers.
When fitting this VN rear disc setup to a standard LH/LX banjo rear drum setup are there any modifications that need to be done to the axles? (e.g. is a spacer required behind the axle retaining flange or is a different oil seal used or is the original oil seal retained?)
Thanks in advance.
VN Rear Disc Setup Question
Started by
antelopeslr5000
, Dec 12 2007 12:06 PM
11 replies to this topic
#1
antelopeslr5000
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Posted 12 December 2007 - 12:06 PM
#2
_Sammy_
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Posted 12 December 2007 - 12:36 PM
i've done this exact mod, all i had to do was get the axles shortened and re-splined to suite the length of the banjo diff .... other than that there were some simple mods to the handle brake cables etc to mount them to pull forwards on the handbrake levers.
so leave the handbrake mechanisms on their original sides, but swap the backing plates as you said.
so leave the handbrake mechanisms on their original sides, but swap the backing plates as you said.
#3
antelopeslr5000
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Posted 12 December 2007 - 12:45 PM
Thanks Sammy.
So I take from your post that you can't use the standard LH/LX axles (i.e. VN axles have to be used in this setup?).
So I take from your post that you can't use the standard LH/LX axles (i.e. VN axles have to be used in this setup?).
#4
_Sammy_
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Posted 13 December 2007 - 01:14 PM
well i dunno about that .... you'd need to measure and see if the Torry axle sits out from the backing plate the same amount as the VN axle, but if that was right the only other thing you'd need to do is get the rear discs drilled to torry pattern (if you planned to use torry rims) or get the axles drilled to commodore pattern if you wanted to use commodore wheels.
half my reason for going commodore brakes was to get commodore stud pattern and hense far more options for rims which then meant more options for decent tyres (theres bugger all for 13 x 7 mags these days!) so for me the easiest option was to shorten and re-spline the axles then just mod the backing plates etc to suit.
plus i already had all the commodore diff parts that i needed for the conversion...
$150 to shorten and re-spline per axle, new steel brake lines (with commodore threads on the ends) and some new pads and discs and i was sorted!
half my reason for going commodore brakes was to get commodore stud pattern and hense far more options for rims which then meant more options for decent tyres (theres bugger all for 13 x 7 mags these days!) so for me the easiest option was to shorten and re-spline the axles then just mod the backing plates etc to suit.
plus i already had all the commodore diff parts that i needed for the conversion...
$150 to shorten and re-spline per axle, new steel brake lines (with commodore threads on the ends) and some new pads and discs and i was sorted!
Edited by Sammy, 13 December 2007 - 01:15 PM.
#5
ls2lxhatch
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Posted 13 December 2007 - 01:25 PM
The Commodore disc is centred on the axle hub not the studs. The stud holes are larger than the studs so there is no contact. The Commodore disc will slip over either HQ or Commodore pattern.
If the Torana axle does not have the correct size hub to locate the disc then you can machine an adaptor to suit that slips over the Torana axle. You will note that the axle in this picture has a disc and rim locater fitted to suit the Commodore disc and rim. This was done by John Taverna Chassis. Rim locator's are a requirement of the NCOP.
The picture is from this thread.
http://www.gmh-toran...pic=17462&st=45
Edited by ls2lxhatch, 13 December 2007 - 01:27 PM.
#6
antelopeslr5000
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Posted 13 December 2007 - 07:28 PM
Thanks Sammy and ls2lxhatch
Sammy, I will be also running a Commodore stud pattern with my brake upgrade but I'm exploring all avenues at present.
I totally agree with you, there are a lot more wheel options when changing to a Commodore stud pattern but as my brother and I were discussing a few nights ago... what if you already had the wheels you wanted to use but in a Torana stud pattern? Would it be just a matter of buying some blank rotors and getting them drilled to the Torana stud pattern and using them with the standard axles?
As you have pointed out Sammy, and my brother and I also realised, the distance the standard Torana axle sits out from the flange would need to be the same as the VN to use the VN setup.
However we didn't even think about the size of the hub so thanks ls2lxhatch for pointing that out. A disc and rim locator might be required.
Hopefully I'll be able to get a hold of a standard complete LX rear end soon to start some experimentation with different combinations and setups.
Thanks again for your advice, greatly appreciated.
Sammy, I will be also running a Commodore stud pattern with my brake upgrade but I'm exploring all avenues at present.
I totally agree with you, there are a lot more wheel options when changing to a Commodore stud pattern but as my brother and I were discussing a few nights ago... what if you already had the wheels you wanted to use but in a Torana stud pattern? Would it be just a matter of buying some blank rotors and getting them drilled to the Torana stud pattern and using them with the standard axles?
As you have pointed out Sammy, and my brother and I also realised, the distance the standard Torana axle sits out from the flange would need to be the same as the VN to use the VN setup.
However we didn't even think about the size of the hub so thanks ls2lxhatch for pointing that out. A disc and rim locator might be required.
Hopefully I'll be able to get a hold of a standard complete LX rear end soon to start some experimentation with different combinations and setups.
Thanks again for your advice, greatly appreciated.
Edited by antelopeslr5000, 13 December 2007 - 07:30 PM.
#7
ls2lxhatch
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Posted 13 December 2007 - 08:34 PM
The difference between Commodore and Torana offset is considerable. I do not think you will find any Commodore rims that fit properly without widening the diff.
This is a picture of the spacer/adaptor Rhys used for the Commodore rims. It looks to be at least an inch thick.
This thread shows why spacers and adaptors are not legal unless factory fitted.
http://www.gmh-toran...showtopic=15445
This is a picture of the spacer/adaptor Rhys used for the Commodore rims. It looks to be at least an inch thick.
This thread shows why spacers and adaptors are not legal unless factory fitted.
http://www.gmh-toran...showtopic=15445
#8
Dr Terry
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Posted 13 December 2007 - 08:43 PM
Hi Guys.
I notice in that last pic, they were bleeding the brakes.
With the caliper mounted at that angle, you can bleed all day & you'll still have air in the caliper.
Dr Terry
I notice in that last pic, they were bleeding the brakes.
With the caliper mounted at that angle, you can bleed all day & you'll still have air in the caliper.
Dr Terry
#9
_Bomber Watson_
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Posted 13 December 2007 - 09:36 PM
Mate, the axles wont work strait up.
The little shank on the inside of the axle is about 5mm longer on the commy, so you will have to have a spacer made up.
Hard to explain with my limited knowledge, as i didnt do the work to fit the ones onto my Torana, i got my diff builder to do all that and then bolted it together.
Cheers.
The little shank on the inside of the axle is about 5mm longer on the commy, so you will have to have a spacer made up.
Hard to explain with my limited knowledge, as i didnt do the work to fit the ones onto my Torana, i got my diff builder to do all that and then bolted it together.
Cheers.
#10
_rocket_
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Posted 13 December 2007 - 10:20 PM
My car had a 9 inch in it when I bought it, I bought vn backing plates and calipers, put them on right to left & vice versa and all fitted perfectly over the existing axels
etc. just did away with the vn handbrake set up, well did away with the handbrake totally, to close to the clutch when your hanging laps, but the handbrake lever on the disc brake set up clashed with the shock. The only mod I had to do was counter sink the holes in the back of the disc, to allow for the big studs that I used.
etc. just did away with the vn handbrake set up, well did away with the handbrake totally, to close to the clutch when your hanging laps, but the handbrake lever on the disc brake set up clashed with the shock. The only mod I had to do was counter sink the holes in the back of the disc, to allow for the big studs that I used.
#11
antelopeslr5000
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Posted 14 December 2007 - 10:08 AM
Thanks for all the info guys.
Rocket, I'm assuming that the 9" setup was running LX Torana drums before you changed it to the VN setup? Did you change the stud pattern to Commodore or redrilled the discs to Torana PCD?
Rocket, I'm assuming that the 9" setup was running LX Torana drums before you changed it to the VN setup? Did you change the stud pattern to Commodore or redrilled the discs to Torana PCD?
#12
_rocket_
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Posted 14 December 2007 - 01:46 PM
Yeh, it was drums, and I just redrilled a set of blank dba 4000 slotted discs, and there still sitting on the floor after a year, still using the ones that came with the backing plates, commodore ones.
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