Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

HELP PLEASE: VT Brake Conversion Issues...

Vlad01

Member
Joined
Nov 28, 2009
Messages
413
Reaction score
0
Points
16
Members Ride
92 VP vacationer, 95 VR II exec, 92 VP S Pack
Yes I talked to Holmart and they say not to use the VT MC or booster, thats the dodgy way they recon.

What is used it the V8 VN-VS MC and booster as the booster on the V8 models is internally different.

otherwise the modifications to eh VT booster and bracket is illegal unless made according to ADR rules which is clearly no whats being done here lol. Which is a big problem for me as I will be registering the car with the brakes already upgraded.

Also the V8 VN-VS booster/MC is direct bolt it.

Well tomorrow I will trade my VT booster/MC for the pre VS V8 1" setup.
 

markovr

Well-Known Member
Joined
Nov 23, 2003
Messages
3,072
Reaction score
252
Points
83
Age
62
Location
northside brisbane
Website
youtu.be
Members Ride
07vessv 94vr .04vz wgn,93vp wgn,82 vhV6 wgn 88 vn
Yes I talked to Holmart and they say not to use the VT MC or booster, thats the dodgy way they recon.

What is used it the V8 VN-VS MC and booster as the booster on the V8 models is internally different.

otherwise the modifications to eh VT booster and bracket is illegal unless made according to ADR rules which is clearly no whats being done here lol. Which is a big problem for me as I will be registering the car with the brakes already upgraded.

Also the V8 VN-VS booster/MC is direct bolt it.

Well tomorrow I will trade my VT booster/MC for the pre VS V8 1" setup.

Holmart are right that the boosters 6cyl to 8 cyl are different.... single diaphram to double diaphram are different...masters 15/16 to 1 inch yes different... but I reckon you will be sorry.....the 1 inch will not be enough...Ive been through all this many years ago and I have the best setup for the money without changing wheels........Ive got a roadworthy on my old vp v6 vacationer wagon to sell to my father with it all vt setup booster/master and nothing was even mentioned by the place doing it...they found a bees dick play in the panhard rod bush that I had to replace and a smear of auto oil around the power steering pump that I had to put a kit through. but no issues with the brakes........its probably technically illegal to run the wheels and tyres that are different to stock and no one even mentions that either.
Its in no way dodgy if anything its over engineered...if its a worry, get it certified by a engineer....Ive hit the brakes hard many times and never locked them up front or rear.
so Marko, what set-up have you got at the wheels? Your VT master cylinder looks really neat. Does installing the VT master and booster give a boost in stopping power or just make it easier to lock-up the wheels? It doesn't look like you've got ABS on yours?
It has slotted dbas with vt calipers and qfm hpx pads...and no abs
The feeling of confidence it gives you makes you almost think something must have been wrong with the original setup because it is so much better.
 
Last edited:

MasterOfReality

Miners go deeper
Joined
Feb 26, 2004
Messages
874
Reaction score
1,070
Points
93
Age
44
Location
All over
Members Ride
2019 LC Sahara TTDV8, 1991 VP Calais V8
When I last spoke to an engineer about the VT brake upgrade on the VP, I was told I needed to get it engineered. This was a kit with hub adaptors and the VT calipers.

If it were the VN Group A setup, then no engineering required.

I did stumble across a company that provided ADR compliant brake upgrade kits for the VN/VP, but that was back in 2006. Can't remember the stuff they used but they weren't VT calipers. They were pricey though, double the standard VT upgrade at the time.
 

chubs0191

New Member
Joined
Jul 13, 2012
Messages
5
Reaction score
0
Points
1
Age
33
Location
victoria
Members Ride
vr 5l turbo
hey all i'm sorry for raising the dead with this post, but i don't see the point in starting an entire new thread for a single question, so i'm doing it anyway.

Mark, I'm mostly asking you, in the picture of the booster rod where you have said that you need to re drill the hole for the push rod at 111mm i am wondering what thickness the plate is that you have welded on the front of the bracket as I imagine this thickness would impact the placement of the new hole?

i understand that you make money off this information so if you don't want to say for free i get it, but any help is appreciated greatly.
cheers and thanks in advance
Blake
 

Attachments

  • vtrod-1.jpg
    vtrod-1.jpg
    11.9 KB · Views: 178

markovr

Well-Known Member
Joined
Nov 23, 2003
Messages
3,072
Reaction score
252
Points
83
Age
62
Location
northside brisbane
Website
youtu.be
Members Ride
07vessv 94vr .04vz wgn,93vp wgn,82 vhV6 wgn 88 vn
No worries if you can do it yourself why not its only steel and a bit of welding
i use 3mm plate roughly 130 x120....a little thicker than the normal bracket....you measure the 112.5(you have 111 in your last post) from the boltup firewall face of the bracket with the bracket bolted on the booster...it usually means the new pushrod hole is about a full hole closer to the booster.
It has taken me a fair bit of trial and error to get it right and now I use jigs and 54mm holesaw to speed up the process and have it installed on 3 of my cars for many years ...my daily drive was my guinea pig initially when the mod was new . . I do offer a complete modded bracket for 100 posted but it isnt hard to do yourself using the check twice before you do anything permanent technique ..you just have to make sure the bracket is square so when its bolted up so the cylinder is square.
 

chubs0191

New Member
Joined
Jul 13, 2012
Messages
5
Reaction score
0
Points
1
Age
33
Location
victoria
Members Ride
vr 5l turbo
thanks for the response, i did this conversion yesterday, it's a significant improvement on standard brakes. However, i have one last question when the engine is off the brake pedal is at the top of its travel and very firm and it doesn't get firmer if you pump the brake (indicating no air), with engine running the pedal can be pressed almost full stroke, is this normal in late model commie's? i understand what and how the brake booster is supposed to work i guess i just wasn't expecting that much assistance from the power assisted brakes. thoughts?
 

VPRob

Well-Known Member
Joined
Feb 10, 2011
Messages
1,120
Reaction score
196
Points
63
Location
nowra, NSW
Members Ride
VP executive sedan V6
I have this conversion in my VP including the VT master and booster. No you should not have the pedal going full stroke (I assume you mean nearly to the floor). For general use I only have about 1 1/2" pedal travel. The pedal WILL also come up higher as the pads bed in to the rotors.
I DID have a problem initially with excessive pedal drop and not quite sure as to the cause. I used a cheap new MC (Roadmaster) first up and I believe it did drop some loose metal particles and may have significantly failed. The brake fluid looked filthy dark after just a few months use.
I kitted a 2nd hand genuine MC to replace it but also made sure that I had free play on the pushrod out of the booster that pushes on the MC piston (with the system at rest) It takes some nifty measuring to establish correct adjustment. This is something that is not mentioned too much in the VT conversion but I am not sure that we can assume the push-rod will be correctly adjusted when pairing MCs and boosters that have not previously been an item.
Have you made any changes since posting or is it still the same? How much pedal travel do you have during normal braking?
 
Top