sr2

Yes you're correct. There are 3 different VH40 slave cylinder sizes, they all run the same 7 1/2 inch vacuum diaphragm. Smallest is the VH40EL at 9/16"; at 20' of vacuum it can produce 1825 PSI. Largest is the VH40D at 7/8"; at 20' of vacuum it can produce 840 PSI. Middle ground is the most common - VH40, VH40AJ, VH40AL, & VH40L; at 5/8" , at 20' of vacuum they can produce 1470 PSI. They are also fitted with simple and compound type control valves which vary the cracking pressure from 20 to 35 psi. The good new is that 9 times out of 10 it will be 5/8" bore, there is not a huge difference between simple & complex valves and the model difference is left or right hand mount - easy job to convert from one to the other. As an added note a PBR Hydrovac failing to release is usually caused by a sized control valve piston in the booster or a blocked compensation port in the master cylinder - the latter being more difficult to diagnose because with the booster disconnected there can often not be enough residual pressure to detect with a road test.

Sounds like they are in series, if so the 5 amp fuse won't protect anything. (i.e. the 2 amp fuse will always blow first!).

I'm struggling to understand your question but with two unequal value fuses in series the lowest value will be the fuse that breaks the circuit and when in parallel it will be the highest.

Thanks guys, sounds like it's as I suspected.

Hi Guys, a quick question. I'm working on a brake & booster upgrade on a mates classic, a 318 VF Regal Coupe he's owned for 30 plus years - it's a babe! I'd like to use copper nickel brake lines (sometimes called cunifer or cupro-nickel) for their corrosion resistance and installed well they look heaps better than bundy tubing. Question is, I know its OK to use in Australia and I would be very surprised if it wasn't OK for NZ but is there any documentation available to confirm before I put a heap of time into making up new brake lines? Cheers, Si.

You're not the first to have 'issues' with Autoblast. A good mate had an underbody blast & paint on his classic a year or so back. When the transmission shat itself a week later we discovered blasting media in the trans oil. Shortly after we discovered their "all care and no responsibility" policy!

LOL, you may have a good point there! Luckily with the recent gun buyback by our glorious leader there are no irresponsible AR15 owners in NZ and all firewall penetration's are drilled to the correct diameter and fitted with the appropriate grommet! On a more serious note I have to admit that after 20 odd years of running Autronic ECU's in our competition cars the majority of failures have been from wiring issues i.e. vibration, heat, rubbing, chaffing etc.

My 10 cents worth if I may. My brother runs the well-known (in Tarmac Rallying) Cheetah race car and yes there are a few decades of sibling rivalry between our two teams – you’ve got to keep these bloody older bro’s in their place! His current motor of choice is a 420 cubes plus Dart “small block” running AFR Heads with the best internals he can source. It’s cam’d to be a torque monster with the standard joke being that despite having a 6 speed Richmond behind it you only needs 2 gears for most Targa stages, it’s just simply buckets of useable power everywhere. Up until 18 months ago it was running a Barry Grant Demon Carb on a single plane manifold - multiple dyno results were great but it struggled with cold/hot starting, public road touring stages, plug fouling when not used in anger and the most unbelievably horrendous fuel consumption in both special and touring stages. 18 months ago in desperation we tried an 800HP FiTech system and the results just blew us away. When we arrived at our favorite dyno we were advised that the system was still tuning itself and we should “go forth and use it in anger”. After some rather spirited play time on highway 16 we arrived back (with licenses barely intact) and ran the beast up. The figures spoke for themselves, no loss in peak HP and a huge improvement in linear torque throughout the rpm range – it had started pulling like a choir boy from 2500 rpm! Obviously the one thing we can’t quantify with fact and figures is the ‘drivability’ of the setup but the consensus of opinion is that hot /cold starts are instantaneous, it never stalls when maneuvering at idle despite having P/S and almost no flywheel, throttle response is as good as it gets, the plugs look great and the list goes on. We also found a good 30% was knocked off the fuel bill when competing in Targa. I have to say I was a little dubious re having the ECU mounted on top of the motor (i.e. heat & vibration) but after 18 months of competitive motorsport it’s been nothing short of 100% reliable. In hindsight I run a 350 MPI EFI V8 Mercruiser in a 28 foot power boat with the ECU and all relays mounted (as per factory) on the inlet manifold – I need to move with the times! There is probably a reason why street versions of this type of aftermarket single point injection systems have taken the classic car industry by storm worldwide. Rant over, thanks for reading.

I couldn't agree with you more mate; hard not to dispute that the NZ LVVTA 'old boys whiskey club' would be both loud and vocal in their objections. In my opinion if the ratio's & engineering (i.e. design, materials and construction) were of an acceptable standard the linkage would be no more complex than many production cars (the RHD E30 or Mk 1 Escort springs to mind).

Am I right in presuming it's the L300 m/cyl?

Sorry - I'm a little late to this thread I'd be wary of not having the compensation port at the highest point of the master-cylinder. In the years I spent in the industry I can only remember one OEM setup where this did not not apply - the very early vertically mounted 'tin type' mini was a dog in more ways than one, it was quickly replaced with a conventional setup. Yes if you bench bleed before installation (as you always should) there's every chance you'll get away with it but don't forget the compensation port is open to the atmosphere when the pedal is at rest effectively leaving leaving the system not only partially exposed to the atmosphere but also at atmospheric pressure. Relying on fluid being held in an 'inverted' syphon is OK in theory but if in practice it's not something I'd be comfortable with. If with a little extra fabrication you could mount conventionally I'd recommend it. I'd be interested in knowing what brakes you're running and if you've considered a booster?

The new m/cyl looks great. Do me a favor and pull the mastervac check valve out, poke the longest finger (or didget!) you posses in there and let me know if there's any residual brake fluid there. if there is PM me and I'll talk you through a booster rebuild or you can bring it (and a bottle) to the world famous sr2 mancave in Milford and we'll do it in person.

Ouch !

The Hunter came out with a Lockheed Hydrovac brake booster from new?

I worked for APPCO brake and clutch in the 80's. Originally we used to re-sleeve with brass inserts; easy to hone, average wearing but most importantly easy to keep in place with an interference fit. Stainless was the holey grail but was not suitable for an interference fit, at the time we put a lot of R&D into finding a suitable adhesive to do the job - these days it's a no brainer! I'd suggest for re-sleeving to contact Just Brakes in Penrose. Many old Holden parts in NZ are exorbitantly priced, I buy most of my Holden 6 bits from Australia. I've bought a lot of parts from these guys.... https://www.ebay.com.au/itm/Holden-FRONT-Brake-Drum-Wheel-Cylinder-PAIR-EH-Wag-Ute-HD-HR-HK-HT-HG-26-98mm/273838515012?fits=Model%3AE+Series&hash=item3fc20c2344:g:uLwAAOSw6lVe6b82

Great info there mate, this one needs to be pinned.

LOL, I'd be taking Weber Specs comments with a grain of salt. They have a reputation for being somewhat.... ahem..... "opinionated" to say the least, (looks like they were angling to sell you a new 32/36?). I ran an XE Coon in the early 90's and the 34ADM on it started, idled and ran smoothly - a huge improvement on the stromberg carb on the XA Coon I'd had before. It's hard to escape that this has been a very common swap in Aussie for decades and most use the existing 'Coon jetting. Classic example from the GMH-Torana Forum - these guys know their stuff. http://www.gmh-torana.com.au/forums/topic/75566-weber-34-adm/

Weber Specs charge like the proverbial wounded bull. Go and see Bruce Manon from Manon & Butler Motors in Barrys Point Rd Takapuna, IMOP hes one of the best Weber tuners in the country.

I'd be asking these guys, they are set up to do custom work as well. http://www.znoelli.co.nz/

Back to your knitting Nana please!

Spoil-sport!

Thanks mate, just bought one. Looks like good value for money.

The modern 'Mastervac' style of booster (the XJ40 Hydraulic system is just a weird , overly complicated version of the same principal) is deliberately designed to be separate from the brake systems hydraulics to avoid complete loss of brakes in the event of booster failure. Its predecessor the 'Hydrovac' is easiest described as a 'hydraulic amplifier' that was plumbed in series with the master-cylinder, in the event of its failure (which wasn't unheard of) the result was a complete loss of brakes.

The bleeding process you're describing is called 'surge bleeding'. It has it's uses but is prone to aerate the fluid, particularly if there is a considerable amount of air in the system (e.g. after replacing a major component) and far more likely to occur in an ABS system (there are a lot of small valves/orifices in there). Aerated brake fluid has had air dissolved in it under pressure (as opposed to air bubbles) and is your 'bleeding enemy' (apologies for the bad pun!). I'm in favor of a more gentle approach; release the bleed nipple with the pedal in the rest position (i.e. compensation port uncovered), have the 2nd man (or the Mrs) smoothly push the pedal to the floor, tighten the bleed nipple, release the pedal and allow to rest for a few seconds - repeat until fluid is clear of bubbles. The air should come out in bubbles, if the fluid looks frothy of milky you're aerating it and things will only get worse. Never re-use fluid when bleeding even if it is new and clean, always allow it to rest for a few days - it takes quite some time for the dissolved air to separate. I'm by no means an XJ40 expert (years since I've worked on one) but don't get sidetracked by the hydraulic booster, it only provides mechanical assistance to the pedal and is not connected to the hydraulics in the braking system. In essence it does the same job as a vacuum suspended mastervac. Hope this helps.

LOL; I can't lay claim to that one but rest assured I share your pain!