46 Ford Build Fails Brke Plate Test With High Pedal Pressure

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Greg N Smith
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Greg N Smith »

If you have a broken leg and you ask the doctor which Band-Aids work best it might not go well. (I am not an expert at anything)

You have an NF Fairlane Master Cylinder and Rear Brakes with Jaguar XJ Series I Front Brakes

I expect those Brakes are dangerous - Too easy to lock the Front Brakes and can't lock the Rears

Especially in low grip conditions I expect you might have a choice between very poor brakes and steering - Not Both - Touch the Brakes and the vehicle ploughs straight ahead

As the Professor would say - Why is it so ? - You have 77% more Front Brake Piston Area than the Ford - That is the Problem that should be Fixed.

I assume that your vehicle has similar total weight and front to rear weight balance as an NF Fairlane

Ford (and other vehicle manufacturers) have spent HUGE Person Hours and Dollars getting Brakes to where they are now

Engineers like systems that have been proven to work and using like systems usually results in less total costs

IF it was my vehicle I would look at fitting Jaguar Series II-III vented front discs - 285mm OD compared to 287mm for NF Fairlane
- Same stud pattern and I expect an easy fit - Hub Hole Diameter may need to be increased from 82mm to 82.5mm - Check how much wheel stud showing on SI and SII-III

Then adapt NF Fairlane type Front Calipers with single 60.3mm bore pistons with the matching Ford Brake Pads and you have duplicated the Ford arrangement
- The 24mm New Disc Thickness is within the 25-22mm Ford range.

References -

https://www.vmaxbrakes.com.au/fits-jagu ... disc~38632

https://www.vmaxbrakes.com.au/rtype-slo ... gJjY_D_BwE

https://www.ebay.com.au/itm/13327545948 ... SwGIVd-Wfk

https://www.bestbrakes.com.au/EA-EB-ED- ... UILD-KIT-2 - Indicates that these all use the same calipers

I suggest talking to who will approve the vehicle and I expect that doing the above would result in good brakes for less than you will spend - and rotors and calipers can be sold if required

As a separate issue pedal position should be considered based on modern vehicles - Many have hit the wrong pedal with disastrous results

But remember - I know nothing ! But Vented and Not Vented Discs are on my kitchen bench, Adaptors are on my desk and at the front door with 4 front calipers.
Greg N Smith wrote:Warning - Brakes (and Steering) are Very Important and I'm called Schultz (from Hogan's Heroes) - I know nothing !

A look on the internet and it appears that -

Jag XJ S1 Front Calipers have 1 x 57mm and 2 x 40mm Pistons - Total Area 7.85 square inches per side - Does yours have 3 Pistons ?

NF Fairlane Front Calipers have 1 x 60.3mm Piston - Total Area 4.43 square inches per side -

Your Jag XJ S1 has 1.77 times more front piston area per side than the NF Fairlane

The real difference is in the total area of all front pistons - a large Difference which I expect would change braking pressures and front to rear brake balance.

Jag XJ S1 Rear Calipers have 2 x 43mm Pistons - Total Area 4.50 square inches per side

NF Fairlane Rear Calipers have 1 x 40.4mm Piston (from Falcon AU size) - Total Area 1.99 square inches per side

Jag XJ S1 Master Cylinder has 15/16" (23.81mm) Bore - Total Area 0.69 square inches per side

NF Fairlane Master Cylinder has 1 x 15/16" (23.81mm) Bore - Area 0.69 square inches AND 1 x 1 1/4" (31.75mm) Bore - Area 1.23 square inches

Some big differences there ... I don't know whether that combination is suitable.

In a safe area with plenty of run-off I would check that you can lock all wheels from moderate speed with someone watching from a safe distance without being an "on-off" switch

In an area with plenty of run-off on loose gravel or wet surface what happens when you brake from moderate speed with a bit of turn - do you lock the fronts and plough straight ahead or do you lock the rears and spin out ?

Please check the booster and all measurements and calculations and let us know how you go.
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Sedandelivery
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Sedandelivery »

Interesting reading Greg N Smith, I also took note of your first contribution and value your comments.

The thing is what I am at a loss to come to terms with is that the Fairlane and Jaguar have the same master cylinder bore 15/16''......if 15/16 works a three piston Jaguar why doesn't a 15/16 Fairlane? Turns out it does......first we have to realise that the large bore in the Fairlane Master Cylinder doesn't apply the brakes, it's some sort of fluid replenishment system for the front calipers as I understand it.

So having this in mind and knowing the result of the standard registration inspection test where the vehicle stopped with acceptable pedal pressure and bearing in mind the examiners opinion, not based on any specification, regarding the pedal position I decided to stop playing with pedal ratios and resubmit the vehicle for a Plate Brake Test.

Different operator this time and he did the first test while I was there to see if there was any point in continuing, this didn't happen the first time. Intially it failed the basic test, only just, so the operator took it out and did three or four hard stops in the driveway, put it back on the machine and it passed. He considered this was satisfactory and would proceed withn the full test later on.

So now I have the paperwork........... Normal Test...
No Booster....
Rear disconnect...
Front disconnect....
the paperwork says it passed......

The examining engineer who requested the Plate Brake Test and nominated the Testing Depot now has the documentation to say that the vehicle complies with the NSW Brake Assesment Manual. Next step is to submit the vehicle to the certifying engineer and see what he picks, he will find something, they always do. The only thing he actually documented after his first examination was that the brake pedal must travel less than half the distance to the floor to apply the brakes. It meets this criteria and complies with the Ford workshop manual for pedal set up.

So, the next step for me, when I can afford it, is to submit it to the Engineer for final approval and see what happens.
Harv
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Harv »

Good news on the pass, and wish you luck with the engineer. The NSW Engineer Waltz is not a fun dance.

Cheers,
Harv
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Sedandelivery
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Sedandelivery »

Thanks Harv, I took your advice re unregistered vehicle permits and took it back under that system. It took two permits because while the application asks how long you want it for in reality they would only issue the permit for one day. I thought that because this was a never before registered vehicle it didn't comply for a permit but as you know you fill out a suitable for use declaration and she's good to go....amazing! I even checked with my local rego inspection bloke because I could believe that any wanker could declare the vehicle fit for purpose......took it to the weighbridge at the same time as it was on the shortest direct route.....so that worked out well all round. Took the van over on a bright sunlight day, came back in pouring rain with a bit of 100kph running in the 102ks there and back. Only thing that failed was the demister and air conditioning because of a defective China glass fuse.....second time that's happened....the fuses look alright but there's no continuity through them....crap parts is an increasing problem these days! Cheers!
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Sedandelivery
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Sedandelivery »

Another comment for chop_shop who asked about the pedal arrangement in my 46.

Now that I'm reasonably confident that this transplant is going to work I can say what was done.....I have got some photos but their crap because with all the wiring and junk around the pedal cradle assembly you can't see much, however, in the Ozrodders workshop manual section for EF EL Falcons under General Brake Service fig 3 section 2-1-4 there's a diagram of the pedal cradle I used and It's all but a bolt in conversion. Where the master cylinder bolts to the cradle goes straight on the inside of the firewall with the booster and master cylinder on the engine bay side. The bolts either side of the steering column go straight under the dash below the standard control knobs etc, and their's a vertical bracket shown as bolting on in a Falcon that I've welded underneath the windscreen on my 46......Like I've mentioned this part of my build was probably the easist task for the results obtained.
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FRANK BASILE
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by FRANK BASILE »

Great to see some headway with the braking. Re the demist failure . I am puzzled as why they still supply/use inline glass fuses . More common today if not fuse block mounted ,blade fuses come with an in line holder.
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chop_shop
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by chop_shop »

thanks for the description and good news about your car passing.
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Tappet Head »

thanks for all the good goss, the info here will come in handy one day
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by jeffa »

Thanks for the update and details Sedandelivery.
Very handy for reference material in future (says he, hoping that the forum stays alive for those who need it!).
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Sedandelivery
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Sedandelivery »

Just an update on my compliance situation. After nine months batteling with a compliance engineer I took the plunge and changed engineers. What a difference, can't speak highly enough of Maddi and Peter from TacTicc certification, Mercury received NSW Conditional Rego today.
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Harv »

Congratulations 8)

Cheers,
Harv
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by Gojeep »

Well done mate. :)
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FRANK BASILE
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by FRANK BASILE »

Well done from me as well. I had a win yesterday myself. The 49 FI was compliance plated . Now for the RWC and a set of plates.
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FX Panelvan
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by FX Panelvan »

Just catching up on the forum now it is back :D :D :D :D :D :D :D :D

Frank

Some photos would be great.

Congratulations as well. Always great to see one finished.
regards

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thatold.chevy
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Re: 46 Ford Build Fails Brke Plate Test With High Pedal Pres

Post by thatold.chevy »

Damn - I'm wanting to run 4 wheel drums with no booster - but I'm in WA....?

8:1 pedal ratio for me then!
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