Engineering tomorrow

[Modena]

twin masters with balance bar wouldn't have this problem

[gjkrv8]

Originally Posted by Modena

twin masters with balance bar wouldn't have this problem

Engineer told this is ok as long as you cant adjust it from the drivers position. i.e. On your back with spanner is ok

Rgds

Gregg

[boxhead]

You are right Modena, balance bar doesn't

[Merv and Sharon]

True as I understand but to get pads right is important first. With Commodore front and Nissan rear calipers and Falcon MC the combination can be tricky!

[byroncobra]

mmmmm I'll try the pads when they arrive on Monday....easiest n' cheapest option.
Let you know after a test drive.

[boxhead]

From memory they have 3 ports going out.
Anyone correct me if I am wrong as I dont have a XF type cylinder, but this is the same housing as fitted to my Valiant Hearse and pipes are as I have labeled.

[Zedn]

Mines pretty much the same except it comes out of the plug instead of the side.

[boxhead]

Interesting Zedn, I have seen cylinders like that before, just cannot remember what they where fitted to.

[Merv and Sharon]

Yes Liam that is right and the same as mine as yours. I was saying, "this is similar to the PBR MC", for the illustration of the sequence of springs, pistons, o-rings, etc. in the MC. Can't seem to find an internal schematic that is exactly the XF anywhere. Do you have one?

[byroncobra]

Yes, 3 outlets as mine, it's the XF m/cylinder. Can't find a schematic either Merv

[LT65]

I have a Gregory's manual for the XF can't post scanned pages here due to size of file but can email them to who ever wants them. Split point for sedan is 2.4mPa and 3.1mPa for goon and commercial. Apparently the figures are stamped in the end if the mc.

Hope this helps

[LT65]

Just checked my car the mc a reco unit is not stamped but the leaky one I originally sourced from a wrecked panelvan is stamped 3.1 on the end where the front brake ports are. However I did notice the rear brake port plugs are a different anodised colour the panelvan mc is green and the one in the car which I am assuming is a seden mc due to braking performance is red. Maybe coincidence can't really know.Maybe a bit more of the puzzle.

Lionel.

[Merv and Sharon]

Thanks very much Lionel. That would be useful, as these are hard to get. My (generic) email is mervhyde@gmail.com


Cheers,

[Outwest34au]

I have an EF wagon and an EF sedan here, (I know that isn't XF) but they both have numbers stamped on the end plug of different values, the wagon also uses different ports to the sedan. Never noticed the piping difference till this topic evolved.

Lionel, if you'd like to email the scans to me at gary@comdotau.com I can host them on one of my sites and post the results here in jpg or pdf as the crowd prefers.

[WKB]

On my car there are no issues with the brakes. All the components of the brakes are either new or reconditioned. I checked my MC and it had 2.4 stamped on it.
Now can anyone explain why some cars have no brake issues and others have on identical setups.

Warren

[Merv and Sharon]

Lionel has kindly supplied an XY schematic and the relevant manual pages for operation, disassembly and assembly:

[stumpeater]

Thanks Lionel & Merv for posting that schematic, very handy. I have one query, on the warning switch, there are 2 pins, I assumed they were opposite sides of the switch and hooked up one to earth and the other to the warning light, but it turns out it is actually an earthing switch, and the pins are joined inside the switch body, where does the second wire go to when used on the Falcon? I've got mine working by removing the earth wire.Thanks.

[boxhead]

Stumpeater, when you say "I have got it working by removing wire"
Are you saying that the dash light is on on your car until you remove the wire?
If so then I personally would say you have wired the switch correctly, and infact the switch has been tripped, to reset the switch, it is just a simple case of removing switch and pumping brake pedal a couple of times, then refitting switch.
No fluid should come out (if it does then there is a fault inside your master cylinder).

Forgive the rough diagram.

Originally Posted by stumpeater

Thanks Lionel & Merv for posting that schematic, very handy. I have one query, on the warning switch, there are 2 pins, I assumed they were opposite sides of the switch and hooked up one to earth and the other to the warning light, but it turns out it is actually an earthing switch, and the pins are joined inside the switch body, where does the second wire go to when used on the Falcon? I've got mine working by removing the earth wire.Thanks.

[Outwest34au]

Originally Posted by boxhead

Stumpeater, when you say "I have got it working by removing wire"
Are you saying that the dash light is on on your car until you remove the wire?
If so then I personally would say you have wired the switch correctly, and infact the switch has been tripped, to reset the switch, it is just a simple case of removing switch and pumping brake pedal a couple of times, then refitting switch.
No fluid should come out (if it does then there is a fault inside your master cylinder).
Forgive the rough diagram.

Thats what it is folks, say it 3 times slow or quick, just say it and know what it is.. "Pressure differential Switch !! Pressure differential Switch !! Pressure differential Switch !! " Thats what she said.
If you blow a hose or run short of fluid and the MC starts to pump air because your fluid evaporated for whatever reason, including worn pads and caliper pistons well extended and hence consuming all available fluid reservoir , too small reservoir, maybe a blown primary seal in the MC or whatever then the piston which is centred by a (relatively) light spring and balanced hydraulic force is displaced and a ramp activates the simple switch to mostly go to earth. This sparks up the dash lamp indicating brake fail or it is possible to have the handbrake and brake fail lamp connected so that either/ or will activate the lamp and having the ISO pic with brackets and exclamation mark (!) or similar is OK, but check with your approving person or locality.

Many people never think of the poor cheap thingy switch, but it is there to serve us and save. As Boxy pointed out if the light is on the switch is tripped. LOOSEN the switch a few turns to reduce the pressure on the spring activated pin then pump the brakes a few times to centre it (the balance piston).
The one rule that is rarely followed is,, When you bleed your brakes LOOSEN the switch a few turns, this will ensure the activation pin is not broken as the piston moves around and it will basically auto reset when the system is bled and all is balanced.

The switch is a very simple circuit that is easily forgotten about but even more easily managed. It's a PITA looking for a new switch if you break it on a sunday arvo.

Not lecturing, I just like to support the little bits that work for us.

Gary.
(spokesperson for often forgotten and neglected and mistreated parts)

[byroncobra]

Stumpy
I was scratching my head over the switch as well, on all the time, until i realised the 2 poles are connected inside.
The solution........the switch earths through the mastercylinder, so you only need a single wire returning to the dash lamp, ie 12v ign supply to the lamp, then the earth running from other side of lamp to either pole on the switch. When the plunger is pushed in by the piston (as per Gary's eloquent description) it completes the circuit and on goes the lamp.