8 replies to this topic

[newmac78]

Hi all,
I'm putting the brake lines in my project car - but as I'm starting from scratch I dont have anything to copy.
Obviously I have a rough idea of where it should all go (from the Moss catalogue) but I thought I'd ask you lovely people to nudge me back on track

I'm putting in a front/rear split system, so of particular interest is where the T piece should be positioned on the rear subframe (from looking last night I guess I drill a hole and bolt it in). I have the Goodrich braided hoses for front and rear so where do they poke through the subframe? Oh, I have a ready done brake kit, so everything is about the right length and ready flared for me to clip together, no troubles there at least!

Also which pipe should go to which connection in the PDWA on the bulkhead?

Any help would be lovely guys and galls! (Pictures would be awesome too)
Ta

[neil_g]

the rear T bolts to a bracket that is part of the rear subby.

rear braided hoses depending on the type you have connect to the radius arm one end and the other end bolts to the rear subby (see pic) were it connects to the hard line (see on the drivers side of the pic theres a small red item? thats the other end of the braided hose).

[newmac78]

Aaaahhh! So thats what those holes in the rear subby are for - cheers neil

Still not sure on the T piece, I dont seem to have a bracket (weird, it is a brand new subby after all)

As for the PDWA - I found this from supermotolee's project - this is the right system for me, right?

fairly self explanatory then...

Ta for your help - not doing it tonight though, its far too cold out there!

[Lomcevac]

Hope these help a bit.

Attached Files

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[Dan]

THAT IS NOT A PDWA!!!!!!!

Sorry, it winds me up that people keep on saying that no matter how many times you tell them otherwise. Still never mind, I suppose you can't educate pork.

That is an FAM7821 valve, if yours is of any age it's best to get a brand new one. Make sure it's fitted the right way around, as above with the cylinder section on the end pointing to the wing. The ports closest to the cylinder end are for the front circuit and the ports closest to the flat end for the rear. You also need to know which port is for front and rear on your M/C, and they are different. Also make sure you should have an FAM7821 and not a PDWA, the two do very different things.

There should be a tag on the rear subframe forward member, on the inside face about 8 inches to the right of centre which the tee piece should be bolted to.

Edited by Dan, 17 March 2006 - 12:30 AM.

[pikey7]

PDWA? (for future reference!)

[Dan]

Pressure Differential Warning Actuator. Basically an electrical switch that closes when there's more pressure in one of the brake circuits than the other. It's how the Mini and lots of other cars detected brake failure long ago before twin-circuit twin-reservoir systems became required. The twin reservoir system means that if one side of the brakes suffers catastrophic loss of fluid then the other side will still work so it's easier with this type of system to just detect low fluid which also has the bonus of detecting smaller leaks that PDWA's won't detect but low fluid switches will over time. Older systems had single or twin circuits but only a single compartment reservoir so if one side failed they both emptied, meaning that after a couple of applications of the brakes you lost everything. The PDWA does nothing else, no pressure regulation or anything, just closes a switch.

[pikey7]

Theres no wonder i'd never heard it before!

Ta for the explanation. Filed in the grey stuff for future use!

[newmac78]

Thanks for the info all - I should be able to sort the braking system out now.
Sorry Dan - didnt mean to unleash the beast in you! Yes, I do have a brand new FAM7821 valve, not a PDWA.