Brake pipe layout??

BryFlyinBy · 29-10-12, 08:13 PM

Evening people,

I need your help, I'm replacing the brake pipes from front to back on my coupe gt.

The problem is the 2 original pipes coming from the back to the front got in the way when I was manouvering the engine & box in the way and in amoment of frustration .......I cut them off.

To add to this annoying situation I changed the original servo and master cylinder to match the B3 brakes I fitted and the ports are differant too

Can anyone who has or knows what the B3 FWD, brake pipe set up looks like, give me an indication of which pipe from the back fits on which port on the master cylinder.....please

I'm afraid I cant even get a schematic on the internet

Thanks

Bry

4v6 · 29-10-12, 09:44 PM

Its probably a split diagonal system Bry.

You may have 4 ports on the master cylinder, if so, you need to run the two pipes from the rear that come from the load sensing valve and connect them similarly:

The black line across the master cylinder indicates the separated chambers.
By connecting them diagonally as shown, if one pipe loses integrity, the other chamber will maintain pressure to a front and rear wheel, do it any other way and a skid can occur if say the front died and all you has was rears. Hope that helps.

BryFlyinBy · 30-10-12, 09:23 AM

Tony you're a Star , thank you - it seems I'm coming to rely on your replies more and more

One question, that may or may not be relevant, seeing as both pipes are coming from the rear load sensing valve, does it matter which pipe goes at the front/rear of the master cylinder?

Thanks

Bry

4v6 · 30-10-12, 12:16 PM

Quote:

Originally Posted by BryFlyinBy

Tony you're a Star , thank you - it seems I'm coming to rely on your replies more and more

One question, that may or may not be relevant, seeing as both pipes are coming from the rear load sensing valve, does it matter which pipe goes at the front/rear of the master cylinder?

Thanks

Bry

Awww shucks Bry, ill go all red in a minute like the coupe.

Matters not which side you plumb it into initially as long as you keep to that diagonal setup.
Just try and set it up to be as neat as you can really and keep the fronts and rears as shown, left front and right rear, left rear and right front....

BryFlyinBy · 31-10-12, 10:23 AM

Ok Tony

I have a new problem, following our discussion on the matter I went out to pipe up the brakes only to find the new Master cylinder liberated from a late model N plate audi 80 cabriolet ( not sure if it made a differance ) only has 3 ports where the early model I removed had 4????
what do I do now ????

I'm assumng the cab had ABS but I cant remember it was a long time ago, the reason I liberated it was it being nearly new and and the brakes were used on mine too as they were bigger. So I thought it made sense to use the master cylinder/servo and braes from the same car but I didnt think about taking the ABS - can I get round this?

4v6 · 31-10-12, 12:19 PM

Im thinking that one of the three ports is connected only to the one side of the master cylinder?ie front or rear chambers?
You could still do it split diagonal but youd just need to add in a "t" to that single port so that you can continue to use it in the diagonal setup.
Chuck us a photo of the offender Bry.

BryFlyinBy · 31-10-12, 12:50 PM

Ok mate, been out with the camera - would have helped if I had done this earlier wouldnt it

Hope this helps

Bry

mikes2 · 31-10-12, 01:39 PM

3 pipes is normal. The rear only has one pipe from the master cylinder. It joins up to a T piece just above the rear suspension beam where it splits

Acidburn · 31-10-12, 02:58 PM

Quote:

Originally Posted by mikes2

3 pipes is normal. The rear only has one pipe from the master cylinder. It joins up to a T piece just above the rear suspension beam where it splits

Yup as above

and for referance the cab did have abs and afaik all type 89's do except possibly the very early one's.

4v6 · 31-10-12, 03:34 PM

You can just use two "T" pieces to give you the split Bry, no issues there.
That masters almost identical to mine except mines got the drillings for the pipes to be plumbed on either side, it all works the same though.

Same basic layout, just slightly altered runs.

31-10-12, 01:39 PM	#8
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	3 pipes is normal. The rear only has one pipe from the master cylinder. It joins up to a T piece just above the rear suspension beam where it splits __________________ 1991 90 quattro 20v sport 1991 90 quattro

29-10-12, 09:44 PM	#2
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	Its probably a split diagonal system Bry. You may have 4 ports on the master cylinder, if so, you need to run the two pipes from the rear that come from the load sensing valve and connect them similarly: The black line across the master cylinder indicates the separated chambers. By connecting them diagonally as shown, if one pipe loses integrity, the other chamber will maintain pressure to a front and rear wheel, do it any other way and a skid can occur if say the front died and all you has was rears. Hope that helps.

30-10-12, 09:23 AM	#3
BryFlyinBy Grown up member Classic Audi Club Member Join Date: Oct 2008 Location: Swindon, Wilts Posts: 641	Tony you're a Star , thank you - it seems I'm coming to rely on your replies more and more One question, that may or may not be relevant, seeing as both pipes are coming from the rear load sensing valve, does it matter which pipe goes at the front/rear of the master cylinder? Thanks Bry

31-10-12, 10:23 AM	#5
BryFlyinBy Grown up member Classic Audi Club Member Join Date: Oct 2008 Location: Swindon, Wilts Posts: 641	Ok Tony I have a new problem, following our discussion on the matter I went out to pipe up the brakes only to find the new Master cylinder liberated from a late model N plate audi 80 cabriolet ( not sure if it made a differance ) only has 3 ports where the early model I removed had 4???? what do I do now ???? I'm assumng the cab had ABS but I cant remember it was a long time ago, the reason I liberated it was it being nearly new and and the brakes were used on mine too as they were bigger. So I thought it made sense to use the master cylinder/servo and braes from the same car but I didnt think about taking the ABS - can I get round this?

31-10-12, 12:19 PM	#6
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	Im thinking that one of the three ports is connected only to the one side of the master cylinder?ie front or rear chambers? You could still do it split diagonal but youd just need to add in a "t" to that single port so that you can continue to use it in the diagonal setup. Chuck us a photo of the offender Bry.

31-10-12, 12:50 PM	#7
BryFlyinBy Grown up member Classic Audi Club Member Join Date: Oct 2008 Location: Swindon, Wilts Posts: 641	Ok mate, been out with the camera - would have helped if I had done this earlier wouldnt it Hope this helps Bry

31-10-12, 03:34 PM	#10
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	You can just use two "T" pieces to give you the split Bry, no issues there. That masters almost identical to mine except mines got the drillings for the pipes to be plumbed on either side, it all works the same though. Same basic layout, just slightly altered runs.