Ok so i put a new brake setup on the ratcer(sei track car with soon 1108 16v)
but we can't get pressure on the system.:bang:

At the front there are alfa 155 discs and calipers and at the back 155 calipers with panda discs. Still the original booster and master cylinder and pressure regulators.

WHY doesn't it work
what do we do wrong. We bleeded the system 3 times already

Either you've flooked the master cylinder seals (not difficult to do), you're not bleeding in the right order, or you have an air leak somewhere.

If you allowed the whole system to drain, there's the potential for a lot of air to get in there.

Some folk like Eezybleeds. I prefer vacuum bleeding.

http://www.ebay.co.uk/itm/Deluxe-Ha...d-Kit-Vacuum-Pump-Car-Motorbike-/200756420457

etc.

Is the flow rate of the master cylinder enough for the calipers you have? My Punto GT conversion was at the limit of the standard set up.

If you're serious about racing the car try a twin master pedal box. You can adjust front and rear bias more effectively (a godsend in wet or loose stuff) and know the masters are nowhere near their operating limit.

You can get a decent kit car pedal box for under £100 and the space freed up under the bonnet can be filled with more interesting things.

Fluid transfer ratio's comes to mind. The rear drum cylinders are quite small as opposed to the large cylinders for the disc callipers.

Thanks guys, talked to someone with uno turbo rear disc and he was running a single brake line to the back with a adjustable pressure regulator.

Fluid transfer was also one of our thoughts, how can i solve this?

Which way up is the bleed nipple? One folk on here or CC(slips my mind which) had issue and it turned out he had the callipers on the wrong way around,meaning they were always full of air. Maybe something along those lines?
EDIT: it was CC hope no one minds me posting this here! http://forum.clubcento.co.uk/viewtopic.php?f=6&t=11759&p=99257&hilit=Caliper#p99257

LeonL said:

Thanks guys, talked to someone with uno turbo rear disc and he was running a single brake line to the back with a adjustable pressure regulator.

Fluid transfer was also one of our thoughts, how can i solve this?

Click to expand...

You could have 10 lines running to the rear, but it would be the same equation. Go back to drums or fit a bigger master cylinder.

This been done before, I have done it with UT front and Alfa rear disc.

If you have no pressure what so ever on the brake then there is something wrong.

It will more spongy compared with drums, but is not too bad.

Quick question, your rear caliper, is the nipple pointing at the sky ?

Some people fit them wrong way round and it won't bleed probably.

There's the "nipple oriented wrongly" issue.

I don't like the rear disk set up (although I concede it might have advantages for some competition uses where you do a lot of handbraking or if you do a lot of trail braking on track). In normal attack mode the front wheels will do almost all the work -- even static the weight bias is something better than 60% to the front.

But it should work just fine with the stock master cylinder.

Think i have the calipers right but will check.
Will look for a bigger master cylinder tomorrow.
fingers, i chose for rear discs cause the car will be used for time attack eventually. and with 120hp as a target it feels nice knowing the car will stop.

LeonL said:

Think i have the calipers right but will check.
Will look for a bigger master cylinder tomorrow.

fingers, i chose for rear discs cause the car will be used for time attack eventually. and with 120hp as a target it feels nice knowing the car will stop.

Click to expand...

Trust me, if you're really going for it, the rear wheels will be in the air, doing absolutely nothing. A brake can only work when there's weight on the wheel! As a sort of proof of this, a fair few folk effectively plumb out the rear brakes on FWD track cars.

Weight transfer will always be onto the front wheels under braking (unless you're in reverse).

Most van aaken are 120 hp plus and running completely standard brakes. I've never found any bigger mc that'll fit but didn't look much eventually I'll run a proper pedal box with remote servo if I go much further with mine

Both big disk/drum and big disk/disk set up work fine with the stock master cylinder and servo.

All the people I know who've driven them back to back prefer the former, but there's not a huge amount in it.

The advantage, apart from the extra stopping power of the big disk conversion is, to my mind, better feel -- you'll loose that with a bigger master cylinder (which may be OK if you're used to modern, over-servoed cars). I just like being able to hold it on the point of lock-up time and time again.

Ok. To start with. Your rear calipers are upside down. But you know that already.
Don't you Leon.

This car will also be fit with a roll cage. So there will be some kilo's on the back wheels. And we can always play something with the suspension. Make it stiffer. Ore replace the fuel tank farther back inside the car.

And Leon i found your topic.... ?

May help. may not.

I'll be convinced when I see 80 - 0 times against a similarly equipped car without a roll cage and lap times against one with the fuel tank in the original location.

The obvious way to transfer weight to the rear is to put the engine there, but using the standard engine, this makes little sense.

Pretty sure that there's a 170+ bhp Cinq turbo running rear drums..........

Got the rear calipers right site up now

Any luck with the bleeding?

Not done yet

well as said by a few people, this has been done many times with the stock master cylinder without issues, myself included but with unoT rears rather than 155 ones..

I would point out though that Pauls old sei had alfa 166 3l V6 front brakes which are absolutely massive!! and 155 rears and that works fine on the stock master cylinder, as fingers says though the rears don't do much, that car can actually lift the rear wheels off the floor under heavy braking so the rears are only really there to look pretty haha. I do generally advise against the rear discs but i think it is excused on something intended for motorsport..

Let us know how you get on with bleeding

Hi Leon

I have punished my bog standard brakes on fast all forwards autotests without getting any fade and think the balance is pretty near perfect without any messing about, with a lovely "just right" heavy braking induced oversteer when entering a corner which suits my driving style.
I don't bother any more with left foot braking, I don't think it would work well on the standard setup and engine, but if you prefer to do that, and have more power I would imagine the discs would be great with an adjustable bias control fitted.
My own experience of rear discs is a woolly handbrake that won't always lock up, forcing you to go down the hydraulic route, which I suspect you may have to do.
The standard drum setup gives an excellent positive locking handbrake even on grippy tarmac, you just have to keep it well adjusted and free of siezed up linkages.
Sounds like you're going to have a great time in it - post a video when you have done some competing