Air in the system (ABS)

bartekki · Post by **bartekki** » Thu Jun 25, 2009 7:45 am

Hallo!

i had to change the pipes because the have been rusty and changed also all gaskets in the rear calipers.

Now I am unable to get read of the air out of the system. I have even hanged (3 times!!) the whole brake head unit.

It looks always the same: ther is no air comming out of the bleeder. Only fluid without any air...

I am doing the front brakes in a 'traditional' way and the rear ones same as written her in the formum (open bleeder, pusching brake pedal, ignition on, 10sec, ignition off, leaving pedal, bleeder close). I have also tried with the over pressure maschine but it doesn't help anyway.

There is no air coming out of the bleeds but i fell that the pedal is quite soft, as if made of rubber... Also if i push the pedal (not hard) but quite fast, about 5...7 times after each other the ABS and brake warning lights are turning on.

What can it be? Is there any other 'trick' that you can not forget during the process? (I have got no Haynes where I could check it

) Is there any bleeder directly on the head unit...

Than you, and I hope that you can understand what i have wrote

bartekki =)

pol · Post by **pol** » Thu Jun 25, 2009 8:36 am

I think the brakes always have a spongy feel even when blead properly. Or is that just me. You seem to be more aware of it when doing the bleeding. I always just blame the ABS system as I know I've been doing it right.

Perhaps you have a leak in the system if yours sounds worse than this?

pol

bartekki · Post by **bartekki** » Thu Jun 25, 2009 8:53 am

Spongy felling... Maybe but before it wasn't this way. I've tested the breaks on the rolls and the breaks are working properly only while first few breakings (about 4, fast 'pumping' withe the pedal).

There are defenetly no leaks.

donaco69 · Post by **donaco69** » Fri Jun 26, 2009 8:46 am

Did you have the fluid resevoir off at all?

Not sure about the ABS system, but I was working on a Non-ABS system on my old 480. In the master cylinder there was a tiny one way valve type thing, little black pin. When I put everything back together i misplaced this tiny part and after I bled the system I experienced exactly the same symptoms as you are describing.
However I'm not sure if this applies to the ABS system, but might be worth a shot?

bartekki · Post by **bartekki** » Fri Jun 26, 2009 10:29 am

Did you have the fluid resevoir off at all?

no and yes...

no: it everything started after i just changed the rear caliper and a bit of rosty pipe.

yes: right now I have hanged the whole head unit in whih I have hanged all rubbers / gaskets but during doing i made notes, marked the positions of screws, so I am 100% sure that it is putted correctly back together...