very annoying brake problem any advice please

Hi all.
Rite on with a series 3 todays mission was to tackle the brakes and I thaught the problem was with the master cylinder poss letting air through the seals so I bought a used pedel box sservo master cylinder and resiover today tested before removed and held a brake fine fitted to mine and used easy bleed on each corner and let alot of fluid flow out at least 2 litres each corner catching fluid in a airline and bottle and re using still no brake just nothing !
So tried bleeding with just airline on nipple to catch non return bottle again at least 2 litres of fluid through each still nothing if anything even worse than before if you pump pedel it will get a brake but fade away leave for a few mins and pedel goes straight to floor !!
Seen my arse now so any ideas what to check next ? Any help advive greatly appreciated
Looked through forum but nothing matches my problem so started a thread
Its a servo and pedel removed from a 90 on my s3 with pump connected
. Cheers

Forgot to add with the easy bleed on resiover it will hold a brake????

new master cylinder then ,pumping pedal to bleed system can bugger old seals and new if your a little harsh ,old m/c often do fail when bleeding as seals are pushed further through cylinder than they have been doing ,servo push rod to m/c can usually be adjusted to improve pedal travel

Thanks for reply is there any way of me testing to see if seal has failed or whats next best thing to do getting pretty bamboozled by it now

often there will be splashing in reservoir when pedals pumped if seals are gone, you can try isolating both fronts and rear by clamping flexis

Yes I do remember a splashing in res
So is it order a new seal kit? And bleed gently with easy bleex next time . Thanks

Well new brake pedel new servo and m/c still no beter argh!!!! Think im going to get a overhaul kit and re pipe and start again

d90matt said:

Well new brake pedel new servo and m/c still no beter argh!!!! Think im going to get a overhaul kit and re pipe and start again

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have you tried clamping flexis to isolate issue clamp all 3 then release one in turn each time checking pedal

I will try that in the morning I think there only flexi pipes on both fronts the rear are copper pipes to the cylinders. Cheers

rear has or should have a flexi from chassis to axle 3way

I will have a check thanks for that this is becoming really annoying now bloody brakes

Clamped rears off and thank you the problem is with rears got a good pedel on fronts only so need to felve in to rear drums and will prob just get s rear overhaul kit them fingers crossed job done

Well not got alot further today it already has almost brand new cylinders and shoes fully adjusted up to drum and still no brake blead system 10 times there a very faint brake right at bottom of pedel when its right go floor but very faint .
Any ideas what to try next I clamped rear off again and there is a awsum brake on front absolutely fine .
Could the problem lie with brake lines and t pice?? All seals are fine on cylinders and as said like new! Any ideas anyone please?

d90matt said:

Well not got alot further today it already has almost brand new cylinders and shoes fully adjusted up to drum and still no brake blead system 10 times there a very faint brake right at bottom of pedel when its right go floor but very faint .
Any ideas what to try next I clamped rear off again and there is a awsum brake on front absolutely fine .
Could the problem lie with brake lines and t pice?? All seals are fine on cylinders and as said like new! Any ideas anyone please?

Click to expand...

do you get a good fluid flow from bleed nipples,is there air in there each time you bleed it

Yes there was a little air each time very fine bubbles but was there and 1 nipple sometimes didnt want to pass fluid without a little step on brake pedel but then flowed ok

if it has air for quite a few pumps it usually means air leak is nearer the front ,pdwa valve can make bleeding rears harder if it shuts line flow

Just a silly comment. I hope with all this bleeding off you are not reusing the fluid and reintroducing air. Have you tried removing the bleed nipple that is slow and cleaning or replacing it ? When that is done try undoing the rear nipple one at a time and letting it gravity bleed on its own, just keep an eye on the master cylinder fluid level whilst you do this, it has worked for me in the past. My series 3 has a good "pedal".

No not reusing fluid done 10 litres in trying to sort this ! No amount of bleeding is fixing fault
Ive cleaned nipple up with no joy
Ive inspected all rear lines one side has a very small kink in copper pipe near the bolt head connection to cylinder that happened when I tried to remove pipe and slightly twisted the copper line but turned it back and seemed to go back to normal and let fluid flow.
So seen as its fine with rear flexi clamped off could it be a poss crack in pipe or air leak in rear connections to t pice or cylinders or even in copper line . Think new lines and flexi and t pice would solve it or am I miles off ???? Cheers

thats the only issue with copper pipes ,they rarely undo without twisting the pipe after theyve been on some time, is pdwa damp ,seals in cylinders perfect

Yea seals are perfect tbh they are brand spanking new was surprised when took drum off
Sorry whats pdwa ?