Soft brakes after disc,pad,line and fliud change

[ghettokartel]

Hi Guys,

Last weekend A friend of mine helped me change the standard disc's on my A4 fsi 2'0l petrol and put some drilled and groved black diamond ones. we also put black diamond predator pads and changed the standard brake line's for hel s/s braided. finally we changed the standard dot 4 fluid and put a dot 5.1 silicon fluid.

since these changes my brakes have been really soft and my stopping distance is about twice what it used to be. after bleading the brakes a second time there was some improvment but not much.

I have been advised by Hel and black diamond that i should use a dot 4 flid and this should solve the problem. I was told by a garage that as I did not use a diagnosis machine to pump out/replace the old fluid there maybe air in the servo (no warning lights present) so he advised I should put dot 4 using a machine!!!

All very confusing, any advise will be a great help. thanks

 

[old-git]

My son had a lot of problems bleeding his S3 when he replaced the rear suspension.

One thing you shouldn't do it push the brake pedal fully to the floor as this can flip the seals in the master cylinder!

We finally achieved a firm pedal after many hours of bleeding - back to front, front to back and side to side

 

[obi_waynne]

The dot rating is irrelevent here. Brake fluid is brake fluid, most do not understand what dot 5.1 is and will point as this as being the problem. I've used it with no issues but bleeding the brakes is an issue and takes time.

 

[ghettokartel]

Thanks wayne, and do you think that not using a diagnosis machine to do the change may have damaged the servo? personally I dont think so as I have done loads of manual fluid changes on toyota 4*4's whislt living in africa and we certanly didnt use no machine!

 

[obi_waynne]

I too really doubt it.

 

[obi_waynne]

There is also a break in coating on the pads that needs to burn off and everything beds in over time so it can only get better.

 

[Yugguy]

Er, something is tickling the back of my brain, iirc when I had my Bora brakes bled about 18 months back, for a fluid change, the mechanic told me it had to be dot 4 as VAG cars didn't like 5.1.

 

[obi_waynne]

Never realised that! I wonder why that is?

 

[obi_waynne]

Dot 5 and 5.1 are different beasts. Let's just make sure we're talking about the same thing here.

I've also heard that you can't go back after using 5.1 as it is really hard to drain it all out.

 

[Yugguy]

Dot 5 and 5.1 are different beasts. Let's just make sure we're talking about the same thing here.

I've also heard that you can't go back after using 5.1 as it is really hard to drain it all out.

Yes, that was it. It was to do with mixing the two types.

 

[ghettokartel]

Right, i have used a dot 5 fluid, not a dot 5.1. dot 5 is not mineral based, its silicon. I have read the instruction and it says that the dot 5 can be used togeather with a diffrent dot fluid but it will spoil the dot 5 fluid meaning it will retain moisture as normal brake fluid does and will boil at the same tempraure as the dot 4.. so do you guys recomend i re-bleed it?

 

[turbonutter69]

I'd say you should re-bleed the brakes and go from there.
Is everything all done up tightly no leaks?

 

[T9 man]

I'd say you should re-bleed the brakes and go from there.
Is everything all done up tightly no leaks?

I agree! also the difference between 5.0 and 5.1 is that 5.1 is specially formulated for use with cars that have ABS! I upgraded my own from 4.0 to 5.1 a few months ago now when I had the last lot of monster brakes fitted.
Also did you bed the brakes in after the brake works were finished? On all of my brake systems that I have had over the years which include new discs and pads, i have always taken the Beast out for a spirited drive then use the brakes heavily to remove the protective coating on the pads. Was advised to do this years ago by a mechanic who said that I would experience the same symptoms as you if I did not.

 

[herb]

i presume most of the original fluid came out whilst changing the hoses. so there is a good chance the abs system ran dry. so vagcom is needed to bleed the abs system. plus are you bleeding the brakes the old fashioned way 1 pushes the pedal down while the other loosens and tightens the bleed screws???
if so i would recommend an eazibleed kit like this 1 they are easy to use!!
also did you just bleed the 4 nipples on the calipers??? cause if yours has the same braking sytem as mine (good chance with vag) there are 7 bleed nipples the 4 obvious 1's, 2 on the master cylinder and 1 for the clutch

 

[old-git]

Also did you bed the brakes in after the brake works were finished? On all of my brake systems that I have had over the years which include new discs and pads, i have always taken the Beast out for a spirited drive then use the brakes heavily to remove the protective coating on the pads. Was advised to do this years ago by a mechanic who said that I would experience the same symptoms as you if I did not.

Ouch, Never listen to what 'mechanics' advise as they usually know SFA about anything technical, all they do is replace parts!

Take a look at this, I think it is pretty definitive:

http://www.stoptech.com/tech_info/wp_bedintheory.shtml

 

[T9 man]

Ouch, Never listen to what 'mechanics' advise as they usually know SFA about anything technical, all they do is replace parts!

Take a look at this, I think it is pretty definitive:

http://www.stoptech.com/tech_info/wp_bedintheory.shtml

Cheers OG! It looked like he got the first bit right anyway
Good reference material there, will keep this in my files! many thanks

 

[pgarner]

quick question, what order did you bleed the brakes ?

dont go by looking at the servo and working what ones furthest away as the lines run funny in VAG - to do with them being converted form LHD the lines are still in the same place but the servo is moved and lines extended.

should be
rear driver
rear passenger
front passenger
front driver
clutch
master cylinder

failing that you may need to vcds bleed the ABS pump. i needed to do this after my brake pipe burst

im using halfords own 5.1 and fine the brake pedal is pretty much solid.

as for my bedding in normally do have a dozen 30 - 10mph then some 60-10 before driving a few miles without braking to allow the brakes to cool then do the same again

 

[T9 man]

quick question, what order did you bleed the brakes ?

dont go by looking at the servo and working what ones furthest away as the lines run funny in VAG - to do with them being converted form LHD the lines are still in the same place but the servo is moved and lines extended.

should be
rear driver
rear passenger
front passenger
front driver
clutch
master cylinder

failing that you may need to vcds bleed the ABS pump. i needed to do this after my brake pipe burst

im using halfords own 5.1 and fine the brake pedal is pretty much solid.

as for my bedding in normally do have a dozen 30 - 10mph then some 60-10 before driving a few miles without braking to allow the brakes to cool then do the same again

Snap! I have the Halfords own 5.1 and I cannot fault it, and my mechanic advised much the same regime for the brakes bedding in procedure

 

[ghettokartel]

Right,We did the bleeding in the way setout in the haynes manule which is as follows.

front pas
front driver
rear pas
rear driver

we Didnt bleed the master cylinder,or the cluch or anything else. do you think that this maybe the problem. do you think that I should go to the garage and get them to rebleed everything/and if so how much will they charge me? I have a booking on saturday to fit an H&R lowering kit which they want £80 for so I will try and get it done at the same time.

How much is the Halfrauds dot 5 per litre

 

[ghettokartel]

PGARNER... Whats a vcds bleed?

 

[Yugguy]

PGARNER... Whats a vcds bleed?

it's a bleed controlled by the diagnostic software.

 

[ghettokartel]

oh,ok. do they bleed all the points at once or is it one at a time like a convetenion bleed?

 

[herb]

oh,ok. do they bleed all the points at once or is it one at a time like a convetenion bleed?

1 at a time and pg has given you the order to do it on post #17

 

[ghettokartel]

Oh, OK. PG'S order and the order in the Haynes manule are diffrent. The say front pas,front driver,rear pas then rear driver. Do you think is should disregards this and use PG'S method?

Many thanks:blink1:

 

[herb]

Just checking but you do have abs dont you?

 

[pgarner]

dont use dot 5 its ether 4 or 5.1

the vcds bleeds the abs pump. cant be done any other way - just uses the front brakes to clear.

the haynes manual sounds wrong as you start furthest from the MC and works towards the closest

 

[obi_waynne]

I'm not sure you can flush dot 5 easily. I'm sure I read somewhere it is a real pain to clean out but dot 4.1 or 5.1 is the stuff you need.

 

[ghettokartel]

Hi Guys,

Got my brakes re-bled in a nice little garage in northampton. The guy also bled the cluch and master cylinder and the results are stunning.I can stop on an six-pence now!!

I am really happy with the pads/disc'sI bought. Have any of you guys ever used the drilled and groved Black Diamond disc's along with their predetor ads? I would recomend them,They really are the business!!

Thanks for all your advise on the bleeding..

 

[T9 man]

Hi Guys,

Got my brakes re-bled in a nice little garage in northampton. The guy also bled the cluch and master cylinder and the results are stunning.I can stop on an six-pence now!!

I am really happy with the pads/disc'sI bought. Have any of you guys ever used the drilled and groved Black Diamond disc's along with their predetor ads? I would recomend them,They really are the business!!

Thanks for all your advise on the bleeding..

Can't say I have ever used the Black Diamond disc's or Predator pads, but i'm very very happy that you can now stop on a sixpence! this means that I can now pass through your neck of the woods without you crashing into my beloved chariot

 

[obi_waynne]

I've heard good stuff about them, I'm glaqd you've got it sorted now.