Bleeding mkiv brakes

[bungy 2]

I've fitted new calipers and have bled the hydraulic circuit using vag-com. The problem is that although the brakes work aggressively and the ABS kicks in i've got more pedal travel than before. I have done some research and think it may be the master cylinder that needs bleeding but i've bled that already and there is no air coming out of the master cylinder or calipers either. Any idea's or tips?

[cabrioman 6]

hmmm strange .... did you use a pressure bleeder ????

[bungy 2]

Yes I did.....

I've got no air coming out of the calipers and none coming out of the master cylinder but i've got long pedal travel with good brakes at the end.

[cabrioman 6]

hmmmm and u done the abs pump yeah .... hmmm strange

[craggsy 91]

im led to beleive that on the R32 that the bleed procedure is different to the furthest to nearest thing.

MAy be same on the 4mo

[bungy 2]

Going by the vag-com procedure you only do the front 2. When you've bled the abs pump this way then you bleed the rest in a set order.

[UnitedMotorsport 55]

How long is your pedal travel?

What is the piston area of the new callipers vs the old ones?

[bungy 2]

Hi Matt. Pedal travel is about halfway and the new calipers are the twin piston R32 ones.

[b road blaster 0]

i take it you have done both bleed nips on the m/c

when i changed mine it did take a few days/miles for the pedel to feel the same as it did before the change

[bungy 2]

i take it you have done both bleed nips on the m/c

when i changed mine it did take a few days/miles for the pedel to feel the same as it did before the change

Yeah, both nipples on the M/C. I put 7 ltrs of brake fluid through the system yesterday bleeding with the vag-com procedure. Good job i've got a trade card.

[b road blaster 0]

ok found the guide i use lol

first you need access to the front bleed nipples, i jacked up the front, placed on axle stands and removed both wheels.

then put the spanner, bleed tube and receptacle on each side.

open the brake fluid resevoir and have your fluid ready to keep the resevoir topped up at all times. i got a friend to do this to speed things up, it's probably possible on your own but will take a while longer.

goto ABS, basic settings blah blah whatever it is and click from 000 up to 001 and then you get a MSG on the screen saying "PRESS AND HOLD PEDAL" or words to that effect. whilst doing this the ABS pump is activated and the pedal can be felt kicking back

(002) it stops pumping and your told to relase the pedal and open the front 2 bleed nipples, then you need to click to continue

(003) it will tell you to wait for 10 secs whilst the ABS pump is activated and fluid is pumped out of the now open bleed nipples

(004) it tells you to pump the pedal 10 times and then close the bleed nipples, then you need to click to continue

(005) "PRESS AND HOLD BRAKE PEDAL" untill told to stop

(006) it stops pumping and your told to relase the pedal and open the front 2 bleed nipples, then you need to click to continue

(007) it will tell you to wait for 10 secs whilst the ABS pump is activated and fluid is pumped out of the now open bleed nipples

(008) it tells you to pump the pedal 10 times and then close the bleed nipples, then you need to click to continue

(009) "PRESS AND HOLD BRAKE PEDAL" untill told to stop

(010) it stops pumping and your told to relase the pedal and open the front 2 bleed nipples, then you need to click to continue

(011) it will tell you to wait for 10 secs whilst the ABS pump is activated and fluid is pumped out of the now open bleed nipples

(012) it tells you to pump the pedal 10 times and then close the bleed nipples, then you need to click to continue

(013) "PRESS AND HOLD BRAKE PEDAL" untill told to stop

(014) it stops pumping and your told to relase the pedal and open the front 2 bleed nipples, then you need to click to continue

(015) it will tell you to wait for 10 secs whilst the ABS pump is activated and fluid is pumped out of the now open bleed nipples

(016) it tells you to pump the pedal 10 times and then close the bleed nipples, then you need to click to continue

(017) ABS BLEED PROCESS COMPLETE

[bungy 2]

Yeah i've done all of that over and over again with no air coming out at all but vag-com doesn't like it for some reason and keeps repeating the process. About 200ml of brake fluid each cycle and i've put 7 ltrs through it and still not complete. I'm reading about restting the sensors, maybe that is where I need to go.

[legvw 0]

Those calipers will require more fluid to operate the pistons, but have you tried pushing the pistons back into the caliper, with the nipple open to see if there is air behind the pistons.

[Bigjobbo 0]

Are all the parts new? If your confident there is no air in the system (7 litres!!!) id let them run in and bleed them again.

[Lukey. 381]

have you tried leaving a block on the brake pedal overnight to try and let any bubbles in the system surface?

helped with mine, seems the VW ABS system is a real PITA to bleed, is it still teves20 on the mk4?

[bungy 2]

I did the block of wood thing last night and it's had all day to do its thing. I'll be driving it in a bit to see if it has worked.

[bungy 2]

Quick update. I took my car for a drive and with the engine off the brakes can be held firm at the top of the pedal travel. As soon as the engine starts the pedal drops some but the brakes still work from there on.

[b road blaster 0]

sounds like you just need a few miles on it mate to let everything settle down

[Lukey. 381]

yea i wouldnt be surprised if the pedal feel starts coming back to the top after using it for a little bit

[bungy 2]

The brakes do work well so I think i'll run it for a few days and then try vacuum bleeding instead.