T6.1 Brake Bleeding Problem

[solway19]

Hi all,

I hope someone can help! I have had my callipers off to paint. I have bled the brakes using a pressure bleeder at 2 bar pressure and started with front right, front left, rear right then rear left. When the engine is off I have a solid pedal but when started the pedal goes soft and slowly goes down. I have been through the above sequence several times and still the same outcome. Can anyone give any suggestions please? TIA

 

[Dellmassive]

there must be air in the system somewhere,?

or its leaking somewhere.?

are you loosing fluid level at the reservoir~?

 

[Paynewright]

There will be a difference in pedal feel between engine on and off. The brake servo assistance is only there when the engine is running.

Have you tested them to actually brake / stop the van or just stationery parked up?

If stopping is a challenge then there is still air in the system. Have you bled all 4 corners, furthest first? Are the callipers back on the right side ie bleed point at the top? Tapping the calliper with a rubber mallet while bleeding can help ‘free’ trapped air.

Ian

 

[solway19]

There is no leaks and I’m not loosing fluid. I have tried al sequences of bleeding still with no success.

I understand the pedal feels different with the server but the brakes are rubbish and the longer you press the pedal the more the pedal disappears.

There is definitely air still in there but I’m at a loss on what to do different to get it out. I was wondering if there was something I could do with vagcom to help.

 

[Dellmassive]

I'll have a look in the download section to see if we had a document covering brake bleeding procedure.

 

[Scottish Scrutineer]

I agree with @Paynewright, the pedal feel is very different with the engine running due to the servo assistance. Leave it overnight and check the pedal fee without the engine running. If it’s solid, then you’ve got all the air out.

 

[CRS Performance]

Hi all,

I hope someone can help! I have had my callipers off to paint. I have bled the brakes using a pressure bleeder at 2 bar pressure and started with front right, front left, rear right then rear left. When the engine is off I have a solid pedal but when started the pedal goes soft and slowly goes down. I have been through the above sequence several times and still the same outcome. Can anyone give any suggestions please? TIA

the pedal must be hard on the first press , if the pedal travels too far and several pumps of the pedal make it hard that is air in the system.
however. If the engine is running and you hit the pedal and keep force on it. The pedal does run away and creeps down. This is normal. It’s something to do with the abs pump.
when you drive the van does it stop normally and does the pedal feel hard on initial press down . If so everything is ok

 

[Howzat]

Changed my front disks and pads today and I also now have this issue.
With the engine off I need to pump 3 or 4 times then the pedal goes hard and stays hard but as soon as I start the van it goes soft again.
I can also hear the 'bike pump' noise before it goes hard as mentioned in this thread so I guess I have air in the system.
With the engine running the pedal is half way down before the brakes engage. Not good.

Question is, will the 2bar presure bleed method really push the air out the abs module without using OBD11/VCDS to activate the abs during bleeding?

 

[paxter]

did you get this problem sorted? i’m having the same issues atm, 2016 T6

 

[Howzat]

I got mine bled at my local National Auto Center via Halfords who had an offer at the time for a brake fluid change for £35. He used over 2 litres to fully bleed so ended up cheaper (and easier) than buying the fluid and bottle to bleed them myself. Was fine after that.

 

[DXX]

Changed my front disks and pads today and I also now have this issue.
With the engine off I need to pump 3 or 4 times then the pedal goes hard and stays hard but as soon as I start the van it goes soft again.
I can also hear the 'bike pump' noise before it goes hard as mentioned in this thread so I guess I have air in the system.
With the engine running the pedal is half way down before the brakes engage. Not good.

Question is, will the 2bar presure bleed method really push the air out the abs module without using OBD11/VCDS to activate the abs during bleeding?

Changing the pads / discs should never allow air into the ABS providing the reservoir has an adequate level.

 

[Paynewright]

When changing pads, I’ve started clamping off the flexi line and opening the bleed nipple when pushing the piston back in, to stop any crud getting pushed back up the line.

 

[Howzat]

Changing the pads / discs should never allow air into the ABS providing the reservoir has an adequate level.

I basically f***ed up. Did the rears one weekend with the res cap off then the following weekend forgot to remove the cap while doing the fronts.
TOP TIP: remove the res cap when changing pads!

 

[DXX]

I basically f***ed up. Did the rears one weekend with the res cap off then the following weekend forgot to remove the cap while doing the fronts.
TOP TIP: remove the res cap when changing pads!

Yes but the only air should be the airspace in the reservoir so by not removing the reservoir cap you pressurised the air in the reservoir which should have resulted in the caliper piston returning as soon as the push back tool was removed

 

[paxter]

do i need to brake bleed the abs pump with the computer? manually bleeding is not letting the air out

 

[DXX]

do i need to brake bleed the abs pump with the computer? manually bleeding is not letting the air out

The manual is available online with VIP Membership.
Normally that’s the process on most vehicles with ABS, I can’t say 100% for a T6.1 or a T6 as I’ve never managed to get air into the ABS unit.
Are you sure you have air in the ABS? That shouldn’t occur with a brake service, brake bleeding or a fluid renewal.

 

[Dundee_Kev]

do i need to brake bleed the abs pump with the computer? manually bleeding is not letting the air out

What have you been doing to the brakes to think air is in the abs unit?

You might need the computer on it to activate the pump, but very seldom you need to. Have you tried opening the nipple and trying to let it bleed on its own? What techniques have you tried so far for bleeding the brakes??

 

[paxter]

i had the van in getting the calipers painted. i don’t know what they’ve done but they can’t get pressure into the system, pedal keeps dropping to the floor

 

[FerrisBFW]

the pedal must be hard on the first press , if the pedal travels too far and several pumps of the pedal make it hard that is air in the system.
however. If the engine is running and you hit the pedal and keep force on it. The pedal does run away and creeps down. This is normal. It’s something to do with the abs pump.
when you drive the van does it stop normally and does the pedal feel hard on initial press down . If so everything is ok

You have read this right?

 

[Dundee_Kev]

i had the van in getting the calipers painted. i don’t know what they’ve done but they can’t get pressure into the system, pedal keeps dropping to the floor

Assuming they haven't let the system run dry, then it should bleed with ease. Unless they have mixed up the brake pads that can cause the pedal to be soft untill the pads bed in