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Discussion Starter · #1 · (Edited)
Hi all,

I've recently replaced a major headache of a Vauxhall Combo van with a mk5 golf se 19tdi .

It has a couple of problems but the main one is the brakes.
The seller said they have air in the system but I very much doubt this.
I haven't tried the pedal when the engine is off but when driving or idling the pedal hits the floor, it does slow the car down but to come to a stop then I need to pump the pedal.

I haven't looked into it yet , I'm just looking for any info to help me, I'm guessing it's probably going to be the servo .

I will leave it there for now but any help would be appreciated.
 

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Why do you doubt the 'air in the system' claim?
First thing has to be bleed them - easiest, cheapest, imo most likely (unless there's evidence to the contrary)
And make sure it's done properly, not just the calipers..
 

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I had this same problem years ago when I upgraded my calipers, I thought I’d bled them through using the pedal pump/bleed method but these defo benefit from either a pressure bleed or a vacuum bleed


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Definitely pressure bleed the brakes first, did the previous owner have it standing around for a while? Does it look like they changed the callipers or did anything to drain the system down? If these loose enough hydraulic to drain up to the ABS unit it can be difficult even with a pressure bleeder - what you then need to do is an ABS bleed with VCDS/Vagcom (whatever it’s called). Mine had a sloppy pedal like yours, an ABS bleed fixed it in my instance.
 

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Discussion Starter · #6 ·
Why do you doubt the 'air in the system' claim?
First thing has to be bleed them - easiest, cheapest, imo most likely (unless there's evidence to the contrary)
And make sure it's done properly, not just the calipers..
Why do you doubt the 'air in the system' claim?
First thing has to be bleed them - easiest, cheapest, imo most likely (unless there's evidence to the contrary)
And make sure it's done properly, not just the calipers..
Thanks for your input..

I tried to bleed the brakes yesterday but only managed to get the front ones done (using pressure bleeder) .. I only had 1 x 335ml bottle of dot4 & it used the full bottle on the 1st brake line (n/s/f) with only a drop coming out into the jug I had to catch it , so I think he could be right about air in the system.

Could I ask you what you meant by bleeding it properly & not just the calipers? I always thought to bleed the brakes it was just a case of using the bleed nipple on the calipers?
 

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Discussion Starter · #8 ·
Definitely pressure bleed the brakes first, did the previous owner have it standing around for a while? Does it look like they changed the callipers or did anything to drain the system down? If these loose enough hydraulic to drain up to the ABS unit it can be difficult even with a pressure bleeder - what you then need to do is an ABS bleed with VCDS/Vagcom (whatever it’s called). Mine had a sloppy pedal like yours, an ABS bleed fixed it in my instance.
Thanks for your input

The previous owner said he replaced the brake hose and since doing so the brakes have been like so
 

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Thanks for your input..

I tried to bleed the brakes yesterday but only managed to get the front ones done (using pressure bleeder) .. I only had 1 x 335ml bottle of dot4 & it used the full bottle on the 1st brake line (n/s/f) with only a drop coming out into the jug I had to catch it , so I think he could be right about air in the system.

Could I ask you what you meant by bleeding it properly & not just the calipers? I always thought to bleed the brakes it was just a case of using the bleed nipple on the calipers?
You have to bleed the master cylinder too..

Or is it the ABS...

I forget...

@northpole which is it....
 

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I always do the complete system when replacing brake lines/pipes... so do brakes, ABS, clutch slave cylinder, than brake master cylinder... you'll need at least 1 litre brake fluid if you do it all. That way you make sure the system is air free.
 

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Discussion Starter · #11 ·
I always do the complete system when replacing brake lines/pipes... so do brakes, ABS, clutch slave cylinder, than brake master cylinder... you'll need at least 1 litre brake fluid if you do it all. That way you make sure the system is air free.
Thanks for your input mate.

I will have to youtube & Google bleeding the ABS & Brake Master Cylinder as I haven't done this before, I know how to do the slave Cylinder but I will look that up too just incase
 

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I always do the complete system when replacing brake lines/pipes... so do brakes, ABS, clutch slave cylinder, than brake master cylinder... you'll need at least 1 litre brake fluid if you do it all. That way you make sure the system is air free.
Thanks chief..... I can never remember.
It's why I send mine to the garage for brakes, too much of a pita.
 

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Discussion Starter · #13 ·
[
I always do the complete system when replacing brake lines/pipes... so do brakes, ABS, clutch slave cylinder, than brake master cylinder... you'll need at least 1 litre brake fluid if you do it all. That way you make sure the system is air free.
Hello again bud, I've just bled the brakes in the following sequence which I'm led to believe is the correct way..
N/S/F
O/S/F
N/S/R
O/S/R

I also found a video on YouTube showing how to bleed the master cylinder
Tube from the nearest caliper to the cylinder O/S/F , crack the nipple & pump the pedal (engine off) & making sure the reservoir is topped up & the tube is submerged at all times..
I've got a slight better pedal now but it's still sinking to the floor.
I I will bleed the clutch slave cylinder tomorrow & probably do the brakes & cylinder once more before getting a garage to have a look at it
 

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Worst case it is the brake servo that causes the problem... or a leak somewhere in the vacuum line going to the servo
 

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If someone can explain to me why there is an order to bleeding a system with ABS I'm all ears.
Explain why you think if you do it without bleeding the abs pump it doesn't matter... I have found that if you do it at random it can trap air and old oil.
 

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its been 16 years since i left the garage trade, without seeing the car and if the bleeding of the system was done and removed most of the air you should still get a pedal with the car off be it a bit spongey, it should not go to the floor and if it still does i would take a guess that the seals have flipped in the master cylinder, Vauxhall used to be really bad for this back in the day, if it was me and i was happy with the bleeding i would be changing the master cylinder.

A leak in the servo / vacuum system will not cause your pedal to go to the floor, all the servo does is assist in the braking power you apply when you push the peddle, all that would do is the peddle would be rock hard like when the engine is off.
 

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I've had that only on Fords never ever on a VW but it is the last thing i would've mentioned as mostly the brake master cylinders don't have this problem but hey it can always happen.
 

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Fluid comes from the master into the ABS module which is then split up via. solenoids in four separate directions - one to each wheel. You are attempting to remove air from each individual line which makes its way back to the ABS. The fluid will pass through the master in a constant flow through to the wheel you're bleeding - nowhere else. Air that exists in an existing line will be removed as you bleed it. Move to the next wheel and there is NO air in the master to ABS module because you removed it just before - now you're removing air in the single line from the module to the wheel.

I cannot understand how there is a specific way. In previous arrangements where opposite wheels were tied together at a meet point you could introduce air in the short left which can feed back upstream to the meet point and then be left - but not in an ABS system.
 
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