Brake Nightmare

[A80Avant]

Well, after a problem with my brakes looking pressure and becoming stiff on and off, until eventually becoming dead all together e have tried these so far without success:

1 new brake servo,
1 used brake servo without any known issues
3 different brake accumulators one being a used one,
1 steering pump new,

Tomorrow the brake master cylinder will be checked as well for the sake of things.

Am I sane to buy and replace the high pressure pipe going from the power steering pump to the bomb? That has always stayed thebssame as it doesn't leak or anything.

Can anyone make a suggestion before I torch the bloody car?

The right answer wins a trip to Greece IF i can afford it after all I have spent on the rs....

[bazburn]

I'll swap you, my brakes are fine...

[GazzaG60]

let me know what you need mate

[A80Avant]

i will contact you shortly

[amanda]

master cyl is the most likely culprit they tend to play up before a failure

[Rocco]

do you want my front brakes Vasilis??

[A80Avant]

Thats not the problem!

Master cylinder will.be replaced and checked.

[A80Avant]

anyone has the high pressure pipe in question by the way? item 8 on the photo

[A80Avant]

Small update:

master cylinder checked and works fine

pressure pipe above, number 8 checked and is open.

BUT the 2 bolts numbers 10 and 11 have a little mesh in there which although was cleaned and looked open, we thought of taking that mesh out and see what happens. We did order 2 more bolts just in case, so ....

the brakes seemed to work a lot better with those off, and no other issues. However they did loose pressure after 10-12 more vigorous pedal presses but the whole thing picked up pressure again fairly fast. This could be down to the fact that the used servo/bomb that is on the car now could be having some old age wear and tear anyway.

So on monday:

My servo will go back on, and be tested with those meshless bolts to see what happens. My bomb will also go on to see if the pressure is kept now. If not, then definitevly i have a broken servo and hence needs to be sent off.

I will update as i go, but i dont know what is the meaning of these meshes in the bolts. They should act as filtering devices but, the hydraulic fluid should be clean anyway. The bolts are restrictors and i assume that since the orifice that they have is tiny, the mesh is there to prevent a total blockage of the orifice at any point.

Once i get the new bolts, what i may try to do is make the smal 1 to 1.2mm orifice slightly bigger to see if that will act as a preventive measure to blockage now that the mesh is off. I will keep the new bolts aside for the time being.

[A80Avant]

Got word by the garage.

The car seems to be working fine with my own servo and master cylinder, as well as the bomb. So lesson learned...

For anyone who is starting to get pulsing feeling on the brake pedal, DO NOT spend money on a new bomb (let alone servos and the rest), but check to see if bolts 10 and 11 are blocked, and consider replacing them before the expensive bomb.

Im still waiting to see if these are actually normal banjo bolts without restrictors or mesh now, just to verify that audi may have actually updated those bits as the years went by...

I am told that the car is having perfect brakes now, so im picking her up for garage no2 on wednesday. Oil dipstick is still to be done.


hope this info will help the forum with similar brake issues...

[Big Lee M]

Was you having the ABS kicking in on only a little peddle pressure?

[A80Avant]

no
abs never kicked in on these occasions