B6 1.9 tdi : Braking issue

[lakers1234]

Hi guys

just bought a 2004 b6 avant 1.9 tdi

Braking at low speed is fine

but as soon as you take it on the motorway, and above 50mph or so, if you want to brake, it feels kind of like when you’re trying to brake on black ice where your brake pedal feels like you’ve got no control … or when you do an emergency stop and your brakes can’t take the force and start rumbling / crunching

The brake pedal doesn’t go completely soft but ever so slightly when the above symptoms occur.
It does brake , but just not so well.

Any ideas of what I need to do to check this or what it may be?

 

[norris_309]

When you're stopped (not sure if engine needs to be on or not.. try both) Press the brake pedal hard & hold it for a while. See if the pedal slowly drops to the floor.

I had an issue with a mk4 golf, where normal braking seemed fine around town, but trying an emergency stop wasn't.. it wouldn't stop you as expected.

This turned out to (thankfully) be a split in one of the brake pipes under the bonnet.
However, I didn't get the rumbling/crunching, so I'd probably be taking the brake pads out & inspecting them, you may have a pad that's coming away from the backing metal?

Another thought regarding the rumbling/crunching, you're not experiencing the abs kicking in are you? so pedal vibrating and making an awful noise... you can properly feel that on the pedal as the brakes go on & off fast

 

[jaluc61]

Have you checked the discs and pads ?