Brake Booster Failure?

[mydeathbynapalm]

So I've been dealing with a potential brake booster failure on my 2002 Golf.

I have replaced all the vacuum lines in the car, including the hard lined vacuum pump to booster. There has been no difference with those replacements. The white/black check valve appears to function fine as well.

Symptoms:
Brake pedal becomes hard(and seems to push back on my foot) after a few seconds of braking, and braking power diminishes to where I have to stomp on the pedal to stop.
I hear a hissing from within the driver's footwell when the brake pedal is pressed.

Short/abrupt stops are fine as the diminished braking comes after a few seconds of pressing the pedal. Brake fluid level is normal. Turbo boost seems to be functioning normally as well.

I haven't been driving the car day to day due to this issue. Is there a test to otherwise perform on the booster? Or are these signs pointing to a failed booster?(and I might as well dive into the repair)

Anyone in the immediate NoVA/DC area who has the pedal release tool? T10006a is the part number for the tool I think.

thanks.

 

[mydeathbynapalm]

No other insight?

 

[decanedemon]

If its pushing back i would think it is abs related. No Codes? The brake booster usually spits oil from the pedal rod or the seal on the outside? I think you have something else going on but hard to tell. You may want to get a diagnostic on the ABS/brake system done if you don't know what you are looking for. Brakes are quite important. I would stop driving this until you sort it out.

 

[mydeathbynapalm]

Car isn't being driven day to day. Parked in the garage... I've only taken it out on a couple short test drives after replacing various vacuum lines and such.
I will see if I can get someone over to run an ABS check. I am reading about stuck valves in the system and such...but I'm not experiencing any lockup. The push back is linear and gradual, not abrupt. And short stops are normal, it's when pressing on the pedal for more than a few seconds that the pedal becomes increasingly hard...and I am hearing the hissing noise.
Brake lines have been flushed on a regular(normally scheduled) basis as well FWIW

 

[decanedemon]

check to make sure you have the vacuum check valves back in the right direction if you moved them . Which other vacuum lines did you change? If i was you i would check all those and ensure proper routing according to the bentley.

Cheers

 

[mydeathbynapalm]

Check valve direction is correct and appears to function properly. I reversed it for kicks and boost went adios, and same issue on the brake pedal.
Vacuum lines have all been replaced.(within the last week with firm silicone lines) Routing is totally redone as EGR was deleted.(and has been for ~5 years, so nothing new with that)
Still trying to get a VAG-COM scan on the ABS...

 

[MayorDJQ]

You shouldn' be hearing hissing. Do you have a MightyVac ornsimilar vacuum tool? You could probably test to see of the booster is holdin vacuum.

 

[BobnOH]

has the fluid ever been changed? sounds like your booster or master cylinder, sure hope it's not

 

[Blownvette]

So I've been dealing with a potential brake booster failure on my 2002 Golf.


Anyone in the immediate NoVA/DC area who has the pedal release tool? T10006a is the part number for the tool I think.

thanks.

I watched mine being replaced and they just pulled very hard on the brake pedel and it came off, no tool needed. Was a easy job and the repair price was fair. Not worth doing it for what I was charged.

 

[mydeathbynapalm]

I watched mine being replaced and they just pulled very hard on the brake pedel and it came off, no tool needed. Was a easy job and the repair price was fair. Not worth doing it for what I was charged.

^^^^Who & where?^^^^
Not looking to pay for towing, and I am a fair distance away from Baltimore

As for the fluid ever being changed...every 2 years! And there was a partial flush when I had the TT brakes put on the front. Fluid shouldn't be the (cause of the) issue.

At least I have other vehicles to tide me over...

 

[Greaseburger]

Take a close look at the rubber grommet that the vacuum line plugs into on the booster, mine was split underneath and caused the same syptoms, it is still available as a seperate part from the dealer as well.

 

[mydeathbynapalm]

Meant to revive this thread. Repair completed.
This thread is a great DIY -

http://forums.vwvortex.com/showthre...and-Stability-control&highlight=brake+booster

Couple of additional points. Remove the metal knee bash plate under the steering column to gain better access to the nuts for the booster and such. Also, it is worthwhile to borrow the brake pedal release tool! And it was when I finally removed the metal knee bash plate that I quickly separated the booster from the pedal. A mirror helps too.

Also, they don't mention in that thread to loosen the 2 11mm brake line(from the MC) nuts on the ABS Unit when you draw it back out of the way. Do so. Undoing the 3 nuts that secure the ABS unit to have more play is also advised.(detach the wiring as well...pull out of the way)

Getting the booster out was a giant PITA. That was partly due to two rear-of-ABS-unit brake lines. I scuffed those on the way out, but no real harm done. I cut myself a small section of Typar(or Tyvec), do to its slipperiness and strength, to tape over those 2 aforementioned lines. If that was the trick that allowed me to get the booster in without hardly an issue, so be it.

I didn't need to bleed to brake system as I kept enough fluid in the reservoir.

I want to publicly thank Oliver (TdiRacing) for loaning me the brake pedal release tool and for a couple pointers on how to get this done right. But don't think he'll do this job for you...it's a killer on the back and neck! ...and I've got my youth...hah

Edit:

Oh...it was the bloody booster that failed by the way. Also... Just best to put Silicone vacuum lines in if they aren't already. And to replace the hard pump-to-booster line as well.
Cheers.