[aprichards]

I have an Audi A4, 2003, while driving and without warning the brake pedal became very hard to press as if the servo had stopped working, exactly the same syptom as when he engine is not running. The fault is intermittent and very dangerous. Has anyone had this experience and if so how was it resolved. :confused:

[divadollz]

Audi A4 intermittent brake failure

Hi there

I am experiencing exactly the same problem at the moment, I drive an audi A4TDi sport, 2002. On several occassions now my brakes have done exactly the same thing - the pedal has gone hard with no response. It did it last week, and the brakes didn't come back, I had to get the car home using the gears and the emergency brake. But magically, in the morning, it is fine again. I had it in the garage most of last week, but they can't find anything wrong. I mentioned the servo but my garage said that if the servo fails, it fails outright, and they can't understand the intermittent problem. The mechanic has suggested it could be a problem with the master cylinder, so he is getting back to me today. But until I find out I am not driving the car.

If you find anything more out I would really appreciate it if you would post your info, and I will do the same. Cheers.

[Sussex Patrol]

Hi

Read this link-may be of some use Link

[marksmead]

A4 (2002) Brake Issue

Just had the same issue,, the brake pedal locking whilst driving...very un nerving...Had car looked at and is apparently the servo and the pipe - cost 700 plus...:mad: :mad:

not something I would expect from Audi - interested that there appear to be multiple insatnces of this, has anyone taken up with Audi?

[Haze1]

Hi my 2003 audi A4 brakes stopped working. after 3 visits to audi I checked all hoses and found the vacuum hose from the manifold had collapsed on itself and broken on the metal pipe that comes upwards from the manifold. The rupture was had to spot but it was on top of the rubber pipe above where the intake metal pipe was. I replaced the hose using proper vacuum rubber because the origial was so thin. The reason the brakes sometimes worked is because the system has an elecvtric backup motor which you can trace to the front right of the engine bay. Two brakes uses in a roww and the electric vacuum runs out. When refitting make sure the smaller id end of the pipe goes to the breather and the larger id goes to the intake pipe.
Paul

[snapdragon]

This is becoming a common problem on many VAG cars, it is usally the servo drawing in water through it's crimped seam and basically getting full of water so there is no room for the air to create assistance.
The crimped seal always leaks air, but a negligible amount, but due to corrosion, blocked plenum drains or generally a lot of water in this area, it can suck water in over a period of time. Be wary that this is most common on the TDis, and if you're not careful, it can fail and dump the water into the engine via the vacuum pump.

[jarydf]

Audi A4 Avant 2002 Brake Failure

This brake failure senario just happened to my wife.

Pedal went hard, no breaks to speak of and she sailed through the intersection rather than turning left as she had planned...:mad:

We have only had the car a month and the pedal going hard happened to me on the 2nd day similar to others describe - second press of the pedal was rock hard.

At the time I thought it was just that I was not used to the car's braking yet.

It is at the dealer now and the gent mentioned "vacuum hose" in that manner of "we have to check it all out throughly (but I have a reasonable idea where I will be looking").

Having read this forum and the other link provided before I went, I nonchalantly replied "probably crimping or a split..." to which he nodded.

It is all pretty disappointing I must say.
We bought the Audi because it was my wife's "practical, super safe, dream car" as she is pregnant with our first baby and the 8 airbags plus the works safety-wise seemed fitting. Now when something as mandatory as the brakes fail she is frowning and looking at her new pride and joy in a whole different light.

Meanwhile I am cursing myself for going back to a german car after years of trouble free motoring driving only cars built in Japan and swearing "never again" after owning a beautiful but ultimately reliability flawed Porsche.

I am sure that they will fix the line no problems but really unless I can come home to the wife and point to an obviously upgraded hose that looks l belongs in the space program the damage is a bit already done.

[Haze1]

Hello there,

Since I found the problem on my A4 the brakes have been fine. The reason you get one good use followed by no servo is because the electric backup servo provides enough vaccum for one use only. Audi should have a warning light on the dash for this. Since changing the vaccum hose which was so thin it was below spec the new hose has been fine. The original hose is a moulded piece of rubber with no reinforcing and collapses on itself. The cost of a foot of standard hose and three bends was less than ten pounds. I didnt check the audi replacement cost. Paul

[mmakari]

Audi A4 Brake Failure

Had the same problem.

Brakes failed while driving at 60 mph with whole family on board. Luckily survived it.

Took it to garage with your postings and spot on the pipes to the servo had collapsed. Asked them to replace all three to take no chances. Around £16 each plus an hours labour if that. The mechanic told me that the new pipes are made of stronger rubber, as though Audi where aware of the problem! There is no doubt in my mind that this was a design fault and should have been the subject of a recall- but can you imagine the negative publicity?

M.

[Haze1]

Hi there,

Glad to see the brake problem was fixed. I like the info about the new pipes being stronger and Audi most likely being aware of the problem. When I checked the original pipes they semed to have no reinforcing. My next problem is the CVT transmission hesitaing so much it is scary and last week it actually slipped on takeoff. My friend with an 04 A4 had her transmission replaced under warranty at 35,000 k ..... Time for a trade in. My 05 Subaru WRX is still going perfectly !!!

Regards Paul

[mmakari]

Time to trade in indeed

Yeah I also am on my next problem. the EMS light has come on. Audi manual- go to dealer. I instead have just ordered a VAGCOM cable from China for £3.65 (ebay) and will test it out. But in the short term I want shot of it. Once the problem is resolved I will be selling also.

M.

[curtc]

What was the fix? Did it work?

[ishcraig]

Im a tech at audi, give me faults and symptoms i might be able to help.
Notice to all; never buy an Audi platform vehicle with a Multitronic gearbox they have far to many faults to list!

[pomracer]

Originally Posted by aprichards

I have an Audi A4, 2003, while driving and without warning the brake pedal became very hard to press as if the servo had stopped working, exactly the same syptom as when he engine is not running. The fault is intermittent and very dangerous. Has anyone had this experience and if so how was it resolved. :confused:

I Google searched and came up with this forum which I have now joined to relay my experience .
My car is an A4 Avant quattro 2.5tdi, 2002. It has just clocked up 89,000 miles. It has full dealer service history. Just before its most recent service last week I expeienced the same terrifying brake loss as described in this forum - it happened to me twice, once at low speed when parking at home, and again when approaching a T junction...which grabbed my attention as you can imagine. What happened was that on first application of te brake pedal everything felt fine, then came off the brakes, then when i went back on for final brake to bring vehicle to a halt there was no servo at all. It was like having a block of wood under the pedal. Luckily there was no car in front and by giving it all I had got I brought the car to a halt as the front wheels went over the give way white line .
I do have some mechanical knowledge, and have a classic car which has no servo, so knew exactly what the pedal felt like. It was very clearly NOT a "soft pedal" or "increased pedal travel" ...the symptoms were as described elsewhere here. After the incident, the brakes worked as normal.
Bear with me please!
The car had already been booked into the dealer so I called them and described this fault, and mentioned the RAC Forum postings on this subject.
On checking the car in I went through the whole thing again with the Service desk asking them to check the servo.
They handed me the usual service paperwork and asked me to sign, which i did, then gave me another sheet to sign which they said was for some "recall work" which I would not have to pay for. I asked waht this was and was told "don't worry, it is not a safety issue, it is simply to clean out the plenum chamber" .....everyone reading this still with me???...I then asked what did they mean by "plenum chamber " as I was thinking they meant air intake or similar, and they told me that it was the area under the battery on the bulkhead that sometimes fills with water if drain holes blocked and it needed cleaning....
Fast forward to collecting the car:-
They went through the invoice covering all the items which included new rear discs and pads which I knew were badly worn. Having gone through everything , I was staggered that they had not mentioned the brake fault, so I asked what they had done about it. I was told that everything had been checked and no fault found. At this point I admit that I did start to get rather irritated and asked them if they were absolutely sure that the car was 100% safe to drive, and they assured me that it was. They then proceeded to lecture me about the rear barkes and how that the fact that the pads were very worn could have caused these symptoms - so I asked to speak with the mechanic (sorry, I mean technician) , as I knew that pad wear, however severe, could not have produced these symptoms - more pedal travel yes, or soft pedal, or even longer stopping distance, but not NO SERVO!- he confirmed that he had checked everything , and he was happy with the car, he had checked the vacuum pipes and so on. He did however listen to what I had to say and was going to look on the Audi computer to see if similar faults had been recorded.Have not heard back
Since the service, and the plenum chamber cleaning, I have done about 250 miles troublefree.
So the question is, am adding 2+2 and making 25, or is this plenum chamber cleaning recall linked to the servo failure scenario and they are keeping quiet about it??
The problem is that as always it is a case of your word against theirs. I am in my late 40's, drive about 20,000 miles a year, and into cars, own a classic car, have raced classic cars, and do much of my own maintenance on my classic. I do not hold out to be an expert but I do know the difference when it comes to describing brake 'failure' or problems.

[ishcraig]

:eek:I guarantee you the recall has nothing to do with brake failure, all that we do on the recall is check the drain tube is not blocked under the battery. Should it be blocked the only complaint that you would have is that the N/S (passenger side) interior carpet is wet!
This being due to the water level rising and entering the vehicle through the pollen filter.

[pomracer]

Ok - thanks for that.
But can you shed any light on this apparent servo failure??

[ishcraig]

The only thing im aware of is when there was a recall on the early A3's and '8D' chassis A4's which was on the servo pipe all the joints became brittle/cracked and had to be replaced by flexible rubber pipe.
If you live in the midlands im more than happy to take a look for you?

[Haze1]

Hello fellow A4 owners today I got the quote to repair the multitronic control unit. a mere $4,500 plus parts ( about 1600 pounds) Its a 2003 model with 134ks and in good condition worth about 6000 pounds so I dont want to spend the money on this lemon. Is there any other option Paul

[Haze1]

In regards to the power brakes my problem was a split servo hose between the engine and the bulkhead where it goes to the electric servo pump. Thats why the fault seems intermitent because the electric pump will provide you with one stop only.

Paul

[john b]

i have a problem with my audi a4 2002 abs warning light staying on traction control light is on also . was told by local garage that this was the switch on the abs unit that failed (in relation to the fault code that came up) but this has been replaced but not fixed the problem. any ideas, as i have been told that the whole abs unit will need replaced

[bytheseatofmy]

Brake Failure - what happened to me

Car: A4 Avant TDi 1.9 130bhp. 51 plate 02.

Approaching a roundabout on a duel carriageway at over 80mph - yes I drive too fast - I applied the brakes only to get a solid brake pedal and very little response, I re-applied pushing the pedal as hard as I could, used the gearbox to slow the car and managed to safely stop the car before the roundabout. Luckly the road was quiet, I had plenty of space, was on a good road and I was travelling in a straight line. The car was recover to a my local garage (not audi - i dont like the attitude of my nearest audi garage so use a SEAT garage instead) As soon as I described the problem they knew exactly what was wrong.

The bulkhead housing the servo unit had filled with water, this had entered the servo, master cylinder and break lines. As a result I had to have all the parts replaced along with a new set of discs all round, damaged by the breaking incident, they ended up jammed on, new pads and all brake lines flushed. The bill for this is huge and all because a small drain hole was blocked. A plug in the offending area has now been removed providing better drainage.

Now my point is that the garage were aware of the issue, infact it affects other Volkswagen models including Passat and also Skoda, so if its a know issue easily solved by removing a small rubber bung why havent I had a re-call letter to sort the problem and why was I in a situation which put my life and the life of other drivers at risk. Audi seriously need to address this issue asap before someone really gets hurt.

[davey_g]

Agree with a previous poster - seems to be a VAG fault with some models not draining water properly which is then sucked into the servo unit. Check out the VWAudi forum...several places you could look but try this:
http://www.vwaudiforum.co.uk/forum/s...ad.php?t=23548

[audiman1972]

Simular problem

Hi All,

Driving towards a traffic lighta and had to brake hard to stop. The brakes pedal totally depressed, car did stop not at the correct distance in my view but did stop.

However once stopped the pedal stayed fully down and I had to pull back up with my foot. Pumped the brakes a bit after and they seemed ok. This is the second time it has happened.

Is this the same issue.

Cheers

[Rolebama]

audiman1972, are you seriously saying that you have a known problem with your brakes, and have made no attempt at a resolution? You have now had the same problem twice, and you are asking on a Forum? Have you had a garage involved? Are you still driving the car?

[Watcher]

Brakes!!

Originally Posted by Rolebama

audiman1972, are you seriously saying that you have a known problem with your brakes, and have made no attempt at a resolution? You have now had the same problem twice, and you are asking on a Forum? Have you had a garage involved? Are you still driving the car?

I'd second that, but I also want to know WHERE you are driving so I can go in the opposite direction!:mad:

[Penge]

Numerous problems. Is the Audi A4 worth it?

Recently acquired one of these cars ( an A4) cheap but discovered lots of problems, mostly with the brakes, which comes as no surprise now I've seen ths board.

I'm wondering if it's worth keeping the car and fixing it up or scrapping it. Am I likely to encounter many more problems with it in the future. How reliable is the Audi A4?

Discovered these problems ... so far.

1) The car knocks really loud when turning hard right or left, mostly happens when turning in a tight right.

2) Something up with brakes at front, I think. ABS light and brake light comes up with a beep on comp display. And I can hear a grinding noise whilst driving.

3) Exhaust roars like a monster when accelerating and then rattles like mad, but Exhaust is not loose. You can hear me coming a mile off.

4) The engines stutters badly (as if it is going to cut out) at low revs, but usually stablilises after a while.

5) The gear changes are really choppy, and there is a hefty kick in the back (right in the kidneys, lol) sometimes when the gear changes quickly.

6) Car doesn't accelerate very well beyond 40/45 miles and hour. Tried pushing it and it seems to resist.

7) The oil is thick with dirt and sludge and the dipstick is broken around the point of entry.

I know what the problem is with the ABS light and grinding noise, and the knocking when turning - that's all I've found out so far. Had an estimate on the CV joint and brakes - about £300.

Someone suggested exhaust noise might be muffler/silencer? Or the cat. Both expensive to fix, I'm told. Mechanic says it's not worth keeping the car. Dunno if he's right...????

Oh and I forgot: the brake pedal vibrates under foot, but that's probably due to do with the brakes and CV joints being damaged.

[audicrash]

Please help

Originally Posted by ishcraig

Im a tech at audi, give me faults and symptoms i might be able to help.
Notice to all; never buy an Audi platform vehicle with a Multitronic gearbox they have far to many faults to list!

My son bought brand new Audi A4 S Line TDI Auto at end of July 2008 and four weeks later and only 1500 miles driven the car suddenly came to abrupt stop (son described it as if car had jumped from drive to park) and resulted in the car following smashing the backend heavily. The other car was a write-off but fortunately those involved were ok excepting whiplash and shock. The other driver apologised and said that he hadn't realised that my son had come to a sudden stop as there were no brakelights shown. My son is an experienced driver (20,000pa) and never been involved in an accident since he started driving 13 years ago. We don't like to think what might have happened if it had been on a motorway. Please ishcraig, with your background and expertise can you help us in any way. Can you suggest what might have gone wrong and where to look. We are led to believe by others working in your industry that there do appear to be rumours that this is a problem with Audi. Can you shed any light for us.
Thank you in advance of your help
TonyB

[stantheman]

Audi brak servo failure

Originally Posted by pomracer

I Google searched and came up with this forum which I have now joined to relay my experience .
My car is an A4 Avant quattro 2.5tdi, 2002. It has just clocked up 89,000 miles. It has full dealer service history. Just before its most recent service last week I expeienced the same terrifying brake loss as described in this forum - it happened to me twice, once at low speed when parking at home, and again when approaching a T junction...which grabbed my attention as you can imagine. What happened was that on first application of te brake pedal everything felt fine, then came off the brakes, then when i went back on for final brake to bring vehicle to a halt there was no servo at all. It was like having a block of wood under the pedal. Luckily there was no car in front and by giving it all I had got I brought the car to a halt as the front wheels went over the give way white line .
I do have some mechanical knowledge, and have a classic car which has no servo, so knew exactly what the pedal felt like. It was very clearly NOT a "soft pedal" or "increased pedal travel" ...the symptoms were as described elsewhere here. After the incident, the brakes worked as normal.
Bear with me please!
The car had already been booked into the dealer so I called them and described this fault, and mentioned the RAC Forum postings on this subject.
On checking the car in I went through the whole thing again with the Service desk asking them to check the servo.
They handed me the usual service paperwork and asked me to sign, which i did, then gave me another sheet to sign which they said was for some "recall work" which I would not have to pay for. I asked waht this was and was told "don't worry, it is not a safety issue, it is simply to clean out the plenum chamber" .....everyone reading this still with me???...I then asked what did they mean by "plenum chamber " as I was thinking they meant air intake or similar, and they told me that it was the area under the battery on the bulkhead that sometimes fills with water if drain holes blocked and it needed cleaning....
Fast forward to collecting the car:-
They went through the invoice covering all the items which included new rear discs and pads which I knew were badly worn. Having gone through everything , I was staggered that they had not mentioned the brake fault, so I asked what they had done about it. I was told that everything had been checked and no fault found. At this point I admit that I did start to get rather irritated and asked them if they were absolutely sure that the car was 100% safe to drive, and they assured me that it was. They then proceeded to lecture me about the rear barkes and how that the fact that the pads were very worn could have caused these symptoms - so I asked to speak with the mechanic (sorry, I mean technician) , as I knew that pad wear, however severe, could not have produced these symptoms - more pedal travel yes, or soft pedal, or even longer stopping distance, but not NO SERVO!- he confirmed that he had checked everything , and he was happy with the car, he had checked the vacuum pipes and so on. He did however listen to what I had to say and was going to look on the Audi computer to see if similar faults had been recorded.Have not heard back
Since the service, and the plenum chamber cleaning, I have done about 250 miles troublefree.
So the question is, am adding 2+2 and making 25, or is this plenum chamber cleaning recall linked to the servo failure scenario and they are keeping quiet about it??
The problem is that as always it is a case of your word against theirs. I am in my late 40's, drive about 20,000 miles a year, and into cars, own a classic car, have raced classic cars, and do much of my own maintenance on my classic. I do not hold out to be an expert but I do know the difference when it comes to describing brake 'failure' or problems.

Its just happened to me!-twice! Having read a few people problems re the servo brake failure..has it been establishe wethere it a gromit , or a servo pipr problems??
Thanks Stan

[stantheman]

Hi -did you get the problem sorted??-Its just happened on my Audi 1.9tdi-pretty scary...are audi dealerships Aware of the problem?
Thanks Stan

[remfanuk]

Hi Folks...my first post to this forum, unfortunately due to the problem that is discussed within this post.

I have a 2001 a4 tdi that some weeks ago exhibited a rock hard brake pedal...whilst going down a steep hill! i managed to stop and the problem disappeared seconds later. i went to a garage and they checked the car (how thoroughly i cannot know) and said what i described sounded like a servo issue but they could not see anything of note.

i have had no problems in the intervening weeks until today when the brake pedal is slow to return to the top of its travel and seems to be dragging...my question is this linked to the previous problem? what is the definitive answer, bulkhead grommet, servo pipelines, the servo itself???

i dont know whether there is a link here but another commonality between these two incidents is that the weather is extremely cold...-2 today and was similarly cold when the brake pedal went rock hard.

any advice would be most appreciated and also any light shed on the weather issue?

many thanks!