I think your ABS kicked in. Had that happen to me once too on a panic brake. It feels as you are not braking but it is and making sure your brakes don't lock up.
I hope this helps you.

 

No I have always felt the ABS kicking in this wasn't like that I didn't have and kick back as you normally would with the ABS, the peddle just went hard. Well going to check out the brake fluid first, second take off a front and back wheel to inspect the brakes. The discs look unused (they are) but no ridge at the top of the disc. I think I might just get the brake fluid replaced as it is an unknown quantity.

 

That's a nasty experience and the ABS should certainly have kicked if you hit that pedal as hard as you say..

Have you used your VCDS to check for any faults?

Certainly you are right to change the brake fluid. It's a 13 stage operation you may want to leave to your local VW dealer tho' I know some DIY.

I'd get the calipers checked to make sure the pistons are all operating correctly.

Then I'd look at the pads and if they don't say PAGID, I'd replace them.

Finally, I think I'd get an MoT station to do a brake efficiency check.

 

That's a nasty experience and the ABS should certainly have kicked if you hit that pedal as hard as you say.. Have you used your VCDS to check for any faults? Certainly you are right to change the brake fluid. It's a 13 stage operation you may want to leave to your local VW dealer tho' I know some DIY. I'd get the calipers checked to make sure the pistons are all operating correctly. Then I'd look at the pads and if they don't say PAGID, I'd replace them. Finally, I think I'd get an MoT station to do a brake efficiency check.

Noobytoogy - what is special about the PAGID brake pads? I'm not being sarcastic; I really am indeed curious...

 

Sounds like it could be a leak in a vacuum hose.

 

EDITED

See page 28 onwards. This might help:

http://www.billswebspace.com/Touaregchassisandawd.pdf

It might also be worth carefully checking the brake fluid piping first.

You've just had work done on the front suspension units.

I wonder if there is a kink in the pipework or a flexible hose trapped/squashed/pinched?

Anyway, found this pretty comprehensive list too:

1. Faulty Brake Power Booster.
2. Worn, Damaged, or Faulty Brake Caliper.
3. Faulty Brake Master Cylinder.
4. Clogged, Kinked or Damaged Brake Hose.
5. Worn, Damaged, or Faulty Wheel Cylinder.
6. Damaged or Faulty Proportioning Valve.
7. Brake Pad/Shoe Contaminated With Grease or Brake Fluid.
8. Brake Pad/Shoe Wet From Driving or Standing in Water.
9. Glazed or Excessively Worn Brake Pad/Shoe.
10. Brake Rotor Is Glazed or Warped From Overheating.
11. Glazed Brake Drum.
12. Contaminated Brake Fluid.

 

I will be checking that lot out once it stops raining here. but from the list the only one I can clear off it is 11. they are not glazed. any ways thanks I will be checking those items very soon.....

 

I had this same thing happen to me earlier today - hard pedal, little or no brake response. This happened in Drive and Reverse. The more I worked it, the more brake there was. Pretty frightening.

 

Have this happen to me every blasted time I get a car wash. I have to be careful braking the first few times afterwards. I have narrowed it down to excessive water / soap on disks. Probably not what happened to you, but loads of water on cool brakes might as there is no heat to burn it off???? I don't know why of all the cars I have owned both my Treg's are so sensitive to this.

I am also pretty religious about flushing my brake fluid. A buddy of mine blew a line one winter day due to water in the line...seeing as brake fluid is hydrophilic I might perform this if not done in the last two years regardless.

 

Have this happen to me every blasted time I get a car wash. I have to be careful braking the first few times afterwards. I have narrowed it down to excessive water / soap on disks. Probably not what happened to you, but loads of water on cool brakes might as there is no heat to burn it off???? I don't know why of all the cars I have owned both my Treg's are so sensitive to this. I am also pretty religious about flushing my brake fluid. A buddy of mine blew a line one winter day due to water in the line...seeing as brake fluid is hydrophilic I might perform this if not done in the last two years regardless.

Thanks for sharing that! I have noticed the same thing after my Treg gets washed. And I think I will have the fluid changed too since I know it's been quite a while! I'd do it myself but from what I've read it's a bit if a "hairdo." Like as in a 13 step procedure...

 

Ian, your last sentence makes virtually all the suggested problems unrealistic. there must be something intermittent (or it is actually wet brakes from a deep puddle or whatever as that will give you almost that feel, just not the hard peddle initially). More likely a sensor for the brake booster for the right amount of vacuum or a similar issue. I haven't checked if the vacuum pump is constantly working or if it is switched by demand so what I have said may be a load of crock. John

 

Ask your dealer for a price.

It was so cheap at mine, albeit in the UK, it was a no-brained.

 

Ask your dealer for a price. It was so cheap at mine, albeit in the UK, it was a no-brained.

I've noticed certain dealers near me are WAY more expensive than others, so I'll definitely price it out

 

Regarding brake flush: I just make an appointment at a local dealer every few years. It isn't too expensive, but I typically couple the service with other flushes (radiator, power steering fluids, and oil change). Doing this doesn't save money, just time. This Monday it is oil and ATF fluid change...now THAT is expensive.

 

I did the ATF pan gasket & filter change recently - now the tranny shifts / feels "like butter." It wasn't that hard and there are a lot of helpful threads here. So many shops screw the procedure up that I thought it might be nice to do a DIY. It was worth it! Also, I retrofitted a Quick Valve oil drain plug and now oil changes are a breeze!

 

I tried the brakes after that at higher speed no problems. Any ideas would be gratefully received.

Ian, I would strongly suggest you have a responsible service engineer (knows V10's) to check the tandem pump on the V10 engine. This is a combination Vacuum and Oil pump that provides the vacuum for you brake booster. As you probably know Diesels produce virtual zero manifold vacuum.

In you description it was normal at higher engine speeds and the problem occurred in traffic where you would virtually at idle or not far away. If the Tandem Pump is not scavenging properly ( leaking internally) this would would require higher engine RPM to develop adequate boost. The fact that it worked correctly after the event virtually rules out most other suggestions. Water can also contribute, however the wetting must be almost immediately beforehand as accumulated heat in the brake combined with the spin of the disk will clear the quite quickly. However if you live in an area that is prone disk wetting there is an option (found in VDCS call Brake Drying) where it wipes the disk with with the pad every so many seconds to keep any water off them.

My money is with the Vacuum Pump.. I would not be doing much driving before this is checked as 2,5 ton is a big nail punch!

As to pads, they all work, some better than others, and some much better in the eyes of others. A lot comes down to personal preference. If like me you don't give a rat's about having dirty wheels, then may I suggest the TRW (Lucas) brand as I have found them very effective especially in extreme situations. Remember on thing, it is how you interface with the vehicle and feedback to you is critical for safe and enjoyable driving. Advice is useful, but experience is everything.

Stuart..

 

Ian, I would strongly suggest you have a responsible service engineer (knows V10's) to check the tandem pump on the V10 engine. This is a combination Vacuum and Oil pump that provides the vacuum for you brake booster. As you probably know Diesels produce virtual zero manifold vacuum. In you description it was normal at higher engine speeds and the problem occurred in traffic where you would virtually at idle or not far away. If the Tandem Pump is not scavenging properly ( leaking internally) this would would require higher engine RPM to develop adequate boost. The fact that it worked correctly after the event virtually rules out most other suggestions. Water can also contribute, however the wetting must be almost immediately beforehand as accumulated heat in the brake combined with the spin of the disk will clear the quite quickly. However if you live in an area that is prone disk wetting there is an option (found in VDCS call Brake Drying) where it wipes the disk with with the pad every so many seconds to keep any water off them. My money is with the Vacuum Pump.. I would not be doing much driving before this is checked as 2,5 ton is a big nail punch! As to pads, they all work, some better than others, and some much better in the eyes of others. A lot comes down to personal preference. If like me you don't give a rat's about having dirty wheels, then may I suggest the TRW (Lucas) brand as I have found them very effective especially in extreme situations. Remember on thing, it is how you interface with the vehicle and feedback to you is critical for safe and enjoyable driving. Advice is useful, but experience is everything. Stuart..

Pardon my ignorance but I read that the TRW's were low dust? My Pagid pads are almost through and I was planning on experimenting with the TRW. Any input? Thanks.

 

Look for this

FIXED MY PROBLEM! I took the rain tray apart and took line off brake booster. I hooked it up to a gauge and it jumped to 20lbs at start then dropped to 12 lbs soon after. So either a weak pump or a leak somewhere. I start chasing the vacuum lines and one of the little lines that goes to the egr valve was split right at the nipple. I cut out the bad section and replaced it. Tested vacuum again and it stayed at 20lbs at idle and went to 27lbs at 3k rpm. If you have any of the symptoms described above check these lines before taking it to stealership!!
Search tags: hard brakes brake booster vacuum pump tandem pump egr lines can't press brake peddle
This is the line pictured

 

Ah now I can add something to this, I have a leaking vacuum pipe that fits under the scuttle, up to now I haven't had the problem resurface but as the weather gets better my mecho will be doing the vacuum pipe. I have it already to fit. I don't like living with a if vacuum pipe but as we are disabled (both of us) and the car is needed for all short trips right now.

 

I had the same issue on my V10. Not sure if it's the same vacuum pipe as yours. The main dealer replaced it for me. The part was around £40 and the whole bill around £100 I think.

Hope this helps.

Mike

 

I had the same braking issue with the dealership diagnosing some leak in the vacuum hose. The technician put some tape on it and it works for now. The real repair was estimated at $1300 !!!

 

Yup. Those molded vacuum hoses are pricey! I had one that was cracked running from the vacuum pump back to the firewall. It was over the head and I think the heat from the exhaust below caused it to crack. I tightened it up with a hose clamp and vacuum assist no longer randomly drops out anymore and is actually better than ever.

 

I have no idea of the price to replace the vacuum pipe but the price is about right for the pipe itself £40 so now I have the pipe I can chose who to let do the job.

The tube is on the drivers side so in the uk the right hand side sitting in the car and under the scuttle there, yah I might just ask the VW garage how much to replace it, and just make sure I get a automatic loan car for the time or the day. I don't think it is a long job just awkward for me any way as it has to be done from the top,and the damned bonnet or hood gets in the way and hurts my neck which is part of my problems so just irritates the crap out of me.
Thanks for the notes though chaps. I will keep you all informed.
Ian

 

If the brake peddle does not travel it's normal distance then it is either lack of vacuum, as in my old range rover ( intermittent faulty valve in vacuum pump) or entire floor mat wedged under brake peddle ( as in my girl friends car).

 

There is a vacuum leak in the vacuume pipe that is under the scuttle, it is a pain to get at and my indy will do the job after this weekend, the rear brake calliper bleed on each side (so 4 nipples) are a bit corroded, so I have to get them out. VW will just use mountains of heat to get them out and in doing so will in all probability damage all the seals which will oh dear cost me a lot of money for there dumb ass approach to the problem. There are much more subtle and dare I say it engineered solution to the problem other than a Brummies Screwdriver and 5000 deg C of heat. However just in case they are more difficult to get out then I have in reserve two used but functioning callipers for both O/S and N/S. So it take me an extra 45 minutes to take off and replace callipers. But no point in trying to bleed the system until the vacuum pipe is replaced. See pictures for vacuum pipe.