Exhaust Flaps FAQ

Post by **rugbybloke** » Sat Aug 25, 2012 6:25 pm

Quick question, both my exhaust flaps are stuck in the closed position. Have given them a liberal spray of WD40 and will be leaving it overnight. My question is which way do the flaps open before I give them a
Gentle nudge. Should I knock the top or bottom of the flap to push it inwards?

Post by **Oh behave** » Mon Aug 27, 2012 8:11 am

Both of mine are stuck closed and lubed it for last three night but hasn't worked, into Audi next week.

You need to tap the bottom of the valve or bottom left for mine, if you look closely there is a faint line running across the circular plate which obviously contains the pin mechanism to allow it to open/close

Post by **Madmonkee** » Mon Aug 27, 2012 10:41 am

I used some soft copper pipe and a hammer, after plenty of lube i freed mine up. Once open use the bar like a lever and work the flaps

on and off it took about a week of doing this to get them working smooth again. The difference in noise is worth it!!

Post by **ArthurPE** » Mon Aug 27, 2012 10:17 pm

good info
thnx

Post by **RIV** » Mon Aug 27, 2012 10:48 pm

I used some soft copper pipe and a hammer, after plenty of lube i freed mine up. Once open use the bar like a lever and work the flaps on and off it took about a week of doing this to get them working smooth again. The difference in noise is worth it!!

I tried this out last night on the mrs her flaps are working fine now, and the noise well that's another story

Post by **rugbybloke** » Tue Aug 28, 2012 12:35 pm

Managed to get them open but they are incredibly stiff and now permanently in the open position. Will continue to lube / work them over the next few days and see if it frees them up.

Post by **bravoit** » Tue Aug 28, 2012 2:15 pm

I had the o/s exhaust flap stuck on mine sometime ago and used various lubes and the hammer/pipe technique to free it. I found wd40 to be not very effective and that rubbing a high temperature grease into the join where the valve mechanism meets the exhaust much more effective. I presume there is some sort of bearing in there?

Post by **adsgreen** » Tue Aug 28, 2012 2:53 pm

bravoit wrote:I had the o/s exhaust flap stuck on mine sometime ago and used various lubes and the hammer/pipe technique to free it. I found wd40 to be not very effective and that rubbing a high temperature grease into the join where the valve mechanism meets the exhaust much more effective. I presume there is some sort of bearing in there?

WD40 is not a lubricant (ignore the crap you read on the tin). It's a water dispersant (formula attempt number 40) that happens to have lubricant like qualities on a very small scale.
It's actually a very good degreaser so kind of the opposite of what you want once the mech is moving - it'll strip any remaining lubricant off the mechanism and allow dirt to get in. Also I'm not sure what it's high temperature characteristics are like. I prefer something like motorcycle chain lubricant as this is designed for heat and moving parts without attracting dirt.

Post by **Madmonkee** » Tue Aug 28, 2012 5:41 pm

I used normal engine oil on the actuator and some old old castrol penetrating oil which is probably carcinogenic now and banned! Worked a treat tho. They are stiff as the "old chap" in a European lap dance club to start, just work them

Post by **Coaster** » Thu Nov 08, 2012 9:57 am

+1 flaps are stuck closed. Audi declined to repair on the Approved Used warranty. £840 to replace!

Post by **adsgreen** » Thu Nov 08, 2012 11:44 am

if it's got FASH then worth pointing out that the mechanism should have been inspected and lubricated at each service so how have they seized if they were doing it properly...
Worth going after market too.
If you are going to replace them anyway worth poking something into the exhaust to see if you can free them. Although I can't recall which way they open so be careful!

Post by **Coaster** » Thu Nov 08, 2012 12:46 pm

Thanks! I had just seen that in this thread and may ask to see maintenance records if this gets 'sticky'! If Audi won't help I'll repair it myself as lots of others have clearly done already.

Post by **neckarsulm** » Sat Nov 10, 2012 8:00 pm

In addition to adsgreen's excellent write up, I used a long pry bar to push some open on an RS4 the other day.
Both sides were stuck completely solid, so much so I had to use a hammer on the end of the bar to get them moving
It's the inner of the two pipes in each tailpipe that has the flap and if you look in there the flap has a stop piece on the lower section of the tailpipe to park it in the correct postion when closed so to open it you need to apply pressure to the bottom half of the flap.

Interesting that spray lube doesn't work, I used a spray lube on mine religiously and it still started to play up. Will try some proper oil next time I work on one.

Presumably there is a diaphragm in the vacuum unit of each tailpipe, judging by diverter valves, surely this can fail in time? Do you reckon a seized mechanism would wear the diaphragm sooner as it's constantly trying to pull the linkage?

£840 per side is a frikkin joke and is one of the reasons why I wont buy another B7 for myself.

Post by **P_G** » Sat Nov 10, 2012 8:35 pm

Can you see that the valves are actually seized? If so, quick tip; Fairy power spray on them for 20 mins, then pressure wash it and then use 3in1 oil spray to lube. then try them. If you are positive therte are no vacuum leaks this gets the valves moving. Very rarely does the actual diaphragm fail.

Post by **wrekka** » Sat Nov 10, 2012 11:24 pm

Do the milltek ones also eventually seize up like this?

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