I decided to change the fuel filter yesterday and I discovered that the fastener that holds the plastic clamp in place is another one of Audi's favorite 12-point female pan-head jobs. Luckily, I still had the driver set that I borrowed a while back when I changed the front axles, so I was able to loosen the screw. Or so I thought. I discovered that the fastener was screwed into a square nut that is "captive" in the upper half of the plastic clamp. Somehow Audi's designers must not have been able to anticiapte the effects of Michigan road salt when they came up with this plan. Needless to say, the nut was turning in the plastic housing and there was no easy access to it while the filter was in place.
At this point I was considering just leaving the old filter in place, but instead, I decided to see what kind of damage I could do with a drill. In what turned out to be a backhanded stroke of luck, while I was drilling out the head of the bolt, it got so hot that it melted the plastic clamp and I was able to pull the bottom half loose. With that done, I could get the old filter out and get a better look at the nut. Because Audi apparently thought it necessary to use a very hard bolt, I had only drilled far enough to remove the 12-point arrangement (and with it any chance of using the drive bit to turn it). Like any good amateur mechanic, I turned to my trusty Vise-Grips to finish the job. I was able to get a 12mm open-end wrench on the nut, but it took a long time to remove the bolt because I could only turn it about a quarter turn at a time and it fought me all the way.
After all of that, changing the filter was easy, and I used another bolt with a large washer to hold it in place. The plastic clamp appears to be permanently attached to the fuel tank, so I don't think it would be easy to replace. Has anyone else run into this problem? If so, did you find a better way to attack it? I'd like to replace the clamp if possible, but I just don't see how. Any advice would be appreciated.
At this point I was considering just leaving the old filter in place, but instead, I decided to see what kind of damage I could do with a drill. In what turned out to be a backhanded stroke of luck, while I was drilling out the head of the bolt, it got so hot that it melted the plastic clamp and I was able to pull the bottom half loose. With that done, I could get the old filter out and get a better look at the nut. Because Audi apparently thought it necessary to use a very hard bolt, I had only drilled far enough to remove the 12-point arrangement (and with it any chance of using the drive bit to turn it). Like any good amateur mechanic, I turned to my trusty Vise-Grips to finish the job. I was able to get a 12mm open-end wrench on the nut, but it took a long time to remove the bolt because I could only turn it about a quarter turn at a time and it fought me all the way.
After all of that, changing the filter was easy, and I used another bolt with a large washer to hold it in place. The plastic clamp appears to be permanently attached to the fuel tank, so I don't think it would be easy to replace. Has anyone else run into this problem? If so, did you find a better way to attack it? I'd like to replace the clamp if possible, but I just don't see how. Any advice would be appreciated.
Junior Member
The exact same thing happened to me a few weeks ago. When I tried to drill out the 12-pt bolt, I melted the plastic enough to pull the entire bolt/nut out. After replacing the filter, I refastened the plastic clamp with a large zip tie. The filter is held up fairly well without the clamp (attached fuel lines hold it), but the zip tie really clamped it down to the fuel tank.
BTW, I also had quite an experience with the banjo bolt washers. Bentley says to replace the washers when you replace the filter. I got some washers from Napa that fit the banjo bolts, but the outer diameter was a bit larger, and probably of a different metal. Anyway, they leaked like a sieve, and gave me a good bath in gasoline. Then I went to Home Depot to find some better fitting washers, and I ended up with a kitchen faucet repair kit with rubber washers. The rubber washers worked fine, but I replaced them a few days later with the OEM Aluminum washers from the dealer. I wasn't sure how the rubber washers would react to gasoline over time. ECS Tuning also caries the washers.
BTW, I also had quite an experience with the banjo bolt washers. Bentley says to replace the washers when you replace the filter. I got some washers from Napa that fit the banjo bolts, but the outer diameter was a bit larger, and probably of a different metal. Anyway, they leaked like a sieve, and gave me a good bath in gasoline. Then I went to Home Depot to find some better fitting washers, and I ended up with a kitchen faucet repair kit with rubber washers. The rubber washers worked fine, but I replaced them a few days later with the OEM Aluminum washers from the dealer. I wasn't sure how the rubber washers would react to gasoline over time. ECS Tuning also caries the washers.
It's good to know I'm not alone! I also took a bath in gas, but it was because I was too lazy to relieve the fuel system pressure before a cracked the banjo fittings loose. I considered the ziptie option, but I didn't have one handy or I would have done that too.
I'm sorry to hear about the washers. I wish I could say that it was due to my good planning, but the only reason I didn't end up at Home Depot was that Blauparts included four new washers with the filter. I'm really starting to like those guys, especially after they threw in a few extra transmission pan bolts with their fluid/filter kit.
The car had just started to misfire, so I changed the spark plugs this morning and the NGK's I installed last year looked terrible. All I could find locally were Autolite 3923's, so those will have to do for now, but in the mean time it runs a lot better. It's always great (especially with this car) when something inexpensive solves the problem! I guess it's still better to be lucky than good.
I'm sorry to hear about the washers. I wish I could say that it was due to my good planning, but the only reason I didn't end up at Home Depot was that Blauparts included four new washers with the filter. I'm really starting to like those guys, especially after they threw in a few extra transmission pan bolts with their fluid/filter kit.
The car had just started to misfire, so I changed the spark plugs this morning and the NGK's I installed last year looked terrible. All I could find locally were Autolite 3923's, so those will have to do for now, but in the mean time it runs a lot better. It's always great (especially with this car) when something inexpensive solves the problem! I guess it's still better to be lucky than good.
Junior Member
I'm seeing a lot of questions about this plastic fuel filter clamp. I'm new to the forum, so here's my first suggestion:
The clamp is part of the tank and not available seperately from Audi.
The way to keep everything intact and not mangle anything or resort to zip ties (at $109 an hour, even the dealers do it,ugh):
If captive backing nut spins in the plastic clamp, it is important to tap the fuel filter out of the clamp to permanently eliminate the problem. It was easy for me because the fuel filter I was replacing had an identification sticker wrapped around it. First I loosened the banjo bolts holding the fuel lines to the filter (old style). The fuel leaking out melted the addhesive of that sticker which acted as lubricant. This helped me tap the filter forward and out of the still tightened clamp (after all, it is only plastic). With that out of the way, now you can work on the clamp. The triple square bolt is seized to the nut by rust but definitely not rusted together. This is because, as I found out, Audi did take some care by making the nut out of brass. So, you can feel confident in it coming loose by using a Vise Grip to squeeze the nut into the clamp. Done right, nothing will be damaged. I then cleaned the nut down to bare brass and chased the threads with a 6MM x 1.00 tap.
I cleaned the surface of the plastic clamp with acetone and then glued the nut back into it with epoxy for plastic. I cleaned the Torx nut and coated it with anti-sieze. That solves the problem so filter replacement is a cinch the next time. Want to go a step further? Replace the triple square bolt with a 6MM x 1.00 stainless steel button or hex head bolt.
The clamp is part of the tank and not available seperately from Audi.
The way to keep everything intact and not mangle anything or resort to zip ties (at $109 an hour, even the dealers do it,ugh):
If captive backing nut spins in the plastic clamp, it is important to tap the fuel filter out of the clamp to permanently eliminate the problem. It was easy for me because the fuel filter I was replacing had an identification sticker wrapped around it. First I loosened the banjo bolts holding the fuel lines to the filter (old style). The fuel leaking out melted the addhesive of that sticker which acted as lubricant. This helped me tap the filter forward and out of the still tightened clamp (after all, it is only plastic). With that out of the way, now you can work on the clamp. The triple square bolt is seized to the nut by rust but definitely not rusted together. This is because, as I found out, Audi did take some care by making the nut out of brass. So, you can feel confident in it coming loose by using a Vise Grip to squeeze the nut into the clamp. Done right, nothing will be damaged. I then cleaned the nut down to bare brass and chased the threads with a 6MM x 1.00 tap.
I cleaned the surface of the plastic clamp with acetone and then glued the nut back into it with epoxy for plastic. I cleaned the Torx nut and coated it with anti-sieze. That solves the problem so filter replacement is a cinch the next time. Want to go a step further? Replace the triple square bolt with a 6MM x 1.00 stainless steel button or hex head bolt.