vacuum plastic nipple repair on EGR or ASV
How to repair broken vacuum nipple
This article shows how to repair a broken plastic vacuum nipple on the exhaust gas recirculation or anti shudder valve.difficulty: 1/5
The original article is at http://www.myturbodiesel.com/threads/fix-for-broken-anti-shudder-actuator-nipple.17652/ , please refer to that thread for support on this article. The original author is mirogi. A mk4 ALH engine is shown but this article can be used on many other engines.
Loctite Epoxy Plastic Bonder with 20-minute setting time
Many of us have found that by bumping the vacuum hose attached to the vacuum actuator on the anti-shudder valve, or by simply trying to remove the hose from the actuator, it is not difficult to break the nipple right off. And we have also discovered that the actuator is not available separately form the EGR/anti-shudder valve, that valve having a dealer price of about $320 or an aftermarket price of about $150-$220. Well, mine broke and I was not willing to pay for a new EGR valve. So, I developed a procedure to repair the actuator.
First, I wanted to take a look at the broken-off nipple. I had to slice the hose lengthwise to get the nipple out. This is the nipple:
I decided to try to attach a new, longer nipple to the actuator. I found a vacuum connector in my parts bin that is close to the diameter of the original nipple and cut it off to the length I wanted. I used a 5/64" drill bit to line up the new nipple with the passageway at the bottom of the "dog house." I then filled the "dog house" with an agressive caulk/sealant that I had on hand.
Well, the caulk didn't cure overnight so I decided to try something different.
I concluded that attaching a new nipple securely to the actuator is a more robust method. I CAREFULLY trimmed away the dog house until only a short nipple remained. I also used a hobby knife to scratch the surface of the actuator around the nipple, to aid in adhesion.
I looked in my collection and found a vacuum adapter that had one end that could be made to fit over the nipple and the other end that was the correct size for the vacuum hose. I trimmed it to length and bored out the large end to fit over the nipple on the actuator. I also roughed up the outside of the adapter to aid in adhesion.
Using Loctite Epoxy Plastic Bonder with 20-minute setting time (the only readily-available plastic adhesive made for use with nylon that I could find--beware, there is, apparently, another Loctite plastic epoxy that has a 5-minute setting time that does not mention being compatible with nylon), I glued the modified adapter to the nipple on the actuator.
Please note that I built the epoxy up around the base of the adapter in order to provide additional lateral support for the adapter (maybe it's overkill, maybe not). After the epoxy cured overnight, I found that the passageway was clogged. I CAREFULLY ran a small drill bit into the passageway at slow speed to clear the clog (do not run the drill bit too deep or you will ruin the actuator bladder). After drilling, I held the actuator with the nipple facing down and quickly pushed the actuator arm to expel any bits that may have fallen into the actuator can.
Here's the result--a vacuum actuator that holds vacuum and fits well in the engine compartment (note that I made the new hose a bit longer than might otherwise be needed in order to kink it around the EGR cooler hose).
And the car operates correctly! All for less than $10.
Since I just completed the repair this morning, I do not have an idea about the longevity of the repair (the long-term adhesion of the epoxy). I will update this thread should I experience any problems.
An afterthought: My original repair idea might have been more successful had I had the plastic epoxy on hand and used it in place of the caulk/sealer. But the integrity of the vacuum passage would not have been as sure as it is with my second method.