Tech Tip: Don’t Take your Injector Seals for Granted!

If you can remember to change your injector seal after every 10 windshield repairs, it will help you avoid increased repair times, wasted resin, and most of all, poor quality repairs. Read on and you will learn even more about injector seal replacement.

Q: Why should I change the injector seal after every 10 repairs?

A: After 10 repairs, the inside walls of the seal begin to wear. This can allow resin to blow past the piston and up into the injector while you are applying pressure to the damage. When this happens, even though the seal is not visibly leaking, your pressure and vacuum cycles will be less effective. This opens the door to poor quality windshield repairs.

Q: Should I flip the injector seal around and use it the other way to get more life out of it?

A: No. It’s not typically the end of the seal that wears out, so there would be no benefit to switching ends, even if they were exactly the same. If you look carefully at both ends of the seal, you will notice a stamp that reads “This Side In” on one end. That side is not a flat surface, due to the writing that’s stamped onto that end of the seal, meaning it will not seal properly if that side is placed against the glass. Both ends are not the same, but the differences are subtle enough that many technicians may not notice the difference without that writing. You will also notice on the end of the seal with the writing that the hole is flared out slightly. This is to make the injector slide in easier. On the end of the seal that touches the glass, the hole is tapered in slightly to create a bit more pressure just as the resin enters the break, and to help prevent leaking.

Q: What if I forget how many repairs I’ve done with my seal? How do I know if it needs to be replaced?

A: The obvious sign of an old injector seal is a constantly leaking injector. When your injector is leaking, that means that you are losing pressure and vacuum. With reduced pressure and vacuum, the repair will take much longer and make the damage more difficult to completely fill. Other signs of a worn out injector seal are the excessive flaring of the seal as it meets the glass, and being able to push the piston all the way down without resin leaking from the injector seal.

Q: What can I do to get the most out of my injector seals?

A: Make sure not to over tighten your injector when you are positioning it over the repair, and try not to press your injector plunger all the way down into the seal. If you are using seven drops of resin as recommended, there is no reason to ever push your injector plunger all the way down.

Here’s a great tip: Take the guesswork out of determining when you should change the injector seal. Grab 10 curing tabs and line them between the foam and the tray in your tool box. Once you’ve used those 10 curing tabs, you will know it’s time to change that injector seal. A special thanks to “Roo” for mentioning this tip on the forum!

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