Tech Tip: Injector Seal

When you fail to get a good seal between the injector and the windshield, each pressure and vacuum cycle is less effective.  A leaking injector seal can lead to increased repair time, excess resin waste, and worst of all, inferior repairs. Many technicians that we talk to assume it is normal for resin to leak between the end seal and the glass. Well, it isn’t normal. In fact, if your injector seal leaks regularly, there is definitely a problem somewhere, so let’s find it.

Do you level your bridge properly? Pay special attention as you are initially setting your bridge over the damage.  Once the injector touches the glass, make sure to add at ½ turn to create a good seal. You don’t want too much pressure against the glass, but you need enough to keep the injector from leaking. Another mistake many technicians make is bringing the back legs down only until they just touch the glass and stopping. Do not do this! Bring the back legs down until they touch the glass and then give each screw 2 full turns. This will be close to getting the getting the seal to uniform thickness, which is the goal, but there are times when additional minor adjustments are needed. By lifting the back of the bridge you are creating a much more even pressure all the way around the seal, which will minimize leaking.

Is all the air out of your vacuum cup? If you are using the B300 Bridge with the pump style vacuum cup, you need to be sure the vacuum cup is completely seated against the glass and is very stable. The red line on the pump is a good guide, but make sure to check the cup itself very closely. If one side is higher than the other or you see a “bump” on one side, keep pumping. A suction cup that is not properly adhered can lift away from the glass, which will increase the likelihood that your injector will leak.

Are you lining up your injector over the damage carefully?  Use your inspection mirror to make sure your injector is centered exactly over the impact point. The 144-7G inspection mirrors are magnified 3X to make it easier to see just what is going on under that seal. If you don’t have a mirror, make sure you check from inside the vehicle.

How often do you change out your end seal? We talk with technicians that are trying to get 40-50 repairs out of a seal. However, you cannot consistently do great repairs unless you are changing your seals regularly. Delta Kits recommends changing your seals every 10 repairs. An old seal is much more likely to leak than a new one, but that is just one reason to change your seal regularly. After about 10 repairs, the walls of the seal begin to break down. This allows some resin to blow past the piston and up into the injector while you are applying pressure to the repair. When this happens, even though the seal is not visibly leaking, your pressure and vacuum cycles will be less effective.

How far down do you push the injector on the pressure cycle? It is important to push the injector piston down into the end seal during the pressure cycle, but don’t over do it. Push the injector about half way into the seal. Use your inspection mirror to watch the seal carefully. As you push the injector down you will see the walls of the seal begin to bow under the pressure. When you see this happen, stop pushing. Never push the injector all the way down.

Are you using two hands? That’s right; windshield repair is just like baseball. Ok, maybe not just like baseball, but it is important to use both hands when you catch a fly ball and when you put your injector in the vacuum or pressure positions. I see too many technicians pull up on the piston with one hand to put their injector in the vacuum position. If you don’t brace the bridge with your other hand you could very likely pull the injector away from the glass and break your seal.

So, if you are having trouble with a leaking injector, pay attention to the details. It will save you a lot of time and trouble. If you still have trouble, make sure to give us a call for technical support.

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