Seat the filter by hand, making certain it is completely inserted into the air cleaner housing before securing the cover in place. To complete a tight seal, apply pressure by hand at the outer rim of the filter, not the flexible center. Never use the service cover to push the filter into place since no cover pressure is required to hold the seal.
Note that a cover gasket is usually supplied with ERA replacement filters. It is important that it be fitted at the same time as the new filter to ensure that the housing is airtight.
Using the cover to apply pressure could damage the housing and cover fasteners, and will void the warranty. If the new filter is not fully in place, remove the cover and push the filter further into the air cleaner with hand pressure on the outer rim. The cover should then go on with no extra force. Then, secure the service cover.