How to Replace a Bosch Vacuum Motor Housing Cover

Before you start#

• Tools: Torx T10 and T15 drivers, a plastic pry tool or spudger, a clean cloth, and silicone sealant only if a separate gasket is not available.
• Part: the model-specific motor housing cover (search by the E/Nr on the BSH parts portal), or just the gasket ring if only the seal is damaged.
• Safety: Unplug the vacuum. There are no high-voltage concerns, but the motor impeller can have sharp edges, so keep your hands out of the motor chamber once the cover is off.

Step by step#

1. Open the motor compartment. Lift out the dust bin or bag, then remove the pre-motor filter (foam or pleated HEPA) that sits in front of the motor housing. The cover — the interior plastic panel dividing the filter chamber from the motor — is now visible. Some BGS bagless models have an extra secondary filter frame to pull first.
2. Remove the cover. On newer clip-style covers (BGS5 and BGS6), find the 4-6 perimeter clips and release each with the pry tool, pressing the tab inward while lifting the edge, and work around until the cover frees. On older screw-style covers (BGL3, BGL4 and similar), remove the 4 Torx T10 or T15 perimeter screws and lift straight up, rocking gently to break the gasket seal rather than prying hard.
3. Inspect the cover and gasket. Run a finger along every edge and around each mount point for cracks — any crack leaks air past filtration. Lay the cover on a flat surface to check for warping, where it will rock or show curvature, usually from motor heat. Then check the gasket: if it is torn, missing, or permanently compressed so it will not spring back, it must be replaced, because that ring is the primary seal.
4. Install the new cover or gasket. For a full cover swap, transfer the old gasket if the new cover has none (peel carefully and clean the residue), seat the cover over the housing aligning all clip or screw points, then press each clip until it clicks, or run the screws finger-tight and snug them in a cross pattern for even gasket compression. For a gasket-only fix, strip the old gasket completely, clean both mating faces with isopropyl alcohol, and seat the new ring in its channel before refitting the cover.
5. Verify the seal. Before full reassembly, place your palm over the filter side and blow — you should feel resistance, proving the seal blocks airflow around the cover. Refit the pre-motor filter and dust bin, power on, and check for strong, consistent suction at the hose with no new whistle or hiss.
6. Reassemble and test. With suction confirmed, push down on the cover edges to confirm every clip is engaged, then vacuum a small patch of carpet — Bosch ProSilence models should run notably quiet, and excess noise flags a seal problem. Check the HEPA exhaust: visible dust in the exhaust stream means dust is still bypassing the pre-motor seal through a cover gap.

Common issues#

• Clips keep popping out: worn cover clips or a broken housing tab; reinforce a broken tab with a small self-tapping screw through the cover, drilling a pilot hole first to avoid cracking.
• Suction still weak after the swap: check the other seals — hose joints, dust-bin seal, exhaust-filter housing — since several small leaks add up.
• Whistling after reassembly: a gap somewhere; pull the cover, reseat the gasket in its channel all the way around, and refit.
• Cover sits loose with all clips engaged: the gasket is missing or too thin — fit a new ring or add a thin foam weatherstrip as a temporary seal.