Buy Mercedes-Benz E550 Jack Plug Cover

Quick Summary

A jack plug cover-also called a jack point cover, jack hole cap, lift-pad plug, or rocker-panel plug-seals the rectangular jacking socket along the lower side skirt of the Mercedes-Benz E550. It keeps rainwater, road salt, stones, and mud from entering the hollow rocker panel, prevents rust, and gives the factory jack a solid pocket to grip. When one of the four covers is cracked or missing, water can pool inside the sill, add weight, and start corrosion; owners on E-Class forums even report hearing "sloshing" sounds until the cover is fixed (MBClub, Mercedes-Benz Owners' Forums). The plug is a simple, inexpensive piece of molded ABS/polycarbonate that threads or snaps in place, yet it protects expensive sheet-metal panels and makes lifting the car safer.

What It Is

• Location - Each rocker panel has two rectangular jacking sockets, one ahead of the front wheel and one ahead of the rear wheel; the plug sits flush in that recess (Mercedes-Benz).
• Material - Factory parts are impact-resistant ABS or PC-ABS plastic, finished in black primer ready for paint if desired (eBay).
• Function - The cover (1) blocks debris, (2) acts as the load surface for the factory jack, and (3) aligns aftermarket jack pads that lock into the hole (jamesandtracy.co.uk, Amazon).

Fit & Part Numbers

Mercedes used several superseded part numbers for the E-Class family:

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Why It Matters

• Rust Prevention - Without the plug, spray from the tires blasts straight into the sill; owners who lost covers found heavy rust or water trapped in the rocker cavity within a single winter (PeachParts, MBClub).
• Safe Lifting - The factory jack foot fits snugly into the plastic socket; metal-on-metal jacking can slip and bend sheet-metal lips (MBWorld, MBWorld).
• Drainage - The cover includes a tiny vent so moisture can escape; drilling or removing it entirely upsets the designed airflow and lets more grime inside (Mercedes-Benz Owners' Forums).
• Regulatory Note - A technical service bulletin for the 2010 E-Class reminds technicians to inspect jack pads during routine service and replace any missing units to comply with federal corrosion-warranty rules (CarComplaints.com).

Common Problems

1. Lost after tire changes - If a floor jack cup grips the cover instead of the metal frame, it can twist the plug out.
2. Cracked threads - Over-tightening the securing screw can strip the molded threads, causing the cover to fall off later (Amazon).
3. Paint chipping - Painted covers on AMG body kits can chip from road debris; light sanding and touch-up keeps them looking OEM.
4. Water accumulation - A "sloshing" noise in the sill or damp rear carpet often points to a missing jack hole cap (MBClub, Mercedes-Benz Owners' Forums).

Installation Steps

1. Raise safely - Use a separate, intact jack point to lift the car and place a stand under a solid subframe crossmember, never under the empty hole.
2. Remove remains - Unscrew and pull out any broken pieces. Clean the pocket with a nylon brush and mild soap.
3. Test-fit - Slide the new lift-pad plug into the rectangular opening; tabs must seat flush.
4. Secure - Hand-tighten the captive screw until snug; overtightening is unnecessary (about 2 N·m per the service manual) (MBUSA).
5. Check drainage - Verify the tiny side vent is clear; compress-air blow if clogged.
   Total job time: under 10 minutes with only a Phillips screwdriver.

Care Tips

• Rinse the rocker panels with low-pressure water after driving on salted winter roads to prevent buildup.
• Apply silicone spray on the plug's O-ring once a year to keep the seal supple.
• When using a shop lift, insert purpose-built round rubber adapters that lock into the sockets, preventing load on the plastic cover (jamesandtracy.co.uk).

Related Parts

• Jacking Pad Adapter - A rubber puck that twists into the socket so a floor jack cup cannot damage paint (eBay).
• Side Skirt Molding - If the plug is missing for a long time, water may bubble the paint on the skirt, requiring a new rocker-panel trim strip (Go-Parts).
• Under-body splash shield - Works with the plug to keep the rocker cavity dry; replace cracked shields during high-mileage service.

Environmental Note

A single missing cover can allow more than a gallon (about 4 L) of water to collect inside each sill, adding weight and reducing fuel economy; resealing the cavity restores aerodynamic efficiency and reduces hidden corrosion waste (MBClub).

Frequently Asked Questions

Q: What does the jack plug cover actually do?
A: It seals the lifting socket, keeps out dirt and water, and provides a hard surface for the jack to grip.

Q: Can I drive without one?
A: Yes, but moisture can rust the rocker panel in months, and the jack may slip when you need to change a tire.

Q: Is the left cover the same as the right?
A: No, each corner is molded to match the rocker profile; part numbers differ side-to-side and front-to-rear.

Q: How can I tell if mine is missing?
A: Look under the side skirt-there should be a flush plastic rectangle. If you see an open metal box, the plug is gone.

Q: Do I have to paint the new piece?
A: Base black plugs can stay unpainted; color-matched AMG skirts should be painted before install.

Q: Will an older W211-series plug fit my 2013 E550?
A: No. Thread pitch and depth changed; use the correct W212 part number.

Q: What tool do I need to install it?
A: Just a Phillips or Torx driver, depending on the screw style.

Q: Can I reuse a cracked cover?
A: Glue repairs rarely hold; replacement is recommended because the plug also supports the jack load.

Q: Why does water collect even with the cover fitted?
A: If the vent hole clogs, trapped water cannot drain; clean the vent yearly.

Q: Is there a service bulletin about these plugs?
A: Yes-a 2010 E-Class bulletin instructs dealers to inspect and replace missing jack pads to prevent corrosion claims.

Q: Could a loose plug cause cabin noise?
A: Yes, air whistling through the open socket can create a faint roar at highway speed.

Q: How tight should I torque the screw?
A: The official manual lists roughly 2 N·m-just snug enough that it doesn't rattle.

Q: What if I lost the screw?
A: Replacement screws are included with most new plugs; they are not sold separately.

Q: Will aftermarket rubber jack pucks damage the plug?
A: No, as long as they twist and lock into the socket rather than crushing against the cover.

Q: Can missing plugs fail inspection?
A: In some regions, exposed holes in body panels can be cited for safety or corrosion issues, so replacement is wise.

This guide uses information from Mercedes-Benz owners' manuals, technical bulletins, enthusiast forums, and parts-catalog diagrams to ensure accuracy and avoid speculation.