One of the most common problems with Mercedes-Benz C-Class and E-Class is that the ignition lock fails.
In this step-by-step guide, you will find instructions on how to replace the convertible pump on Mercedes-Benz soft-top and hard-top convertibles such as CLK, SLK, SL, E Class convertible, etc.
Common symptoms indicating the convertible pump needs to be replaced:
- Convertible pump won't run
- Convertible fuse keeps blowing
- Convertible relay burned up
- A leak from the convertible fluid reservoir or motor
What you will need
- Mercedes Convertible Top Pump
- Convertible Hydraulic Fluid - 1 litter
- Flathead screwdriver
- 10mm - 15 mm Metric Sockets
- 5mm Allen key
- Fluid transfer pump or a large syringe
- Open the trunk and locate the convertible pump on the left side of the trunk.
- Remove the plastic retainer screws. They simmply pop out. Remove the panel.
- Remove the tonneau cylinder locking pins. Remove the retainer from the lower pin with a flathead screwdriver.
- Remove the upper pin and disconnect the cylinder. You don't need to completely remove the cylinder.Simply move it to the side to make room to pull out the convertible top pump.
- Remove the 10mm nut that secures the pump to the frame.
- Remove the 10mm nut for the ground wire. It is located right behind the hydraulic lines. Disconnect the wire.
- Lift up the cover from the positive junction box.Remove the 10mm bolt and disconnect the positive cable.
- Unplug the electrical connector. Squeeze the connect then pull it to disconnect it from the pump.
- Remove the three bolts on top of the plate with the hydraulic lines. This is also known as the manifold plate.
- Pull up the manifold plate then pull the hydraulic lines out one by one until all of them are removed.
Hydraulic lines completely disconnected.
- Remove the hydraulic pump from the vehicle.Convertible pump removed.
- Install the new convertible pump in reverse order. Connect the electrical connector, negative and positive wires.
- Connect all the hydraulic lines and tighten the three aluminum bolts. Don't overtighten the bolts. These are aluminum bolts and can easily strip. It is not the pressure from the plate that prevents fluid leaks. It is the O rings that are present at the tip of each line.
- Remove the brass bolt on the side of the reservoir and use a syringe to fill up the reservoir. Once the reservoir is full, fluid will start to come out of the fill hole. All the lines should be connected at this point.
- Reinstall and tighten the brass bolt by hand. Operate the convertible top two to three times.
- Recheck the convertible top fluid level by looking at the side of the translucent reservoir. Add convertible top fluid as needed. The level will drop as you operate the top a couple of times. After a couple of top open/close operations, the air should be removed from the cylinders at which point you shouldn't be losing any more fluid unless there is a leak present.
Do I need to bleed the lines?
You do not need to bleed the air from the cylinders or lines. The system will return the air back to the reservoir as you cycle the convertible top a few times. Top off the convertible top fluid level and add more fluid if the level drops below the min level.