Fix a jamming Cybex Pallas S-Fix

28 Dec 2018

My Cybex Pallas S-Fix car seat already as new had a tendency to jam. Specifically its mechanism to retract the isofix mounts. The problem got progressively worse. Here's how I fixed it.

The first step was to detach the seat from the base. Surprisingly it's only four little plastic pieces that keep them together. Two screws torx screws are in the back of the base (one already undone in the picture): Two further on the bottom: Additionally I had to detach two springs on either side: which were hooked onto these plastic pieces: With the base free the next thing to do was to unscrew a plastic cover. Six screws on top: and one on the bottom of the base:

Then the mechanism was unveiled. Pulling the light-grey lever moves two plastic sled, encircled in red. As seen below sled had not enough clearance along the way. Sometimes it took considerable force to get it past the conflict points, sometimes it hopelessly jammed.

I melted the material away with a soldering iron. I had to remove quite some material to ensure smooth travel:

After the fix the mechanism can be operated with one finger. Problem solved!

When putting the seat back together I noticed that the plastic pieces that hold the seat and base fit in one way only: