Handbrake Handle Mercedes-Benz W126 1985-1991

thingiverse

The original handbrake handle in the W126, after many years, is prone to cracking. Many second-hand parts available online can be just as problematic, as they are typically salvaged from scrap and their brittleness is due to the ageing of the plastic. This 3D-printed alternative provides a brand new option! I've taken the liberty of adjusting the shape slightly to avoid the original thin section that promoted cracking, and making the whole section a bit chunkier to allow for the (sometimes mediocre) material properties of 3D printed parts. There are two variations: the "counterbore" parts use the existing bolt from the original handle. The "countersink" parts are designed for an M5x25 countersunk machine screw, and provide more plastic 'meat' for strength. Make sure you pick and print a matching pair (note the nut recess is also different in depth for the different bolt lengths). Enjoy! As always, no guarantees or warranties express or implied - take care making any modifications to a vehicle (even what seems to be minor ones), no responsibility will be taken by the author for any misadventure or loss incurred by using this design. Print Settings Printer Brand: MakerGear Printer: MakerGear M2 Rafts: No Supports: No Resolution: 0.2mm Infill: 25% or more Notes: This is printed in two halves, print flat-side-down. Both should fit on a 200mm x 200mm bed. The strength of this part depends on plenty of walls - aim for 4x or 2mm minimum (remember bottom and top too). You may choose to add support for the cutout depending on your slicer/printer/preference. I printed at 25% infill, and it feels solid - the walls are the key. Post-Printing Step 1: Initial prep Clean up any burrs, brim and/or 'elephant foot' from the part Drill out the locating pin holes to 2mm (careful not to drill through!) Drill out the bolt hole to 5mm (optional - if you don't have a nut, you may prefer to simply thread the bolt into the plastic) Clean up any droops / loops in the cutout, ensuring you get the full length Cut 10x pieces of 1.75mm filament 10-12mm in length to use as locating pins (coathanger wire could be substituted, also being typically about 2mm diameter). Source/prepare the appropriate bolt and nut (M5x25mm countersunk, or the existing M5x16mm SHCS, and a regular M5 nut (8mm across flats)). Insert the M5 nut into the nut recess, I like to use the screw to help pull it through. Two halves prepared with locating pins ready Step 2: Glue I recommend super-glue for speed, but you could equally substitute epoxy or ABS+acetone mix. Always a good idea to do a trial fit before committing to glue. Apply glue to holes in first half Insert pins (these are kind of optional, but they should improve strength and help align the two halves in assembly) Spread glue over face of first half Apply glue to holes in second half Push the two halves together Clamp together in at least two places (you can use the screw and nut here). Step 3: Final prep IMPORTANT: with the bolt removed, ensure you clean up the hole in the bottom of the shaft recess with a 5mm drill bit (gently! there's only about 1mm between the end of the recess and the face of the handle). If there are bumps in here, or the resulting hole is undersized, it may make it difficult to assemble the handle. You may choose to file the parting line back flush, as I did. After filing, a brush with paper towel and a small amount of acetone removed white marks and restored some shine. Step 4: Assembly Using a 4mm allen key, remove the bolt from the old handle completely Pull the old handle off the shaft Push the new handle on (might take a bit of force - you will need to hold the shaft in place) Insert the bolt though and tighten until firm Try not to over-tighten the bolt - it's not necessary, as the load is predominantly in shear, the plastic should help stop it self-loosening (a bit like a nyloc nut), and over-tightening will just crush the infill. Assembled! How I Designed This Measurement of existing, modelled in CAD software.