3D model description
The stock trunk partition (aka cargo partition) on the BMW Z4 E89 (2009 - 2016) has hinges that are prone to stress related failure. Generally, the hinge halves will either break at the three points that it's plastic welded (on the inside), or the outer shell will break/crack. This is usually caused from either overloading the trunk and trying to put the partition in place, or from push/pull related stress from normal use. Since the hinges are plastic-welded around the trunk partition bar, BMW's official fix for this is to replace the entire trunk partition assembly (for hundreds of dollars).
This is a direct replacement for the hinges in question. The hinges will fit on either side and were designed to look very similar to the factory part. Several strengthening improvements have been made and the hinges are held together with metric M4 fasteners that can be obtained at any hardware store.
[FASTENERS]
* Eight M4-0.7x25mm hex bolts
* Eight 4mm flat washers
* Eight M4-0.7 nylon insert/locking nuts.
Lowes PNs are: 880641 (x2), 880810 (x2), 880764 (x1)
Home Depot PNs are: 801318 (x4), 803528 (x2), 803668 (x4).
NOTE: The bolts go in the top, the washers and nuts go on the bottom. The bolts should lock in the recesses that are in the top and will sit almost flush when everything is tightened. If the head of the bolt sinks more than 0.5mm, it means it's probably too tight (you are crushing the plastic). Because these sit flush (within 0.25mm), you could easily cover the top with a vinyl or a sticker to conceal all the fasteners.
[LICENSE INFORMATION]
This copyrighted model, and like most paid models on Cults, it is provided exclusively for your private and personal use. Redistribution or sale of the model (or any derivative of the model, including prints) for economic or financial gain is not permitted without the express permission of the author.
3D printing settings
The build volume needed for this model is 106x87x23mm. You will need to print each model twice to have complete set of (2) hinges. My total print time on a FF AD3 for a single hinge (0.4mm nozzle, 1.75mm ABS, 0.18mm layer height, 4 shells (1.6mm), 30% infill) was 13.5 hours (double this time for a set of two hinges).
Supports are highly recommended for the recessed areas where fasteners sit. I would also recommend a shell count of four or more (>=1.5mm shell thickness) for overall strength, and to beef up the areas where fasteners go. I've used 30% infill with great results. ABS or ASA is probably the best material for heat resistance and overall durability. Annealed PLA would probably be my third choice material wise (better temperature resistance than PTFE). Other materials are possible too (nylon, etc). Plain PLA probably isn't a good idea if your summer temperatures exceed 25C/77F. For ABS, it's possible to print this with a 100C bed, but I would recommend 105-110C if possible. If you have issues with corners lifting at 100C you may need to use a brim, a better printing surface (pei), and/or a gluestick.