Bruiser/Mountaineer replacement driveshafts (How-To)

If you've ever run a Tamiya Bruiser or Mountaineer, chances are you've had to deal with the stock drive shafts wearing out pretty quickly.  For me, it was the rear universal joint nearest the rear axle.  The weight of the truck, which nears 10lbs with battery and radio gear, plus the decent torque from the Mabuchi RS750 motor combine to really destroy the stock brass Tamiya drive shaft universal joint in just a few battery packs.  The soft brass cannot take the power being transmitted to the rear wheels.  I literally wore a universal joint down to the point that it actually sheared in two.  I tried to fit the identically-sized Tamiya green colored hardened steel universal joints (like those found on the Super Champ) instead of the stock brass ones, but the drive shaft design, with its wobbly extension fitting on the opposite end and general lack of tolerances made using them impossible in the rear.  The front drive shaft could tolerate the hardened universal a little better, but I knew there had to be a better way.

Back when I came up with this idea, which was early 2003, RC4WD was still a fledgling company.  Their drive shaft designs for the Bruiser and Mountaineer were in their infancy.  Plus they were expensive, and today I think they still are, though they are now made much stronger.  Other alternatives are available today, such as those by JunFac.

Anyway, here is the how-to for building replacement front and rear drive shafts for the Bruiser and Mountaineer.  Note that the pictures presented here are from Jan 2003, so please excuse the quality.

Parts needed:

Traxxas #4628X Drive Yokes (2 packages)
Traxxas #1953 Extra long slider shaft (1 package)

Front driveshaft
Take one male and one female shaft from the #1953 package and trim 18.5mm of shaft length from each piece:

Discard the 18.5mm pieces.  Sand each yoke piece to make the ends smooth and uniform. Install a #4628X yoke to each piece.

That's it for the front!

Rear driveshaft

Take two male and two female shafts and do the following:

Female shaft 1: This will be the piece that will hold the yoke. Trim 10mm of shaft length from
the piece. Discard the 10mm piece. Sand the cut end smooth and flat. It is very important that the cut end be flat and uniform, as it will be glued to female shaft 2 to make one longer shaft:

Female shaft 2: This shaft piece will be the extension of female shaft 1. Cut the shaft off
about 1mm from the yoke mount so the length of the cut piece is 40mm. Discard the yoke mount portion. Sand the cut end smooth and flat. It is very important that the cut end be smooth and flat, as it will be glued to female shaft 1 to make one longer shaft:

Male shaft 1: This will be the piece that will hold the yoke. Trim 15mm of shaft length from
the piece. Discard the 15mm piece. Sand the end smooth and uniform:

Male shaft 2: This will be the piece that will hold the two female shafts together. Cut the
shaft off about 1mm from the yoke mount, leaving about 44mm. Discard the yoke mount portion. Sand the end smooth and roughen the entire shaft so the glue will adhere better:

Assembly
Unfortunately I didn't take pictures of the assembly process since I had no idea that it would work.  Instead, here are the instructions for assembly:
Coat the outer surface of male shaft 2 with super glue (CA glue) and insert into female shaft 1 all the way. Male shaft 2 should stick out of female shaft 2 about 15mm when inserted fully. While the glue is still wet, slide female shaft 2 onto male shaft 2 so both female shafts meet together. The two cut ends of each female shaft should be touching each other. Align the female shafts so they are as straight as possible in order to make one long drive shaft. Wipe off any excess glue, but make sure the drive shaft is as straight as possible!  Let it dry for at least an hour or two before installing the yokes (which are a real pain to get on, by the way).

Results

Front shaft installed on a Mountaineer

 Rear shaft installed on a Mountaineer

Long term results
It has been many years and a fair number of runs since I installed these drive shafts on my Mountaineer, and they are still holding up amazingly well.  Traxxas makes an excellent drive shaft that can really take abuse.  The only drawback to using these drive shafts is that the thickness of the rear shaft rubs on the radio box a little bit.  You can see it in the above picture right where the corner of the radio box touches the drive shaft, making it create a white dust where the plastic has rubbed off a little.  It is really close to where the two female shafts are bonded together.  It isn't a big deal unless the drive shaft isn't glued straight, making the whole shaft wobble, so pay attention!