Sunday 6 January 2013

Handbrake cable routing

Handbrake cable routing

The rear uprights on my Sylva J15 are a fabricated part by Jeremy making reuse of the Ford donor drive shafts. Apparently it takes either a VW Passat or Hydra OEM calliper from Rally Design. The main problem with this arrangement is getting an adequate routing where the handbrake cable neither fouls the AVO shocks or more importantly the boot for the outer CV joint. The completed assembly must give a relatively friction free performance for the VOSA/IVA man.

I have thought long and hard about this problem and I have come to the conclusion there is no perfect solution with that Passat calliper. I may have to resort to trying out a hydraulic handbrake calliper if I cannot find a solution soon.

I did measure the outer dimension of the handbrake cable which was 9.5mm (including plastic covering). I also discovered that B&Q supply a piece of 12mm alloy tubing with a 10mm inner hole diameter EAN 3232630508756. I also have a plumbers bending jig for 15 and 22mm pipe. Putting all this together my approach for IVA is to clad the last 400mm of handbrake cable in this alloy tubing and then bend the whole lot to the exact shape to avoid the aforementioned obstacles.

I have now done this and as said before it is far from being an ideal solution but will it be good enough to get me through the test? Your comments are welcome. I can think of various potential pitfalls, like lack of cable flexibility resulting in a fatigue failure of the mechanism. I have jumped up and down on the chassis and it appears to be a good solution.

P.S. I also discovered there is very little clearance between the hydraulic connection and the outer CV boot. See image 2.




References


Contents http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html

2 comments:

  1. This is exactly the process I went through.
    The routing seemed too onerous so I swapped the mechanical actuating mechanism from each side to route the cable below the driveshafts. My concern was that handbrake use also winds in the pads as they wear and I had to ensure that this mechanism along with the handbrake actuation itself wasn't 'handed'.
    The first one I tried worked fine and the other appeared to but I'm finding it difficult to get an even pull and one side locks before the other. The cable routing is perfect though.
    I'm also concerned about the banjo clearance because if the pads dont wear evenly there could be a problem.
    Really wish I hadnt gone this caliper route.

    ReplyDelete
  2. Yup! we agree totally, there are a number of challenges on this build and this ranks with the best. I regret using this caliper, the Ford one seams a better bet. I am not changing the calipers now. This is not the time to shave bits off the upright esp when the paintwork looks so good. The mod I have done gives a good handbrake feel. The banjo is still an issue esp on the near side for some reason. I am going to reband the NS outer CV joint and see if I can make it as good as the OS. failing that I have a Lathe!

    ReplyDelete