MK Indy Front Brake Hoses

After already fitting the steering rack and front suspension it was time to connect the MK Indy front brake hoses.

Cutting Holes

The first thing was to cut sufficient clearance for the hoses to go through the bodywork. There are 2 approaches to fitting the flexible brake hoses. Some people fix them directly to the GRP bodywork, which I didn’t like the idea of, due to the level of flex the GRP would have compared to fixing to the chassis. There is also a welded tab on the chassis which you can use, which is normally used for the race cars or SX bodywork where all the GRP is cut away in this area.

I decided to use the chassis tab for the fixing point, which meant I had to cut more bodywork for the flexible hose to pass through. Originally I was going to cut a hole just for the flexible pipe and use a grommet, but then I realised how close it was to an existing wishbone hole that was already cut. I decided instead to make this existing hole into a teardrop shape to accommodate both. The following is a guide for the size and position of the hole I cut that hopefully others can follow. This is for the righthand side bodywork.

  • Mask the area with masking tape at the bottom of the top-left wishbone hole.
  • Draw a vertical line downward from the right-hand edge of the top-left wishbone hole.
  • Align a ruler with the bottom edge of the top-left wishbone hole and the bottom-left edge of the bottom-right wishbone hole (see image).
  • Draw a diagonal line from the bottom-left edge of the top-left wishbone hole, until in intersects the first line.
  • Use a 35mm hole saw to drill a hole on the inside of the intersected lines.
  • Use a junior hacksaw blade to remove the remaining material on the line and clean up with a file and 400 grit sandpaper.
  • Repeat the same in mirror image on the left-hand side panel.

Fitting Flexible Brake Hoses

I then fitted the brake hoses loosely to the tab. Then fitted the banjo end to the brake caliper with new banjo bolts and copper washers.

The hose was then twisted slightly at the chassis tab end to provide a curve in the hose. This is to help keep it clear of the wishbones when on full lock. Then I nipped up the chassis fixing tight once I was happy with happy with the clearance to the wishbone.

Steering Rack Stops

When fitting the flexible hoses I noticed the next issue. The steering rack could extend further than the flexible hoses would allow. So potentially leading to the hose being pulled out or damaged if over extended. Now, I knew that a small steering rack stop was needed, but I realised I had made the issue worse by using the chassis tab which is further in than the bodywork.

So, I needed a stop to limit the steering movement. I decided to design and 3D print some rack stops to the exact size I needed. MK suggested using 3x 5mm cable ties as the rack stop. I didn’t think was a brilliant engineering solution and it wasn’t anywhere wide enough for what I needed. I needed a stop which was more like 20mm.

The design I used was 21mm internal hole, 37mm external diameter the righthand side was 21mm wide and the left was 17mm wide. I printed 3x 3mm holes into the stop and threaded them with an M4 thread (after printing). I then used 3x flat M4 grub screws to secure the stops in place at the end of the rack. The print used PETG filament which is stronger than PLA and more resistant to oils. I used 50% infill and 8 walls for the print to allow for the tapping of the holes.

To install the stops you have to remove the ball joint from the end of the steering rack shaft. Then slide on the stop from the end. Then replace the ball joint with a bit of medium 243 Loctite.

This works perfectly and stops the rack just at the right point now. It might limit my turning circle a bit. If this is a problem, I can later on change the flexible hoses for slightly longer ones and reduce the stop size. For now, it is fine.

The MK Indy front brake system is now ready to have the brake fluid reservoirs fitted and filled with brake fluid.

Summary of Build Costs and Hours

Here is a summary of the costs and person hours (total number of hours for every person that has helped) for the build so far. This should hopefully help others with the planning of their builds, by providing cost and time actually incurred for this build. A more detailed breakdown of all the costs and hours worked on the build to date can be viewed here.

Person Hours Worked This Post
Fit Flexible hoses and Cut Holes1 hrs
Fit Steering Rack Stops1 hrs
Tool Costs This Post
Loctite 243£11
Totals This Post To Date All Posts
Person Hours Worked 2 hrs 404 hrs 404 hrs
Car Build £0 £13,202 £13,202
Tools / Consumables £11 £470 £470
Total Cost £11 £13,672 £13,672

Leave a Reply

Your email address will not be published. Required fields are marked *