How it’s Made! New Yerf Dog Brake Caliper w/ Parking Brake

Welcome to the very first article in our new How It’s Made! series.  These articles will serve as “build threads” to cover our progress on new products, technology and equipment built in-house.

Yerf Dog GX150 Brake Caliper

It’s been a long time since we’ve been able to get brake calipers for the Yerf Dog GX150.  After Yerf Dog went out of business, the manufacturer in China eventually destroyed the tooling to make those calipers.  Unfortunate as it was, it’s now presented us with the opportunity to do better.

With parking brake!

Any Yerf Dog owner will tell you an real hassle with these karts is lack of a way to park it on an incline.  I know, we’ve all been suffering.  So while we’re at it, a major point during our redesign is to add this feature.  Gone are the days of runaway karts.  No more parking against trees or carrying a brick to stuff under the tire!

This will be cable actuated and run to a shifter beside the driver’s seat, just like the  more modern buggies.

Getting Started on the Design

The first thing we need to do is source a caliper that will physically fit the cart and rear brake rotor.  We arrived at a familiar caliper to use as a starting point.


After making a number of tweaks and changes, it’s time to start working on mounting!

Designing the mount in CAD

To make the new frame mount, we pulled out the digital calipers and got to work.  Here is a rendering of our first version of the mount.


Firing up the 3D printer!


With the rough design finished in CAD, we load it into the printer software and adjust settings.


Making the Proofs

A proof is a wafer-thin version of the design that we use to check dimensional accuracy of the part.  It’s the same exact 2-dimensional shape, but only uses a minimal thickness to reduce the amount of plastic and print time.


The proof printed in about 25 minutes. 

Now it’s time to mock up the install on the Yerf Dog and let’s see how everything lines up.


This picture is of the final proof.  It took about a dozen iterations before all of the adjustments were made and everything was ready for a full prototype!

Printing the Prototype

After the proofing phase, a full scale prototype is printed.

20150308_211157The prototype printed in 52 minutes.

Then a pair of barrels are printed, and all of the holes are threaded using a standard metal tap.

Let’s see how it fits!


The end result worked very well.  The dimensions are all on point, and all of our criteria for fit of the caliper and cable are met.


Ready for production

With the successful mock up, we’re ready to have the first batch made.  Look out for an update in the next few days when the finished pieces arrive.

2 thoughts on “How it’s Made! New Yerf Dog Brake Caliper w/ Parking Brake

  1. Avatar walter pruitt

    where and how can I get one

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