1. SAEⓇBaja - Brakes and Rear Suspension
Kathryn Kempema

2. Overview Objectives Design Testing Failure Analysis Conclusions

3. SAE BAJA 2015 Design Competition - Portland Oregon May 2015
Tasks include:
Brake Test
Lock up all 4 tires
Endurance Race
4 hrs. rough terrain
Hill Climb & Rock Crawl
Photos courtesy of 2014 UWYO SAE Baja Team

4. Brakes - Objectives Rules: Hydraulically controlled brakes
Hydraulic brake light switch
Independent brake circuits (front and rear)
Lock up all four tires on any surface
Ours:
Foot operated brake
Improve bias adjustments between circuits
Prevent brake drag

5. Brake Schematic

6. Brake Model
Assumed inputs were brake pedal force and rotor coefficient of friction
Model shows that car will lock up all 4 wheels regardless of operating surface

7. Braking Test
The brakes generated 1200 psi line pressure in both lines for a 50:50 balance with no bias
This is in the range of inputs which will ensure that the car can lock all 4 tires at once
Maximum Pressure 1400 psig < 2600 psig Maximum Pressure for components in the system

8. Preventing brake drag Last year the brags dragged: To solve:
Removed Gum from the O-rings in the Calipers
Proper alignment of Caliper mounts
Proper Alignment
Incorrect Alignment

9. Financial Analysis Initial proposed budget: Brakes: $1,184.00*
Actual spent:
Brakes: $690.00
*Amounts budgeted were based on early cost estimates and included parts that were not purchased.

10. Conclusions Objective Met? Hydraulically Controlled Brakes* YES
Hydraulic Brake Light Switch*
Independent Brake Circuits*
Lock up all 4 tires on any Surface*
Improved bias adjustments
TESTING REQUIRED
Prevent brake drag
* Objectives which we are required to meet by competition rules

11. Acknowledgments Sponsors UW Department of Mechanical Engineering
Polaris
Wilwood
Shop Personnel
Mike Schilt, Master Technician
Korey Kreitman, Master Technician
Vincent Dauer, Master Technician
Advisors
Dr. Robert G. Erickson
Dr. Kevin Kilty
Dr. Nancy Peck
Dr. Paul A. Dellenback
Group Members
Jason Christensen
Jesse Grosinger
Seth Koertner

13. Expense Report Part Amount needed Cost per unit Master Cylinder 2
$90.00
Pedal Assembly 1
$177.00
Front Rotor
$57.00
Brake Light Switch Pressure
$14.00
Brake Line
20 ft.
$40.00
Brake Line- Braided hose
$47.00
Assorted Plumbing and Brake Fluid
$50.00