The article addresses the issue of increasing the diagnostic capabilities of the car's suspension in the EUSAMA test. A new, quantitative approach was proposed to enable the assessment of the degree of wear and clearance of the lower suspension mount. An active diagnostic experiment was performed to model the clearance in the lower suspension mounting. During the research, bolts with different diameters were used. In the signal analysis, wavelet decomposition into 12 levels was performed using the Db4 wavelet. The resonance area of the system was extracted from an approximate signal, which contained 43.5% of the relative energy. From these signals, a number of point vibration measures were calculated. Finally, the maximum value was selected due to its sensitivity to the condition, which was 48% more than the original EUSAMA results. Based on the selected diagnostic parameter, a clearance model allowing for an assessment of the clearance with statistically significant coefficients was developed.