Is faulty repair work a factor in a motor vehicle accident?

In Heppel v. Stewart et al. (1968), 1968 CanLII 18 (SCC), 69 D.L.R. (2d) 88, [1968] S.C.R. 707, the appellant was a service station operator who had repaired the defendant's motor vehicle two or three days before the accident. The accident occurred on June 15, 1964, when the defendant's motor vehicle collided from the rear with the plaintiff's motor vehicle at a stop street. The plaintiff suffered personal injuries and damage to her motor vehicle. The writ of summons was issued on April 2, 1965, and the statement of defence was delivered on June 17, 1965. The defence alleged that the brakes of the defendant's motor vehicle failed due to faulty repair work.