In a previous edition of Daily Halacha, we noted the ruling of Hacham Bension Abba Shaul (Israel, 1923-1998) that when one attends a Siyum on Ereb Pesah to absolve himself from the Ta’anit Bechorot fast, he must eat a Ke’zayit of Mezonot food or a Rebi’it of wine. If he does not, Hacham Bension maintained, he has not absolved himself from the fast. It must be added, however, that Hacham Ovadia Yosef, in his Yabia Omer (and in Yalkut Yosef – Hilchot Pesah, p. 327), rules that it also suffices to eat a Ke’zayit of fruit at the Siyum. And thus if apples or other fruits are served at the Siyum, one may eat a fruit and thereby fulfill his obligation, even if he does not eat a Mezonot food or drink wine.
In another context, we cited Hacham Bension’s ruling permitting bringing one’s car to a mechanic on Hol Ha’mo’ed. Even if the repairs require "Ma’aseh Uman" – professional work – they are nevertheless allowed on Hol Ha’mo’ed, according to Hacham Bension. Hacham Ovadia, however, in Hazon Ovadia (p. 175), disputes this ruling. In his view, one may bring his car to the mechanic for repairs on Hol Ha’mo’ed only if the car does not require professional servicing. If the work entails a simple job that any ordinary person can do, then it may be done during Hol Ha’mo’ed, even by a professional. Examples include changing a flat tire and plugging a tire by placing a piece of rubber over the hole. Since these are very simple tasks which anybody can do and do not require professionals, it may done by Hol Ha’mo’ed, even by a professional. Professional mechanical work, however, may not be done on Hol Ha’mo’ed according to Hacham Ovadia.
An exception to this rule is a case where a car breaks down while one is driving, and he finds himself stuck on the road or away from home. The Mishmeret Mo’ed (p. 92; listen to audio recording for precise citation) explains that in such a case, one who does not have his car repaired will experience Sa’ar (distress) and incur a financial loss by having to hire a taxicab or rent a car. Therefore, even professional servicing is allowed in such a case. Furthermore, the need to get home or to one’s destination qualifies as "Sorech Ha’mo’ed" – the needs of the holiday – for which professional work is permissible. Therefore, if one’s car breaks down during a trip he may have the car repaired so he can reach his home or other destination.
Summary: A firstborn attending a Siyum to absolve himself from the Ta’anit Bechorot fast on Ereb Pesah must either drink a Rebi’it of wine, or eat a Ke’zayit of Mezonot food or fruit. Otherwise, the Siyum does not absolve him from the fast. One may not bring his car to the mechanic for professional repairs during Hol Ha’mo’ed, though simple repairs – such as changing a tire or plugging a tire – is allowed. Additionally, if one’s car breaks down while he is driving on Hol Ha’mo’ed he may have it fixed – even if it requires professional servicing – so he can reach his destination.
