Two reasons a car will pull under braking:
1. suspension geometry changes due to loose parts.
2. unequal braking force applied at the wheels
Let's look at 1. You just replaced the left control arm but not the right? I would start the hunt right there - if one is shot, chances are the other on is too. Under braking, the arms shifts, changes toe value and voila! it pulls to the right. This one will generally be like an on/off switch as the failed bushing allows the arm to move.
It's also possible you have a stuck caliper or restricted hose. Dealer "checked them"? How? looked them over? are all the pads wearing evenly? Did they operate smoothly when applied? That's worth looking into again...and yes, flex hose can fail internally, so it is like a dissected artery, with internal layers blocking flow (in some cases, causing the hose to act like a check valve). This one will be more progressive in nature, with the pull being proportional to braking force.
But I would start with the suspension first...
2006 Corolla (kid's car - 165K, Eco Contacts, Castrol Edge 5W30)
2005 MB S600 (84K, Michelin AS3, M1 0W40)
2002 V70-XC (201K, AltiMax RT43, Pennzoil Ultra 5W40)
2002 V70-T5 (179K, IPD bars, Bilsteins, Conti PureContact, Mobil 1 0W40)
1992 MB 300E (Sportline - 160K, Yokohama Avid, Castrol Edge 0W40)
1990 4-Runner (V6, 4WD, mild lift - 257K, 31" BFG AT KO, Castrol 10W40)
1932 Packard Sedan (straight 8, dual sidemount spares, original paint and interior, Shell Rotella 15W40)