1. Runs hot (almost overheats) in hot weather--only when the air conditioning is on.

2. Brake pedal very spongy/goes all the way to the floor, only in hot weather and car is warmed up (and even then not all the time). Otherwise the brakes work fine.

Any ideas?

Brake failure is the No. 1 fear of drivers. You need to completely change your brake fluid immediately. You obviously have not been flushing your brake system every 2 years, as recommended by Honda, and you have a lot of moisture and air throughout your fluid. Braking converts kinetic energy into heat. Heat from the disks is transmitted to the calipers. If the brake fluid contains moisture, it will be converted to a gas, which is compressible, and allow your brake pedal to go to the floor. This is what vapor lock is all about. Part of the problem could also be that you need to replace your master cylinder. The soft parts have worn, due to not replacing the fluid regularly. Try just changing the brake fluid first.

I recommend Valvoline SynPower Brake Fluid for your Honda. It has a much higher wet boiling point than most other brake fluids and it's not very expensive ($4.95/qt.)

It's difficult to give specific advice for your overheating problem. Make sure the cooling system is properly maintained with a 50/50 mixture of antifreeze and distilled water. Tap water can cause minerals to plate out and interfere with heat transfer. Remove the radiator cap and examine the inside of your radiator. There should be no buildup in the cooling tubes (veins). It there is, then there's probably not too much you can do about it, unless you replace your radiator. The cooling system should be properly drained every 36 months, according to Honda.

Your car overheating is not good. First look at the fluid in the radiator, if the fluids are low full them. Then I would change the thermostat (I think they are like $12) and then start your car and see when the car gets to normal oportating temp if the fan come on to cool the radiator. If the fan doesn't come on then you need to start looking at the thermosensor. The thermosensor is what tells the fan to come on, the engine is getting to hot. I hope this helps.