Do I have to bleed my breaks when adding fluid?

Hey guys, I just bought my truck (03 trd sr5) about a month ago and the brake light has been on since I bought it. I thought it was a bad sensor from the e brake this whole time, however I recently found out that the brake light might be on from actual brake problems.

Well, I checked the reservoir and there is no visible fluid in it at all. The brake pedal goes pretty low to the floor (I never thought much of this, I feel dumb) also.

I have dot3 fluid (the cap on the tank says to add only dot3) and was planning on topping her off to the correct levels later. Do I have to bleed the brakes then after doing this?

I've taken apart engines and swapped trannies, however never even touched brakes Lol.

Thanks guys.

 

If you have run low enough that the pedal goes to the floor, then typically that means you have got air into the system. Good idea to bleed the brakes.

 

Well it goes low but not tooooo low. If I have air will it hurt anything?

 

If there's that much fluid missing in the system, do you have a leak somewhere? Are your pads pretty much non-existent?

If it was me, I'd definitely bleed the brakes and get the air out of the system. Hydraulic systems work best with no air in it... and considering it's your brakes, you probably want them working to their maximum potential.

 

^^^^^^x2^^^^^^

 

I had all new brakes around when I bought it. I just topped it off and the brake light turned off and completely night and day braking difference

 

In a properly working brake system you should never have to top off. Low fluid would be caused by what Madjik_Man pointed out. If you top off a properly working system, where is that fluid going to go when you need to replace the pads? It will potentially spill out due to being over filled.

 

I feel like it was in need of being topped off because the mechanics replaced the calipers a few days prior to buying it. Though I'll check all the lines, from what I've seen though they look fine on the lines and cylinders.

 

air=not good....for safety's sake bleed the brakes...I doubt it got so low there was nothing in the reservoir, otherwise you prolly would not have had any brakes to begin with...and, I would be looking for leakage for sure......