Hey guy, so I have a 2003 Lexus gx470 and I just installed the brake rotor, and was wondering do I need to bleed all 4 or just the 1 I changed

 

You shouldn't need to bleed anything if you changed a rotor. Caliper yes, rotor no.

 

If you didn't open the hydraulic line, there's no need to bleed.

 

While I agree with the above, ideally you would flush your brake fluid every 3 years.

Pro tip:The rears you don't pump like a normal brake bleed job, there's a pump for the rear brakes, so you just hold the brake pedal down and have a helper crack the line until the fluid runs clear, and make sure you don't run the reservoir dry.

 

I just changed my front pads and rotors this weekend. I wasn't planning on bleeding or flushing since I didn't remove any bleed screws. However, I DID loosen the brake fluid reservoir cap to assist in pressing the caliper pistons back in. Not sure if it's necessary but I didn't think it would hurt. Anyway, I forgot to make sure the cap was completely tightened before closing the hood and bedding in the brakes. Also drove about 40 miles or so over the weekend before the thought came to me that I may have left the cap loose! The GX has sort of a two stage reservoir cap where it doesn't simply unscrew and I had it in the middle stage for about 48 hrs and now I'm worried that moisture may have entered the system.

Should I be worried about this and have it flushed? Should I just empty the fluid from the reservoir and fill with new? Any advice would be greatly appreciated!

 

Flushing yourself on an electro/hydraulic brake system can be tricky. The biggest thing is that you pushed dirty fluid back into the pump and reservoir. NEVER do this. Always crack a bleeder screw to allow pistons to be compressed. Get a bleeder hose and catch bottle. I recommend going to a shop or dealer to bleed with scan tool and manual bleed as well . Both is best.