How to re-attach a servo after it's been detached?

For my robot I'm using a couple of servos I modded to spin continuously without stopping to drive the wheels. I'm also using an ultrasonic sensor to detect walls. When a wall is detected the only way I found to stop the servo was to just detach it. Then the robot is supposed to roll backwards for 1 second, then spin only the left wheel to turn, then turn both wheels again until another wall is detected.

The problem I'm having is once I detach the servo, I'm not sure what I need to write to reattach it. Do you know what function I need to write for this? I've tried using the attach function with no luck so far.

Just use attach.
Or don't detach.

Is there a way to get the servo modded this way to completely stop rotating, then start up again without using detach?

Why not just set the "angle" to 90 (or whatever pulse width corresponds to "stop")?

RoboticsJB:
Is there a way to get the servo modded this way to completely stop rotating, then start up again without using detach?

Why do you want to do this ? Is it because you can't write a value to the servo that makes it stop ?

AWOL:
Why not just set the "angle" to 90 (or whatever pulse width corresponds to "stop")?

I was trying that but it didn't work.

UKHeliBob:
Why do you want to do this ? Is it because you can't write a value to the servo that makes it stop ?

Yes, in the code when I wrote servo1.write(180);
Then wrote servo1.write(0); the servo would just keep spinning the same direction.

I figured out the problem. When you mod the servo like I did, you mess with the knob that's right under where you attach an arm to a servo. When you mod it, you drill a hole through that part and chisel out the middle of the knob so you can turn it with a screwdriver. I had that knob turned to the wrong position I guess. So, anyone reading this if you have the same problem with a servo you modded, try messing with that knob.

Anyone who doesn't know what the hell I'm talking about (I had trouble explaining it) watch this.