The slider bolts that go into the carrier probably need to be stripped of the grease and re-greased. Make sure you don't add too much grease or it can prematurely hydro lock the slider bolts causing the brake pads to be engaged even with your foot off the brake. With the carrier off and new grease added, you should be able to push the slider bolts in and they should not pop back out. If they pop back out, that means that there's too much grease.

Long

Hi Jaymi. You should definitely get one. They give you an affordable sense of independence. Very quiet, convenient an easy to transport. As for not replacing the inner tube, eventually if you drove on it the tire would start to crack on the sides from being compressed. You would more than likely burn out your wheel hub motor with the added stress. If you get a flat inner tube you must replace it before riding again. They do sell solid tires that will never go flat, however they ride rougher from what I've heard. I personally haven't used them yet. I will be doing a review on my current scooter I have in the next month or so possibly. It's an incredible scooter that's really affordable. You won't want to miss it!

Vacuum only increases when the throttle plate starts to close. If you're at 8,000 RPM wide open throttle, the vacuum isn't going to be as great as if you're at 8,000 RPM and then you're letting off the throttle. A closed throttle plate produces the greatest amount of vacuum. A open throttle plate produces the least amount of vacuum.