I've been told this needs replacing as it has a minor leak. Clear to see, as there is a bit of oil caught on the inside of the tire. Is this a job I can do myself? I have access to wholesale parts, and I'm pretty broke, so trying to save a buck, but don't want to muck things up. Keep in mind that my mechanical aptitude is...well, let's just say I wouldn't call it aptitude. But I can follow directions, and I can always pick up a manual if its' a simple enough job. TIA. skid