idler arm, replace or retighten? 89 GM c3500

About two months ago I replaced the idler arm on my 1989 GMC Sierra c3500. It started wobbling again, so I jacked it up and sure enough there was up/down play at the idler arm. I pulled the cotter pin and tightened it up further, seemingly fixing the issue. Is this safe? A google search only brings results for replacing not re-tightening. Thanks in advance for any experience or advice.