It did used to lift all the way. We noticed a couple things when we realized it wasn't going 'up' fully: the door where the rubber from the top meets the bottom has a 'rub' mark and it's a good 2" lower now. My husband seems to hit his head on the bunk bed more now - again probably because the top is just a bit lower. It has always locked in the 'up' position (the motor squeals letting us know it's up as far as it'll go) - even when it's too low. I just can't say for sure if it happened after the cable broke and we fixed it or not. We use it more now, so we seem to notice it a lot more now.
He did make an adjustment to the one cable after it broke. I think at the time he 'leveled' it to the other back corner (just to make sure they were even).
We just came from outside where my husband worked to adjust the top "up" as far as he could. We, of course, did this while the camper was up. We now have the front corners at 30" from bottom of the camper to bottom of the top, and the two back corners are 28 1/4". Still a good 1 3/4" difference front-to-back, and even if they were all at 30", it still needs to come up more for the seals to line up and the door to show it's closing like it used to.
Do you think replacing all 4 cables will fix this? I have a call into J&R Trailer I got from this forum to see what that would run us. Lord knows there's a lot of things deteriorating under this old camper, but we love it and want to keep it as long as we possibly can.