Air in lines/pressure problems/suction leak?

Hi all. First, thanks for the forum... I've been studying it for weeks I have an 85' well with a single pipe deep well jet setup. The pump is 1 HP (oversized, because it's the only one they had when the last one burned up). The drop pipe was 35' until yesterday when we added 4 more feet, hoping that was the problem. Here's what we've got: unable to build pressure above 31 lbs, air in the lines which has gotten 10x worse since before the extra drop pipe. I think an existing hole got worse whe we added the new section (there was some pounding involved in getting the pipe back down. The drop pipe is galvanized and in horrible shape even though it was only installed 4 years ago. I think the casing is under 2"... the drop is 1 1/4" and it barely fits into the casing. My main question is this: If I replace all the pipe, what type is best? Poly, pvc, or back to galvanized? Also, I'd really appreciate any other advice, opinions, or general input anyone can offer.

Thanks,
Jen

Why do you think the pump is oversized?

If the pipe is in terrible shape, why didn't you change it then? Pulling jets is not fun.

Adding 4 feet did absolutely nothing to help the situation unless the jet was 25 feet above the water level.

The only place you can get air is from the first fitting on the casing adaptor on towards the pump. The pipes in the well are all under pressure. Usually all pipes are under pressure, but with the plugged jet you have, the suction pipe is under a vacuum. When you pull this next time, change all pipe, the jet and the casing adaptor. You should change the pump also, if it has scale in it.

bob...

Did he get a new injector assembly to go with the new pump? I wonder if a tailpipe would do any good, if the new pump was more than the well could supply.

Actually, I just assumed the 1 hp was overkill because the original pump was a 1/2 hp. when we added the 4', it was because it had been suggested that maybe the water level had dropped and that was where our pressure problem came from. I was under the impression that the jet assembly actually had to be in the water. It never occurred to me that all of that was under pressure, so it wouldn't matter. It makes perfect sense now, but I'm learning as I go. We only pulled the drop pipe about 8" up and added the extra pipe, which is why we didn't change everything else at the time.
So, if I understand correctly, I have a clogged jet. I need to pull and replace everything in the well. Can there be another cause for the low pressure? Because the pressure has never been over 45 lbs with the 1/2 HP shallow or deep well setup. The new 1 HP pump is only a few weeks old, so no scale yet (all of it is hard nasty, and perhaps slightly greasy, black stuff in and on the galvanized pipe). Is it acceptable that the 1 1/4" is such a tight fit or should I go with a smaller diameter? Also, what kind of pipe is going to be best? I'm thinking pvc, because the only hard thick build up (corrosion, I guess) we've ever had is on this galvanized pipe. Again, any other advice or input is appreciated for any questions I've forgotten to ask.

Thanks again!

The black stuff is sulphur and that is what plugs jets. You should replace all the pipe (1" pipe is fine) with galvanized unless you don't care if you ever see it again.

By moving the jet up then down, you probably loosened the leathers enough that they won't seal anymore. So pulling the jet is going to be a must.

bob...

Thanks for the reply and the advice, Bob.