Center bubbles will not level to center when it was turn to 180 degrees

I would check the fluid levels for the pumps on your wheels. It may also have worked an air bubble in there or it may need adjusted.

You need a carpenters level longer than the Abney level. Find a smooth flat level surface like a table with the carpenters level. Double check the carpenters level by turning it 180 degrees and see if it still shows level. If it doesn't get another carpenters level. Set the Abney level at zero and lay it on the carpenters level or the flat table. The bubble should center on the index line. There is usually two screws that allow you to move the glass tube (and the index at the same time) to center the bubble and index if it is off. Then check your findings. Put a piece of contrasting tape on a wall at eye level. Walk back 20 or 30 feet and see what the angle reading on the Abney level shows. If you keep your feet in the same position; that is your eye at the same level, you should read zero.

I assume you are talking about a bubble level. If so, you should be able to remove the cover over the bubble and find adjusting screws used to calibrate the level. Make sure the bottom surface is free of nicks and rust and is not twisted or bowed. To test for bow, after you have removed any nicks or rust, set the level on a smooth flat surface. Try to " spin " the level gently from one end. If it rotates about the center of the level it is bowed with the center high. If the center is high enough to rock the level you will never get it adjusted until you correct that condition. If it rotates about the end of the level it is bowed with the center low. If your surface is reasonably flat you can rub the level and look for shiney spots on the bottom. If it worn badly have the bottom resurfaced. If it is reasonably flat on the bottom, find a smooth, flat surface that you think is reasonable level. Set the level on the surface and mark its position. Take note of the bubble position, even if it all the way to one side. Reverse the level position 180 degrees and note the position of the bubble again. Make an adjustment to move the bubble half of the difference between the two readings and repeat the notations of the bubble and reverse position bubble. Continue until you obtain the same bubble reading in each position. If you don't get a final reading that is on the scale of the level, find a surface that is more level and try again. As long as the surface is level within the range of the level scale you should be able to adjust it until you get the same reading in each position. (If the surface is not level within the range of the level scale you can't complete the calabration.) The final reading should then be the amount the surface is out of level.

Google 9.5mm X 25mm Acrylic Tube Bubble Spirit Level Vial. Thats ~ 3/8" x 1" Cost a few dollars including shipping. Carefully peel back the warning stickers, take out the 4 screws, pry the broken one out, clean up the old epoxy, epoxy the new one in and put back together. The whole operation takes less than 6 minutes assuming that you use 5 min epoxy to reset the new bubbles.

Make sure that yours are 3/8" x 1" before you buy replacements.

Here's how a bubble level works a small tube is filled with liquid allowing only a small pocket of air inside. The concept is that air will always rise to the highest point. The idea is that if you lay this tube horizontal to the earths gravitational pull and the pocket of air goes to one side than that side is higher than the other. If the bubble rests in the center than both sides are of equal height. Your particular level has three bubble dials for vertical, horizontal, and 45 degree placement. Say you want to level a picture on the wall. if you place the level on top of the picture frame you will use the center dial and adjust the frame until the pocket of air sits between the two indicator lines in the tube. You hold the level on the side of the frame, in which case you would adjust using the dial that is perpendicular to the level. the 45 degree would only be used if you want something to be 45 degrees from the gravitational plane.

take a topedo level and get the tripod base as level as possible. attach your level to the tripod. put all screws in the middle and level it. turn 180 degrees, level it. turn 180 and check. if withing the bubble, turn 90 degrees and level. turn 180 and so on and so forth. the adjustments should be slight from turn to turn. make sure the feet are secured firmly in the ground. If this does not level the automatic level, it needs sent in for calibration. I dont know the web address but I hope this helps

I just assisted a friend "re-calibrate" his D.W. L6-20 Level Transit. Follow the following steps.
1. Set up the tripod & transit in the garage. Get the platform with the protractor, close to level.
2. Position the telescope at "0". The telescope should be over 2 of the adjusting screws.
3. Adjust the screws to get the top bubble close to level. Adjust with a screwdriver the spring loaded screw to get the bubble closer to center.
4. Rotate the scope 180 degrees. Note the difference in the bubble position. Split the difference from the first bubble location by adjusting the same top screw.
5. Rotate back to 0. Adjust the same top screw to split the difference in bubble position.
6. Rotate back to 180 degrees. The bubble should be off by the same amount. Adjust the 2 bottom screw to place the level in the center.
7. Rotate back to 0. The bubble should not move.
8. Rotate to 90 degrees and adjust the 2 bottom screws to place the bubble in the center.
9. Rotate to 270 degrees. The bubble should be centered.
10. From this point on, all you need to do is place the level on the tripod and position it over your reference point with a plumb bob. Adjust the bottom 2 screws at 0 and again at 90. The level is set to use.

You do not need to replace it. If it does not read the same when you reverse it, on one end there are a nut over and under the tube and plug assembly. Adjust those up or down until it reads the same.

Starrett Tech Support

The level is meant for 360* of USE not from one single position check both horizontal and vertical... I think that one is a Moveable

Laser? Level?
OH I just found .. is it on a tripod like attachment? there should be a small round "level" on the physical Base of the level itself .... (like the ones your drill would have for drilling down into the floor boards) You must level it that way First.... then you can use it ...

There are 2 allen screws on the fish eye bubble that can be adjusted to correct that problem.

First level the instrument;

Then turn 180 degrees

Adjust the vial until the bubble is half way from where it is back towards the inner circle.

Relevel the level using the foot screws

Then turn 180 degrees again (back to where you started)

It should be mostly fixed, however if it is not just repeat the steps above; it gets exponentially better everytime until you can no longer detect the error.