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Water level accuracy for squaring a car frame

  1. Dec 23, 2016 #1
    I have a 1968 Mustang that I bought at auction from my grandfather's estate it is almost completely apart and I want to rebuild it for him has sadly he ran out of time, I have a reproduction manual from 1968 with frame dimensions in it and some of the dimensions car vertical to a datum line.
    I have thought about lasers and things from the local hardware store but to be honest when reading the reviews it seems like there is a lot of variation in them I wondered if a water level would be accurate and if so how accurate I was thinking of using it to level all four wheels and to possibly establish some sort of datum line as well as possibly leveling I beams that I would use to make a sort of cart for the car to ride on just lots of ideas in my head right now so basically my question is is one of those electric water levels you purchase accurate and if so how accurate is there any way to make them more accurate it seems I read they can be accurate to with one sixteenth of an inch but I may be wrong any help is appreciated I just want to make sure this car is square and okay before proceeding
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  3. Dec 23, 2016 #2


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    DIY water in a tube levels can be very accurate. Main issue is the miniscus caused by surface tension making it harder to see exactly where the surface is.

    A standard check for a spirit level is to turn it around and see if the surface is still level. You could do that by using a water level to make two marks say 10 foot apart on a wall then swap the ends of the tube over and see if the marks still apear to be level.
  4. Dec 23, 2016 #3

    Ranger Mike

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    see these posts o n the Mechanical Engineering forum. Race Car Suspension class
    squaring the car page 14 post # 270, page 27 post # 479,
    Stringing the car page 14 post # 269
    page 15 post # 293

    one big thing to check before you do anything...make sure your garage floor is flat.
    I once was bench marking a race car in a new garage...the owner had a nice floor drain so we could hose off the race car mud and dirt from the track.
    The floor was sloped like 1/4” per three feet...no way could we use it.
  5. Dec 23, 2016 #4


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  6. Dec 23, 2016 #5
    I read that using windshield washer fluid in a water level is more acurate due to surface tension. Is this true.
  7. Dec 24, 2016 #6

    Ranger Mike

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    Baluncore- thanks for catching that..lack of coffee when i wrote it in error
  8. Dec 24, 2016 #7


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    Find someone with a dumpy level and ask them to survey your garage floor . Record the levels at a selection of useful places for future reference .

    Use packing or adjustable height stools to level any work in progress .

    Optionally skim the garage floor to true level or set in some metal plates to true level .
    Last edited: Dec 24, 2016
  9. Jan 22, 2017 #8
    You can use a spirit level easily to do what you want. Make two simple stands with well-marked yardsticks on the vertical sections to hold the tubing. Keep one stand stationary at all times. Now you can shim or jack the chassis until four data points are level. Compare the other data points to see if they are at the correct level. The best way to check for out of square is with a steel tape measure, measuring diagonals.

    A little soap is all you need to reduce the meniscus, but that sometimes causes bubbling problems. I just use tap water with a little food coloring and read the bottom of the meniscus. Chassis are not that perfect ever, slight error in meniscus reading is not an issue.
  10. Jan 28, 2017 #9
    Just to get a few things clarified. These cars were unibody with sub-frames in the front. How far is the car torn down?
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