Measurement between spring perches needed

[JSmall]

Before I cut my brackets off I measured 36” between the centers of the perches. I would like to confirm that measurement before I make any more progress. Anyone have a 9” that’s not under their Bronco right now that can take the measurement for me?

For some reason my axle isn’t centered under the frame using the measurements I took so I want to start over. Thanks

 

[DirtDonk]

What about measuring from the brake backing plates instead then? The center of the housing should be easy to determine too of course, but the hump in the middle makes some measuring methods problematic. If measuring from the outside of the perch to the inside of the backing plate, wouldn't that give you an easier point of reference?

Paul

 

[Apogee]

I'll split the difference...my '77 perch spacing is 35.75 center to center.

 

[JSmall]

What about measuring from the brake backing plates instead then? The center of the housing should be easy to determine too of course, but the hump in the middle makes some measuring methods problematic. If measuring from the outside of the perch to the inside of the backing plate, wouldn't that give you an easier point of reference?

Paul

That would work and that is currently the measurement I'm using to mock mine up. I have 7" on each side measuring from the outside of the perch to the inside of the backing plate using Ruff Stuff 2.5" purches. When I drop a string down from each frame rail, I get different measurements on each side. I'm off by 5/8" when I take the measurement from the frame.

My next plan is to take the 35.75" to 36" center to center perch mount and subtract the width between the backing plates to give me the location of the center of the new mounts. If that makes sense at all.

50" between backing plates - 35.75" perch width = 14.25" / 2 = 7 1/8" each. Run a square down the axle tube from the backing plate and mark at 7 1/8". That was my next idea.

My '67 is 35 1/2" center to center. 8 1/2" from center of perch to backing plate near the tube (If that make sense)

Before I cut I got 8" from the center perch to the backing plate.

I'll split the difference...my '77 perch spacing is 35.75 center to center.

35.75" is the other measurement I came up with when I did a search. Thanks!

 

[JSmall]

Measurements before I cut. I'm measuring from the inside of the backing plate.

 

[Steve83]

...I measured 36” between the centers of the perches.
...
When I drop a string down from each frame rail...

Why not just measure the frame directly? That's the distance you need to match, anyway. Click this & read the caption:



Centering that distance across the axle might be a little more difficult, but a long ruler & a couple of carpenter's squares should do it. You should find something like this at Lowe's/HD for about half this price:

http://www.amazon.com/Empire-Level-4008-Aluminum-Straight/dp/B0015YHEKO/

 

[JSmall]

Why not just measure the frame directly? That's the distance you need to match, anyway. Click this & read the caption:



Centering that distance across the axle might be a little more difficult, but a long ruler & a couple of carpenter's squares should do it. You should find something like this at Lowe's/HD for about half this price:

http://www.amazon.com/Empire-Level-4008-Aluminum-Straight/dp/B0015YHEKO/

Sorry for my ignorance here. If I measure the frame width, how does that correspond to where the perches need to go? The diagram you linked shows the frame rails are 29.5” apart and I think that’s what I got when I measured mine last night. Any help would be appreciated. Thanks

 

[methcat]

i don't know how accurate the above drawing is, but i scaled the spring hangers on that dwg, and got 35.75 exactly. (x/2.86=46.625/3.73). came out right on....

 

[JSmall]

i don't know how accurate the above drawing is, but i scaled the spring hangers on that dwg, and got 35.75 exactly. (x/2.86=46.625/3.73). came out right on....

Thank you! That will help

 

[Steve83]

If you read the caption, it explains how to get any orthographic measurement you want, directly from the drawing.

The spring perches on the axle go directly below the leaf springs, which are straight (viewed vertically) & parallel, so the distance between the spring mounts on the frame is the same as the perches.

 

[JSmall]

If you read the caption, it explains how to get any orthographic measurement you want, directly from the drawing.

The spring perches on the axle go directly below the leaf springs, which are straight (viewed vertically) & parallel, so the distance between the spring mounts on the frame is the same as the perches.

I read the caption. Didn't know how to accomplish what it said to do.

 

[Steve83]

Which step? Right-clicking & saving to your hard disk? Or opening it with MSPaint & dragging a selection box over what you want to measure?

 

[JSmall]

Which step? Right-clicking & saving to your hard disk? Or opening it with MSPaint & dragging a selection box over what you want to measure?

Opening in MSpaint and getting the measurement.

 

[Steve83]

Is your computer a PC running Windows, or is it a Mac, or a Unix box? Paint is included with all Windows OSs since ~2.x, IIRC. It's usually in the Accessories folder of the Start menu. The selection tool is the dashed box at the top of the toolbox (LH top sidebar). Click it, then drag a selection across the drawing where you want to know the dimensions, and watch the status bar (bottom R corner). The first pair of numbers is the cartesian coordinates (+X, -Y) where you started the box; ignore that set. The second pair is the dimensions of the box, in pixels. Since the caption of that drawing (and the embedded text at the top) says that 1 pixel is 1/16", you can simply divide that number by 16 to get the size of your box (and thus whatever you drew it around) in inches.

I haven't looked, but I assume there are a few hundred YouTube videos explaining how to use MSPaint. There are undoubtedly many other programs that work at least as well, on whatever OS you run.

 

[Apogee]

...or he could just believe the guy in post #3 who slapped a good 'ol fashioned Stanley tape measure across his perches, then his springs and came up with the exact same measurement derived from the frame drawing.

I'm all for making things as complicated as possible most of the time, but I'm an MS Paint idiot as well, so maybe instead I should have created a SolidWorks model of the frame so that we could take the 3rd dimension and material properties into consideration, but I actually thought a tape might suffice in this instance. I've been wrong before and I'm sure I will be again.

Tobin

 

[Steve83]

Yeah, that would be easier.






...if the spring perch dimensinon is the ONLY one he'll ever need. I'm all for "teaching a man to fish."

 

[Mark]

Measurements before I cut. I'm measuring from the inside of the backing plate.

I'd go from the inside of the axle flange myself, rather than the backing plate.
I came up with 8.5" to the center of the spring perch hole.