EB 9" axle dimensions

[markw]

Hi, I'm in the process of ordering a new full floater axle for my Bronco. I've found hub face to hub face of 53 3/8 or 1/2" but cannot find the driver side hub face to pinion center dimension in my Google search. Does anyone have that measurement offhand? Thank you in advance, Mark

 

[Apogee]

The axle lengths are the same, so won't that set the pinion location? FWIW, I've found two measurements online for the standard 9" offset, one being .94" and the other being 1.25". After taking a quick measurement on my '77 EB, I measured a difference of 2 inches from housing end to pinion centerline on each side, so that would make me believe the .94" dimension is the accurate one.

 

[markw]

Thank you Apogee. If my math is correct that should be 25.81 Inches.

 

[DirtDonk]

What am I missing here? You running a full-size axle assembly?
Only the full-size had equal length axle shafts. All stock EB axles had a left and a right of different lengths.

My chart shows the '76/'77 shafts being 27.18" on the left, and 29.68 on the right.
This is measured from the outside of the wheel mounting flange to the tip of the splines.

I don't know how that equates to the pinion center you're asking about, but it shows a definitely offset and axle length difference that might come into play when ordering.

Paul

 

[Apogee]

Thank you Apogee. If my math is correct that should be 25.81 Inches.

Yes, if you're housing width is 53.5" (half = 26.75"), and the pinion offset were .938", then the measurement on one side would be 25.81" and the other would be 27.69". That said, I've usually seen the pinion offset given as a measurement from the pinion centerline to the housing centerline on most axle builder worksheets, but some do A+B type measurements.

Who is building your full-floater for you?

 

[markw]

To Paul, no, standard width EB.
Apogee, the offset is consistently 0.94 when I started searching using different language.
Ron Schreiner is building the axle. He's asking for wheel mounting surface to center of pinion on each side. Mark

 

[Apogee]

Sorry about that, Paul is correct about axle lengths. The F150's I run are equal, but the EB shafts are not. That said, the .94" offset of the pinion relative to the centerline of the differential housing is true regardless of application, housing width, etc., since that's just a function of pinion axis offset relative to the carrier. But it sounds like your axle builder wants the pinion offset relative to the housing ends, A+B = Overall Width.

So with that said, I pulled the tape on the '77 EB rear end on my shop floor, and measured 24" passenger and 26.25" driver +/-1/16" from the inboard side of the outer lip of the drum backing plates to the centerline of the pinion as best I could eyeball with a tape measure. If you go by that, then the pinion is offset 1.125" towards the passenger side relative to the housing ends.

http://www.9inchfloater.com/images/dwg1_lg.gif

Schreiner will supply axle lengths to suit the housing they build, so axle lengths don't really matter at this point, just pinion offset. Sorry for my confusion above.

Tobin

 

[Broncobowsher]

Crawl under the Bronco. Measure the transfer case output to the frame rails. It will be closer to the passenger side. That will have an offset from the centerline. That is about the same offset you will want for the pinion. From what Google tells me the 9" puts the pinion 0.94" toward the passenger side off the centerline.

So there are more options. If you set the offset at the 0.94" you can make left and right axle lengths the same. It will probably set the U-joint angles at a slight lateral angle. Nothing wrong with that. If you are doing links, the centered third member (equal length shafts) it will be much easier to make symmetrical brackets.

Nobody says you have to set the lengths and offsets exactly like stock even if you are doing stock width. Have your wheels picked out yet? If you are doing a LUBR you can pretty much pick the wheel you really want and set it just right inside the fenders and measure width. It may not be stock width, but you can make it fit right.

 

[markw]

Thank you both for your answers. Seems simple but a little confusing. This is an axle for my NORRA Pioneer class contender. So all stock mounting points and suspension design. Wheel offset 4". I have the info now to place my order. Cool!