[tiessen]

Message to anyone with an 87-96 F150 or FS Bronco. I'm looking for the backing plate bolt pattern measurements for the rear drums onto the rear axle. What is the spacing? You should be able to measure with the tire on, 4 bolts. What's the vertical between 2 and horizontal between 2.

I'm looking to swap some F150 drums onto my Explorer 8.8". I think the backing plate pattern is the same, but not sure.

Thanks
Dale

 

[Rogue Bronco]

8.8
--------
3.410" horizontal (top)
3.076" horizontal (bott)
1.680" verticle

Big Ford (new style) the one yur askin about
--------------------------
3.562" horizontal
2.000" vertical

Big ford
----------
3.500" horizontal
2.375" vertical

Small Ford
--------------
3.375" horizontal
2.000" vertical

 

[Rogue Bronco]

plug weld the bolt holes on the backing plate (F-150 ones) and then lay out the new pattern so ya can re-drill your 8.8 pattern in them. Just make sure the holes are centered on the bearing bore hole.
One dimension you might wanna keep an eye on is the housing flange to axle flange measure.
By my 'crude' measure guess, the bearing hole in the F-150 backing plate will ALMOST connect to the housing flange bolt holes if you use 1/2" bolts on the housing flange. (I wasn't too critical with measures)
The 8.8 has a 2.840" bearing and the F-150 has a 3.150" bearing.
If you draw out the 8.8 bolt pattern(Hor.= 3.410"(top),3.076"(bott) X Vert.=1.680") , and put the F-150 bearing circle centered in the center (3.150") you'll know what I mean. (if ya don't already).

 

[tiessen]

8.8
--------
3.410" horizontal (top)
3.076" horizontal (bott)
1.680" verticle

Big Ford (new style) the one yur askin about
--------------------------
3.562" horizontal
2.000" vertical

Big ford
----------
3.500" horizontal
2.375" vertical

Small Ford
--------------
3.375" horizontal
2.000" vertical

OK, now I'm confused. I have an Explorer 8.8. It is big bearing, like the F150's with 31 spline axles and 10" drums. I want to 'bolt up' the 11" drums from a mid 80's to mid 90's, 5 on 5.5", big bearing, 31 spline 8.8" from an F150 or Bronco. The patterns should be the same?! So which one of the above mentioned patterns is for the 87-96 F150?

Thanks for all the help Rogue Bronco.

Cheers
Dale

 

[tiessen]

My backing plate holes are:

horizontal 3.53"
vertical 2"

these measurements are by sight using my slide caliper with the wheel still on.

Anyone with a F150?

Cheers
Dale

 

[Rogue Bronco]

Oops, shoulda noticed the '87 newer F-150, I thought you meant from a 9"(my bad).
Should still be the same tho.
The 'small Ford/big Ford' are early 9" ends. The 'Big Ford(new style)' is later 9" and full size 8.8's (I think).
My catalogue only shows one pattern for the 8.8, but being big bearing it's prob. the same as the 'Big Ford(new style)'. Your measures are very close to the 'Big Ford(new style)'.
I'ld go with it.
On the 8.8 pattern I have, sez the top and bottom (horizontal measures) are different by 0.33" (big 5/16).
Hope this helps.

 

[tiessen]

Question answered. 3.5" and 2", same as mine.

Thanks
Dale