any update on the axle fitment
8&3/4 axle fitment problem
- Thread starter Rapid Robert
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Rapid Robert
Well-Known Member
I am taking a break from it (alot going on). I will get it pulled & peek in each side & hopefully see an (easily) fixable problem & I will update you. RR
Rapid Robert
Well-Known Member
pumpkin out. OE SBP 8&3/4 axle will slide in 3&1/16" and the dr diff BBP axle will slide in 3&3/8". looked in both sides & still see the round "flat" wall. sticking a tape in, the depth of round flat on the one side I checked is 3&3/8". nothing looks out of place. RR
Put both OEM axles in with the center section out. Be sure they are fully pressed inward and held there.
Then measure the distance between the two axles.
Do the same for the dr. Diff axles.
Then rig up a way to measure the space on the inside of the center section where the axles would bottom.
That distance should be about the same as the axle spacing. When I say about I mean the adjustable OEM axles have 3/8" ? of an inch of adjustment. The green bearings have no adjustment.
Then measure the distance between the two axles.
Do the same for the dr. Diff axles.
Then rig up a way to measure the space on the inside of the center section where the axles would bottom.
That distance should be about the same as the axle spacing. When I say about I mean the adjustable OEM axles have 3/8" ? of an inch of adjustment. The green bearings have no adjustment.
Rapid Robert
Well-Known Member
I superglued a thin flat paint stirring stick on either adjuster on the sides & got 8" across between the two & the depth of the thrust block in from the adjuster(s) is 3&3/8 on each side so 8 - (3&3/8 x2) = 8- 6&3/4 for a thrust block width of 1&1/4" but the OE SBP 8&3/4 axles would not go in either then it hit me that I drove the thick grease seals in 1&1/16 on each side, ( I drove em in till the outer side was just past the point where the dia narrows slightly, a slight lip) & the light bulb came on & I'm thinking that I did not drive em in far enough & that is where the interference is, further strengthened by the fact that even the SBP axles would not go in either. what do you guys think? RR
junkyardhero
Well-Known Member
are you talking about the outer seal on the axle plate or the inner seal that's in the housing?
I can 3D print a seal driver that I used to set my seals in.
If you want one pm me
Rapid Robert
Well-Known Member
the inner thick seal that is in the housing. how far should it be driven in? Dana I think I have a spray can of the right diameter (not the best contact area but seemed to work on this one). Let me check the dia of the can I think I used. RR
I always use a large socket and extension as driver.. should bottom out on axle tube inner lip, reach your pinky in to check if its fully seated.
Rapid Robert
Well-Known Member
how far would you guestimate the seal is in there?
I can check 1 of my housings when home this evening, unless you find out faster.
Rapid Robert
Well-Known Member
I'd appreciate that bro
junkyardhero
Well-Known Member
here's a thread with some pics of an install
www.forabodiesonly.com
if you notice, in the housing there is a lip that the bearing seats against. the seal, obviously inboard of that needs to go in far enough so that the bearing retainer will clear. so like 1.75" or so from the flange of the housing.
it's not a measurement that's set in stone, because there's a lot of seal surface area on the axle. but it's critical that it clears the bearing retainer and *if* the axle is previously damaged/scored that the new seal doesn't ride in that groove.
here's a pic of about where the seal should sit.
edited to reflect the correct distance of seal face from housing flange
8 3/4 axle seals
I’m installing new axle seals in my rear end. Did they go just to the upper lip or are they supposed to be inserted all the way down until they stop leaving about a quarter inch or so above the seal? Currently I have mine tapped in just far enough to where they’re flush with the upper edge.
www.forabodiesonly.com
if you notice, in the housing there is a lip that the bearing seats against. the seal, obviously inboard of that needs to go in far enough so that the bearing retainer will clear. so like 1.75" or so from the flange of the housing.
it's not a measurement that's set in stone, because there's a lot of seal surface area on the axle. but it's critical that it clears the bearing retainer and *if* the axle is previously damaged/scored that the new seal doesn't ride in that groove.
here's a pic of about where the seal should sit.
edited to reflect the correct distance of seal face from housing flange
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My seal driver sets the outer face of the seal 1.75" from the flange of the housing.
The back side is not seated against anything as the ends of 4 out of 4 housings do not have a flat positive stop like a Ford 9" has.
I did extensive testing with Green and taper bearings and several different housings and axles to land at this dimension where the seal is in the seal surface of the axle and the seal body does not come in contact with the bearing retainer.
Now that I have a larger printer I can make the stop / striking surface a full circle.
My original broke one of the ears off on the last strike to set the seals.
The back side is not seated against anything as the ends of 4 out of 4 housings do not have a flat positive stop like a Ford 9" has.
I did extensive testing with Green and taper bearings and several different housings and axles to land at this dimension where the seal is in the seal surface of the axle and the seal body does not come in contact with the bearing retainer.
Now that I have a larger printer I can make the stop / striking surface a full circle.
My original broke one of the ears off on the last strike to set the seals.
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junkyardhero
Well-Known Member
thank you D-money for the indepth on this. i didn't have the housing in front of me, but measured two when i got to the shop and they both are the same at 1.75" +/- a CH. i don't know where i came up with that 1 1/16 number, but i've subsequently edited my post.
It always surprised me that there was no positive stop. There is a tool called out in the FSM but no details
Rapid Robert
Well-Known Member
good very comprehensive info & very much appreciated, thank you. It looks like you guys have found the issue, I didn't have the seal in far enough, I had it even with the lip which is about 1&1/16" in from the outside flange & it needs to go in further to your posted spec.
Rapid Robert
Well-Known Member
Update; took out the seal on one side & the 8&3/4 bbp axle will not go in anywhere near all the way & the SBP 8&3/4 will if I smack it harder than I would like. I'm lost right now. RR
junkyardhero
Well-Known Member
pictures would be pretty helpful at this point...
Rapid Robert
Well-Known Member
OK
Rapid Robert
Well-Known Member
I shoulda got close ups but this is what I have now. with a tape hooked on the wheel flange I get 28&1/8" out to the splined end & 26&1/16 from the five hole flange with it & the bearing race held on the tapered bearing out to the splined end on the Dr Diff BBP A body 8&3/4 axles and 27&3/4 and 26 on the OE SBP A body 8&3/4 axles.
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