Aftermarket Birf Removal Question (1 Viewer)

[Blue77FJ40]

When I first installed the original Longfield Birfs, I had to clearance the axle bell flats as the longs were larger in diameter than the stocker on my '77. I did so, and the birfs then fit. However, after torquing the top and bottom end caps on the knuckles, they wouldn't go in. So I disassembled and ground some more and they then fit. Then, when I recently went to remove the same birfs, they wouldn't come out. Flats were verified and but no joy. I had to loosen the top end cap/steering arm before they would come out. Anyone know why this would happen?

I'll be measuring the new RCV birfs for size and if the same or larger in diameter, will obviously have to regrind some more on the flats.

I'm wondering, for fitment purposes pre-greasing only, if anyone has ever tried to fit birfs after installing and torquing the top end cap/steering arm and lower caps? I say this, because I have found out that the cap torquing does clamp the bell ends together a small amount - in some cases enough to prevent birf install.

 

[iptman]

I had the same experience going to 79+ birfs on my 77. Totally annoying since you have to clean out all the fresh grease you just packed in to the knuckle ball.

 

[Jakes40]

Mine were the same way. I did not have to clearance my bells but I run Marlin Berfs.

 

[matzell]

Could be knuckle is not centered...just loosen the top caps, smack with a hammer in the center of the bolts and loose them enough to get birf out.

 

[Blue77FJ40]

Could be knuckle is not centered...just loosen the top caps, smack with a hammer in the center of the bolts and loose them enough to get birf out.

That's exactly what I did do. I was just wondering if anyone had tried to see after tightening the top and lower caps, if the birfs still fit after clearancing, but obviously without the grease being applied yet. Just to see if they fit before I greased everything.

 

[jcj_78FJ40]

Dan, It's been a long time since I installed mine but I'm thinking the RCV 40 axles had a bell size more inline with the 77, 78 birfs. I do know they went in with no issues.

 

[Blue77FJ40]

Thanks Charleton, I just ordered them and will measure them against the old Longs once received. At worst, I'll have to grind the knuckle flats some more.

 

[shmukster]

Dan dumb question but could one (or more) of the screws holding the upper arm on be too long and intrude into the internal bell space? Just a thought here as I've never experienced this problem.

 

[Blue77FJ40]

Nope. All hardware is original and proper length. When you add an aftermarket birf to a stock '77, the flats of the axle ball ends have to be ground enough to allow the larger birf to fit. Even after clearancing, when you torque the upper and lower end caps, the ball end gets squeezed slightly, enough to stop the birf from entry/removal. That necessitates more grinding for more clearance. Common occurrence on older '40s getting upgraded birfs. As stated, I wondered if anyone has tried what I suggested on post 1.

Besides, the studs for the upper and lower caps are screwed into blind tapped holes, none intrude into the knuckle interior. But thanks for the thought.

Ed: Since knuckles are out waiting on new axles, I just checked them and found out I was wrong, the stud holes are not blind, but go all the way through the casing. At any rate, none of the studs extend into the interior of the knuckle. Still a good thought Gary.

Side note: I'm looking into a knuckle swap from mini truck/newer 40/60/80 and everything from knuckles out. This can wait, but am looking into all the bits needed. Will need to borrow knuckle centering tool at some point.