RE: [ihc] RA-15 / RA-20

[bearbvd@xxxxxxxxxxxxxx (Greg Hermann)]

At 10:05 PM 11/2/03, Mac @ TRIAD wrote:
>## >> CAREFUL, here. In earlier years, BEFORE IH started using Dana
>## >> 60's in the
>## >> rear of 3/4 tons, they had an axle that LOOKED like an RA15, but was
>## >> smaller. Think sort of halfway in size between an RA15 and a
>## >> Ford 9". These
>## >> ALSO had 6 on 7.25 hubs, drums, and wheels. Which is not to
>## >> say that you
>## >> did NOT get an RA15 in a heavy GVW optioned 3/4 ton !!
>
>ummmmmmm...  would that be the RA-5/RA-10, maybe?

Dunno about the code numbers, but these sound likely for it.

  i'm told these two look
>just like an RA15/RA20 only smaller, but i've never seen either one in
>person so i don't know if that's true.

What I'm trying to say is that you MAY well have seen a couple of them
without realizing it !! Was pretty standard stuff in the 120/1200's thru
'66.

  does this smaller axle you mention
>use the same third member as an RA15/RA20?

NO!!

  or is all of it smaller?

ALL smaller. AND--there's a Powr-Lok type limited slip that came in some of
them.
>
>the two axles i had, the one from the B122 and the one from the D1200, had
>the same pumpkin.  i'm pretty certain the D1200 had an RA15 because the two
>had the same third member.  i KNOW the one from the B122 was an RA15.  14"
>drums, 12" or so ring gear, 4" tubes, hub centres so big the wheels barely
>fit over them.  when i blew up the diff in the B, i just stole the third
>member from the D1200.  it was exactly the same in every way, and it popped
>right in, same spline count on the shafts, and both were No-Spins.  they
>both had the same 6.17 gear ratio, too.  the only *real* work i had to do
>was dropping the third member and then lifting it back up again.  those
>things are HEAVY.
>
>## >> As for the thing about 16" wheels over 14" drums--MAYBE they
>## >> go if you are
>## >> talking about 16" SPLIT RIMS, but NFW with 16" drop centers !!!!
>
>ummmmmm...  what's a drop centre?  all i've ever had on these things is
>splitrims.

A drop center rim takes tubeless tires--

 the B122 came with those funny-shaped-centre 16" splits,

Canadian made shiite !! Better know to real truckers as "widow makers"--and
for GOOD reason !! The VERY BEST thing you can do with that type of wheel
is cut 'em in two with a torch !!!

and the
>new axle came with deep-offset 16" split duals.  why don't "drop centre"
>wheels fit?

Captain Obvious sez : Because the center portion of the rim drops to a
smaller diameter so that you have a place to let one side of the bead of a
tubeless tire drop into when slipping the opposite side of the bead over
the rim while mounting it !! :-)

  what exactly is different about those from split rims?  are
>these the kinds of wheels that say my TravelAll has, the big 8-lug 16.5"
>mags?

Don't know of anybody ever made 16.5" wheels in anything but a drop
center--in fact don't know of ANY _1/2"_ size wheels ANYWHERE in anything
but a drop center. In TRUCK wheels, at least, a drop center wheel nominally
2-1/2" larger diameter is designed to be a DIRECT replacement for a split
rim:
22.5" replaces 20", 24.5" replaces 22", 19.5" replaces 17", 18.5" replaces
16", 16.5" replaces 14", etc. !!

This even extends to the tires: an 11x24.5 tire has exactly the same
rolling diameter as a 10x22, an 8.00 x 19.5 matches a 7.50x 17, a 9.00x22.5
matches an 8.25x20, etc.--and all these pairs match closely enough so that
you can run one dualled with another in a pinch !!

  or something else?  unless they're regular dish wheels or split rims,
>i know almost nothng about wheels at all.
>
>the drums from my first RA15 were 14" for sure, i measured them when i had
>to replace them (THREE DRUMS IN EIGHT MONTHS!!), and it was a nightmare
>getting more.  one yard, Fresno Truck Salvage, had three of them tucked
>away.  i got all three.  and the stupid truck cracked all three, on the
>right side.  i never did find out why or how it was doing that.

Crud on the mounting face of the hub or wrong lug studs or the stamped lugs
on the backing plates that support the brake shoes laterally and align them
square to the drum were worn or grooved--or a bent backing plate. Solution
to the worn support lugs is to build 'em up with gas weld, hard face them
(with a carburizing flame) (quench to harden) and then grind flat, smooth,
and true. Makes 'em work FAR better & smoother than original, and the hard
facing solves the wear problem PERMANENTLY !! Either fixed as above OR
original, you're supposed to put some lubriplate on those lugs when
installing new shoes --but hardly anyone DOES it !!!

  i rebuilt
>the wheel cylinders, changed the shoes, replaced the springs and other
>hardware...  and it would break the next drum.

See above.

 that got expensive in a
>hurry.  you don't want to know what that yard was charging me for those
>drums.

These days, those drums go for $300--$400 apiece for good ones IF you can
find 'em !!

Greg