Hello, my name is John Kelly and this is the WeberAuto YouTube channel. Today I'm going to
show you how to Center a universal joint in the driveshaft yoke ears and set the axial
play correctly we have just changed this universal joint and I have a separate video on how to change
the universal joints properly without doing any damage once we change the u-joint then we have
to make sure that we set the axial play and Center the u joint properly with the snap rings and there
are many different snap ring thicknesses as I discussed in another YouTube video on universal
joint differences so let me show you how to check the axial play and Center a you joint now okay
I've taken the drive shaft that we just replaced this u joint in and I've brought it over to a vise
with copper jaws and I'm very carefully just put a like clamping load on the slip joint I'm not going
to damage that if I have copper jaws so what we need to check is axial play and as we saw when
we were installing the new joint there's a whole bunch before we got the snap rings in but we want
to have no more than just a little bit under mm of an inch 1.97 thousandths of an answer so we'll
just call it two axial play in either direction we do not want to have 0 we do not want it to be
pre-loaded so we want the joints to be able to move it was if it's pre-loaded you there stuck
real solid and you're going to have to bend them to make them push on really hard to make a move
neither of these are pre-loaded we may have a zero axial play in the steel yoke ears for that portion
of the u-joint but I've got a dial indicator I've just got a magnetic dial indicator set up
it's sitting on top of the u-joint bearing in the aluminum ears for our aluminum axle or driveshaft
here so I've got a dial indicator set up let me zoom in so you can see the the dial okay so I've
pulled down and have it set at zero the next thing to do is to lift up so I'm just going to lift up
here and I've got one two three three-and-a-half thousands axial play right there that's too much
that's almost double what we should have so that means that the fifty nine thousandths of an inch
copper-colored snap rings that the kit came with are too thin for the aluminum ears but it also
came with grey and purple snap rings which were our grand pink the 61 and 63 thousands of an inch
so it theoretically your mathematically if we go an inch or a thousandth of an inch thicker snap
ring on each side that'll take mm out of the axial play we're at three and a half minus two
that should give us one and a half thousands right there so that's that's what I would do I would put
the gray snap rings that came with the kit in and see where that leaves us but before we do
that let's measure the axial play on the other end of the u-joint so let me get that set up okay I've
repositioned the drive shaft in device by turning it a quarter turn 90 degrees and clamp the yoke
back in the copper jaws and now our magnetic dial indicator bass can still attached to the yoke but
instead of going to the top of the u-joint bearing cap because we used to have it on this one we are
going to put it on the end yoke the flange yoke of the drive shaft and then as we lift up and down to
measure the axial play this way it should show up over here so let me zoom in on the dial indicator
push down first zero the dial indicator and then push up one one and a half thousandth so back down
so this one I thought was too tight is actually right in spec one and a half thousands of an inch
so that's I in several of my episodes here on universal joints that I can't feel personally
I can't feel clearance is that small I have to measure them and I suspect many of you are the
same way so before we can put this driveshaft back in the vehicle I've got to change the
snap rings from the copper to be gray here on the on the side and then we'll remesh just to
make sure that we're in in specification and then we're good to go back together so let
me go change those real quick okay I've put the gray snap rings in instead of the copper
colored ones I've got the dial indicator set up again to measure the axial play push down
I've got the dial indicator zeroed now let's lift up and see how much play we have whoa
no change here zero there's one two three and a half nothing changed what is interesting all
right let's go with the pink they're supposed to be sixty three thousands I have not actually
measured these snap rings that came with this kit see if they're what they claim to be and as
you can see I've got the pink snap ring installed which is 63 thousands okay I'm going to push down
with the pink snap rings in zero hour dial indicator and we better not have three and
half thousands and lift up whoa we have a half that wasn't good so as I said we do not want
zero we don't have zero we have we have a half we started with four and a half thousands with copper
snap rings I install the gray snap rings that came with a kit it didn't make any difference
which makes me think I measured something wrong with the copper hand and then I put in the pink
because it comes with four of them so I have two left over and the axial play has gone down to a
half thousand so on this u-joint cross and these bearing caps I have 1/2 of a thousandth of axial
play we have two pink snap rings in nice clean grooves that centers the u-joint in the ears
of the oak on the steel yoke side ears we have the black 57,000 snap rings and one and a half
doesn't axial play now if we would have put the 58 in we would have mathematically
if we're a one and a half and we increased the thickness by one thousandth of an inch on each
side we would have been preloaded by half of a thousandth of an inch if we would have
forced the copper ones in at 59 then we would be pre-loaded two and a half thousands of an
inch now if we would have a interesting thought here if we would have had the aftermarket kit
and seeing the aftermarket kit snap rings were how thick fifty four fifty four thousandths of
an inch so the after the aftermarket u-joint came with fifty four thousands shams and you
can probably guess why that way there they're going to fit no matter what at 50 where it's
67-59 over we are at fifty seven thousand seven it's snap rings right now and we have one and a
half thousand axial play if we went clear down to fifty four thousand switch that cheapo kit
comes with that is three thousandths of an inch per side that's an additional six thousand we
would have seven and a half thousand axial play in this u-joint that's more than is allowed for
class four through eight heavy duty trucks the big semi trucks driving down the road where the
u-joints are gigantic they have a maximum axial play of six thousandths of an inch
so the 54 is would have fit most technicians or do-it-yourselfers without oh great I'm done
in a way we go and here's the tricky part it may or may not cause any type of a problem it really
depends on the rotational speed of your drive shaft which is based on your tire height and
your axle gear ratio it's based on how much run-out did you have in your drive shaft to
begin with is in other words what I'm talking about is will you end up with a vibration after
you've changed the u-joint can you see now that if you if all you did was changes your joint and
put into thinner shims and now we have the entire u joint flopping to one side seven thousand seven
we've just added seven thousandths of an inch run out to this driveshaft and if you were already on
the edge of too much run out now you're going to be over the edge with that okay so that is you
joint centering by equal thickness snap rings and then axial play by changing the snap ring
thickness until a reading on a dial indicator indicates that you are within whatever the
manufacturer specification is the Toyota spec that I found was point zero zero one nine seven
which is almost two thousand seven amps that is a Spicer 1350 u joint this is a Spicer 1330
the only difference is the width same bearing caps so it's it's got to be the same axial play
this if you look in the General Motors service information they don't tell you to do anything
but replace the u joint they don't tell you to measure axial play the Chrysler book the
instructions don't say anything about it some manufacturers do some don't but I've
always wondered why when I change u joints or some super stiff some super loose some fail sooner than
others what is the original ones last what seems like forever and I believe this is why so this has
been a demonstration of checking the axial play and centering a universal joint in a driveshaft
you