Tips and Techniques on Repacking CV (Birfield) Joints and Wheel Bearings


Brought to you by the one and only, Norm of

 

 
 
 
It is said that a picture is worth a thousand words. It is also a lot  easier to insert them than it is to type long, ambiguous, and difficult to understand text.

So here are some pics with a little bit of text to explain each.

This is NOT a step by step instruction on doing a front-end repack. It is simply what the title suggests. Please use your shop manual for correct procedure.

The pics were taken in a workshop environment and show some special tools/equipment. Please substitute whatever you need to get the job done.

Credit for the greasy fingers goes to Stuart Roberts who served his apprenticeship with Mitsubishi, just "luurrves" working on Toyotas, but drives a diesel GQ Patrol.
 
 

REMOVING THE CONE WASHERS

 

The quick ones amongst you will notice that this pic was taken as the bits were going back together. Well, poetic licence allows that!

The workshop manual describes a special shaped little punch that is driven into the split of the cone to remove it. Most times this merely demolishes the cone. By far the easiest way to remove cones is to loosen the nuts (but leave them on to prevent cone flying or damage to thread if you miss), then use a copper or brass hammer to give a sharp blow as shown in pic. Several blows may be necessary. If the first cone is stubborn, rotate the hub and try another. As more are loosened, the remainder will become easier to "pop". A steel hammer can be used if you are confident that you can hit the flange dead square. Any burrs that may be created on flange or hub should be filed off before re-assembly.

For those of you with part time 4WD models, the technique is the same. You are simply removing a free wheel hub instead of a drive flange.

While looking at this pic, and remembering that the bits are going back together, please note that there is a generous amount of grease on the drive flange and outer axle splines. This is important to avoid wear in this spline. Wear from lack of lubricant, through none being put there at service, or it being washed out by water, is the MAJOR reason that CV joints have to be replaced.
 

REMOVING/REPLACING THE CV (BIRFIELD)

 

This pic shows the flat(s) on the CV that must be lined up top and bottom to remove/replace the joint. When removing, simply stick a finger in the grease to feel for the flats, put them top and bottom, and jiggle the joint while pulling it (the joint;-). When replacing, put a generous amount of grease in axle seal and slide inner axle carefully through the seal to avoid damage. The splined end of the inner axle will enter an UN-splined diameter in the side gear to locate it for entry into the spline. The driveshaft may need to be rotated a little to line up side gear spline.

What this pic does NOT show is the ABS sensor and the toothed ring on the CV. This vehicle does not have ABS. If yours does, remove the sensor (it lives just behind the square plug) to avoid damaging it.
 

PACKING THE CV

 

The question "Should I dismantle the CV to clean and repack it?" is often asked. Well, it's up to you. The inner axle is held in the CV "star" by a round section circlip. This circlip must be sheared to remove the axle. The normal way to remove the axle is to hold it in a vice and pound the crap out of the CV joint with a soft (but heavy) hammer. In many cases the circlip will be expanded a little and sometimes is so tight that the CV will not separate without shattering the star.

The joint can be successfully cleaned and repacked without separating it. A good dousing in solvent, petrol, kerosene, or whatever you choose, and the use of a stiff brush will remove old grease.

It is important that ALL old grease is removed. This means that to do the repack properly. The knuckle housing should be removed for cleaning. Mixing old and fresh grease, or mixing different brands/types of grease can cause the greases to break down to a liquid.

As in the pic, a spatula, or the palm of a hand, can be used to force fresh grease down through one side of the joint until it comes up through the other.
 

HOW MUCH GREASE GOES IN THE CAVITY?

 

There is some controversy over how full the cavity should be. Suffice to say that it should NOT be totally filled. Overfilling will inevitably lead to premature leaks at wiper seals, and possibly the forcing of grease through the axle seal into diff housing and through the spindle into the wheel-bearing cavity.

Stuart is shown filling the space between the joint and the ball of the axle housing. He will then push a good handful of grease into the knuckle-housing cavity.

At the top left of the pic you can see the square plug on the knuckle housing. It is obvious that pushing grease through this plug will not get fresh grease to the inside of the joint.

At the bottom centre of the pic you can just see the cone of the lower king pin bearing. Kingpin bearings are packed with grease similarly to wheel bearings (see pic after next).
 

TRICKY LITTLE STUDS

 

A simple way to locate all the bits that bolt to the knuckle housing. Those in the pic are actually manifold studs, but a screw with the head sawn off will suffice. My locating studs (these are Stuart's) have a screwdriver slot hack-sawed into the end to aid in their removal.

The idea is to put all the bits over the locating studs, start a couple of the bolts to hold it all in place, then remove the locating studs.
 

PACKING THE WHEEL BEARINGS

 

This is a bearing packer for use with a power grease gun. It is fast and efficient, but the same result can be achieved by forcing grease through the bearings with the palm of the hand. It is important to ensure that the spaces between rollers are filled with grease.

As with the CVs, it is important to remove ALL old grease (from bearings and hub). If you have access to compressed air, it can be used to advantage for cleaning; BUT do not be tempted to spin the bearing with the air. I know it is good fun, but it is also a good way to damage a bearing.

 

FILLING THE HUB CAVITY

 

Again, it is important to NOT overfill the hub cavity. Grease should be placed between the inner and outer cups, and to about the level of the inner diameter of those cups.

Wipe a film of grease over all surfaces to prevent corrosion should any moisture enter the hub (this goes for all bits, like the inside of the drive flange and inside the metal dust cap).

For those who have standard models, it is worth mentioning here the greasing of free wheeling hubs. The hubs should NOT be filled with grease. This will cause the sliding part to "hydraulic" and the hubs may not engage fully. The correct procedure is to lightly coat all the parts with the same type of grease used in the wheel bearings.

Wipe a film of grease around the machined diameter where the dust seal runs. This will not only save the seal from wear, but will act as a first defence against water entry.
 

FITTING THE HUB SEAL

 

The seal should be tapped down to be level with the hub. Use a soft hammer. The one in the pic is aluminium.

The casting of the hub is relatively soft, and can be easily damaged. If others have previously serviced bearings, inspect this area closely for hammer marks and bruising. It may be necessary to file or machine the diameter where the seal fits.

 

FITTING THE CIRCLIP

 

After the drive flange is fitted and the cone washer nuts are torqued, the circlip can be fitted. Screw an 8 x 1.25 pitch bolt into the axle to pull it out and expose the circlip groove.
 

ANOTHER LITTLE TRICK

 

The ends of the circlip are angled. I cheated a little and exaggerated the angle with a file (for the pic). Hold the circlip with the narrow side of the gap to the outside. If you hold it the other way, your next exclamation is likely to be "where the #&#@ did that go?"