xTo rebuild a universal joint you will need a rebuild kit and some lithium-based grease. Dirt and grit are the enemies of universal joints, so be certain that the working area and your hands are clean. The new joints should contain adequate grease to hold needle rollers in place, but remove the caps to check anyway.
The flange must be clean and have no burrs. Fit one of the new caps, dead square into the flange and with the vice, get it in about 3mm then insert the spider. Make certain that no needle rollers are displaced. Press the cap in as far as the vice can manage and then use a spacer to push it right in. The exposed end of the spider can then accept the second cap to hold the needle rollers in place while the assembly is pushed back the opposite way.
Beware of needle rollers dropping out of place during assembly and preventing bearing caps from being properly installed. Ensure that the second cap is flush with the flange and fit the circlip to the first cap. With the first cap fully home, fit its circlip.
When fitting the flange to the main body, the process is repeated.
The universal joints should move smoothly and easily. If they feel a bit stiff, support the shaft and lightly tap caps in the direction of the circlips.
Whenever a shaft is disturbed, the seal in the extension housing should be renewed, but don’t panic if there is a slight leak here because that is normal - no more than slight though! Remember that seals can be easily damaged by any roughness on the slip yoke. Lightly lubricate the yoke before fitting it to the housing.
Fit new nuts and bolts to the flange, according to the marks you made. Now torque flange bolts to the correct settings. These vary, so check your friendly local mechanic, or a shop manual.
RESTORING THE CORRECT OPERATING ANGLE
Occasionally, even with new joints fitted correctly there is roughness at certain speeds due to too large an operating angle at the rear joint. Check or seek advice on the recommended angle and vehicle ride height. It might be possible to restore the correct angle by inserting a wedge between the leaf spring and axle housing.
An incorrect front angle may show similar symptoms to rear angle faults and sometimes judder at low speeds under acceleration. Here it is best to visit a main agent for a check. The main culprit for angle faults on relatively late cars is repeatedly towing a heavy load.
A damaged or badly bent propshaft is, strictly speaking, good only for scrap.
It is not worth trying to straighten because invariably imbalance problems will remain, no matter how careful you are.
Buying a used shaft is a risky business and you have to rely a lot on the breaker for guidance.
If you have to check one yourself, look for hammer marks around the yokes – and if there are any, that’s bad news, so give that one a miss and seek another. Sadly, there is no foolproof way to check the condition of a used shaft except by dismantling. - The Star