I just realized the modern general JOINTS layout for all type of wheel drives: all cars need Tripods CVJ. For FWD, tripod is used on the inner side of the haft shaft, to provide axle movement for suspension distorsion. As for RWD, both sides of half shaft are similar because the outer CVJ does not need steering ability, in which 6 balls (Zeppa or Birdfield) CVJ is used. RWD and 4WD need additional UJs set to lengthen the drive transfer to the distant wheel drives from the transmission.
CV shorts for Constant velocity, it means as the drive angle changes, the drive speed delivered is still preserved. As for universal joint, the drive delivered from driving shaft through the trunnion to the driven shaft is not constant( universal joint post ;link;) so this needs another universal joint to cancel out this difference, so in the end drive is responsively 100% transferred to the pinion gear/ final drive. The universal joint design is ideal for RWD vehicle because of this, not for FWD, totally unnecessary and not logical.
Why CV joint? FWD or RWD, they need a short, homo-kinetically transferable at variously wide amount of drive angle; simply because from output transmission-final drive- half shafts to drive wheels is short, therefore high angle drive occurs. The design of CVJ just overwhelms the UJs. First of all is the Tripod CVJ. This CVJ is needed for any half shaft because they are the last link of drive transfer from transmission to THE wheel drive. Due to various load conditions put on the suspension, the joint has to be able to operate successfully compensating changes in angle, distance from wheel drive axle to the differential/ final drive. This is why tripods joint is very important. The design consists of 3-balls or 3-spherical rollers (set 120 degree apart) around the interconnecting shaft and a sliding hub( outer race) providing end travel(plunger type): the key for the tripod to CONSUME angles and length variations.
In FWD, it is crucial that the outboard of the half shaft is fixed type. This to me simply mean it is the 6-balls Zeppa or Birdfield( watever) type. 6 balls rollers trapped between the cage and the inner race, smoothly sliding in their outer race grooves, plus the inner race has splines connected to the interconnecting shaft, providing very high and direct angle drive transfer, allowing for steering ability of a FWD. The balls movement is sequential and coordinated, like when a ball move outwards, the opposite ball is dug deep inside the outer race, this makes the whole balls set fixed inside the outer race.
Dismantling these is easy as we got instruction. But the real thing that makes your money is looking at parts that have the tendency to be damaged.
1- Tripods: Its really easy to unclip the boot cover to get into the rollers housing ad then just slide them out. Before that, remember to remove the seal. So what do I look for? Moving parts always get damaged by the way they operate, they have never been perfect. What gets damaged more when doing burnouts, tyres or the tripods rollers? I'd rather check the rollers for right-on cracks, damages...and the needle bearing inside them. Then I check the whole inter shaft for torsion as assumed that excessive load applied. Outer race and splines grooves are also important to check out for cracks, frays, corrsion etc...This is because, if any of these gets worn out, firstly noticeable is the noise it makes when driving, then drive is not efficiently transmitted, eventually cause high fuel consumption, poor performance. And most dangerously, the sliding plunge joint gets bind up, or the shaft gets 2 much torsion would probly break on point.
The rubber boot cover is important as well as it keeps all the lubes inside the rollers joint housing, keeping it smooth. Always keep an eyes for any cracks, leaks on the rubber boot especially the retainer and collar strap make sure they are tight. Because when a leak of lube happens, clearly your joint lose out on lube that it heats stronger/ faster while operating, hence corrosion happens faster. Also, leaks allow all sort of dirt deposit into the joint, corroding, binding it from smooth operation.
2- 6 balls: The difference between the Tripod and the Birdfield is that the 6-balls has a retain circlip plus its design that allow no end movement. This circlip is often noted as to take the balls housing out of the outer race. Without the circlip, the inner race and ball cage can move freely as to the point where the balls can be removed out of the cage one by one. Special puller/ press tool is required if the outer housing refuse to move. But in my experience, i just need to be as precise as choosing the right corner then use a soft face hammer n a press to press 1 side of the housing down. There is usually a more opened cage hole than the other 5s that is the right one to level. Once the 1 ball is taken out the rest should be easy.
Again, I check for cracks on the balls, damage on the outer race, cage, inner race splines etc, make sure the rubber boot is tight, nt leaking, n everything regreased. The reason i did those is the same as why i have to check the tripods...
When all done, I check for all smooth operation of them joints.
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