'85 CV Replacement

[Discseven]

I’m replacing my CVs due to their all looking like this.

There’s no consideration for cleaning and inspecting these CVs. I’m certain road grit has eaten away at the bearings to the point where --- since I’m already pulling the engine & trans out for maintenance --- I might as well replace them.
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CV's exist at each end of a drive shaft. For easy bolt removal, shafts should be free to rotate.

The last bolt in each CV is loosely left in position to support the shaft in place until the time comes to extract the shaft. The trans mounted CV comes straight down first then the wheel end comes away from the wheel.



As soon as a shaft is extracted from the car, I remove the bearings from each CV. In my case… they fall out easily clearly suggesting they are indeed worn. If they did not come out easily, I’d immediately wrap the CVs with plastic kitchen wrap. The idea is to prevent the greasy bearings from falling out unexpectedly. When bearings do do this… it’s a f**king mess! I know first hand!

After removing the bearings, the cir-clip at the end of each shaft is next to remove. These are often hidden under grease. Next, the shaft is pressed out of the CV, in this case with a hydrolic press.



It’s possible to beat CV’s and shafts apart with a hammer and drift but care is needed when doing so. One powerful off-centered wack can flare a drive shaft's end. Once flared, the difficulty in removing the CV behind the flare is increased dramatically. Should this occur, I would suggest beating the parts apart should stop… and a hydrolic press be found one way or another.

Once a CV is off a flared end, splines on that shaft’s end may need redressing (filing) to put them back in good working order. The idea being to prepare the shaft to “easily” receive the replacement CV. Without redressing, more damage may occur when attempting to replace the CV.

If going to a shop and paying... both shafts can be pressed in under a minute by someone who knows what they're doing so “minimum charges” should apply. “Set up” fees are BS charges IMHO (in my humble opinion.)


CLEANING

My CVs have been trashed so only shaft splines and four washers need cleaning. The best portable metal cleaner I know of is spray brake cleaner (BC). It dissolves grease easily and dries in seconds. A few burst of BC on all splines and washers and they look like new.


CV KIT

As of this post, the Pelican CV kit provides the boot with attached flange, CV, grease, cir-clip, inner boot clamp and 2 sticky gaskets per kit. NOT included: 6 Allen bolts, 6 lock washers, 3 two-hole C washers, and 1 large washer (per CV.)



CV INSTALLATION

1. Place the narrow boot end’s clamp on the shaft first (if using one. I’m using zip ties.)
2. Pack CV full of grease. (I think it's easier to pack CVs with grease before putting them back on the shaft.)
3. Place the boot/flange onto the shaft without grease in it. The narrow end positions over the seat provided for it on the shaft.
4. Place washer on shaft with the crown facing inwards on the shaft.
5. Load all extra CV grease into the boot. Because of the conical shape of these boots, centrifugal force (when a shaft rotates) moves grease from the boot into the CV.
6. Clean gasket surface areas on trans and wheel flanges.
7. Apply new sticky gaskets on flanges… positioning so the indentations in the gasket aligns with the bolt holes in the flange. Flanges are shown below with sticky gaskets pointed to.





8. CV goes onto the shaft with the groove that circles the CV positioned closer to the end of the shaft. Now's also the time to choose how to align companion CVs. My preference is to position companion CV’s with the bolt holes of one CV aligned between the holes of the opposite CV. (Shown below) I’m sure a variety of opinions exist on this subject. In the absence of a hydrolic press, there are any number of ways to get the CV onto the shaft. Before applying any significant force to mate the CV and shaft, splines between CV and shaft are aligned… then, only enough force is applied to begin the matting process. If the splines are aligned, mating will proceed with an even pressure requirement. If splines are not aligned, the pressure to join the CV and shaft will increase --- stop immediately if increasing resistance is felt and remove the parts for inspection. Any damage has to be sorted out appropriately. With confirmation that the splines are aligned, mating proceeds.
9. After each CV is fully on the shaft, the retaining cir-clip goes on the end of the shaft to lock the assembly on the shaft. This cir-clip seats in a recess cut around the end of the shaft. Note that the inner washer on the shaft may exert just enough pressure on the CV to prevent the cir-clip from seating or even seating fully. In this case the CV needs to be pushed slightly onto the shaft giving the cir-clip the space it needs to fully seat. I make absolutely sure the cir clip is fully seated. If in doubt, push the CV onto the shaft and check the cir-clip with no grease obstructing the inspection.
10. If using the two-hole C washers, these join two bolts after lock washers are on the bolts, and the bolts are loaded into their holes. Bolts will loosely stay in a CV due to the configuration of the boots.

A completed shaft with “non-aligned bolts.” (I place a marker on each shaft before removing them in order to return each shaft to the side and rotational torque each shaft is accustomed to.)



If completed shafts are not going to be immediately installed, it’s a good idea to bag or plasti-wrap the CVs.
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Fastening specs call for 8 x 50 mm Allen bolts, lock washers and two-hole C washers. I’m foregoing the two-holed Cs and going with slightly longer bolts and new hardened lock washers. I’m using the longer bolts in order to consume all threads in the trans & wheel flanges. Below is the spec bolt next to an 8 x 55 mm Class 12.9 I’m using.



Before installation, parts are etch-coded to tell part origin, installer, and install date.
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Before lifting the shafts into position, the mounting surface on each CV is wiped clean. Wheel-side CVs are put in position and attached first with just a single bolt to hang that end while the other end is lifted straight up and attached to the trans. I’m careful to avoid (as much as is possible) getting grease on the flange gaskets when attaching the CVs.

Allens are tightened in a star progression with split torque sessions --- half the torque value is applied first. Same tightening sequence is repeated with the full torque value… I’m applying 31 ft. lbs. total. (Having extra fastener bits on hand serves to keep things moving forward in the event of mishaps like blown out lock washers. 3 “hardened” locks blew out on me.)



Passenger-side trans mounted CV (looking towards back of chassis.)

Passenger-side wheel mounted CV (looking forward in chassis. Angle of the shaft to the wheel is severe here because there’s no weight on the wheel.)

With my 911 on a friend’s lift and using his hydrolic press, replacing these 4 Cvs took under two hours.
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Home to these new CVs… my ’80 Targa.




BACK END NOTES

Both shafts must experience resistance in order to transmit power to the wheels. In other words, if one CV comes completely undone while driving, driving comes to a coasting end.

I was with a friend in his ’82 911 on the highway outside of Atlanta… All of a sudden… there’s no power to the wheels --- but the engine works fine. As we coast off an exit, gears are carefully shifted… engine rev’d… what the f**k! Brakes work! Wipers! Stereo! We speculate about being in the twilight zone… then return to reality calculating how much a trans inspection might be, and who might be willing to do it right away on a Sunday afternoon. The mood is somber.

Once halted, both of us scramble to look under the car. It all looks normal. Over and over our eyeballs scan the engine & trans and nothing. Perplexed, and rather than leave the car in what appears to be an unsavory parking location, a flat bed is called. With the car up on the flat bed, a different perspective is provided so once again we both go into scan mode.

There it is! From this angle, the disconnected wheel mounted CV is spotted right away. Amazingly, all the bolts are STILL THERE! “Drop the car we’ve changed our mind!” my friend Komo calls out. The flatbed driver --- who's bigger than both of us combined (and we’re both 6’+ and 200 lbs) --- insisted it’s too late… “Yo! Once this car is up like this and I called it in… it goes to the yard. I got no choice. You got no choice.” A bribe fails. Plan C = we connect it in the yard.

“ABSOLUTELY NO WORK on impounded cars is allowed in the yard,” a sign reads. So, under a light drizzle and after a greasy half hour spent covertly making the reconnection in the yard… the $100 tow is paid (through 2” thick bullet proof glass) and we’re happily back on the road heading first to get degreased and then on to South City Kitchen for She Crab soup.

I never did ask Komo if he had torqued his CVs. Didn’t have to ~