Where to get half shaft bolts

Pete Whitstone

Pete Whitstone

True Classic
Hey all, where can one obtain replacement bolts for the allen headed cap screws that secure the CV joint on either end? I know this is often talked about as a replacement/maintenance item, but I don't recall any discussions on where to actually obtain them. Anybody got a source?

Thanks,
Pete
 
Fastenal can get them for you if you take them an old one. Or the online bolt places if you go off the measurements.
 
Pete Whitstone said:
Anybody got a source?
Click to expand...

They're a standard piece of 12.8 hardware. I bought a box of 50 from Fastenal, and BelMetric and McMaster-Carr both carry them. So will the local Ace hardware, although they probably won't have enough in stock to do an entire car.

Just measure the length and thread on one of your old ones and you're good to buy from whoever you usually buy your hardware from.
 
Pete Whitstone said:
Hey all, where can one obtain replacement bolts for the allen headed cap screws that secure the CV joint on either end? I know this is often talked about as a replacement/maintenance item, but I don't recall any discussions on where to actually obtain them. Anybody got a source?

Thanks,
Pete
Click to expand...

I took one into my local NAPA store and they matched it and ordered me a dozen.
 
M8 x 45mm long, Grade 12.9, Hex Socket Head.

Check your local industrial hardware supplier. Typically $25 to $35 per 100 pc. Balance this cost to purchase locally with shipping cost.

These are replaced each time the CV joints come off.

Use a good quality 6mm hex bit and torque to FIAT oe spec.



Bernice
 
Or use VW CV joint bolts.
They are identical, except 48 instead of 45mm long.
They use a torx head instead of hex which don't round off as easily.
 
Which raises the question of why they are not to be reused? They seem rather substantial and Xs are not torque monsters.
 
Are the VW ones Torx or triple square? I thought they were triple square (which is also a great drive standard)
 
cv bolts

you can use the old ones, just don't forget the loc tite. the new bolts have a smear of yellow on the threads which locks the bolts in place once tightened. I have a box of new and used ones here if you don't want to go through the vendors or fastener outlets. leeme know
mikemo
 
I was trying to remove some from an axle on my workbench and they would not break free even with my impact gun! Thats some locktite considering the torque spec is 31 ft/lbs. Now I have to cut the heads off to free the CV from the axle stub.

All 24 on my ex race car came free without any hassle.
 
cv bolts

crank up the impact gun to it's highest setting and oil it before you try again . the oil out of the exhaust is messy, but you will be surprised how much better they work. had a bunch of air tools here that I considered POS and once oiled they are better than the replacements.
mikemo
 
VW cv joint screws and similar German brands use internal triple square recess instead of internal hex. They do have higher theoretical torque capability over internal hex, but the tensile strength rating is much the same.


Bernice


Ulix said:
I am not sure what the pattern on the bolt heads is exactly.
Click to expand...
 
No thread lock used OEM as delivered from Fiat. Some might have paint on the screw heads, not thread lock.

If there is a drive adapter between the impact wrench to hex bit socket, that could be where a lot of the loosening torque from impact is disappearing. Use the same square drive size hex bit socket as the impact wrench, no adapters, no extensions, no ball joints or etc each item added reduced torque transmitted.

Use high quality, proper fitting hex bit sockets. They can make all the difference between instant removal to not moving the fastener at all.

A drop or two of air tool oil at the inlet should be done as routine air tool care. It does make a difference in air tool life and power output.

Air line size and length can make a HUGE difference. A 3/4" drive impact wrench rated near 1600 ft/lbs being run at the end of a 1/4" air hose that is 100 ft long is likely to not even start up due to the pressure drop and restricted air volume delivery to the end of that hose.

https://www.youtube.com/watch?v=kmTmI0_9s-I

or

https://www.youtube.com/watch?v=FjtnE3ScINE


Putting that flywheel nut back on. Torque to ~350 ft/lb.
https://www.youtube.com/watch?v=twfutkuf7ho



As for re-using the stock cv joint screws, why?
Replacements are not expensive or difficult to obtain, after one stuck or difficult removal, the internal hex is more often than not destroyed. If screw is over torqued or abused during service, screw failure can result. So much can go wrong producing so much grief that can be easily prevented at low cost.


Forget about using thread lock (Loctite) or similar due to the problem of cv joint grease in the threaded area and overall problem of keeping that area petro lube free. If the intent is to stop these cv joint screws from loosening in service, drill out the threaded flanges to tight clearance fit M8, spot face opposite side of the drive flange and used proper aerospace bolts (MS21250 or similar) with prevailing torque nuts. This is what should be done to cure the never ending cv screws coming loose problem prevalent on ALL cv joints produced this way.



Bernice


carl said:
I was trying to remove some from an axle on my workbench and they would not break free even with my impact gun! Thats some locktite considering the torque spec is 31 ft/lbs. Now I have to cut the heads off to free the CV from the axle stub.

All 24 on my ex race car came free without any hassle.
Click to expand...
 
I was finally able to loosen the bolts by using my allen wrench (not my allen socket) with a two foot cheater bar on it. One bolt had the socket half filled with grease and dirt and even tapping the allen socket with a hammer to make sure it was fully seated it only went half way in and with only half depth insertion it ruined the socket, hence my switch to the allen wrench....and I was careful to clean out all the screw socket heads after that.

Since the car this axle is going into recently had the clutch replaced, I'm hoping there will be no issues getting those screws out.
 
cv bolts

if the allen is fudged up, replace then, but the old ones will work just fine with the Loctite if all surfaces are clean. and that is a fastener enhancement on the threads. and it is yellow. gm has being doing the same, but there adhesive is a dark maroon. customers would balk at the expense of all the money they had to spend on bolts for a head or intake job.
basically it was COA so there were no comebacks to hamper the shops bottom line or warranty issues.
mikemo
 
You could probably get similar hardwate from aircraft spruce. Maybe even hardware with safety wire holes.
 
Hmmm.....

Let me throw this out for comments:

Since there seems to be a tendency for these bolts to loosen off in service (been reported several time on this forum) - and the difficulty of using Loctite (too much grease around) - and the difficulty in finding the OE type bolts - and the not ideal hex drive (rounds out too easily).....

How about using the VW bolts with a Nordlock ???

The VW bolts are easy and cheap to obtain (and good quality too), and have a superior triple square drive. The slightly longer length would allow nicely for the Nordlocks.

A quick google seems to indicate the Porsche crowd (they use a similar cv joint with 8mm bolts) having the same problem of them loosening off. Many of them swear by the Nordlocks as a solution.....

This is merely a suggestion not a stated ultimate solution.

Discussion please. Bernice, anyone ???
 
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axle bolts

there is a corundum to using nuts . there is no clearance between the stub axle and the trans. hence the bolts being flush with the axle. use the Loctite and for insurance, wick some in at the bolt hole after installation. I assume all parts will be squeaky clean, so that won't enter the install process.
oh, and bern.. the yellow is indeed on the threads, not the heads.
mikemo
 
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