V2Rocket

There is a lot of open space in the stock mount, between the rubber and metal - you add a lot of urethane in there, I don't think it would ever fail after that job.

mikey_audiogeek

+1, works well.

If you use windscreen urethane, no need to build dams as the windscreen urethane doesn't pour or slump. Just like icing a cake. Good bond too.

Cheers,
Mike

74goldtarga

I bought and installed a set of VW axles and broke the left side cage I believe due to using the grease that came packed with the axle. Drained out like hot water when I removed the shaft trackside. I have a urethane mount which I think has been fine. Subsequently I used quality moly grease which probably goes without saying as a recommendation.

The OEM turbo cages are beefier (bigger *****) than the VW replacements aren't they? Also, the shafts come in 2 styles with a different number of splines and I can't remember what is what. Regardless, if you are tracking the car you always want a spare complete shaft on hand.

Has anyone ever broken a shaft without first breaking the cage - the cage is the weak link - no?

As an aside where do we get spare triple-square bolts for these?

chrenan

I use the Stage 8 locking bolts, Lindsey carries them.

Laust Pedersen

Any healthy 951 should be able to spin the wheels on dry asphalt in 1st gear, which really sets the upper torque limit that the drive shafts should be able to handle. A more powerful engine will likely get to the upper torque limit for the shafts more often, but not exceed it.

So I think that the broken cage is mainly a wear issue. Specifically, if the inner race of the CV-joint is pitted from marginal lubrication and age, then the ***** will get stuck in those pits under hard acceleration, which will result in extreme stresses in the cage, when the CV-joint angle needs to change (bumps or pot holes).


Here are some numbers and calculations justifying that even our unmodified cars should be able to spin the rear wheels in 1st gear.

Based on a few numbers from the early 951 such as:
Engine torque: 243 ft-lb (@3500 rpm)
First gear ratio: 3.5 (2nd gear ration is 2.095)
Differential ratio: 3.375
Tire diameter: 25.25 inches = 2.104 ft
Car weight: 3000 lb
Estimated weight transfer factor for 1.0g acceleration: 1.3
Weight on one rear corner for 1.0g acceleration: 3000*1.3/4 = 975 lb

The following can be calculated:
Max torque for 1.0g acceleration with 1.3 as weight transfer factor: 975*2.104/2 = 1026 ft-lb
Max torque delivered to each half shaft: 3.5*3.375*243/2 = 1435 ft-lb (859 ft-lb in 2nd gear)


Tom, how does your inner race of the bad CV-joint look?

Laust

Arominus

Do the pour urethane, i did the window weld and while it works it took ages to cure properly, i pierced the outer shell and still got a squirt of liquid weld a week after i did it. It firmed up more over the summer, but the McMaster stuff with an activator to cure the material would be my first choice if I did it again.

V2Rocket

I wonder if Pontiac GTO (2004-2006) 5.7L or 6.0L shafts could be made to work, with flange adapter plates...
they only appear to be about 1" shorter than the 951 axles. And handle 400tq stock.

Tom M'Guinn

I couldn't get this advice out of my head, so ended up asking Xschop to make me a pair of axles, and ordering the 98-5084-B joints. Also getting a semi-solid mount from Xschop, and will ponder the possibility of a reinforcement bar when I'm under there -- though suspect the mount will eliminate the motion. I chose his mount over the others in part because he identifies the bushings used so they can be replaced if worn and/or swapped out if too hard or soft. Fingers crossed.

George D

Tom,

Contact the: http://www.driveshaftshop.com/ directly. They'll make axles for you and ship directly. After three stock cages blown, these have held up extremely well. I'll send you a pic of these on my car.

George

George D

Pictures of axles from Driveshaft Shop.

Tom M'Guinn

Thanks George. Do you know what material those use and what kind of joint is in there? Also, did you do anything to the mount in your car? urethane fill, solid, semi-solid, or just stock?

333pg333

Good option Tom. It's all about insurance of not being stranded somewhere far from home in my opinion.

EDIT: What George has is what I have also. I went to the Driveshaft Shop to get some backup parts at a later date and the guy that dealt with me was an inattentive fool and sent the wrong parts however if you call them directly I'm sure you'll get what you need. Having said that, I don't know if they're any better or worse than what Rob offers? As you can see, they're GKN parts. Not bespoke. I'd say they just make the axles themselves.

George D

LR semi solid. Call driveshaft shop about the material and joints used. They stated they'll hold 1000lbs of torque. Originally purchased them from LR - the 968 versions DON'T fit our cars. Too many calls to LR - got fed up and sent them directly to the driveshaft shop with exact measurements. They cut them to size for around $300 bucks, and now have proper side to side play. Very well built units. I'm not familiar with the company you're considering using, but if they're a good machine shop you'll be fine, especially if they're close to you.

Good luck with whatever you do - zero issues for over a year with consistent 500wt - but I'm easy on her in first gear. With NT01's - hooks up in 2nd once the tires are warm - with a little rubber smell.

George D

Patrick, sorry you had an issue. I have the name of the person I worked with at my office. He was the manager of the particular department I worked with at the driveshaft shop. They were turned around in about 5 working days with lengths exactly as requested. The reason the factory 968 axles "sort of" fit into our cars is from the additional side to side play - but it's still not a good solution - one side have much less play than the other. Don't recall which side - but blew out three factory CV's. With proper cleaning and a little locktite - the factory axle bolts are fine. Those stage 8 bolts are a bitch and found not necessary when everything is grease free - and a very small amount of locktite at the ends. Zero backing out for over a year.

George D

Is Xschop Evil? If so - likely very well made units.

G