Outer CV

Campbell

New member
Hi,

I run a MK2 Scirocco with a welded diff and seem to chronically break the outer cv on the drivers side, like every event. Has anyone dealt with this issue? or even better, solved it? thanks
 
Common theory is that you are breaking it because it runs out of "plunge" travel - in and out. Raise the ride height so it runs at more of an angle with more room to move.

K
 
My book tells how to measure it.
Also, often if you buy a replacement axle, they may be for the Golf, not the Mk 1,. and they are 1/4in longer. Max torque is about 200-250#, not 300or more.
WE run the same setup, welded diff , many hrs between any thing breaking. I repack them every 20 hrs or so. MM
 
In the 6 years of racing my VW Wabbit, in both ITB and GP trim, I only lost one CV joint on track, and it was an inner. I also swapped out the entire 1/2 shaft after every 6-8 events.

Like the others have said, check the length of the 1/2 shaft. If it's too long, you will put additional pressure on the CV cages. I realize that in IT you can't shorten the axle, but you could remove the circlip that would allow the axle to protrude further into the CV, with out causing the binding that might lead to failure.
 
Car sounds too low and has no balljoint spacer, I broke 2 axles when my control arms weren't level. Got balljoint extensions and made cable travel limiters for the shock and spring so the axle will not droop. Haven't had a problem since and I'm running 250 ft/lbs of tourque.
 
I think so.. I was using an aftermarket cv shaft, when I compared it to a stock Golf GTI shaft (supposed to be common with the Scirocco) it was 1/2" longer!! I put in the shorter shaft and now have 5/8" plunge - DS, the PS has 3/8" and has never broken. I will be back on the track in 2 weeks and see if this was the problem. Thanks for your help. (for reference neither of the inside cv's have ever broken, only the DS outer)
 
I am taking orders now for the next axle run.
All 100mm inner, 90mm outer . Blueprinted , 200$ each warranted one year, serial #ed.
The Chumps get 40hrs out of them between repacks.

I can also do the 90 inners but need your old proper length cores. @ $100per , no warrentee.
All axles include the FWDracingguide that tells how to measure the plunge and correct it.
 
OK, my ride height is 5" but my control arms are not level; they angle up on the outside a bit. I have read that bump steer may be bad with the control arms angled, but I have also read in GRM that this set-up is fast. So, I am going to give it a shot.

BUT, I don't want to break axles and/or CVs. Is this a real danger with the axles sitting at an angle?

I also have my new welded diff tranny installed . . .

TIA
 
From my E book;
For axle plunge; Unscrew the axle nut about 3/4.in or remove .
With the car sitting on the wheels fully loaded as raced, Push the axle towards the trans.
It should move around 3/8 in or a little more. The low spec is 1/4 in ,and the high spec is 1/2in. One side is usually more than the other.
If you have broken one axle more than once, and the plunge value is less than the other side , move the engine across the car, increasing the broken side's value.
Also with the new motor mount rules, I stuff the PS engine mount so that the engine can not move laterally.
The value can be changed by, taking camber out at the strut top, adding some at the knuckle, moving the ball joint out,
I track the axles by cleaning the drive flange very well and painting the inner flange and rubber seal. Any scuffs on the paint let me know that the axle has hit the flange.
Grinding the end of the axle alittle back to the C clip helps. Moving the shim spacer behind the CV to the outside can help.
Often the "dime store" axles are not the correct items. Mk 2 axles will fit the Mk 1 on the street- may work- but they are 1/4 in longer, same Mk 3/Mk 2 /Mk 1. Some may work in other cars and the parts store axle rebuilders may sell the incorrect numbers.

RE ride height, low front seems to work just fine. Lower the rear until the axle hits the body, keep the brake line clear.

HTH,
MM
 
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