A1 Custom shortened axles?

The inner spline is modified. It is shortened to prevent the axle from poking a hole in the drive flange seal when the car is run at a lower ride height. This is especially a problem on the left side, as it's shorter. When the car is lowered, the lower control arm is pointed upwards and when it swings through an arc under load, it pulls the hub closer to the transmission. Eventually, the CV's run out of plunge and this forces the inner end of the axle into the drive flange seal. WHen the seal is ruptured, the transaxle oil will wash the grease out of the inner CV, leading to premature failure.

The axle is shortened by machining off a little bit (around 1/8" is usually enough) and then the circlip groove that retains the inner CV joint is re-machined on the shaft.

MC
#14 ITC VW Scirocco
 
damn, that's ironic. I have some transaxle oil on the bottom of the differential, not pouring out, but a small drip. I was going to investigate it later - had the trans rebuilt recently, and have autoxed it and driven it to and from a few events this year.

Would the front control arms being level be considered 'low' ride height. I thought that lots of track/autox Rabbits ran this way, but I've never heard of this problem or this modification. I was getting some clicking from the CV too but the CVs were new when I bought the car...

Now, the ruptured drive flange seal, do I have to remove or tear apart the trans to fix this? Please say no...

PJ

------------------
83 Rabbit GTI - future ITB
 
PJ,

No, you don't have to remove the transaxle to repair the drive flange seal. It's a "Button" seal that goes on from the outside. It's in the middle of the drive flange.

Another thing that we do that can cause this problem is the extra negative camber we run on the front. This tilts the hub closer to the gearbox, so combined with lowering the car this can cause the axles to hit the button seal in the drive flanges. Also, if you have this symptom, check and make sure your engine/transaxle is centered in the motor mounts. If it's offset to one side or the other, even by just a little bit, it can cause the axles to hit the seals.

If you have a leak from the bottom of the gearbox, I doubt it's coming from the drive flange seals. More likely, you have a leaky clutch pushrod seal. Or it could be a leaky rear seal on the engine (are you sure it's gearbox oil?).

Mark Coffin
#14 ITC VW Scirocco
 
I don't know where the oil is coming from, but it's wet on the bottom of the diff case, directly below where the axles connect, and it's clearish, just like the trans oil I put in. It's not wet below the clutch or rear main seal area.

I did not take great care in centering the motor mounts (didn't think to) - I assume you mean the rear mount, as the others aren't really 'adjustable'. I have a poly mount back there too, not alot of movement. Is there a guideline or do I just 'center' the mount?

I also have about 1 degree of camber as well.

I'm glad it's as simple as you described, I'm going to order the necessary stuff from BSI and get around to it before I drive it again.

Thanks for the info Mark. This VW forum rocks ;-)

PJ

------------------
83 Rabbit GTI - future ITB
 
Originally posted by racer14itc:
The axle is shortened by machining off a little bit (around 1/8" is usually enough) and then the circlip groove that retains the inner CV joint is re-machined on the shaft.
Click to expand...

My copy of the ITCS seems to be missing the section that allows this modification. Am I missing something?

Back to lurking.

------------------
Jim Krom
ITC Renault Encore EFSC (Exotic French Sports Car)
 
I make no claims to whether this is a legal IT mod or not. PJ was just asking what was done to the axles, and I answered his question.

I don't use them (shortened axles) on my ITC car, as I take great care to center the engine/transaxle in the mounts (Yes, PJ, the right and left motor mounts do have adjustment for side to side) and I don't run the car as low as some VW's.

They are legal for production VW's (GP, HP).

Mark Coffin
#14 ITC VW Scirocco
 
I'm sorry to sound like a stick-in-the-mud, but an illegal modification that allows for more negative camber and/or lower ride height is DEFINATELY an unfair performance advantage.

------------------
Jim Krom
ITC Renault Encore EFSC (Exotic French Sports Car)
 
I believe that Jim is correct in his assesment that these would not be IT legal. But w/ a 5" min. IT ride height, you shouldn't need them. I've had no problems on my car, and I run ~2.5 deg of camber. They will be legal on Prod cars, even limited prep. If I end up getting to keep my car and convert it to GProd, I'll be talking to Stu about some of these.

------------------
MARRS #25 ITB Rabbit GTI
 
Renault guy, the short axles do not permit added negative camber or lower ride height - they just determine tranny maintenance frequency. Think about pulling the half-shafts after each race weekend and replacing a $1.50 seal - no big deal, strictly a maintenance thing. Incindentally, I don't use the short drivers side axle - I found a better way that IS worth 7 hp (anybody think this might stir something up?)

------------------
OFC
 
I don't know if the same applies to A2 Golfs. I've never broken the seal ,but the cage in the CV joint will break after being run off center. Jim, your point about an advantage for being able to go lower doesn't matter anyway. Once you go past parallel with the a-arms on an A2 (and I assume an A1,too) the geometry goes to h___. Roll center drops faster than the CG. I alway let other Golf racers "win"he argument about ride height being better if it's lower and then leave mine looking like a 4x4. I believe the shortened axles are probably illegal, but I don't see them as a performance advantage. It really is a maintenance thing. And since I started buying axles at Murry's I haven't busted one.
 
OFC,

Let me see if I understand this. Are you saying it's ok to use an illegal part because if it means you can reduce your maint. interval on other parts? I'm not trying to put words in your mouth, but that's what it sounds like you're saying.

------------------
MARRS #25 ITB Rabbit GTI
 
Bill, I didn't intend to express an opinion about the legality or lack there of, re: shortened axles. In theory, they probably do not meet the letter of the ITCS. In reality, a protest based on this mod would be akin to swallowing horses and gagging on gnats.
OFC

------------------
OFC
 
OFC,

That's how the rules start to creep. Yeah, it's not legal to the letter of the rules, but since it's a 'small' thing, we'll just look the other way. The problem is, a bunch of 'small' things eventually add up to a 'big' thing.

If you want to see rules creep, you should read the Prod BB. For example, there are a ton of guys out there that are using non-OEM steering columns, essentailly NASCAR or short-track style colums that use a support w/ a heim joint for a bearing. No where in the PCS does it say that you can replace the steering column, yet a bunch of guys have done it, and several are now defending it because it is a safety issue (which I agree, it is a safety issue). But if you feel that it's a safety issue, get the rule changed and then do it. There are many other examples of this as well.

The "if it doesn't say you can, you can't" philosphy doesn't work in my opinion. What that does, is get people to start coming up w/ creative ways to do things that are legal, that will also provide additional benefits. I think they should list the things that we're not allowed to do to a car. It won't be a complete list, but when new things are found that shouldn't be done, they can be added to the list. I think it would remove a lot of the gray areas.

------------------
MARRS #25 ITB Rabbit GTI
 
Bill, SCCA depends on competitors, for the most part, to enforce technical regulations through the protest procedure. If the shortened half shaft is a problem for you, find a user, file a protest, and let the powers-that-be adjudicate the issue. I see no relationship to rules creep.

Folks, I have enjoyed this exchange of views, but will not be able to continue my participation. I did near-mortal damage to my racecar a few weeks ago at VIR and,after appropriate mourning and reflection, have decided to return to evenings in the garage.
OFC
 
>>If the shortened half shaft is a problem for you, find a user, file a protest, and let the powers-that-be adjudicate the issue.

This point of view indicates a blatent disregard for the rules. Shortened halfshafts are not stock...they are not legal in IT.
 
BILDON, how did I get myself in this mess? I commented to RENAULT GUY that the short halfshafts did not affect a competitor's ability to change camber or ride height.
Subsequently, I commented on time/cost of not using shortened halfshafts and indicated that I don't use them because there is a better (ITCS compliant) way to cure the problem. Then I suggested that the issue could be resolved using a remedy prescribed in the GCR. Now I am accused of having a blatent disregard for the rules - makes a lot of sense to me.
OFC
 
You must log in or register to reply here.
Back
Top