Axle split boot advice

[Dodaman]

Hello everyone, the other day was doing so routine undercarriage checks and noticed a nice amount of grease thrown all over my front suspension. . The inside driver side boot had a good tear in it. I am planning on doing some suspension work soon, so I’ll pull the axle and replace with a new one. But in the mean time, I’d like to just use a split boot and refill with grease. I’ve looked around and saw a few types. I was wondering if anyone had advice on a split boot that is better to use for the A4 B6? I appreciate the advice. Have a great weekend.


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[shurur9]

This is my semi-newby advice.

You definitely want an OEM boot with 4+ baffles, as the ones with less tend to split along the baffle rings because the grooves are stretched-stressed too much.

The outer cv is easily removed and you can get a removal tool on ebay if you want.

Both inner and outer boots can be replaced with the outer cv joint removed, by just sliding the inner boot down the greased shaft.

The quality German bearings in the OEM joints are of very high quality; cleaning them up with dish soap and water or even superclean-purple power with a rinse, then regreasing them with a high temp synthetic should be fine.

Even if you buy a new-used shaft, you should keep the original and refurbish it yourself.

Not a fan of Raxles as there seem to be a decent amount of returns and reinstalls under there lifetime warranty.

Let the shit-storm begin...

[Dodaman]

Thanks. I hear that. Heard a few horror stories about them, too. I’ll def replace with oem. But not for a couple months. Thanks for the tips


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[Turbo510]

To me, the Raxles solution doesn't make sense, because to use the warranty, you need to (a) remove the drive shaft, (b) pack it up, (c) take it to wherever it will be shipped to Raxles and pay shipping cost, (d) install the rebuild after the thing gets delivered back to you. All this time your car is out of service. I say, do step (a), overhaul yourself which takes 1 hr if doing it slowly, then do step (d).

[Dodaman]

Yes. I’m not replacing it. Will pull it and replace the boot. Then put axle back on. Just don’t want to do it twice. So waiting a bit till I do all the parts while I’m there Just don’t have the time to do it all at once right now. That’s why want to use a split boot for a bandaid now, so I can keep using it. Commute isn’t bad. 10 miles round trip over side roads with traffic. So no high speed hwys


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[codemode]

Those OEM joints are tough! They can withstand a lot. I wouldn’t worry that much about the outer boot being torn. I’ve driven my car with a torn cv boot multiple times for a while, without any issues. Aftermarket joints suck, don’t replace them unless visibly or audibly broken. IMHO the inner boot being torn would be a bigger of an issues since the grease is not as thick and spills out more easily. You don’t need a special tool to remove the joint, just remove it from the hub and screw the big bolt until the joint pops. The inner one can be a bitch, having a secured vice is a must, the tripodic roller can appear stuck in some cases. Also the outer casing needs to be hit at a certain angle forcefully. You can avoid all that if you replace the boot from the other side. Remember pack the grease inside the joint and then what’s left over in the boot.

[Puddin Tane]

VAG specifies an unusually liquid grease (G052186A3) for these inner joints versus the usual stiff MoS2 stuff, and I can vouch for its superiority. At 150K miles everything in there looks like new. The needle bearings and large rollers in these joints don't want the same grease Rzeppa joints get.

You really should clean the inner joint and inspect it for damage before repack and reassembly, and to do that I don't see any way around removing the axle from the car and pulling the inner joint apart, versus sliding the new boot from the other end. There's also no way to apply the above grease without removing the axle, since the inner joint's "cup" has to be kept inverted to keep this grease from flowing out (it's almost like oil).

How I took the inner joint apart (easy once the axle is off the car). This post also has the part number for the Genuine reboot kit. Others in the thread also talk about other ways of disassembling this joint.

If upon inspection you see any irregularity in the roller races inside the "cup," a new inner joint is in order, but that doesn't have to mean an entire replacement shaft. VAG also sells replacement kits for the joint alone (includes the G052186A3 special grease). I don't have that part # handy but can dig it out if you want it.

[Puddin Tane]

I wouldn’t worry that much about the outer boot being torn.

He said inner joint. On the front that's a totally different animal, and the boots are less flexible / more prone to splitting than the outers. The rear axles have Rzeppas on both ends.

[codemode]

He said inner joint. On the front that's a totally different animal, and the boots are less flexible / more prone to splitting than the outers. The rear axles have Rzeppas on both ends.

Oh! My bad.
Also I was talking about the front axle, since I have a FWD and I’ve done both boots recently, and have to do a third one in a few days.

I would definitely avoid any dirt roads, large puddles of water and detergents.

And yes, doing it the right way is recommended. (aka removing the roller).

[shurur9]

Depending on what cash you have, you could put some cheap complete Amazon shafts in and buy yourself a bit of time to refurbish both OEMs..dunno..just an idea.

[Kevin C]

I don’t know of a good split boot for quick repairs on the inners. The inner joints have a weird body to them that is hard to seal even with the correct boot. The OEM grease for the inners appears to be non molly and quite thin. The reasoning Audi gave is that it lowers friction to reduce the chance of shudder. The compromise is that molly is better for wear under high loading but theoretically may interfere with the fine needle bearings used on the inners, causing them to slide and not roll.

Also it interesting to note that roller wheel bearings use a moly based lube ( NLGI GC-LB). U joints in old school drive shafts? They have the same moly non molly debate. Turns out most joints with needle bearings have been getting lubes with a percentage of moly. Some literature suggests that moly not be used in high speed needle bearings that undergo a full rotation. That same literature says that CV bearings only oscillate back and forth, for those applications moly is recommended since it has improved impact performance. The correct answer seems to be is not just molly or no molly, its the percentage and how heavy the carrier grease is.


https://www.machinerylubrication.com...20CV%20joints.

GKN the OEM manufacturer has app notes that says no molly on the inners that are tripods but ships its inner kits with a moly based lube. They even have a special inner tripod joint grease that they don't ship with their inner kits, so it’s not like they don’t have it. Super confusing.

It possible that in the 20+ years since our cars were made the moly based lubes have been refined and can work in either joint or that the skidding roller issue is not an issue? It's hard to say. My personal experience is that in five years 45,000 miles the moly based lube that came with my GKN boot kit on the inners has not been an issue. That’s 300 WHP, 8000 miles a year.

I have seen one complaint about the moly lube not working on the inners. It's hard to know for sure since there are a lot of other factors that can cause an issue. That includes contamination, condition of the joint prior to relubing it and possible damage from the repair. Determining cause and effect on a sample of one is at best a guess.


If you have a known good joint that you just want to freshen with a new boot my recommendation is to not take it apart. If the boot is torn its a judgment call if the joint has been contaminated and need to be inspected for damage.

That bring me to my next point. In my experience the best way to handle a roller type bearing is to avoid any sharp blows to it. Impacts can cause damage and lead to failure. Disassembly and reassembly leads to the chance of mixing up what parts were running together. In a perfect world you don't have to hammer the inner off and you put the rollers in the same joint with the same roller in the same slot.

My personal preference is if the inner joint has not been contaminated and I'm doing both boots is to not disturb the joint and just put in new lube put a fresh boot on, that keeps the parts that have been running together in the same location. The old lube is easy to get out and a bit for mineral spirits removes all residue. I refill the joint with fresh lube, work it back and forth a bit and put a new boot on. A good crimp tool and OEM type clamps reduce the change of seepage.


Short story? The OEM lube is not supplied with most inner kits, you need to look for it. I have 5 years and 45,000 miles on the GKN kit using the supplied moly based lube without issue. We have had some pretty extreme weather, cold and hot. My only gripe with the GKN kit was getting the inner clamps to not seep grease, an upgraded crimp tool helped. The OEM kit appears to have better crimp bands but is a lot more expensive. The better crimp tool was a nice addition to the tool box. Some non GKN greases may be an issue?

I have a couple of OEM kits for the next refresh and will swap over (I have a stash of OEM boot kits and new GKN outer joints in my spares cabinets and two good front axle assemblies).

[Spike00513]

Hello everyone, the other day was doing so routine undercarriage checks and noticed a nice amount of grease thrown all over my front suspension. . The inside driver side boot had a good tear in it. I am planning on doing some suspension work soon, so I’ll pull the axle and replace with a new one. But in the mean time, I’d like to just use a split boot and refill with grease. I’ve looked around and saw a few types. I was wondering if anyone had advice on a split boot that is better to use for the A4 B6? I appreciate the advice. Have a great weekend.


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If the boot tears after 10+ years due to age (as they do)
and it is not clicking
you take it out and install $30 new boot kits