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Seems to me that probably nothing good could come from it, but some people on forums, and one guy on a YouTube video (for a Subaru) in particular, claims he "does it all the time", (continues to operate the vehicle when the CV boot/ axle is leaking grease or making noise). He claims the end result is that the car eventually just loses power and needs to be towed.

YouTube guy claims it is a "non- critical component" that essentially poses no danger in a failure scenario.

On the other hand I've heard of the issue remaining unaddressed and eventually leading to a wheel coming off the car at freeway speeds.

Is the YouTube guy just a blowing smoke or what?

What could happen in theory if someone were to just keep driving the vehicle without repairing the problem?

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  • I don't have the chops to say (maybe someone more mechanically inclined could say?) but it seems to me that if your CV joint breaks that's one out of two -- if it breaks in a way that would allow it to spin freely suddenly you'd run into a scenario where all the engine power is being applied to only one side of a FWD system leading to torque steer.
    – Sidney
    Commented Oct 28 at 21:12
  • "Is the YouTube guy just a blowing smoke or what?" If that's his general attitude towards car repair then yes, there's probably lots of smoke involved.
    – aquaticapetheory
    Commented Oct 29 at 14:11
  • In the UK this would cause the vehicle to fail its annual inspection (MOT test) and would have to be fixed before you could use the vehicle.
    – uɐɪ
    Commented Oct 29 at 14:37
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    @Sidney No. The differential applies the same torque on both sides. When left side can no longer apply power, the power to right side goes to zero thanks to differential.
    – juhist
    Commented Oct 31 at 18:36

4 Answers 4

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A wheel isn't going to fall off because of a CV joint failure, that's a bunch of baloney. Your wheels will stay on just fine. When the CV fails the mechanism that transfers the power from the transmission to the wheels is essentially snapped, so you lose power. I had a CV fail on me, and when that happened the engine stalled as well, leaving me without power steering and brakes.

If you lose power at highway speeds it can be dangerous, especially if your engine stalls like mine did, so I wouldn't say it's a zero danger scenario. You could also be stranded in a situation or place where you are at risk. How likely these possibilities are depends on your situation, where you drive and how you drive.

Driving your car until your CV fails isn't sensible. If you have a leaky boot you may be able to get away with just having a new boot and some maintenance of the joint rather then replacing the joint, so it's worth dealing with that early. If your joint is going to fail you gain nothing by waiting to fix it. Although you may save cash in the short term, long term you'll have to pay for a tow, and then may not have a choice in where you get the car fixed. Add to that the inconvenience of being stranded and any cost savings is eroded.

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  • 5
    WRT not waiting until failure, it makes sense to get it fixed on your time instead of on the car's time. It will almost ALWAYS fail when you can least afford the car to leave you stranded. I don't know about anyone else, but the noises the CVJ makes when failing would drive me crazy while I'd be waiting on it to fail, lol.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Commented Oct 28 at 12:21
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    When mine went it was on a deserted street with 4 inches of snow in February in Wisconsin, and about -20, so that proves your point @Pᴀᴜʟsᴛᴇʀ2!
    – GdD
    Commented Oct 28 at 15:40
  • If the CV boot doesn't get a repair (ie, it leaks grease, admits dirt, water, increases corrosion rate) then the CV joint (the bit making the noise) will fail much faster So if the joint is not making a noise when the boot is leaky then it will start to do much earlier than if the boot were repaired. And a boot is much cheaper than the CV joint. If your joint is already on its way to failure then just fixing the boot isn't going to cut it anyway. Fix them both at your convenience, before the CV fails.
    – simon coleman
    Commented Oct 29 at 14:53
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Eventually, it will break and your engine will no longer turn the wheels.

At least in older Honda cars, a failing CV joint will start making a clacking noise when turning, the sharper you turn the louder it gets. Eventually, it will break - but you can let it clack for quite a while (months) and it will get really loud before breaking. If it's only making a slight noise, it can wait. But no point in waiting until it breaks, it's much cheaper to fix as a scheduled repair than a roadside tow.

If it's not making noise yet, repacking the grease and repairing any tears in the boot can be a low cost repair to make it last longer.

Source: Personal experience with multiple 1980's thru 2000's Honda cars

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    a clacking noise when turning - an ex had this problem with her car; I said she should get it looked at immediately in case it was a failing CV joint, so she took it to the garage and left it there. When she went to collect it at the end of the day, every mechanic in the garage was at the desk, big smiles all round. They handed her the bill: "Removal of two loose golf balls from passenger-side map pocket; no charge". She gave me Hell over that - principally as I was the idiot who'd left them there.
    – Spratty
    Commented Oct 30 at 14:09
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What can happen if a damaged CV boot isn't repaired, allowed to operate until failure?

Well in short, the grease will keep coming out and dirt will keep getting in until the bearings fail.

Over time you will experience increased difficulty in steering, decreased fuel economy, and overall greater engine/transmission strain due to the extra resistance of wearing out your bearings prematurely.

Will your CV axle snap in an immediate and catastrophic way at highway speeds? Probably not.

Will the sudden mechanical failure of one wheel cause you to lose control of your vehicle? Never not no so always possibly yes.

Please don't selfishly endanger people and families who have to share the road with you.

As for repair options, apparently you can use a bicycle tire patch kit.

It may be tempting to only replace the boot in terms of parts cost but consider that replacing the boot takes just as many labor hours as replacing the whole CV axle.

If the CV axle has more than 100k miles then this is a good excuse to replace the whole axle and plan for replacement of the opposing axle as well.

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From my own experience with a failing CV joint (2005 Audi A4): the first that went didn’t announce itself (or I didn’t notice). I was on a motorway (on my way to vacation, some 600 km from home and another 600 km left to my destination) when the car suddenly started pulling to one side so I had to hold the wheel firmly to keep going straight, at the same time the steering wheel vibrated as if driving on a gravel road, despite there being firm asphalt below me. I ended up calling a tow truck, although probably I could still have driven to the repair shop myself.

The second one that went started making popping noises when driving with the wheels fully turned to one side. A telltale sign that it is from the axle (or any part spinning with the wheels) is that the frequency varies with speed. Not knowing where it was coming from, I still went on a 5000 km road trip, and only some time after I returned did the noises start occurring when driving normally. That’s when I took my car to the repair shop, who diagnosed that the fault was with the CV joint. The mechanic clearly said he wouldn’t recommend driving the car until it got fixed.

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