98 V70 Inject grease into CV axle boot

[98v70dad]

Vibration under acceleration or load that goes away when you lift off gas pedal is usually an indicator of worn inner cv joints. The outers click.

The inners usually wear a pattern in the metal cup and adding new bearings will be a very short lived solution if at all. The Oreillys import direct axles are so cheap and durable I can't remember the last time I did a single joint or even a boot on a customers car.

Well thanks, but I never indicated that I would be adding new bearings.

My question was if injecting some grease into the boots would quiet the noise and vibration enough (for a short time) to be relatively sure that its the CV joint that is causing the issue. I'm trying to isolate the problem rather than replacing everything that it might be. I have OEM axles from a wrecked car that so no sign of any play at all. They have good boots on them. However, if I can isolate the problem and be relatively sure its the cv axle I'll go ahead and clean out the grease in the extras I have, put in new grease and install new boots. I don't want to invest a couple of days doing that and then find that the vibration and noise was coming from my wheel bearing if I can avoid it.

You mentioned your were going to rebuild your used axle and you can't properly rebuild a cv joint without changing bearings (if worn), replacing grease and honing housing to tolerance and heat/stress treating the newly ground surface. I was saving time for all those who did not know that putting new bearings in or just adding grease doesn't normally cure the issue. The issue is wear and the tolerances must be restored before adding grease and bearings. Extra grease will not fill the void created by wear under load. It can't hurt but it wont help much either

As far as grease , make sure you use cv axle grease . There is a blend for outers and one for inners now ,as they each have a different style of bearing (Big debates in the cv axle rebuild community about this - I stay out of lubricant issues as folks go nuts ) . Most companies use a cv grease for both and I have never had a problem using it in outers or inners. With the clamping and unclamping of the boots it seems like to much hassle for the reward but its cheap and may help in diagnostics. I prefer to spend $125-$140 and throw in 2 new axles. I was forced to go to the Oreillys axles as GKN has made it impossible to get a deal on their cv's. Its been over 2 years now and no complaints or comebacks.

If the wheel bearing isn't howling its probably fine. I've changed hundreds and have seen them go as early as 60K (rare) but normally around 125-150K. Bearings will make noise consistently while the inners or outer cv joints need the load to make them act up. Inners give a vibration that many people say they feel in the floorboard or gas pedal or steering wheel. From what you have explained so far it sounds like inner cvs are worn which is normal for your 150K.

Best Wishes on your repairs,
John

Thanks. Saying I'm rebuilding the axles was not strictly correct. I should have said I'm replacing the boots and applying fresh grease while they're off. What you describe is an overhaul. A rebuild and an overhaul are completely different things but I get your point. I do not have the necessary resources to do an overhaul.

I waded through a huge pile of axles at a used Volvo parts store in Atlanta and found two that had no play in them. I expect that they will not show a lot of wear, if any, when I get them apart. The two I picked are tight like new parts. Most of the axles in the pile had a lot of slop. Replacing the boots and refreshing the grease seems like the smart thing to do since they are 18 years old, even though they must have come from a wrecked car with low miles.

[JDS60R]

What an excellent find. Sounds like if you grease them up they will be a great part.

[cn90]

Actually this (injecting grease inside the CV Joint) is an easy experiment to do:

- Undo the Oetiker clamp at the shaft area (the CV Boot smaller side). If you are careful, you can re-use this clamp.
- Gently lift the edge of the rubber boot with a blunt flat screwdriver.
- Fill a syringe with grease and blunt needle (you can buy those at local auto parts store).
- Slide the tip of the syringe under the CV Boot and inject grease, it is a slow process.
- Once done, put the Oetiker clamp back on.


PS: Grease is simply a mix of "soap"+ oil. After some 10 years/100K miles, the "soap" part is gone, leaving behind a liquidy substance. If you ever replace a CV Boot, you will know what I mean.

[98v70dad]

Actually this (injecting grease inside the CV Joint) is an easy experiment to do:

- Undo the Oetiker clamp at the shaft area (the CV Boot smaller side). If you are careful, you can re-use this clamp.
- Gently lift the edge of the rubber boot with a blunt flat screwdriver.
- Fill a syringe with grease and blunt needle (you can buy those at local auto parts store).
- Slide the tip of the syringe under the CV Boot and inject grease, it is a slow process.
- Once done, put the Oetiker clamp back on.


PS: Grease is simply a mix of "soap"+ oil. After some 10 years/100K miles, the "soap" part is gone, leaving behind a liquidy substance. If you ever replace a CV Boot, you will know what I mean.

This is what I wanted to do just to see if it quiets my noise and vibration. Its not a meant to be a repair but a diagnostic tool. If it quiets the noise and/or vibration I can conclude with more certainty that its my cv axle that needs replacement as opposed to the wheel bearing. Of course it could be both the axle and the bearing. Old cars often have more than one thing wrong.

[sleddriver]

My take is relubing a worn CV joint won't make a difference. Why? Because the moly-grease just isn't very thick at all, even cold. At 70mph, the angular velocity of the joint itself will be quite high, plus it will warm up, so it'll be even less viscious.

Worn metal joints are WMJs: Period. Lub won't fix that.

My two cents is to disassemble, clean, relub and reboot the OEM axles you found, then install on another day. FAR QUICKER than removing the old ones, cleaning them, then reinstalling. I may pull a pair from a JY to do just that having relubed my current aftermarkets while changing boots.

[98v70dad]

My take is relubing a worn CV joint won't make a difference. Why? Because the moly-grease just isn't very thick at all, even cold. At 70mph, the angular velocity of the joint itself will be quite high, plus it will warm up, so it'll be even less viscious.

Worn metal joints are WMJs: Period. Lub won't fix that.

My two cents is to disassemble, clean, relub and reboot the OEM axles you found, then install on another day. FAR QUICKER than removing the old ones, cleaning them, then reinstalling. I may pull a pair from a JY to do just that having relubed my current aftermarkets while changing boots.

Thanks. Good advice.