w123 Half Shaft Flex Boot lifespan
 

I just got my car back on the road after a few years of rust repair and I've been driving it daily for a few weeks. Sure enough, something else decided to go wrong. Passenger's side outer flex boot busted on the commute home last night.

So I can report that the Astoria 2000 Flexx boots (FB3001 specifically) lasted 151,000 miles and 10 years of driving.

FlexxBoot FB3001 Large Shaft Universal CV Boot Kit Constant Velocity Boot Set

I'll be doing this repair with the same boots and using gear oil. Definitely worth it.

Did four on one W123 with the Astoria boots, it worked well but used grease. I'd think the gear oil would be more likely to leak. Used their manual tool, it took some muscle.

I did all four with the Astoria boots and used gear oil. This is the first leak and its how I knew there was a problem. I came out to the parking lot and noticed oil on the ground.

I know this is a controversial subject, but I prefer the gear oil to the grease as the grease is more likely to be flung to the boot and away from the joint. The oil is constantly moving and will continue to lubricate the joint.

That is a good point about the grease getting flung away. If yours didn't leak with gear oil go for it, the oil also probably lubes the joint better by getting into smaller spaces.

I think 10 years is a reasonably life.

I am a low milage driver and my rebuilt Cardone stock type axle boots started cracking after 5 years.

Well, the well know CV Axle rebuilder CVJ in Colorado uses CV joint grease unless you specify the oil. I believe that company knows their business.

What other passenger cars use oil in their CV joints. My Mercedes is the only one I know of.

The below explains it. "A true grease consists of an oil or other fluid lubricant that is mixed with a thickener, typically a soap, to form a solid or semisolid.[1] Greases are usually shear-thinning or pseudo-plastic fluids, which means that the viscosity of the fluid is reduced under shear stress. After sufficient force to shear the grease has been applied, the viscosity drops and approaches that of the base lubricant, such as mineral oil. This sudden drop in shear force means that grease is considered a plastic fluid, and the reduction of shear force with time makes it thixotropic. A few greases are rheotropic, meaning they become more viscous when worked.[2] Grease is often applied using a grease gun, which applies the grease to the part being lubricated under pressure, forcing the solid grease into the spaces in the part."

https://en.wikipedia.org/wiki/Grease_(lubricant)

I was surprised to see oil in the last CV I tried to repair on an early w123. Every other car I've ever worked on uses grease. Even my later W123 had grease in the CV. I learned that BMW used oil in the 2002 also, so maybe it was a '70s thing?

Also, did you guys own the special tool to crimp the flange on the new CV kit? What a pain that process is to replace. Cut off the old cup with a special tool, or cut off wheel, then disassemble, then install new cup, and need to crimp with another special tool.

I just bought a complete replacement axle due to not having or wanting to buy the special tool.

I have rebooted hundreds of axles with the flexx boots...
I always use oil.

Mercedes switched to grease in the 124 axles... the number of rusted axles i have had to throw away is astonishing...

Grease sucks.

Are you saying the axles rusted inside of the axle boots?

If the exterior of the axle is rusting clean that off and keep them painted.

These are the boots which can be pulled over the cups/cans.

I didn't see a way to disassemble the CV without cutting the cup seal. How did you put the new CV boot on without doing so? Did you use one of those pneumatic expander tools?

Yes.
The bare steel inside the boots rust away to nothing...
Search the threads ive posted in.
Pics are grusome.

You could use the pneumatic tool, but there's a manual option as well.

I use a tool like this, but you could also use a modified transmission funnel.

https://i.ebayimg.com/images/g/I1MAA...ol/s-l1600.jpg

You lube up the tool with oil, place it over the can while the shaft is secured in a vertical position and then grabbing the boot with both hands pull it over the tool and over the can.

I've had better luck with putting the boots in a bucket of hot water for a few minutes prior to installing them. But I've also had to put my body weight into the mix to get them over the can.

I purchased a set of GNK boots and watched a couple videos of that funnel method but there was no way I was ever going to expand the small side of the boot to the diameter of the CV. Doing this on my G500 it was a difficult task to expand the boot just over the small lip of the axle.

G500 boot
https://i.imgur.com/jcF5Zoh.jpg

I suppose 150K on these one-size-fits-all boots is impressive, however using the real boots will give you much more mileage. It's more work to do it the right way, but it will only have to be done once. I replaced my original boots at 275K and with that same mileage on new OEMs, I'll be dead before they need another replacement.

Afaik, the 123/126 boots cannot be changed with the original boots.
That axle is designed with compression peened bearing, and has to be cut off, and newly peened on a factory to reassemble...

124 is different.

Lemme know if anyone wants to rent the flexx boot pneumatic expander i have.

Will you be sending the air compressor with it? (Humor.)

W123 CV Joint Boots
 

I'm guessing most of us older hands here have gone through this .

IMO 10 years is plenty .

Mercedes them selves say to use grease when re booting CV joints .

I used to go and find factory late production replacement axles that bolted to the inner end, they come with flanges, I used factory boot kits and yes, if you're *VERY* careful you can snug up the band clamps with a pair of dykes, I did plenty then found a low co$t crimping tool thanx to someone here and bought it , I don't mind the expense as ruining just *one* clamp stops you dead in your tracks .

Good data point on 150k. That’s a lot of wear.

I’ve used Astoria and Dorman on my cars. Last month I noticed some surface cracks on one of my flex boots. I’d say it was 6 years old and had 15,000miles on it. There was some oil spotting but I couldn’t find a leak. Likely it had a pinhole.

I was disappointed because we don’t drive that car much. Six years is recent history for the repair. The problem is I cannot remember if it was an Astoria or Dorman. I replaced all four boots with a mix because the Dorman boots kept ripping on the tool. It might have been the Dorman because their quality has gone to hell in recent years.

I used grease. I’ve never had issues with grease (rebooted 3 cars 2xw123, 1xw126). But I think I have only put 70,000 miles on the car I use most since booting. Note those were older Dorman from 2014. I’ve noticed the Dorman rubber compound has varied greatly from 2005 to present. It has gotten stiffer and more likely to tear when stretching with the pneumatic tool. So I went to Astoria and things are better.

The boot that cracked had some installation issues. I clamped it a little too tight and I think that started the cracking on the small end. Instead of the cracks starting on the bellows they started near the clamp kind of like what happens when you tighten down a radiator hose too tight. I got carried away with the banding tool that looks like a sardine can key and lever and I squeezed the beans out of it.

Anyhow it’s all changed out with an Astoria flex boot. Greased and not tightened too aggressively.

The other flex boots I’ve mounted seem to be holding up fine. If I get 150,000 miles out of them I’ll be happy. I may not even have the cars by then.

I agree with 911 in that the Cardone rebuilds showed surface cracking after five years. I had those on my 240d. They looked like OE boots but they cracked up enough to need rebooting with flex boots.

I'll post this again because the confusion is still out there.

For a w123 the service manual calls for oil, not grease. (35-660)

https://live.staticflickr.com/65535/...c.jpg[/img

For a w124 and later car, the service manual calls for grease. (35-660)

https://live.staticflickr.com/65535/...abd22693_c.jpg

That is a true fact.

The Mercedes W123 factory service manual also has to use a dial indicator to adjust wheel bearing clearances (as I do). From what I have read most members don't do that.

It is also a true fact that when joined this forum in 2007 after just purchasing my 84 300D it arrived needing axle boots.

I was too new to the forum to know about the stretchy boots,
so, I bought a pair of Cardone rebuilt axles.

After 5 years of use the stock type boots on the Cardone Axles started to crack and by that time I knew about the stretchy boots. I decided not to wait till they cracked all the way through and rebooted the axles as per the below thread.
http://www.peachparts.com/shopforum/diesel-discussion/317950-cv-boot-installation-problems-dorman-pneumatic-cone-type-boot-installation.html

The point here is that the Cardone axles came with CV Joint Grease in them. When I did the re-booting, I left as much of that grease in place and added more grease.

In 2018 (bout 6 years from the last re-booting) The stretchy doorman boots I had put on also started cracking. I re-booted again using grease. I used Dorman boots again because I had bought a kit that had 12 boots in it.

The same axes have been on the car in 2022 when I did not finish a job on the car, and it has sat in the driveway. Zero issues with the greased axles.

The well know axle rebuilder CVJ uses grease unless you request oil.

So, between what is in the Mercedes Factory Service Manual and the fact that the proper grease for CV joints is what is most often used I believe there is sufficient info for people to decide what they want to use.

Another side issue is that some who have used oil in their axles did not buy the Mercedes oil made for the job but used differential oil.

Thanks for sharing this topic again Martureo.

Just out of curiosity, there is an Italian split boot that requires glue to seal the ends.
Has anybody tried these and have results over time?

I think they are hippored from Italy, not the Dorman junk.

https://www.peachparts.com/shopforum/diesel-discussion/26260-axle-boots.html



Just a DIY link:
https://www.peachparts.com/shopforum/diesel-discussion/220000-w123-how-replacing-rear-axles.html

https://mercedesdiy.blogspot.com/2019/09/w123-mercedes-cv-boots-and-axles.html

The spilt boot thing has been a holy grail type object since 2007 when I joined

A member said that Astoria flexx boots would not guarantee oil would not leak from their boots. That makes sense because the rubber on the stock type boots is about 3 times thicker allowing the clamped boot to fill in irregularities.

I would not expect a split boot to hold oil after some use.

The more obvious issue is if you are a company that makes spit boots that work on a W123 wouldn't that show up on a search? I mean you would have the Mercedes W123 on the list of vehicles that it can be used on.

Another reason to use grease is the astoria boots come with grease, so its cheaper.

I have dozens of bags of grease in my expander, and i use d to have issues tearing the boots with the tool, so i polished all the splines on the tool and havnt broken one since.
My expander tool also has a pair of snap ring pliers in the kit as well.

So...
Again, if anybody needs it, just drop me a line.

Good to know Vstech!
I searched your past postings but am not seeing the topic of internal axle shaft rust.

I know that you have better things to do, but if later you come across a link, it would benefit this thread !

Thanks

Since you are mentioning grease the Astoria boot grease packet is larger than the Dorman boot grease packet.

If someone ureses Dorman boots which I do not recommend now you will need more grease than is in the Dorman packets.

However, I have also used the Dorman boots on another vehicle where they did not need to be stretched. Fine for that.

CV Joint Lubrication
 

Mindlessly posting obsolete pages from the FSM means one doesn't trust the engineers who designed the thing .

Mercedes no longer specifies using oil .

IMO oil is the better lube but the modern short fiber greases are worlds better than anything available when our cats were new .

The bull**** about dial indicators and proper wheel bearing adjustments is only pushed by those who are not Journeyman Mechanics and makes them look foolish or afraid to learn .

I think few here are journeymen mechanics so perhaps they can use a accurate method. If they ever have to do the rear wheel bearings, they will need the dial indicator.

Also, I have noticed that on this forum and especially over on benzworld the people have less abilities to fix their vehicles than they did back in 2007 when I first joined this forum.

The older member dormison posted a thread where he had various guys adjust the bearings by hand in his shop and they all got them too loose.

I started fixing cars when I was a teenager, went to a diesel mechanics trade school and worked as a diesel mechanic for 18 years. I a teenager and bought my first car when I was 17 years old in 1969; fast forward to around 2007 when I first joined.

I had been adjusting my wheel bearing pay on all of my vehicles by hand since 1969 with no issues. When it came time to do the Mercedes, I had 2 dial incubators setups and one with a magnetic base. But they had been missing in action for many years, and I did not want to look for them.

The short story is I adjusted the bearings by hand and after few blocks of driving I had overheated the grease.

So, I had to start over and get rid of that overheated grease and I had the spend the over 2 hours finding those dial indicators.

Ever since I used the dial indicator, I have had zero issues setting the play on the front rear wheel bearings. It is just a repeatable way to get the job done every time.

My chevy Astro Van also had a spec for a dial indictor. I also did it to that also. I got a bit of a shock there. The wheel hub and brake rotor are all one piece.

The replacements were Chinese. When I used the dial indicator, I found out that the castigations on the nuts for the cotter pins were spaced too far and there was no way I could adjust it to spec without making it too lose or too tight and still beagle to get the cotter pin in.

The dial indictor allowed me to shim it so I could get the proper adjustment and get the cotter pin in.

As long as I have dial indicator, I will use it and get it done right each and every time. If I don't have one, I will do the best I can.

Obsolete? Do you have a technical bulletin or update from the w123 manual?


Otherwise you're confusing the w123 manual from the w124 manual. There's something to be said about what was specified for a model.

Okay ;

Like some here I've been adjusting wheel bearings by hand since the 1960's and never had one fail yet .

Claiming the Mercedes bearings are different some how means you don't grasp how they work and also that roller bearings are standard items if different for various applications, just look up the interchange on the bearings used .

As far as oil vs. grease, there are none so blind as those who refuse to see .

Oddly, one of the very best Mechanics I ever knew was a crazy old woman (she was NO 'lady' !) who insisted to her death the only non detergent oild should be used in older engines.....

The intentional obtusity (I made up this word) is mind boggling .

Yes, I agree oil may well be the better lubricant in CV joints but believe it or don't, the engineers who design things know more about auto repair than you ever will .

And yet you won't provide any material which would cite those engineers.

For The Obtuse
 

The simple fact that Mercedes no longer provides the obsolete spider oil in their boot kits tells anyone who has rational thinking ability what's what here .

When one comes to a tech help site then wants to argue that the manufacturer is wrong, well, I leave that to you sir .

Ah, I'm still not seeing this citation you're touting.

"Obvious" means you can't support your claim.

Yes.
As with all things, the dollar wins.
It is cheaper and faster to use grease than oil in the cv axles.

I have opened up hundreds of 123 and 124 axles… look at the thread I linked above.

The greased axles RUST AWAY and fail.

I have NEVER SEEN THE SLIGHTEST CORROSION in any 123/126 oiled axles. Zero.

Dozens and dozens of 124 axles were rusty, and many of them the metal was so far gone as to be unsafe, and I have had 2 fail from rust.

I could understand it being a decision based on saving a few bucks or just easier to service, but I'd expect a service bulletin or some literature which advised the use of grease.

The idea that something comes in a service kit means I should use it is silly. There used to be several service kits for different steering boxes, now they are all superseded by a single kit. I can't use all the parts supplied on any one box and some of those seals aren't the best choice for some boxes.

I'm willing to be wrong about the appropriateness of oil for CV joints, I just want to be able to repeat the correct position with some way of defending it when someone asks me. There's no way I'm switching to grease and saying "yeah, some guy online said it was obvious."

Well, who has access to the service bulletins? Also, I doubt if Mercedes has expectations of the car owners working on their own axles other than removing and re-installing.

Using stretchy boots over the axle cans is not in the Mercedes factory manual and beyond a hydraulic press who has used the actual Mercedes can cutting tools and the factory can crimp tools when they re-booted axles?

It is already known that the German language printed factory service manuals have more information in them compared to the English language versions of the printed manuals.

And I know for a fact the older manual on CDs had less information compared to what is in the English language printed manuals.

Obviously is nothing wrong with telling someone the factory authorized methods.