w123 Half Shaft Flex Boot lifespan

[martureo]

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.

[Sugar Bear]

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.

[martureo]

Originally Posted by Sugar Bear

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.

[Sugar Bear]

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.

[Diesel911]

Originally Posted by martureo

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.

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.

[Diesel911]

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)

[BirthdayBenz]

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.

[martureo]

Originally Posted by BirthdayBenz

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.

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

[BirthdayBenz]

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?

[martureo]

Originally Posted by BirthdayBenz

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?

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.



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.

[vstech]

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.

[Diesel911]

Originally Posted by vstech

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.

[vstech]

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

[BirthdayBenz]

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

[280EZRider]

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.