I have a 1981 240D. Noticed that the rear axle boots are beginning to crack. No holes yet and nothing leaking. Thought I could clean the boot and coat it with something rubber like and flexible to seal the cracks. Maybe something like black silicone RTV or silicone high temp gasket maker or even windshield sealer or glue. Any opinions?

Just buy the new Chinese one,s they're dirt cheap now .

Or, go to some PAP's in time you'll find a pair of annular drive axles, they're dead easy to re boot and the M-B Classic Center will ship you the axle boot kits cheaper than your M-B dealer will sell them .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Home Depot sells Flex Seal spray. I don't know if they have the brush on or not. I have only used it on a Motor Home Roof Leak so I don't know what it would do on the Boots. You perhaps need to read up on it. They have Black.

Get the rear wheels off of the ground and after cleaning get the axle you want to spray rotating slowly and spray it as evenly as you can. I don't know if one can would do all 4 boots but do the worst looking boots first.

If you are willing to experiment.

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84 300D, 82 Volvo 244Gl Diesel

There's a post about this somewhere in the archive.
From memory, the stuff used was 3m Marine adhesive sealant 5200. Search for that term and you should find the thread.

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1981 240D 4sp manual. Ivory White.

...or clean em out and put in fresh moly grease,
I did the dorman stretch boots with a funnel. Soften in hot water, a good (dry) grip, and straight downward force. Used a vice bolted to plywood and set on the floor to hold the axle vertical.

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1985 300TD 1981 Scirocco 1.6D conv 1986 Golf 1.6D 2003 Golf TDI

I also used the Dorman Boots but that was about 6 years ago but 2 years ago one of our members had several Dorman Boots splits. Safest right now is to use the Astora Flex Boots.
The Member contacted Dorman and sent some of the split boots to them but I never followed the thread so I don't know if Dorman found some manufacturing issue or not.

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84 300D, 82 Volvo 244Gl Diesel

Present day Chinese metallurgy generally doesn’t compare well with 80’s german metallurgy. It would be a shame to replace serviceable original axles with chinese knock offs to save a couple hours of labor.

Another vote for flex boots. Iv’e tried both of the above methods.

I could not agree more.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Yeah I have a huge pile of Dorman boots. They tried to make good on it after the split issue. I never want to use that again. I use them as gasket rubber after I cut them up.

From here on out it’s Astoria.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

Do NOT purchase the Chinese axles. They are known to be poor quality.

Use rebuilders like CV source who use OE suppliers for parts when they rebuild axles to OE specs.

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Why I will never do business with "DieselKraut" again

http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/378935-why-i-will-never-do-business-dieselkraut-again.html

I think everybody is at the end of life era for original axel boots. You cannot repair them, they have to be replaced.

I bought a kit with 12 of them but that was years before you used them so they could have changed who makes them for Dorman or the formula for the rubber since that time.

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84 300D, 82 Volvo 244Gl Diesel

Yeah I’ve used the dormans since 2004. Somehow the last batch I bought was total trash. All they need is a little bubble in the rubber or a nick and they’ll tear. Somehow Dorman seemed to understand and they quietly sent me a huge case of replacements. It was like twelve or fifteen. Just a stupid number. But it didn’t matter I’m done.

I bought a couple of extra astorias and the salesman asked why? I said in case they rip. He laughed. I put on the first one and now have two on the shelf.

I’ve got to say the old Dormans have lasted. My SD has a pair I put on in 2010 and they look great.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

I've used the cheap Chinese ones from Rock before and they worked great with no issues - going on 3 years now without any signs of letting up

Years ago , a tech member by the name of BenzMac, stated that the boots not only deteriorate from outside but also from within.

Superficial 'cracks' or 'spidering' are just that.
Superficial.
Don't be pressing on them or spraying stuff that has solvent based vehicles.

You can spray 100% silicone spray into a plastic cup and brush it onto the boots.
That feeds the rubber and helps prolong it. That is what I do.

Don't spray directly because you might get it on your brakes and also the propellant or spray vehicle might not be the best for your rubber.

Some scuba shops sell 100% silicone pump bottles for maintaining masks etc..

Brush it on.

You can try GACO 100% silicone paint.
That is roof paint.

Just wash boots lightly with dish soap and let dry.
Then brush on the GACO.

The good stuff might not be available in CA. but the water base stuff yes.
Put it all into quart size cans for storage.
If you leave it in a gallon can,it will probably dry up.

Some members here rebuild them. research archives.

"reinventingthewheel' is operated by a former member.

BTW some axle shafts can be specific to your model.
Some aftermarket have 'proud' hubs that do not allow proper setting. you have to grind them down.

Don't sweat it.

Some oldies last forever. Some don't.
road salt reduces longevity.

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD