Hey guys. I have a 1981 300D. After about an hour or so of highway driving I get a rather loud knocking sound coming from the rear of the vehicle. It isn't constant, it will knock rapidly for 5 or 10 seocnds, stop for another 5 or 10 off and on. The first time this happened I took an offramp to see what was going on back there, the knock slowed with the speed of the vehicle. Stopped, jumpe dout to see if anything gruesome was happening. Shut off car jumped in drove off, fine for another hour until it started knocking again. Pulled over on the side of the highway, turned off the car, waited maybe 10 seconds turned it back on, fine for another hour. Not a clue where to start.

Sounds like you may not have enough lubrication in one of your rear cv joints. It heats up and gets noisy. Cools off and its good for awhile. you could try adding a little lubricant. Inspect your axel boots carefully for cracks or leakage first.

Boots look good, can I just pull those back and squirt some oil in there?

Yes it is worth a try to add some lubricant. Your discription is almost always cv joints.
I would probably get some smaller tubing and figure out a way to get some in there causing the least disturbance of the boots. Perhaps a large syringe from a drug store should work. You do not need the needle but just some small diameter tubing. Those syringes of the larger vairety have a plastic nipple to couple the tubing to.

I had to get new tires so I had those guys check the boots. Hence the 'the boots are okay'. I got under there to squeeze in some grease, and both boots on the right axle were split totally open, completely around. I'm assuming it's time for a new axle. Time to do some reading about how to do that. When I buy the new axle is there anything else I should get along with it?

dont forget to get the clip for inside the differential.I was not informed of this originally and had to borrow a car to get one.since you are going to have your hubs mostly apart to remove old axle,good time to check things like parking brake shoe integrity.I found a cracked shoe(still worked,but why wait to replace)
You may need a brass hammer or drift to remove the axle from hub and/or diff.I got lucky on one and fought the other.I posted a copy of directions given to me by someone else on the site.was VERY helpful.also check the integrity of the seal at the axle/diff meeting point,not sure how to replace if bad,but I sure that someone here can guide you through that.good luck,use chocks and jack stands.you will also need a jack to support the diff after you crack it open.

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1984 300D turbo 155k

www.interactivepainmanagement.com

Do you happen to know the name for the clip? I'm having trouble finding what you mean.

Could you post those directions again, I'm not seeing the link.

Hmmm... a knocking from the rear of the car? Forget to feed the trunk monkey?

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

I was ready to get my calipers and half shaft from advanced via internet, but it says it won't ship until friday. So I'm chekcing out Autozone. I've read some not so great reviews about their half shaft, but it seems like this is one is twice as expensive as the one people were complaining about. Did they switch?

check out CVJ in denver.their turnaround time is outstanding

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1984 300D turbo 155k

www.interactivepainmanagement.com

Happen to remember the name of that clip and where I can get one? I'm having trouble finding it.

Thanks just got the message. Where'd you get the clip?

Mattbob,

I got my axles from CVJ and am very pleased.

The rest of the parts I got from here or Mercedes OE. Do you have the FSM?? If not, it is very helpful on this subject and calls out the correct PN's for all the extra bits you need if you want to do the job to FSM specs.

Replaced the diff side seals. Also a great time to have a look at your sway bar links, sway bar bushings, diff mount and exhaust hangers.

Theres a great thread on the subject by Jeremy4858 that helped me out greatly.

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I bought the axles from CVJ and found a local family owned transmission place on the internet that charged me 4 hrs labor to replace both. It was worth it for me because I didn't have the proper tools, but mainly my sloping driveway talked me out of doing it myself. I bought the seals from Phil and he e-mailed me the part number for the crush washer (also called tension washer, FSM calls it clamping disc). For the 1985 300D Turbo that part number is 1153570675. Phil doesn't carry it. I bought it from my Mercedes dealer. A couple bucks I remember but not in stock so dealer ordered it. It goes behind the bolt holding the axle to the wheel hub. So you need 2. It looks like a washer with a raised center, but raised on both sides. The ones you take out will have one side crushed flat. I usually just call the Mercedes dealer and ask for the parts department. If I do my research on this site so I know exactly what I'm looking for and describe where it's located on the car, the parts department will pull up the part on the screen, get the parts number, price, whether in stock. I give them my debit card number and UPS drops it off.
Yeah read Jeremy's thread that Dieseldan44 recommends. I must have read that thread 3 times. Even though I ended up not doing the job myself, it was still useful when talking to the mechanic who did the job. I also had the car steam cleaned ($30 I think it was and since they mainly get the front, paid the guy an extra $5 to back the car up the ramps and get the diff and rear end). I just figured the mechanic could do a better job changing the axles.

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1985 300D Turbo
"Evolution is God's way of giving upgrades" Francis Collins