I have never had to do it in the car yet, always had the engine out.

But in the junkyard, dropping the auto trans crossmember gave me alot of access to that bolt. I think the driveline may have been disconnected at the front flex disk for that much movement.

Tip: pic some valve grinding compound on the hex key to give it more bite inside the bolt. You're less likely to round it out that way. I went from above with a 10mm gear-wrench as well.

-Tad

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1995 G320
2003 C230 Kompressor Coupe
2005 ML500
2007 ML350

There is actually a special "wobble" extension available that will allow you to get to this bolt. If you decide to use a universal joint, wrap some masking tape or duct tape around it so it doesn't wobble so much that you cant get the 10mm hex key in the bolt head. The special tool costs about $18. I agree that a 1/2" breaker bar is a good tool to use on this bolt.

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"Life is tough...it's even tougher if you're stupid." John Wayne


Dave
Pawleys Island, SC

'79 300CD

I watched my Indy do mine on a lift by drooping the tranny support just a few inches; that gave him enough room to have straight access with a long extension.

Thats probably one of the best tips yet, good for changing out the clutch slave on a manual 617 also, a couple inches more room makes life a breeze

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

A 12 " Breaker bar on the end of the ratchet helps ,you do have to go back and forth to make sure youve got a good solid fit on the bolt (hex) before giving it a final break .Thats one tight bolt usually and can be stripped if your not careful.I remember something like 3 ft of extentsions ,1 swivel at the socket ,you basically are doing the ratcheting near the middle of the trannie.The two handed finger dance to get that bolt back in ,you have to do this job on your back under the car so use plenty of jack stands and chucks for the wheels.Im of the type that 3 stands are my minimium Ill use.

PB Blaster and as a last resort, MAPP Gas. Expect busted knuckles.

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http://i106.photobucket.com/albums/m...73378_30-1.jpg

Jack up the whole right side of the car and come at it from behind the tranny with a lot of extensions and a universal joint. Don't know if a wobble joint will allow the extensions to drop down behind the tranny. It takes a lot of force to crack that bolt loose.
If that allen end is stuck in the bolt, I'd consider cutting a hole in the firewall/tunnel with a dremel tool to get better access to it.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

DD

Did mine a few years ago. I think long extension was used( even though sd is a little different). Heat the cool a few times. Add PB blaster when warm. Let me know if you need an impact wrench.

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81 300D Turbo 190K sold
83 300sd 319K best $500 I ever spent-daily driverw/ 2 tank WVO set up

Thanks guys for the tips.

I was able to get it out with:
- 1" chunk of 10mm allen key
- 1/2" drive, 10mm, 6pt socket
- 1/2" drive universal joint
- 1/2" drive, 20" long extension
- 18" breaker bar


-Applied aero-kroil
-Heated with torch from below with a helper spotting where I was putting the flame.
- put allen chunk in to bolt head from top
- put 10mm socket on from top
- threaded the extension+universal through between exhaust and transmission
- breaker bar

I took pictures and I hope to write it up.

The new starter is a HUGE improvement in cranking speed/power...wow. Didn't expect how much more force the new starter would have.

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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

Pictorial: W123 300D Turbo Starter Motor Replacement

I wrote the job up so others can have it easier

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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

On a W126....some extensions and a 10mm allen socket. On the W123, a chopped off piece of 10mm allen key, with 10mm allen wrench slid over, and a breaker bar/pipe on the wrench....hasn't failed me yet. The starter on a W123 is much more of a pain than on the W126.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)