Hey guys...tried to R&R a motor mount after work but got stuck when I tried to remove that last allen bolt up throught the center of the mount...what size is that little bugger? I don't own the right one and am stuck until I get to the right store which has it...7mm? Please, someone save me from driving my teeny Buick all over hell's half acre...

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

8.

I have an 8 and it was too big, a torx 50 was close but don't know how a 50 crosses to metric allen... but I tried an 8 every which way and I swear it was too big to fit in...seriously

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

did you clean out the gunk from the bolt? I don't know what size it is, but if it is 8 and your 8 won't fit, maybe there is some cooked gunk on the inside of the allen head. try a very sharp small screwdriver and scrape all six sides.
let me know if you get 8 to fit, I gotta do this soon!
John

New motor mounts in 83 300SD 3.5hrs

I really don't think it will help but I will give it try just to make sure...tomorrow. I am still hoping against hope that Tangofox007 is wrong and that someone else will say it's a 7 or that some other English will do the job. Just an FYI...there are 2, 6mm allens coming down into the frame which you can break loose "double wrench" style and a 17mm nut on top that I got loose with a socket and a breaker bar...except for the ???mm allen going up it's been pretty breezy so far...

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

DRAT!!! If it actually does take an 8 then I will return tomorrow and kiss your crown/tierra in whatever town square there is here...but I fuddled for about 10 minutes with my 8mm with no bite at all...not even close. Now I'm wanting to go back out with a mag-lite and try again...I aint gonna sleep a wink now...grrrr

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

Anything is possible. Maybe your car was re-engineered at some point. Maybe you have an SAE bolt instead of a metric bolt. Folks using the Haynes manual tend to strip the threads due to the fact that the Haynes torque value for the mount bolt is way too high. MB calls for 70 Nm.

Sometimes you need to give a hex bit a little encouragement, like tapping it in with a hammer. After cleaning out the bolt hex real good.

Don't dismiss the possibility that some genius shoved a 5/16 screw in there. However, the 8mm allen wrench should still fit. Try a 5/16 allen......it's .003" smaller.....you've got nothing to lose.

THANKS!!! Many thanks...I was hoping there was a "close-enuf" English cross and who knows who done what before I bought it. Thanks a bunch Mr Tango and Mr Carlton, I'll post results and will really feel the fool if it turns out to be an 8...

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

Thanks Brian, tango, vstech you were all correct, it was/still is an 8, and a 5/16 is right close enuf as well. I feel silly and realise that it was a matter of me turning a minor mechanical ineptitude on my part into a denial of the correct opinions from experienced MB wrench turners...aka I was 'tupid and ya'll was rite all-along.
To anyone who needs to R&R a right side monor mount on an 83 300 SD you need a 6mm allen wrench for the two bolts going down into the frame, an 8mm allen socket for the bolt going up through and into the center of the mount and also a 17mm wrench or socket ( socket and breaker bar for me ) to remove the top bolt. All bolts can be pulled from underside but the outboard 6mm can get got from topside most easily, the rest can be got while in more relaxed position undercar...drinking beer, smoking cigarettes etc. Use of PB Blaster will give you a slight edge against bolt breakage, apply spray and tap bolts to help it penetrate...worked for me. Also drink half of beer while topside, half-beers are more easily drunk in prone position undercar...less spillage.

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown