Author Topic: Head bolt  (Read 1778 times)

mazmonza

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  • 1967 250sl zf 5 speed. colour 172 anthracite
Head bolt
« on: June 15, 2019, 09:27:21 »
I have removed all head bolts except one that won't budge, the hex key is starting to turn in the bolt.

Anyone any ideas?

Maurice
1967 250sl ZF 5 speed
1991 300ce-24 coupe Sportline
1962 Lambretta TV175/ RB20
2000 Ducati 748s
1970 Ducati Monza

DaveB

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Re: Head bolt
« Reply #1 on: June 15, 2019, 11:16:24 »
With the turning problem, is it the hex key or the bolt head that's deforming? If the former I'd say try a high quality hex socket on a breaker bar. If the latter maybe weld a nut onto the bolt head then get a socket onto it - the heat may also help free the bolt.
It might just help to reinstall and tighten a couple of the adjacent bolts before trying to loosen the stuck one??
« Last Edit: June 15, 2019, 11:20:29 by DaveB »
DaveB
'65 US 230sl 4-speed, DB190

ja17

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Re: Head bolt
« Reply #2 on: June 15, 2019, 14:12:27 »
Use a large steel mallet on it. The impact will loosen the rusty threads and also deform the head of the bolt inward so you can get a new fresh grip with your tool. Replace the bolt before re-installation.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

DaveB

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Re: Head bolt
« Reply #3 on: June 23, 2019, 12:12:34 »
Use a large steel mallet on it.
That sounds a good simple solution - did that work for you Maurice?
And Joe, how have you been able to post so regularly lately? (which is universally appreciated I'm sure). Did you retire? :)
DaveB
'65 US 230sl 4-speed, DB190

ja17

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Re: Head bolt
« Reply #4 on: June 23, 2019, 15:06:57 »
Hi Dave,

Not retired yet. Notice a lot of my posts are after midnight and a busy day. It also seems we have a lot of new pagoda owners asking unique questions and needing help.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

Benz Dr.

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Re: Head bolt
« Reply #5 on: June 23, 2019, 16:20:36 »
You probably have a leaking head gasket and coolant has leaked into the hole where the head bolt goes the head and maybe further down into the threads in the block. Depending on which head bolt is stuck can make a bit of a difference. If it's near one of the side covers on the block, you may be able to get a torch on that area and heat it until the bolt starts to turn. I've seen this before and heat was the only thing that broke it loose.
Forget about penetrant, it won't work. 
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

DaveB

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Re: Head bolt
« Reply #6 on: June 24, 2019, 12:16:55 »
Not retired yet. Notice a lot of my posts are after midnight and a busy day. It also seems we have a lot of new pagoda owners asking unique questions and needing help.

I see. That certainly does not sound like retirement, more like a job and a half. Thank you.
DaveB
'65 US 230sl 4-speed, DB190