Author Topic: Injection pump bolts  (Read 4488 times)

jan lauwers

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Injection pump bolts
« on: November 01, 2015, 09:32:59 »
Hello folks,

One of the 3 bolts that holds the Injection Pump to the block is damaged (Thread is ruined). Does anybody know how this bolt is fitted into the block? Is it screwed in, and can I replace it? What is the best solution to this problem please?

See picture.

Many tanks!

Jan
Jan Lauwers, Geel, Belgium 

White 280 SL 1969

jameshoward

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Re: Injection pump bolts
« Reply #1 on: November 01, 2015, 10:42:32 »
The best solution is probably the easiest, which would seem to be applying the appropriately sized thread file to the threads, or attempting to re-cut. The damage doesn't look that bad at all. I'd hardly say it's ruined.
James Howard
1966 LHD 230SL

ja17

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Re: Injection pump bolts
« Reply #2 on: November 01, 2015, 14:19:34 »
It is a stud which is threaded into the block. Caution, these can be hard to remove. Do not snap it off.  I like the idea of restoring the old threads. Otherwise some heat from a propane torch may help to release the stud.
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: Injection pump bolts
« Reply #3 on: November 01, 2015, 21:51:33 »
I would use a die to re-cut the original threads. You will probably need to use a vice grip to turn the die do to limited space.
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

UJJ

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Re: Injection pump bolts
« Reply #4 on: November 02, 2015, 12:52:40 »
The die is available as a hex, so you can use a socket to turn it.
Good luck
Urban Janssen
Grass Valley, CA
1968 280 SL - 4speed manual
173 anthracite grey

ejboyd5

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Re: Injection pump bolts
« Reply #5 on: November 02, 2015, 13:07:23 »
Considering the importance of the stud involved (and the difficulty in replacing it if the repair gets messed up) I would definitely seek out a rethreading die rather than a threading die.  A rethreading die tends to push the threads back into proper orientation rather than cutting away quantities of metal thereby leaving a stronger fitting.

Benz Dr.

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Re: Injection pump bolts
« Reply #6 on: November 02, 2015, 22:59:35 »
Considering the importance of the stud involved (and the difficulty in replacing it if the repair gets messed up) I would definitely seek out a rethreading die rather than a threading die.  A rethreading die tends to push the threads back into proper orientation rather than cutting away quantities of metal thereby leaving a stronger fitting.

Good consideration to make. 8) The IP is held in place very firmly and is not likely to come loose or move around if tightened properly. I have however, seen cases when oil would seep out if the nuts on the flange weren't tight. Come to think of it, there are a multitude of places where things can seep out on our cars. Take your pick, there's lots to choose from. :) :) :)
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

wwheeler

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Re: Injection pump bolts
« Reply #7 on: November 04, 2015, 04:00:50 »
I have found that using a threading die to clean up existing damaged threads, results in a MUCH looser fit with the nut. The rethreading die maintains a better fit. So I would agree to use a rethreading die here. Should be easy to find. I have a kit and use it constantly. I would highly recommend this to anybody who works on their own car.

http://www.amazon.com/Kastar-972-Piece-Master-Rethreader/dp/B0080IKATU

I have this kit and even comes with the thread files. Don't try to force fit threads. Use this kit and clean the threads so they fit well before you assemble.
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

ja17

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Re: Injection pump bolts
« Reply #8 on: November 04, 2015, 14:23:18 »
If you decide to change the stud, borrow or buy a good stud removal tool. They work nicely. Make sure to source a new stud first. Restoring the old threads is still the best option.
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