Manifold Bolts

J

james melberg

New member
Oct 2, 1999
641
0
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> Well, I seem to be backing up.
> Bought a right angle drill adapter to work in the
> tight space between the
> head and the frame; broke 20 or so high speed steel
> drill bits trying to
> drill out broken bolt (obviously grade 8); bought
> left hand drill bits -
> broke 'em; bought set of Cobalt drill bits, broke 2,
> warped one; finally
> broke through by starting with smallest cobalt bit
> and working upward toward
> 1/4" by 1/16' increments; finally got hole large
> enough to insert screw
> extractor - BROKE IT OFF INSIDE THE BOLT - cobalt
> bit won't scratch it.
>
> What's next (I know what you're thinking,......
> remove the heads) ?? Any
> other suggestions?
>
Been there, done most of, and am still there. Just
haven't broken an extractor bit yet. Looks like we
will have to pull the head. As long as we are doing
that we may as well get the manifolds resurfaced, make
sure the cross-over had been plugged, etc.

What is it they say, "Bad things come in threes"? Who
is next?

Jim
75PB in MN

PS. The only good thing to come of this, at least as
far as I am concerned, is that our two week trip over
the fourth got cancelled. Why is it good you ask.
Mama and me, daughter and boy friend and three grand
kids (15, 12 and 4), son (the master mechanic and
electronics tech) and two dogs (labs).... for two
weeks in a 26 footer!!???

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pull the head; have the broken stuff burned out; retap the holes; might have
to go up a size; worked for me.
Good luck, thats not as bad as it seems, you just need a bigger hammer than
you have been using :)

Louie D

76pb
- ----- Original Message -----
From:
To:
Sent: Wednesday, July 05, 2000 7:16 PM
Subject: GMC: Manifold Bolts

> Well, I seem to be backing up.
> Bought a right angle drill adapter to work in the tight space between the
> head and the frame; broke 20 or so high speed steel drill bits trying to
> drill out broken bolt (obviously grade 8); bought left hand drill bits -
> broke 'em; bought set of Cobalt drill bits, broke 2, warped one; finally
> broke through by starting with smallest cobalt bit and working upward
toward
> 1/4" by 1/16' increments; finally got hole large enough to insert screw
> extractor - BROKE IT OFF INSIDE THE BOLT - cobalt bit won't scratch it.
>
> What's next (I know what you're thinking,...... remove the heads) ?? Any
> other suggestions?
>
> TRIVIA - What do you call a parts-changer who would: (1) Install new
exhaust
> gaskets and not replace broken manifold bolts? (2) Use 1 1/2" bolts in the
> center hole of the manifold? (3) use an impact wrench to install manifold
> bolts?
>
> Lanier Foote
> F37894
> ''73 GMC Excalibur (JimiSue)
> '29 Mercedes SSK Roadster (Maybelline)
> '94 Geo Tracker (BN TOAD)
> Jackson, MS
>
> "The fruit falls not far from
> the tree. .........................
> unless, of course, the tree
> stands atop the hill."
>
 
this little voice says,
AS always, this leads to more.

While you have the heads off good time to get your intake manifold magna
fluxed to look for a crack between the throats. Good chance it is cracked
but they are welded and repaired all the time.

Might want to check the timing chain since most of the front is off of the
engine.

I guess a valve job is no big deal once the heads are off.

Water Temp sender is out so might as well put in the new one with the
better range.

Could check the little plugs in the bottom of the quadraJet to see if they
are leaking....could go for a carb rebuild.

Might consider blocking the temperature probe for the automatic choke and
go to an electric choke. Not sure if the old one works with blocked heads
any way.

what the heck, the fan is off a new Hayden severe duty fan would be good.

The radiator is old might be time to ------ nah-- it is ok

Lessee--If you put in an O2 sensor you could check the results of your
work. The exhaust pipes are off any way.

Might as well resurface the exhaust manifolds at the same time, that way
you can put it back together stock with no exhaust gasket.

Course, new belts and hoses come with the territory.

And those old vacuum lines are just laying there might as well change those.

Wonder how old that loose water pump is?

wonder how long it would run if we ignored that little bolt??

;>)

Your pain is our pain.
gene

>In a message dated 7/6/2000 12:23:39 AM Central Daylight Time,

>
> the heads would probably be very little more than that required to drill
'em
> out again. Your chance of permanently damaging the heads is great, so take
> 'em to a machine shop. Use the opportunity to resurface the exhaust
>manifold
> mounting surfaces and block the crossovers. >>
>
>Agreed - just needed to have it 'splained to me in a form I could
understand.
>I knew I was through with it as soon as it broke.
>Thanks.
>
>Lanier Foote
>F37894
>''73 GMC Excalibur (JimiSue)
>'29 Mercedes SSK Roadster (Maybelline)
>'94 Geo Tracker (BN TOAD)
>Jackson, MS
>
>"The fruit falls not far from
>the tree. .........................
>unless, of course, the tree
>stands atop the hill."
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Once you have broken off an extractor or a tap in the hole
you have limited options. Both of these are hard! they sell
carbide tipped drills but they are brittle and really do
not work well in a hand held application. If it was me I
would remove the head and bring it to a machine shop that
has a ram EDM. The EDM is a Electronic Discharge Machine
and it eats away at the metal with an electric spark. This
machine does not care how hard the metal is. I would offer
to help as I have one of these machines but I am in CT. The
carbide drill option is cheaper but you really need to do
it in a drill press and be very gentle. There is of course
the final option,,,, a new head.

=====
Alan Bredbury
Clinton, Ct.
1974 GMC 26' Classic Motorhome
http://www.finesttool.com/index.html/special.htm

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