Removal Of Broken Bolt (With Snapped Screw Extractor!)

Hi All,

After attempting to remove the passenger seat from my vauxhall vectra and
finding that the bolt nearer the centre of the car had seized I now have a
problem. For those who aren't familiar with the car there is a torx head
bolt screwed into a moveable plate retained in a box section in the vehicle
floor (i.e. it is only accesible from the top).

Firstly I managed to round the torx head, then I drill the head and remove
it by hammering a screwdriver under the seat rail. This left 5mm protruding,
which I attempted to drill out (using increasing size bits until I could
pick the remnants of the thread from the hole). I succesfully snapped the
drill bit in the bolt, and after soaking the whole mess in plusgas went at
it with a set of mole grips (shearing the protruding bolt but removing the
drill bit).

It was suggested that I use a screw extractor which I did & managed to shear
off flush so I am now left with a totally seized bolt in the floor of my car
which is non-removable from the vehicle and has a snapped, hardened screw
extractor roughly off centre in the shank of the ex-bolt.

I have been told that spark erosion could be an option, but is expensive and
requires the part to be removed from the vehicle?? It has also been
suggested that I tack weld the seat rail to the floor (great until I want to
remove the seat!). Being such a critical component (and after having a nasty
accident in my last car), and seeing that the seat is held in place by two
brackets at the front and two bolts at the back I really don't want to take
any chances (or bodge the job!).

Would helicoiling be an option even though it's not a blind hole?

Any other suggestions would be great as I'm at my wits end with this and
don't really want to spend a fortune!

Cheers for reading my exceptionally long post

Dan

-Crossposted to a few (relevant) groups as I'm desperate for a response!

 

I notice you haven't posted it to "Top Gear"!
I'm sure Jeremy & crew have the ultimate solution!

Tom

 

After attempting to remove the passenger seat from my vauxhall vectra and

Cut out that section of box, make a new bit complete with nut ready welded
on underneath, weld new section in.

 

Hi Itm,
Sounds like you are a bit of a liability, I would stick to washing up or
dusting, your more likely to do less damage. Regards. Ben

 

If you're desperate you can remove snapped screw extractors with a dremel
.. Boring though, easiest solution is to remove the old nut & screw with a
holesaw & weld a plate & nut in.

 

It's a little late now.....
Screw extractors never work on seized bolts, as they spread the bolt remnant
if they are turned hard.
Extractors work well if you shear a bolt by over tightning it and you just
need to apply a small force to back the remnant out, they are worse than
useless on seized bolts.

No it is not, spark erosion can remove a broken bolt from a casting that can
be put in the eroders oil filled tank..... there is NO WAY you can get a car
in an eroder.

It's a reasonable soloution, and if you want to remove the seat you would
have to use an angle grinder.

You can helicoil only if you can get the bolt and extractor remains out.

Heating to orange heat relaxes the residual force that rusting creates..
this is what seizes the bolt thread.
The heating of the remains of the bolt as a new pice of steel is welded with
oxy-acetaline to the stub will also un seize it. With luck the extended stub
can then be un wound.
If you get realy lucky the origonal thread will be in tact, if not the hole
can be drilled out and fited with a " clinch nut " also called " riv nut "
blind rivet with a thread ) that fits in sheet steel.
As the riv nut needs a special setting tool, and the hole size is critical I
sugest you get this done by someone, rather than trying to do it for
yourself.
You can then secure the seat by bolting it to the riv nut.

Hope this helps.


--
Jonathan

Barnes's theorem; for every foolproof device
there is a fool greater than the proof.

To reply remove AT

 

You can then secure the seat by bolting it to the riv nut.

Hi Dan, I'm not sure that I would feel very comfortable driving a
motor vehicle with a riv nut holding in the seat. If it was mine, I
would get the bolt out, I,m sure that this would prove easier than
cutting, welding etc. without being there I can't tell you how I would
go about it, but a little bit of thought would go a long way, even if
you damaged the thread, you could probably tap it the next size up &
drill a larger hole in the seat frame.
First you need to get the extractor out, as these have a severe
taper, you won't have to turn it far CLOCKWISE to release it. A deep
cut with a Dremell & a large screwdriver with a shifting spanner on
the blade close to the end might do it, or try & tap it clockwise with
a centre punch. AT ALL TIMES make sure that you are wearing adequate
eye protection. After you have the extractor out, (be positive) It's
really only a case of working on the bolt either with increasing drill
sizes (trying to keep central) or with mounted points in a Dremell
(tedious) 'till you can put a tap in the original size or larger.
Good luck, don't give up. Ian Sutherland. (Oz)

 

In my experience the sheet steel to which the riv nut is attached or the
bolt will fail before the riv nut.


--
Jonathan

Barnes's theorem; for every foolproof device
there is a fool greater than the proof.

To reply remove AT

 

I got to that stage when replacing a cylinder-head gasket, after an
exhaust manifold stud snapped off, probably due to heat hardening.

At that point I got a lift into work with the cylinder head on my knee,
and placed myself at the mercy of the millwrights and machine tool
maintenance guys, who somehow removed it.

The also de-carbed it and sent the works lorry out for a new valve and a
set of valve springs and re-assembled it for me.

Those were the days.... (Early 60s).

 

You can then secure the seat by bolting it to the riv nut.

I'll second that, rivnuts are plenty strong enough to hold a seat down.

 

Ian Sutherland () gurgled happily, sounding much
like they were saying :

One of my fleet has the seats held down by small bent pegs into holes in
the floor on the two front corners, and a small clip on one rear corner.

To move it fore/aft, you unclip the rear, tilt the seat forwards 45deg,
lift, and lower into a different set of holes.

This is exactly as it left the factory.