Crank pulley bolt (Timing belt replacement DIY)

  • Thread starter Thread starter sonata owner
  • Start date Start date
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sonata owner

Hi all,

I'm having a hard time tigthening the crank pulley bolt with the proper
torque (about 130 pounds).
A click-type torque wrench wouldn't work, since the crank turning while
applying torque.


Under-torque may ruin crank sporacket and others. I heard horror
stories about under-torque.
There are not many terrible stories about over-torque. I can imagine
that it may ruin the crank pulley bolt.

I have an electric impact wrench, which says it produces maximum 185
pounds torque. A cheap one at Wal-mart, but it works fine.

I ran the impact wrench on the bolt until I heard "Clang" sounds coming
from the engine case. Which could be a sign that tells "hey it is
over-torqued".

What kind of risk I'm running here? Any ideas?

Should I buy an impact wrench extension socket or something?

Thanks,
Jae
 
That's not a terribly powerful impact, so you're probably fine as far as
tightening the bolt with it. I suspect you'd have a hard time finding a
professional who doesn't tighten these bolts with an impact. The
difference is that you probably don't have the experience to be able to
use reasonable judgment with an impact on a crank pulley bolt.

A clanking from the engine case disturbs me, however. I'd expect the
whack-whack from the impact wrench, but no noise from the engine case
itself. Make sure you've got everything installed properly and that the
engine turns all the way around (two crank turns) by hand.
 
Related topic: I managed to break the crank pulley bolt free without
using an impact wrench for a DIY timing belt change. Here's how I did
it for any other brave DIY's:

- Jack the car up with a stand on the passenger side
- pull the fuel pump fuse
- start the car and run it until the fuel pressure drops enough so that
it stalls (it will stall after 5-10s)
- use a 1/2" drive johnson bar with crank bolt socket and enough
extensions to clear the wheel well (you'll need about 18" long of 1/2"
drive extensions to clear the wheel well). Use a jackstand to support
the free end of the extensions+ johnson bar
- put a long pipe on the end of the johnson bar so that the pipe
touches the ground in front of the car. The pipe will react the
starter motor torque. Note the crank pulley rotates clockwise when
viewed from the end (from passenger side of vehicle).
- get an assistant to crank the starter (briefly). The starter easily
has enough torque to break the crank bolt loose.

I imagine there might be a risk of breaking a tooth off the ring gear
or the starter motor pinon, but it worked for me!
 
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