Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

Crank position sensor nightmare.

Thread Tools
 
Search this Thread
 
Old 11-09-2015, 11:34 AM
  #1  
siscogts
Burning Brakes
Thread Starter
 
siscogts's Avatar
 
Join Date: Apr 2013
Location: North Italy
Posts: 972
Received 16 Likes on 11 Posts
Default Crank position sensor nightmare.

Hi!

I have read a lot of tips and procedure....I applied any of them, but the hex bolt won't turn , not even slightly.

I strongly believe the body of the sensor is seized as well.

Tried PB blaster, WD40, a large amount of other products, I put an allen key and hammered the bolt slightly, less slightly, I tried to apply heat with a plumber solder( an electronic joint solder look-a-like , but larger), used a small impact wrench , then a bigger one, then re-tried with every tool used before adding a lot of curses, to no avail. More: the hex bolt is not stripped, has not a single mark of my effort to unbolt it,like it is made of a special unbreakable material from an alien spacecraft .

Can you suggest me another worthwhile shock therapy .

Thank you.
Old 11-09-2015, 12:35 PM
  #2  
Imo000
Captain Obvious
Super User
 
Imo000's Avatar
 
Join Date: Aug 2003
Location: Cambridge, Ontario, Canada
Posts: 22,846
Received 338 Likes on 244 Posts
Default

Liquid nitrogen.
Old 11-09-2015, 01:22 PM
  #3  
siscogts
Burning Brakes
Thread Starter
 
siscogts's Avatar
 
Join Date: Apr 2013
Location: North Italy
Posts: 972
Received 16 Likes on 11 Posts
Default

really?
Francesco
Old 11-09-2015, 02:43 PM
  #4  
SeanR
Rennlist Member
 
SeanR's Avatar
 
Join Date: Apr 2006
Posts: 35,700
Received 500 Likes on 267 Posts
Default

Run the engine to get everything nice and hot. The CPS bolt is held in with blue thread locker so getting it warm is important.
Old 11-09-2015, 04:36 PM
  #5  
siscogts
Burning Brakes
Thread Starter
 
siscogts's Avatar
 
Join Date: Apr 2013
Location: North Italy
Posts: 972
Received 16 Likes on 11 Posts
Default

That is usefull, didn't know about blue stuff on bolt thread. Thank you...
Old 11-09-2015, 08:35 PM
  #6  
GUMBALL
Rennlist Member
 
GUMBALL's Avatar
 
Join Date: Jul 2004
Location: Portland, Oregon
Posts: 702
Received 23 Likes on 22 Posts
Default

The release temp for blue Loctite is about 350 degrees F. getting the "engine hot" is not sufficient.
Old 11-09-2015, 11:10 PM
  #7  
Lizard928
Nordschleife Master
 
Lizard928's Avatar
 
Join Date: Apr 2003
Location: Abbotsford B.C.
Posts: 9,600
Received 34 Likes on 25 Posts
Default

get a 5mm allen key in a socket, and use an impact screwdriver if needed. Though I have always been able to extract with a regular socket, extension and ratchet without issue. It can take a fair bit of torque.
Alternatively get an external bolt/stud extractor that grips the outside of the bolt and remove with that.
Old 11-09-2015, 11:14 PM
  #8  
AO
Supercharged
Rennlist Member
 
AO's Avatar
 
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 60 Likes on 34 Posts
Default

If it's not stripped, your lever arm is too short. If it strips or breaks, drill it off. PITA to do, but sometimes the only solution.
Old 11-10-2015, 12:35 AM
  #9  
siscogts
Burning Brakes
Thread Starter
 
siscogts's Avatar
 
Join Date: Apr 2013
Location: North Italy
Posts: 972
Received 16 Likes on 11 Posts
Default

Used impact screw driver and socket, socket and a 15 " lever.nothing, it seems it turno some degrees, but it is just flexing.
AO, i think you are one of the voices of wisdom here....but drilling bits in that area of the engine bay, make new thread, and still not knowing if the sensor is seized as the bolt... Sounds a bit scary.. I hope to solve problem without that estreme solution. That CPS works, so i can leave it in place for the moment.
Old 11-10-2015, 12:42 AM
  #10  
928 at last
Rennlist Member
 
928 at last's Avatar
 
Join Date: Jul 2008
Location: Aurora, Ontario, Canada
Posts: 2,200
Received 2 Likes on 2 Posts
Default

Francesco,
Heat Heat Heat (with a MAP torch)
Quench with a 50/50 mix of Acetone and ATF or your favorite penetrating oil(s), do not inhale while doing this.
Smack with a ball peen and a punch...
Repeat until bored and then soak for a few days in a 50/50 mix of Acetone and ATF or your favorite penetrating oil(s).
Try an impact driver as Lizard (Colin) suggested. (Do not use a 2 kg. sledge hammer on it though, no matter how tempting).
Repeat as necessary until it releases or breaks.
The idea is to break the corrosion with repeated heat cycles and rapping with the hammer. Ideally, you heat the surrounding metal, and don't heat the bolt directly.
The Liquid Nitrogen option works too, but you have to try to keep it on the bolt itself...the idea is to shock/contract the bolt enough to break the corrosion free.
Old 11-10-2015, 03:25 AM
  #11  
Mongo
Official Bay Area Patriot
Fuse 24 Assassin
Rennlist Member
 
Mongo's Avatar
 
Join Date: Nov 2001
Posts: 31,653
Received 119 Likes on 62 Posts
Default

Not sure if I was lucky or not but I soaked it in PB Blaster and walked away for a whole day. I CAREFULLY broke it loose the next day and then pulled the sensor out by the cord, jiggling and yanking on it.
Old 11-10-2015, 09:44 AM
  #12  
WallyP

Rennlist Member
Rennlist Site Sponsor

 
WallyP's Avatar
 
Join Date: Jun 2001
Location: Acworth, GA
Posts: 6,469
Likes: 0
Received 11 Likes on 11 Posts
Default

She was just messin' with you...
Old 11-11-2015, 01:30 PM
  #13  
siscogts
Burning Brakes
Thread Starter
 
siscogts's Avatar
 
Join Date: Apr 2013
Location: North Italy
Posts: 972
Received 16 Likes on 11 Posts
Default

Boys, sensor is out!
Acetone and ATF, 3-4 times , then I hammered the bolt with a plastic hammer.then it with no much effort.
The sensor at that point came out about1 inch, than was again blocked. some acetone/ATF mix and the sensor now is out...

acetone /aTF is the most penetrating lube ^ have ever tried.it melted also the blue thread locker.

Thank you guys!

After this effort , I hope the new sensor will better the engine behaviour....

Francesco from North Italy



Quick Reply: Crank position sensor nightmare.



All times are GMT -3. The time now is 05:48 AM.