Removing broken wheel speed sensor - help!

Removing broken wheel speed sensor - help!

Author
Discussion

g3org3y

Original Poster:

20,606 posts

190 months

Saturday 30th May 2020
quotequote all
Bit of bother chaps.

I've mentioned on my Readers' Cars thread about the wheel speed sensor on my BMW E46 330

When trying to replace the sensor a while back, head of the bolt sheared.
Old sensor:


Clearer view of the sheared bolt


Today, thought I'd give it another go and see if I could get it off and perhaps tackle the bolt.

This sensor was solid. Hit it with a hammer - nothing. Tried to prise it off with a flat head screw driver - nothing.

Turns out trying to pull it off (Oh er!) with mole grips...


Results in this:


Hmmm....



Any ideas? (Apart from the inevitable take it to the garage next week option...)

Penelope Stopit

11,209 posts

108 months

Saturday 30th May 2020
quotequote all
Burn it out

or

Angled drill through center and then go bigger and bigger and....

Should then collapse with a few taps and come out, don't damage the teeth below

Drill through center of broken bolt, near enough will do, go bigger and tap a new thread, near enough will do

g3org3y

Original Poster:

20,606 posts

190 months

Saturday 30th May 2020
quotequote all
Penelope Stopit said:
Burn it out

or

Angled drill through center and then go bigger and bigger and....

Should then collapse with a few taps and come out, don't damage the teeth below

Drill through center of broken bolt, near enough will do, go bigger and tap a new thread, near enough will do
Thanks for the advice.

Did think about drilling out the sensor but it goes in quite deep. Am concerned I'd break the upper half and have the rest stuck inside.

It appears my drill bits are too crap to drill properly into the bolt.

I think, as a courtesy to the mechanic, less is more. Don't want to make their job even harder.

GreenV8S

30,150 posts

283 months

Saturday 30th May 2020
quotequote all
If that's just a push-in sensor held in by the bolt next to it, I'd just keep pulling/twisting at any of it that's sticking out to see if you can pry it loose - when that's all broken off, attack it with a hammer and chisel until what's left falls out. To help your mechanic (or yourself, if you decide to press on with it) apply penetrating oil to the broken stud a couple of times a day.

NMNeil

5,860 posts

49 months

Saturday 30th May 2020
quotequote all
Screw a nut onto the broken stud and MIG weld it in place from the top.
Put a socket on the nut and while it's still hot try and unscrew it. If it's still stubborn cool it down by spraying WD40 around the base of the stud.
Theory is that as it's heated any air trapped inside the rust expands and is expelled. As it cools it will pull the WD40 back into the rust rather than just air.
Give it a while to work it's magic from within, then try and shift it again.

g3org3y

Original Poster:

20,606 posts

190 months

Sunday 5th July 2020
quotequote all
If anyone is interested, despite my best efforts (blow torch etc), the bloody bolt wouldn't shift. Had to take it to the local garage. They eventually had to drill it out, said it was a bd of a job. Makes me feel a bit happier about my failed attempts.