Reference Sensors broken off in Bellhousing. MT

[samsonevickis]

Well, I was replacing the reference sensors in the E28 over the weekend and, as I was twisting the old ones out, the "handle" snapped off, on both. The magnetic cylinders are stuck in the bellhousing holes.

As far as the records indicate these might be original, but that seems almost impossible. It's an '86, Manual.

I cut a lip in the bottom one and pryed out the middle magnet, but the plastic bits are still coming out slowly.

The top sensor is harder to reach and still has the middle cylinder in there.

I hope this doesn't happen to anyone often, I mean in the few years I have been dealing with the reference sensors on older German cars, this is the first time I have had these break off!

The car was driven on heavily salted roads in Virginia about 20yrs ago. The whole exhaust is rusted out too.

Any tips?

[86GT635]

There might be enough room for you to maneuver a sharp bolt into the center, and pry it out. Like popping a wine cork.

I've had abs sensors stuck too. Not a whole lot you can do to save the pieces, sometimes.

[danny2010]

I had the metal cover come off one, I may or may not have just pushed it through in hopes it would make it out the bottom... I never saw it again until I took the trans out for my 5 speed swap lol

[samsonevickis]

Well I tried the cork idea, it worked, BUT the bottom bit is still in there.

Apparently there is a magnet in the center, plastic around it and a metal tip.

I don't think there is any kind of lip on the bellhousing so if it falls in, I would be worried it would get eaten by the flywheel or something.

I have heard of pushing them through and on the AT you can remove the inspection plate and retrieve the bits.

NO inspection plate on this MT though.

[86GT635]

If you can get it to spin without pushing it into the bellhousing you can get it out.

[danny2010]

The inspection plate doesn't work as good as you'd think... Like DJ said, try to get it to spin so it's atleast loose and you should be able to get it out

[86GT635]

Personally I feel like if the case is corroded to the hole, I would want to figure out a way to get a very small hole into the center, and then introducing a larger screw with a aggressive tip/thread and pry it out.

If you break it free without a way to grab it there isn't much to grab..

I would go to the hardware store/screw bucket and keep pressing to clear out the innards of the sensor and eventually pierce the "cap" of the mess.

- - - Updated - - -

Thought about this again.

Try to clear out as much of the plastic as possible, then hammer a sharp nail through the metal cap.

[samsonevickis]

Ok, after 6 months of the car sitting I am ready to get back out there and try again.

I have been a little busy with 100 other BMWs and of course the house.

But mostly because the client hasn't sent me a check or been on me about fixing it.

So I have the car safely jacked up, last time the car was NOT safely lifted or supported so I was hesitant with my use of force.

I am going to attempt the lower one as the magnet is already out and then I have some more tools than I did, a flex dremel line should help.

With any luck I will have the car running and moving about by Monday.

If anyone has any tips at all, please chime in!

[EuroGeorge]

Ok, after 6 months of the car sitting I am ready to get back out there and try again.

I have been a little busy with 100 other BMWs and of course the house.

But mostly because the client hasn't sent me a check or been on me about fixing it.

So I have the car safely jacked up, last time the car was NOT safely lifted or supported so I was hesitant with my use of force.

I am going to attempt the lower one as the magnet is already out and then I have some more tools than I did, a flex dremel line should help.

With any luck I will have the car running and moving about by Monday.

If anyone has any tips at all, please chime in!

If you can maneuver a propane torch in there, a little heat might help free things up. Not too much though

[samsonevickis]

Well the inner magnet cylinder will pop out.

The plastic housing around the inner cylinder would just melt?

The deepest section, the metal tip end is my issue, I am going to try and drill a pilot hole and then get a self tapping metal screw, a big head one, and then try and pop it out. Albeit with some heat.

[CW6er]

Let use know how you finally get it out?

[samsonevickis]

Ok to update.

Still working on it.

BUT there was a large metal panel that I was able to remove and then see the flywheel.

The Bentley and Real OEM didn't say this panel could be removed, further more the 5 rusted Etorx bolts didn't strip, which is a miracle all by itself.

So I can see the inside of the reference sensors now.

I have so far, heated the upper sensor with propane and tried to wedge it would with a big flat head screw driver. I am not pushing very hard, because I don't want to chip a tooth off the flywheel. I have only heated for about 30 seconds, I think I will heat till the inner metal cap of the sensor is red hot and then pry it out. I would be doing that now, but the car is outside and after a severe drought, it's FINALLY pouring.

In addition the bottom sensor I smacked into the transmission and it's touching the flywheel, so I broke the rust ring holding it in place, but now can't wedge anything in there to pry it out.

As a last resort I have the Bosch Multi tool, with a metal cutting tip blade. So if heat doesn't do it, I will just cut the tip of the sensor off, then smack it into the transmission and snip another section, until it all falls out.

I will indeed have the car back to running before Tuesday.

Just completed a spark plug change on my V12, did it in under an hr and didn't removed anything from the engine bay!

On the other side of the garage I finally dropped the old pan from the 633 and the new pan is ready to go in as soon as I get some gasket sealer...
Long weekend!

[samsonevickis]

DONE!!!

Ok, I ended up using a 3/8 10mm deep socket and an extension to smack the old sensor into the fly wheel, then I would take a chisel and break off what popped through. Repeat till it's all gone. That is the lower one.

The upper one I couldn't get a good angle on it due to the upper control arm bushing being in the way, I tried to remove the bolt and it was ON THERE, so I got a U joint and a 1/4 10mm deep socket, smacked it through like the lower one. Bing, Bing, Bing.

Lots of other little things cropped up, chiefly a hornet nest was made in the bell housing in the few days the damn thing was open, ask me how I found out! haha

Lastly I cleaned the holes out and used anti seize to lube the holes and the metal sleeves on the sensors.

I got the car started after I charged the battery, the 93 octane was over 11 months old, so it wasn't staying started very well. I grooved over to the gas station and had the car die 3 separate times while on the road. Pulled over the first two times, just restarted on the road the last time. Drove maybe 3 mi.

Barring some weird unrelated issue, my guess is that the new magnets have attracted shavings and debris from the old ones I knocked out and fell into the bell housing somewhere. Causing an interruption of the pulse sending. The car was fine, then it wasn't getting fuel, so I am thinking it's reference sensor related. Other wise the car revved and worked great!

So glad to be able to close this chapter.

I will pull the sensors tomorrow and clean them, if it still dies on the road, I guess I will start a new thread...

If anyone finds this in the future feel free to PM and I will elaborate in anyway I can help.

[CW6er]

Great job!
i saw just wondering where this access plate you managed to get off is located? Does the transmission have a removable bell housing or a one piece?

[samsonevickis]

It is directly in front of the trans bell housing. On my 633 it isn't there.

I thought initially that it was part of the bell housing, but it was a separate piece and covered the rear of the oil pan on the 535.