Speedsensor Replaced

tommygun

Registered user
Joined
Apr 14, 2009
Messages
168
Reaction score
0
Location
London, England
A couple of weeks back I wrote about the dreaded triangle of death/brake failure symptoms I had. Dreading the worst after reading of potential ABS pump failures, final drive disasters, etc, I called BMW who quoted me £1400 for the replacement ABS pump :barf. Once I'd soiled and changed my shorts, I spoke to the chaps down Beemer bikes who suggested I change the speedsensor first. £60 later and a lot of cutting of cable ties, the error had gone and i was a happy man.

The sensor looked like it had actually burnt out with a hole about half a milimetre wide, and covered in metal filings. Is this a sign of the FD on its way out? Jim von Baaden seems to think this is quite normal. I also answered my own question about whether the bike goes into 'limp' mode when the triangle appears, and I guess it does, as there was no hesitation and/or stuttering once the part was replaced.

Anyhow - happy to be back on the road, although I did notice a bit of salt damage from the winter whilst tracing the sensor wire. I feel a date with Hammerite and ACF-50 coming on...
 
The metal filings on the sensor are normal-ish, though it's hard to accept that something is producing them without it wearing out. From experience the best indication of a failing FD (as it doesn't always result in wheel play) is black smelly oil and a rapid increase in the amout of filings stuck to the sensor. The latest FDs have a strong magnet in the drian plug which catches most of the crud
 
Define smelly oil. I thought my gloves smelt a bit rank when i took the sensor out and cleaned the filings off. Difficult to describe the smell but it wasn't pleasant.
 
Brand new FD oil stinks the same - can't tell the difference when used.

You are dead right about new and old gearbox oil smelling the same, it's a bit like old tom cats. However, for some reason it does smell different, and worse when the FD internals start to get added. I usually change the FD every 6k and over the years have experienced two FD failures, both at around 60-80k
 


Back
Top Bottom