Speed sensor (again).

[AMG Merc]

After occasionally suffering from the damp - and always recovering - my speedo seems to be having an on-off realtionship with reality...

I thought it was just a case of getting a new sensor (80-odd £s dealer price - how much Ford price?), cutting the cable, unlocking the retaining nut on the old one, popping it out, popping in the new one, nut on, connecting to old lead and hey presto! But no, apparently mine's a version that won't just pop out (something do do with a recess?) - it needs drilling (so wheel/disc off).

Does anyone know what I'm on about, and if I'm correct, why isn't this a 5 minute job?

Edited by AMG Merc on Saturday 12th December 15:10

[peterguk M500]

Thought there was only one type of wheel speed sensor - 5 minute job to replace... Just bought one for my 2.5 (speedo is gearbox driven)-to-M400 upgrade - about £40 from Noble...

[AMG Merc]

peterguk M500 said:

Thought there was only one type of wheel speed sensor - 5 minute job to replace... Just bought one for my 2.5 (speedo is gearbox driven)-to-M400 upgrade - about £40 from Noble...

Peter, I'm guessing yours is a 5-speed box. If so, AFAIK it doesn't use the wheel hub speed sensor but instead goes straight to the gearbox.

[peterguk M500]

Sorry, didn't make myself clear...

I've taken out my 2.5 engine & 5 speed gearbox with gearbox driven speedo and replaced with M400 engine & 6 speed gearbox so have changed front hub and fitted wheel speed sensor.

Edited by peterguk M500 on Saturday 12th December 16:30

[AMG Merc]

peterguk M500 said:

Sorry, didn't make myself clear...

I've taken out my 2.5 engine & 5 speed gearbox with gearbox driven speedo and replaced with M400 engine & 6 speed gearbox so have changed front hub and fitted wheel speed sensor.

Edited by peterguk M500 on Saturday 12th December 16:30

Ah good. Do you recall when you unscrewed the retaining nut did the sensor just pop out? Mine seems to be stuffed in tight.

[peterguk M500]

I didn't have to remove one. I fitted a new one to the hub as my car has never had a wheel speed sensor.

[AMG Merc]

peterguk M500 said:

I didn't have to remove one. I fitted a new one to the hub as my car has never had a wheel speed sensor.

Ah, thanks. So, I need to hear from somone who has changed their hub-mounted speed sensor - please?

[daddysumo]

AMG Merc said:

peterguk M500 said:

I didn't have to remove one. I fitted a new one to the hub as my car has never had a wheel speed sensor.

Ah, thanks. So, I need to hear from somone who has changed their hub-mounted speed sensor - please?

On mine the nut was on the inside of the hub, loosen it off and tap the sensor out as its only bonded in position with some adhesive goo, clean out the hole, position the new sensor as close to the castellations as poss without it touching,goo it from the outer face and use the lock nut to hold the adjustment as set.

HTH

Steve

[AMG Merc]

daddysumo said:

AMG Merc said:

peterguk M500 said:

I didn't have to remove one. I fitted a new one to the hub as my car has never had a wheel speed sensor.

Ah, thanks. So, I need to hear from somone who has changed their hub-mounted speed sensor - please?

On mine the nut was on the inside of the hub, loosen it off and tap the sensor out as its only bonded in position with some adhesive goo, clean out the hole, position the new sensor as close to the castellations as poss without it touching,goo it from the outer face and use the lock nut to hold the adjustment as set.

HTH

Steve

Thanks Steve. I presume I need to remove the wheel for access but how about the disc?

[Adrian W]

AMG Merc said:

daddysumo said:

AMG Merc said:

peterguk M500 said:

I didn't have to remove one. I fitted a new one to the hub as my car has never had a wheel speed sensor.

Ah, thanks. So, I need to hear from somone who has changed their hub-mounted speed sensor - please?

On mine the nut was on the inside of the hub, loosen it off and tap the sensor out as its only bonded in position with some adhesive goo, clean out the hole, position the new sensor as close to the castellations as poss without it touching,goo it from the outer face and use the lock nut to hold the adjustment as set.

HTH

Steve

Thanks Steve. I presume I need to remove the wheel for access but how about the disc?

Yep wheel, disc , calliper, top and bottom ball joints, remove upright place on dining table so you can see it perfectly, then remove the little nut that locks it in place. re assembly is the reverse.

Or just lie under the car and have a look.

[Jim O.]

On the M400's I've done, there wasn't any real need to remove the upright to change the speedo sensor. The easiest way that I've found is to remove the wheel, remove the axle nut/bolt, pull out the interrupter wheel (hamster cage), and then use a deep socket to remove the inner lock nut off the sensor. From the inside of the upright, push the sensor out of the upright.

[Ash 996 GT2]

I will call you.

[AMG Merc]

Ash 996 GT2 said:

I will call you.

Thanks Ash, will check those areas out...

[AMG Merc]

AMG Merc said:

Ash 996 GT2 said:

I will call you.

Thanks Ash, will check those areas out...

Hi Ash, checked those areas out and no evidence of water. Of course, a relay could still have a dirty contact though...

[AMG Merc]

Guys, still looking at this problem. Please excuse the quick diagram below but I'd appreciate it if someone could join the dots - wiring-wise please. I've looked at the workshop manual and the wiring doesn't match mine at all.

As I understand it the 5-speed box speed sensor was of a design that picked up directly at the gearbox (via the triangular three-pin connector on top of the gearbox (near the selector fork) - see diagram. As mine's a 6-speeder this pickup was redundant and instead they used the front o/s wheel hub speed sensor instead (but left the connector in the engine bay anyway).

The dealer did a test proving? that there is a short (water or otherwise?) in the redundant line but they don't want to chop it off in case it feeds something else.

Hope this makes some sense

[url]
|http://thumbsnap.com/v/ZmsRQ59K.jpg[/url]

[Adrian W]

+5v 0v signal, i spemt ages trying to fault find mine, got all clever and tested everything, turnd out th be a broken 0v about 2mm from the sensor, so after wasting hours stuck a new one in.

[Metalman]

I know it's an old thread but how did you get your speedo sensor out in the end? Mine is really stuck in good and it wont budge. I have the upright on a bench and have removed the locking nut and thought it would push out.

[AMG Merc]

Metalman said:

I know it's an old thread but how did you get your speedo sensor out in the end? Mine is really stuck in good and it wont budge. I have the upright on a bench and have removed the locking nut and thought it would push out.

Mine was in there for England! I ended up paying mole valley 2-3 hours labour. Warren drilled it out and fitted a new sensor. All perfect after that.

[Metalman]

Hmmm, sounds like its time to get the drill out. Another brilliant design by noble, it's a good job i love my car so much.