stinkydog

Sometime in the past 10-12 days, the wheel bearings on my fan belt tension sensor (part # 964 106 035 03) locked up and the wheel ate itself, along with a couple millimeters of the inner belt.

Unlike most of the OEM parts I've dealt with so far, this one is plastic and very flimsy. I think my kid's toy cars have better bearings, so I'm not surprised that it failed - but given the fact that it's a $85-$95 part (and then throw in another $40 worth of new belts), I'm gritting my teeth a bit.

I already ordered the replacements necessary, but I'm wondering if anybody has bypassed the circuit with a simple rewire of the signal connector? Seems kind of silly to have a cheap plastic "sensor" that is prone to failure long before the actual belt it's supposed to protect - and most likely won't trigger the error light until it eventually burns all the way through.

Les Dawes

Hi; mine failed quite a while ago, I replaced the OEM bearing with a standard metal sealed bearing (the same size) from a bearing supply factor and Loctited it onto the spindle. Only cost me about £3-£5ish. Sorry, don't have the sizes of the one I used, just measure your removed one and get them to match it. Regards, Les.

stinkydog

Yeah, my first thought was to just press a new wheel/bearings on, but then I tried moving the arm itself, and it felt like the thing was full of beach sand. Then I extended the arm into the full "there's no belt here" position, but there was no warning light.

I'm actually surprised at the cheapness of this (OEM Made in Germany) part - it's something I would expect to see on a Dodge Neon.

August West

Having had one seize and then rip my belt apart, leaving me stranded on the freeway, I've made it part of my pre-flight check before starting my car to check that the wheel spins freely. It's part of my engine-bay check looking for mice nesting or anything else out of the ordinary. I simply use my finger to spin the wheel as I hold it off of the belt. One less thing I have to worry about when I go driving.

stinkydog

It's definitely on my checklist now....

Although, a guy should be able to drive the car for at least a few hundred miles (or a few thousand) without worrying about this cheap plastic part.

Hence my original question - has anyone simply bypassed the thing?

Rob in Oz

Sure - you can remove it completely - but you'd better watch your temp gauge like a hawk - that's the only way you'll tell if you've broken a belt...

JasonAndreas

That sensor will easily last 10-15 years... The vbelts should be checked and retensioned (although most are just replaced) every 15k miles.

power_up

Yes, I just tie it up. 2 years until now.

mglassup

A zip tie does the job, I replaced mine though after it broke and a zip tie got me out of trouble, if it lasts another 80k i'll be well happy!

Goughary

During my top end rebuild last fall I noticed that the idler wheel on mine was cracking from being old and dry. So I replaced it. I am suprised noone offers an alluminum repacement with a decent bearing - that part litterally has no excuse for not lasting forever....it's just built too cheeply. Sooo, if soemone with a machine shop wants to whip up some idler wheels and bearings that are a bolt on replacement....I'm in.

stinkydog

How about an electronic sensor? (Probably optical/LED-based - something along the lines of the "dirt sensor" in a vacuum cleaner)... could be a cool little project. At least if it failed, it wouldn't eat up the belt.

jody stowitts

Stinkydog: Just replaced mine @ 91k. Was tipped off by some "new" high pitched vibrato singing coming from the stern. Down to the smaller inner metal wheel below the "at one time" outer plastic wheel, so was able to prevent belt demolition.

anto1150

could be a brilliant project

tbennett017

Uh oh.. I'll call Ricardo on the machine shop end of things. We could have them made at a Web shop anywhere... . :-)

The other problem that comes with these is that the 'cam' inside the assembly can wear. After 10 years of vibration, it had a worn spot where the electric switch pushes against it, like a detent. So even if the belt did break, the wheel wouldn't 'fall' into the gap. It was never going to rotate and warn me of anything.

stinkydog

I'm actually kind of tempted to pick up something like this and put together a hack.

I'm not sure if that actual unit would do the job (might be too sensitive, beam too wide, not sensitive enough, etc.).. but hey, it's the price of a 6-pack.

I need to first spend 60 seconds looking at the wiring diagram for that part to see which way the circuit is opened/closed.