Air Cleaner Sensor

[herbinohio 0]

My 520-H and a 518-H both have air clener sensors that have the nipples broke off. Anyone have any advise on how to fix them ? I called the dealer and they want $60.00 for new ones...:thumbs2:

[Save Old Iron 1,568]

Try this new product

http://www.supergluecorp.com/pacer-industr...stic-fuse%C2%AE

I used this adhesive to repair a broken plastic windshield washer jet on a car and it worked great. This is one of few recommended products for use with nylon, polyethylene and polypropylene based materials that are sometimes used to construct these types of switch housings.

The body and broken nipple of the sensor should be cleaned and dried thoroughly and this adhesive applied. Follow manufacturer's instructions.

The important part of repairing a fracture on these switches is to get an absolute air tight seal at the break - they sense a relatively small vacuum to activate the switch and a small air leak in the switch body will compromise their function.

If any air gaps exist after applying this adhesive, a SMALL AMOUNT of silicone sealer in the remaining gap may be used to ensure an airtight repair, Remember, do not block off the nipple with any adhesive or silicone spillage.

An alternate method would be using regular super glue as the adhesive and baking soda as a "filler" - works better than you might imagine. The baking soda forms a rock hard filler that is even able to be sanded to a final contour around the broken nipple. Plenty of info on the internet regarding this type of repair.

$4 to save $120 - sounds like a good deal to me.

Good luck

[herbinohio 0]

Thanks Chuck. I'll probably stop at the local ACE today and see if they carry this product, or something similar. It cannot hurt to try this route first. The mfg of the switch was stamped on the back, so i called them directly and was able to get a cheaper rate than Toro. They will sell me the switch for $22.00 /ea . The new part # is 8111-150 if anyone is interested. There is a 1-2 week delay since it is an old part. Here is a link to the company i called to get the replacement switch.

http://www.globalepower.com/

[Save Old Iron 1,568]

THANK YOU, sir

I am sure the day will come when I also need a replacement and the info you provided will be very helpful.

[Save Old Iron 1,568]

Herb,

I followed the link you supplied to the manufacture's site.

Seems like the switch body is made of a polycarbonate material. You may need to use Methylene chloride as a solvent to repair the polycarbonate nipple back onto the sensor shell.

There are special plastic adhesives that work on polycarbonate.

Poly-Zap Multi Purpose Formula by Pacer Technology.

from the manufacture's site

"FEATURES: A specialty CA adhesive developed for use on today's newer plastic.

Ideal for Lexan...one of the more difficult plastics to bond.

Poly-Zap also works with delron, polycarbonate, ABS, styrene, nylon,

and most acrylics."

This is usually available at hobby stores that sell remote control car accessories.

[Herbl 10]

Talking about the air cleaner sensor, on my 520H the sensor on one side it has a tube connecting to the bottom of the air cleaner and the other side it just has a nipple but nothing attached, is that correct?

[Save Old Iron 1,568]

This might explain.

The red blocks are the switch contacts - orange color represents a rubber diaphragm enclosed in the sensor body

Vacuum applied to the left nipple draws the flexible diaphragm toward the vacuum source and brings the electrical contacts together.

Blue arrows show air coming in on the "unattached " nipple This arrangement allows the diaphragm to flex upward in the activated position and then return to the open switch position when the vacuum is not applied.

No Vacuum = engine not running or clean air filter

Vacuum = clogged air cleaner

side labeled "vacuum"____________________side labeled "pressure"

So an unattached 2nd fitting is OK, It just allows air in and out of the sensor body.

[Herbl 10]

So I'm good, thanks Guys....

Poughkeepsie, NY

[Save Old Iron 1,568]

Herbl,

your switch sounds like its hooked to air filter correctly - to check to see if it functions as intended,

hook a manual vacuum pump / brake bleeder to the tubing leading to the switch

and with the tractor running, SLOWLY start pulling a vacuum into the switch. At the trip point, the air cleaner alarm light should come on.

I do not have any specs on the vacuum level needed to trigger the switch but I imagine it could not be much more than a few inches ( guessing 1 - 5 in vac)

Anyone else every measured it ????

I'll try to check it on my 520 when it stops raining - whenever that will be - i don't know.

[Save Old Iron 1,568]

Email response from the sensor manufactuer

To: dsherman@globalepower.com

Subject: 8111-150 trip point

I am using an older part # 8111-150 switch in a lawn care application to

measure pressure drop for clogged air filters. Can you tell me what the

"trip point" ( in inches of vacuum ) is for this switch to sense an

elevated vacuum condition ?

Thanks

Chuck

-----------------------------------------------------------------

the response was -15 inches of vacuum - a much higher trip point than I would have ever guessed

[herbinohio 0]

Chuck,

Would it be safe to say you could unhook the hose and cover the hole on the switch with your finger to see if the indicator light comes on ? I know this test would not tell you if the switch is working properly at the -15 setting. However it would indicate that the switch is working ?

Thanks,

shane

[Save Old Iron 1,568]

Shane,

assuming that every item in the air filter check circuit is working properly,

the switch (and therefore the status indicator) are only going to be activated if there is a 15 inch DIFFERENCE in pressure between the port marked "pressure" and the port marked "vacuum". This vacuum would be developed if an extremely dirty air filter did not allow air to flow thru the filter element into the engine. The engine's vacuum would be "captured" inside the air filter element and would trigger the sensor.

so... putting your finger over the vacuum port will not apply vacuum or pressure in the "vacuum" side of the switch - so no difference in pressure between the two ports = no switch activation.

Its also important to know this switch does not sense engine vacuum ( that's the job of the vacuum gauge on the dash). This sensor measures the PRESSURE DROP ACROSS THE AIR FILTER ELEMENT.

1/ test your status indicator on the dash panel by using the test rocker switch on the dash indicator panel - the air filter status indicator should come on

2/ check the "pressure" port is open to outside air (no tubing attached)

3/ attach a vacuum hand pump ( pictured in an earlier reply in this post) to the "vacuum" port on the sensor

4/ slowly buildup a -15 inch vacuum to the "vacuum" port of the sensor, at or around a -15 the status indicator should come on. **note** the vacuum indication on the hand pump should not decrease rapidly when you stop building the vacuum - if it does - the sensor body may be cracked and require replacement.

Of course the steps outlined above would show an indicator light turned on only if both the switch and the wiring are functional.

If the indicator does not turn on, the switch could be good but the wiring may be corroded.

In that case - clean the sensor wiring contacts and hook an ohmmeter directly across the sensor wiring contacts. When you draw a -15 inch vacuum on the "vacuum" port - the ohmmeter should suddenly jump to nearly 0 ohms (switch activated). This confirms the switch is OK and you can now turn your attention to the wiring.

If more troubleshooting is needed to make the sensor circuit functional, check the +12 volts to the switch and also the quality of the ground connection to the sensor.

Glad you guys brought up this topic. When I checked the 520 I'm currently rebuilding, the vacuum port nipple was broken from the sensor body, the wiring was corroded and the tubing leading from the sensor to the air cleaner base was missing entirely. Just one more thing on the to do list.

Any questions, let me know.

Cheers

[dwcphoto 7]

"Do any of you have a photo of the sensor? Mine just snapped off. Thank you, dwc

 

[lynnmor 7,577]

It is the PSF-102 series.  Website  You can try to buy there, I did years ago and the price was reasonable.

 

I fixed several of those switches, where the nipple broke off, by making an aluminum plate with a nipple and screwed it to the side using four very small screws after sanding it flat.  I made a small recess for a tiny o-ring to seal it.

[dwcphoto 7]

I did the old round toothpick in the hose trick and it fired right up.  I might get a sensor, too, but this got it back in the shed. Thank you! David