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IAC Discussion Summary

Oil Temp/Press Unit

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Disclaimer: These IAC pages are developed by individual IAC members and do not represent official IAC policy or opinion.

Collected by: Dave Swartz


The sensor line for my Pitts S2B oil temp gauge failed and I need to either get the gauge/sensor assembly rebuilt or buy a new assembly. Does anyone on the list have experience with this? The routing of the sensor line looks like removal/replacement will be interesting. The sensor line is prone to damage from being flexed each time the upper oil screen is checked.

Question Supplement:

Thanks for the response. The biggest problem I'm having with it right now is determining what alternative to take for getting through the instrument bulkhead with the capillary line. It looks like the capillary line is put in first during original assembly (through the 3/4 inch hole in the bulkhead) and then the two hardlines and several cables are put through the same hole. To remove the original capillary line and retrofit the new one in the same hole would require enlarging the hole first so that enough space (3/4 inch) is available to push the probe compression nut through. I'm also concerned with how to dress the probe end in such a way that the new line doesn't fail like the original did. The line broke about 2-3 inches from the probe end after being stressed by all of the top oil screen inspections required during the life of a 1400 hour aircraft. I've had some mechanics tell me the line should be left attached to the screen cover when the cover is removed to limit the stress on the line and others have told me that the line should always be removed before the cover is removed. Since mine broke during a inspection when the cover was removed with the line still attached, I'm inclined to make certain that it gets removed from the cover for inspections in the future. The original installation uses the probe attach fitting as a tie point for a safety wire for a plug on the back of the cover - is this still done this way on the latest aircraft?

From: "Dave Swartz"


We saw your note on the IAC exploder thought maybe we should give you a quick response.

Top Cowling will need to be removed. Remove Fuel over. Remove right side top panel, Release at least 1/2 way down the Right front side panel.

Then you'll be able to access the fitting, cut tie wrap to undo front top panel clamp. May have to undo right side cockpit panel to access grommet in bulk head.

Undo gauge and back out, reroute opposite direction to put in the new one.

If we can help clarify any of this information, please feel free to give us a call.

From: "Aviat Aircraft"

If you remove the loser row of screws from the RH panel over the bulkhead where the RH fuel selector is then bring your line around the frame instead of going through the hole, it will solve your problem. Bring the wire up over the brace and run it forward with the rest of the wires. There is enough flex in the panel that it will and does fit nicely and work well for the lack of space per your note. If we can help any further let me know. Carol

From: "Aviat Aircraft"

We are the Southeastern US Pitts service center. I might suggest giving our service department a call for advice. The telephone number for the service center (Air Winston) is 336-776-3030. Suggest you speak with Larry Small.

From: "Bob Brown"

Another thing, the whole length of capilliary tubing goes to the gauge non-stop, so you'll have to fish it out of the panel and possibly pull some skin panels to get the line out. I did mine at annual, so it was already open. The direct reading oil pressure gauge has a standard an fitting on the back of the gauge, but the darn cap. oil temp. line is one piece.

From: "Richard Klarich"

Assuming you have the capillary bulb direct reading oil temp line...

I used Wag-Aero's overhaul from Wisconsin for my S1S oil temp bulb line- they clean up the unit and put on a new line. Turnaround was 2 weeks, it's about $190 shipped. 800-558-6868. Check to see if they yellow-tag the work for a certified plane, I'm pretty sure they are a CRS and do yellow tag their work for airworthiness. You can probably ask/pay for a faster turnaround.

From: "Richard Klarich"

same thing happened to me.......youi need to get a new 3-in -1 gauge , and when you install it leave enough slack in the sensor line to allow alot of motion when you check the screen.....even if you have to "tie-wrap " it to keep it from moveing and cut it loose to allow youi to get the screen out ..........Tom

From: "tom or lori adams"

That's a sealed unit, you have to replace the entire gauge assembly. I've had to do it on both our Pitts and Extra. You might want to change to an electric unit. That's what they're doing on all new Extras. That's what I'll do the next time one of mine fails. Call Southeast Aero Services, in St. Augustine. Kramer gave me a good deal on one that they had pulled out of a new Extra. He may have more.

On another subject...Have you had any problems with your Maule tailwheel on your S2B? I've been through 3 in the last 50hrs and it looks like I'm due for another. The rubber is actually pulling off the wheel. I've talked to Aviat about it, and they've had problems as well. I've been trying to push them to get a STC for another wheel, any other wheel and was wondering if you had any problems.

From: "Matt Wilderman"

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