Fuel guage repair

How to keep the Cessna 170 flying and airworthy.

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Thomas Arsenault
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Fuel guage repair

Post by Thomas Arsenault »

I have a '48 C - 170 and am having trouble with one of the fuel gauges. The right gauge many times shows "No take off" even though the tank may be full. Some times it will show fuel level correctly in flight. Yesterday I used a long wire to move the float in the tank and it started to work on the ground. Later, it went back to its prefered 'empty' position.

Does this mean that the float is still sealed and not fuel logged?
I have had the gauge out once and found a small part loose. I removed it and assumed that would fix the problem but it did not. I intend to use the plane for part of my commerical test and should have it fixed.

Should I just get another gauge? Any suggestions?

Thanks
Tom Arsenault
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GAHorn
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Post by GAHorn »

These guages use a float/lever/gear arrangement to move a magnet to influence the needle in the gauge. After years of bobbing about, they become pretty worn. You can purchase an entirely new replacement guage from Aircraft Spruce for $44, their pn 05-16700. 877/477-7823
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3958v
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Post by 3958v »

Tom I had a simlar problem with my fuel gauge. The problem turned out to be that the magnet was lose on the shaft that is supose to turn it. I used the tank sealer used on the RV series of planes to affix the magnet to the shaft. Try to find an RV builder to supply the sealer as you will only need the volume of a pea. Bill K.
Polished 48 170 Cat 22 JD 620 & Pug
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wa4jr
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Post by wa4jr »

While I have the right gauge out of the tank for tank welding, I noticed the cork float is in dire need of recoating. The gauge still works, but I need to recoat the float to prevent future failure. What is the proper coating for the cork fuel gauge float and where can I get it? I have a fuel gauge trivia question as well. My right gauge is all over the place as soon as the fuel level comes down from the full level. The gauge is accurate but even in stabilized level flight it moves around a lot. My left fuel gauge appears to have a damper of some type working, as even in bumpy air it moves slowly and smoothly while the right gauge is doing the jiggly-jiggly. Does anyone know if the gauges are supposed to be dampened or free to jiggle about :?
John, 2734C in Summit Point, WV
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GAHorn
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Post by GAHorn »

If your cork is fuel-saturated to the point of nuetral bouyancy it might not float so readily. It might "submarine" quite a bit in turbulence and give this impression.
Or your magnetic gauge might be damaged somehow.
There is an article written by Steve Grimsley in the SRAM that details recoating/re-varnishing the floats.
The current manufacturer of the gauges is Rochester Gauges, Inc, P. O. Box 29242, Dallas, TX 75229 (800-982-0030). This is their 7000 series Magnetic, Liquid-level gauge, model F-57-19-45. Their data states the standard float is epoxy-coated cork.
There is also an alternate float material for "aggressive" fuels :roll: that may be of interest to you, should you wish to pursue replacing the float completely or replacing the gauge completely. It is"Nitrophyl", available at extra cost.
When it comes time to re-install, the gasket is Buna-N, their PN 0015-00004 or 0015-00079.

P.S. This gauge is also available thru Aircraft Spruce 877-477-7823, their PN 05-16700 for about $44.
Hope this helps.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
DensityDog
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Post by DensityDog »

wa4jr,

This sloshing sealer works well to re-seal your float. Once you have dried the cork out, you can dunk the whole float into a quart can of the sealer. Let it dry and do it again. Works well on new cork, too. Or save yourself the trouble and get the new gauge like George sez.

http://www.aircraftspruce.com/catalog/a ... shseal.php

Standard disclaimer applies. "Your mileage may vary, any resemblance to actual persons is coincidental, use at your own risk", etc etc.

Max 8)
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GAHorn
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Post by GAHorn »

Max, I really appreciate your signature "..any resemblance to actual persons..."
This helps with my concerns about whether or not Ole GAR is an actual person. I'm pretty sure any resemblance of that must be co-incidental! :lol:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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wa4jr
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Post by wa4jr »

What a nice surprise from Rochester Gauges today. Searching for the fuel gauge gasket, I eventually was handed off to Gus, who insisted that I had to go to Cessna for the gasket, but of course Hill Aircraft says these gaskets are no longer available. Since I did not have the part # with me and Gus was lost without a part #, I called back and spoke with a lady who indeed confirmed that they had the gasket PN 0015-00004...but that their minimum order was $125 8O Even before I could express profound amazement at their minimum order figure, she offered to send me two gaskets free in the mail if I sent the request in via fax...so I did :lol: Not sure if she will extend the offer to others, but worth a try. BTW, part #0015-00079 shows up as a square gasket and not the round one that I need for the original Scott gauge.
John, 2734C in Summit Point, WV
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thammer
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fuel gauges

Post by thammer »

gahorn wrote:These guages use a float/lever/gear arrangement to move a magnet to influence the needle in the gauge. After years of bobbing about, they become pretty worn. You can purchase an entirely new replacement guage from Aircraft Spruce for $44, their pn 05-16700. 877/477-7823
That new part is not an approved part. Are there any sources of approved gauges?

tye
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GAHorn
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Post by GAHorn »

wa4jr wrote:What a nice surprise from Rochester Gauges today. Searching for the fuel gauge gasket, I eventually was handed off to Gus, who insisted that I had to go to Cessna for the gasket, but of course Hill Aircraft says these gaskets are no longer available. Since I did not have the part # with me and Gus was lost without a part #, I called back and spoke with a lady who indeed confirmed that they had the gasket PN 0015-00004...but that their minimum order was $125 8O Even before I could express profound amazement at their minimum order figure, she offered to send me two gaskets free in the mail if I sent the request in via fax...so I did :lol: Not sure if she will extend the offer to others, but worth a try. BTW, part #0015-00079 shows up as a square gasket and not the round one that I need for the original Scott gauge.
John, that's a good story. While researching this gauge, I discovered that Spruce (877-477-7823) also sells the gasket, their PN: 15-4 ROCHESTER GASKET FOR Mechanical Fuel Gauge 05-16700 $2.95
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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mit
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Re: fuel gauges

Post by mit »

That new part is not an approved part. Are there any sources of approved gauges?

tye[/quote]


Why isn't it?
Tim
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thammer
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Re: fuel gauges

Post by thammer »

That new part is not an approved part. Are there any sources of approved gauges?

tye
Why isn't it?
I'm not an A&P so I'm going on what others who are A&P's have told me and what I've read in various aircraft maintenance magazines. To be "approved" it either has to be supplied by Cessna or it has to be supplied by a maunfacturer with a PMA (Part Manufacture Authorization) to make that part. Basically Rochester would have to meet whtever requirements the FAA has for getting a PMA and probably pay some sort of fee for the privilege.

If you flip through Spruce or univair catalogs you'll see some stuff is labelled "Approved" and some is not. Spruce either has a PMA for the approved parts or is a reseller for the company that does. Just because Aircraft Spruce is sellignit doesn't mean it's an FAA approved part.

Plus, I called Spruce and asked. They said it's not an "approved" part. If someone could convince Rochester to get a PMA for the gauges that'd be a good thing.

Tye
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GAHorn
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Post by GAHorn »

Well, I've spent the last week or so chasing this one down. (gravelly voice now).... Here's the deal. (sounded like Jack Nicholson a bit, heh?)

From the Certified Repair Station that Rochester sent me to for the straight skinney:
Cessna PN 0422006-2, gauge, fuel, is made by Rochester (their PN 7083-1) , for Scott, who in turn supplies it to Cessna. Rochester therefore does not, on their own, have a PMA for the gauge. The gauge is approved for installation by virtue of it's OEM status if obtained from Cessna.
The same gauge is also sold to Spruce, who re-assigns a Spruce PN, and offers it without approval basis to the experimental market. Installation of that PN in a certificated aircraft will require another basis of approval.
My own aircraft logs indicate that my Cessna "gage, fuel, PN 0422006-2 has been ...repaired". :roll:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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thammer
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fuel gauges

Post by thammer »

gahorn wrote:Well, I've spent the last week or so chasing this one down. (gravelly voice now).... Here's the deal. (sounded like Jack Nicholson a bit, heh?)

From the Certified Repair Station that Rochester sent me to for the straight skinney:
Cessna PN 0422006-2, gauge, fuel, is made by Rochester (their PN 7083-1) , for Scott, who in turn supplies it to Cessna. Rochester therefore does not, on their own, have a PMA for the gauge. The gauge is approved for installation by virtue of it's OEM status if obtained from Cessna.
The same gauge is also sold to Spruce, who re-assigns a Spruce PN, and offers it without approval basis to the experimental market. Installation of that PN in a certificated aircraft will require another basis of approval.
My own aircraft logs indicate that my Cessna "gage, fuel, PN 0422006-2 has been ...repaired". :roll:
Yep, that voice raised the hair on my neck alright. That's an interesting tale. I'll bet there is some contract language between Rochester and Cessna which prohibits Rochester from selling the gauge as an approved part. Cessna wouldn't get any royalties otherwise. Can't blame them for trying to protect their cashflow I guess. At least this gives one a level of confort that the gauge is built in accordance with proper specifications.

tye
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Bikini
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Re: Fuel guage repair

Post by Bikini »

gahorn,
did you have to modify your guage at all for it to work in a 170? There's a whole discussion about having to shorten the arm or something. or is the Spruce product fit our plane?

Bill
Bikini
High Point NC
F-16, B727, A300, C170B
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