The International Cessna 170 Association

Gary, thank you. I notice however, that instruction is not relative to the eye-bolt PN 062105 which is the subject of this thread. It appears to be with regard to a different bolt (as well as different washers) not specified in the illustration, which is accompanied by a seperate tie-down fixture.

George, I'd encourage you to read paragraph 4-353 a little closer. It refers to Figure 4-29 on page 4-56. There the eyebolt (19) when crossed to the L-19 IPC fig. 54-9 comes up with p/n 0642105. Somewhere in this thread the "4" in the p/n got dropped. Might be helpful to edit previous entries to correct this.

Thanks..the typo is corrected.. Still, the L19 MX manual does not address the PN0642105 specifically, and the illustration is clearly NOT PN0642105... for whatever that's worth....

George, You are correct in that the top illustration, fig. 4-29A, shows a regular bolt rather than an eyebolt. This is the illustration "for all aircraft modified to 2800-pound gross weight configuration". I cannot find a matching description of this in the L-19 IPC. It is this configuration with the straight bolt (rather than eyebolt) that requires a torque of 650-700 inch-pounds and special washers on page 4-60A of the L-19 maintenance manual in paragraph 4-353 b.(1)-(3). You are correct, this does not apply to our use of the eyebolt. It might be a configuration the Alaska guys want to copy (with appropriate approval).

But the lower illustration you copied, fig. 54, from the L-19 IPC, matches fig. 4-29 in the L-19 Maintenance Manual. This is for "all aircraft not modified to 2800-pound gross weight configuration." This is the configuration that shows the eyebolt, p/n 0642105. Paragraph 4-353 a.(3) on page 4-60 and 4-61 calls for torquing this eyebolt to 600-650 inch-pounds.

Thanks for this research, Gary! This is what the British would call "Good Duff!"

I edited my earlier comment which used the 100 Series manual to refer any reader to THIS page so as not be misled.

A point which deserves to be restated: Be certain that sufficient washers are installed on that AN7 OR PN0642105 eyebolt such that the nut actually tightens/torques properly and doesn't simply run-out of threads on the shank. This is especially possible with original 170 leaf springs and MAY be possible when using an L-19 leafspring.

I continue to have problems with the eye-bolt on my tailwheel assembly becoming loose. I have sufficient washers stacked on the shank and a steel locknut but it works loose after just a few landings. I've started keeping a wrench in the plane to check it frequently.

I recently learned about Nord Lock lock washers. I'm considering having them installed on my tailwheel bolt to see if they will correct the problem. That and a witness mark so I can more easily detect it if it loosens.

Anyone have experience with Nord Locks? Any reason I wouldn't want to use them in this application?

I'm not at the hanger to measure it but according to this thread it's a AN 7 bolt which is 7/16. Is that correct? I apparently have to order a box of 10 of these and don't want to order the wrong size.

Thanks for any input.

Keith

It's difficult to comprehend how a self-locking nut would loosen if not jammed on the bolt-shank and not a worn-nut...
I wonder if drilling the eyebolt and using a castellated nut would be useful..

gahorn wrote:It's difficult to comprehend how a self-locking nut would loosen if not jammed on the bolt-shank and not a worn-nut...
I wonder if drilling the eyebolt and using a castellated nut would be useful..

I thought the same thing. Perhaps the nut is worn out. I need to get it apart and find a solution before I break something.

It is and AN-7 and that is 7/16. Let us know how the Nord works Keith.

I don't use the L-19 eyebolt but I do use a drilled bolt with a castellated nut secured with a cotter pin on the recommendation of an IA friend who regularly maintains a Bird Dog tow plane of a glider club. In his experience, he says, its the only way to reliably ensure that the nut doesn't loosen. I've not had any problems with mine loosening.

Keith, I experienced the same issue for many years. I would get the bolt tightened and after several landings the bolt would have turned 10-15 degrees. I added washers as George suggested, but that in of itself didn't cure the problem. Then George prompted me to make sure I was using the proper torque which I apparently wasn't using. I set my torque wrench to the suggested value (think it is 60 ft lbs?) and was afraid I was going to twist the bolt off before reaching the set torque (it didn't). That seemed to help a bunch. Maybe we can compare notes soon neighbor.

I need to purchase a new L-19 eyebolt that attaches the Scott 3200 tailwheel assembly to the leaf spring. Does anyone know a supply source for this eyebolt. Thanks.

Karl,
Welcome to forum! Air Repair has them. Their number is 622-846-0228. I think they may give a discount for 170 Association members. Could you ask them what torque they recommend for the the eyebolt when you order it?

FWIW I had a new steel locknut with nord-lock washers installed and insured the proper torque was applied to my tailwheel bolt recently. I marked it with a sharpie pen and so far, after a few landings, it hasn't moved. I don't know which of the three things corrected the problem bit it seems to be ok now.

I researched the web for torque values and came up with anything from 54 to 65 ft/lbs for 7/16th bolts, grade 8. I had it torqued to 60.

I like the nord-lock washers.

Just ordered L-19 eyebolt from Air Repair. Thanks. Also ordered steel lock nut and nord lock washer.

No torque recommendation. Sorry.

The 100 Series Service Manual recommends 460-500 in lbs (about 45 ft-lbs) for 7/16 with steel lock nuts.