Ask Questions and Offer Advice Related to the Cessna 120 & 140 Type
Forum rules
You must be a member of the Cessna 120-140 Association in order to post new topics, reply to existing topics, or search for information on this forum. Use the "Join" link in the red menu bar.
7698 wrote: ↑Thu Apr 23, 2020 10:40 amI'll opt for -30 on the basis of better to be looking at it than for it.
Make sure you have enough washers! (tradition says more than 3 and you should use a shorter bolt...) The best washers to use are MS20002-4 washers, which match the strength of the bolt and nut. Don't put washers under the bolt head; the gear leg is chamfered to match the radius between the bolt head and shank. Regular washers are not. If you insist, MS20002-C4 washers are chamfered.
Maybe the best thing to do is measure what you have, or get both.
7698 wrote: ↑Thu Apr 23, 2020 10:40 amI'll opt for -30 on the basis of better to be looking at it than for it.
Make sure you have enough washers! (tradition says more than 3 and you should use a shorter bolt...) The best washers to use are MS20002-4 washers, which match the strength of the bolt and nut. Don't put washers under the bolt head; the gear leg is chamfered to match the radius between the bolt head and shank. Regular washers are not. If you insist, MS20002-C4 washers are chamfered.
Maybe the best thing to do is measure what you have, or get both.
Ive measured today and if I add in the thickness of the wheel pant back plate, the grip length need to be 1-3/4" so not exactly sure if thats a -28 or -30?
I didnt pick up on it last time, but you mention that gear leg being chamfered; does that mean that the bolts should go through the legg end first and the nut be against the brake fixing plate? Currently the nuts are onto the gear leg.
7698 wrote: ↑Thu Apr 23, 2020 10:40 amI'll opt for -30 on the basis of better to be looking at it than for it.
Make sure you have enough washers! (tradition says more than 3 and you should use a shorter bolt...) The best washers to use are MS20002-4 washers, which match the strength of the bolt and nut. Don't put washers under the bolt head; the gear leg is chamfered to match the radius between the bolt head and shank. Regular washers are not. If you insist, MS20002-C4 washers are chamfered.
Maybe the best thing to do is measure what you have, or get both.
Ive measured today and if I add in the thickness of the wheel pant back plate, the grip length need to be 1-3/4" so not exactly sure if thats a -28 or -30?
I didnt pick up on it last time, but you mention that gear leg being chamfered; does that mean that the bolts should go through the legg end first and the nut be against the brake fixing plate? Currently the nuts are onto the gear leg.
Ok, stupid question time... Does MS20004-28 mean that grip length is 28 x 1/16"... = 1-3/4"
7698 wrote: ↑Sat May 16, 2020 11:10 am
Ive measured today and if I add in the thickness of the wheel pant back plate, the grip length need to be 1-3/4" so not exactly sure if thats a -28 or -30?
Yes, -28 is 28/16" or 1.75" not including the threaded portion.
I didnt pick up on it last time, but you mention that gear leg being chamfered; does that mean that the bolts should go through the legg end first and the nut be against the brake fixing plate? Currently the nuts are onto the gear leg.
Yes, the inside surface of the gear leg is chamfered and the bolt head should bear directly on it.
No, the larger AN5 bolt has similar strength to the MS20004 bolt, so use them. If you have socket head bolts now they are almost certainly MS20004's. Do you recall what wrench you used on the nuts? Nuts for AN5 bolts take a 1/2" wrench.
Trivia: the original nuts look like AN365-4 nuts but they aren't (weren't). They were a 1940's off the shelf high strength nut and there is no AN/MS/NAS equivalent that I could find. The best I could find was NAS1804-4 nuts, which are the right strength, but 12 points instead of 6 flats. A 12 point socket or wrench will fit.
