yoke freeplay

[canav8]

This is a very timely topic. I am complaining of slop in my control train. I agree that the universals are the brunt of slop. I went and took out the universals and found out something interesting. I replaced the left control yoke joint with one that is called out in the 170B IPC page 102 fig 61-14. The Cessna part number is 0411257. The part number stamped on the Left Universal joint is APEX Dayton 0411079-0. I found replacement universals, the part comes from a later model 152 that has the samepart number stamped on the universals. I used the supplied piece of what looks like automotive hose to shield the universal. This is also from the 152. This is not NAPA engineering. I replaced the left universal, and there is no slop in the left side anymore. The right is not as bad but I had the extra joint so I replaced it as well.
But here is the interesting thing. The right control yoke universal has a different part number stamped on it that came out of the 170B. It has the same number as the other joint except it has a dash 1 behind it. APEX Dayton 0411079-1. The part numbers that are stamped on the universals are different that came out of the 170B. The Universals are also different in that the holes that pass through the universal are 90degrees out and the right Universal (-1),has a greater operating angle. When I went to put in the replacement that I got APEX Dayton 0411079-0 in the right side. The controls are now bound so tightly it is unbelievable. When I put the old universal back in, it was free as it was before. I believe it is because the right universal is a different one then the 170IPC calls out for. Can anyone shed any light on this? Here is a picture. The joint on the right was the same one that was called out for in the 170 IPC. If you will notice the pin that sticks out in the middle is 90 degrees out compared to the left one.

I hope I am clear enough on what I am trying to explain. The aircraft is a 1952 serial 25255. Since the aircraft is so old, could the universals have been replace before with the wrong ones? I do not want to spend $330 to find out that I have the wrong one. Thanks, Doug

[GAHorn]

I know it takes a bit of effort to type these descriptive texts, and I know that it is very clear in the typists mind what he/she is attempting to express...but it isn't as clear at the readers position as one might hope.

I've read this last msg from canav8 several times, and I've seen several different possibilities of meaning within each reading. When contemplating the problem with the possible meanings, I come to the following understanding, so let me state it to be certain we are saying the same thing:

You found excessive play in your 170's installed u-joints and obtained replacements salvaged from a Cessna 152. The right side had binding after the installation. These parts had mfr'r numbers identical to that removed from the left side of the 170, however the original part removed from the right side of the 170 had a different "dash" number, "-1".

You noticed that these different (mfr'r) numbers actually stamped on the removed 170 parts are also different than those numbers Cessna uses for a 170. (Additionally, Cessna uses the same number for left and right.)

The C-152 parts have identical mfr'r numbers stamped upon them as that originally found only on the left side of the 170.

Is that a correct summation?

[canav8]

LOL, yes George and thanks. I think I am speaking a different language or something. Doug

[GAHorn]

Well, the variables in this particular "solution" are many, and I suspect that's where the problem lies.

The Apex numbering differences may or may not be significant. Apex's dash numbers probably apply to the physical differences you've noted between them, but that may/may not be significant in Cessna's application.

Apex probably makes these things for many different applications. Cessna may use both Apex parts for interchangeable purposes. (Or thay may not, in the case of a C-152 which could have differing control-wheel geometry from left-to-right.)

There's no guarantee that your 170 ujoints are original. What you found is merely what you found. Same thing applies to the 152.

There's no guarantee that the 152 part that binds is actually serviceable. It may be binding because it's defective. Have you attempted to operate that binding-ujoint removed and in comparison with the original 170 ujoint (the -1)? Are they equally flexible when not installed? Did you lubricate them when you installed them? Did you confirm they both operated without binding prior to installation?

Anyway, this is a type of problem that can occur when using salvaged parts, especially when salvaged from different model aircraft. I admit that it's curious the Apex part numbers originally found in the 170 left/right differ.

This may boil down to the old "if it ain't broke....." and I can appreciate your desire to replace both while you're in there...but if is it really a warm and fuzzy feeling to replace a serviceable used part with another used part?

I'd have chosen to purchase the new MS parts from Spruce.

[canav8]

H George, I did lubricate and checked operation of the universals before I installed them as well. The system was working fine after I installed the left Universal as before. It wasnt till I installed the right universal did I notice a problem. I agree that it is a geometry issue. The original universal I removed from the right side has a different operating angle then the left side. That is why I believe that a different part was used. The question I would like to have answered is: If I order new parts, (which I must) I know I will be getting IPC parts but will it be different then the ones I removed? Can anyone tell me what the original parts from the IPC have stamped on them? Thanks

[GAHorn]

I cannot tell you what the mfr'r number on the replacements will be. (Mine were tossed so long ago that I can't "un-ring the bell".) Perhaps someone else may have theirs at a stage of disassembly that can make a comparison for you.

But consider this: Getting this last question answered may not solve your problem. The -0 you found on your left side of the 170 may not have been correct. It's possible that both should have been -1's. And Cessna's supplier may or may not still be Apex, and it may or may not still be the same Apex number.

The range of motion of the genuine Cessna PN 0411257 will doubtless accomodate the application. So will the MS parts from Spruce. The original Apex numbers assembled at original build may have been different, which Cessna may have solved a distribution problem by substituting a different replacement part number that will service both sides. (Example Cessna now specifies both a 0411257 and a 0411257-0 part, the latter of which supercedes to the former.)

Sorry not to be able to solve the particular mfr'r numbering difference for you.

[echild]

I've seen a couple of airplanes with one control wheel cocked at an angle and have been told it was due to the improper installation of a u-joint. Is this the same u-joint?

I've seen it on two different airplanes so am wondering if this is an easy thing to get off-center during the installation.

Keith

I replaced the co-pilot's u-joint annual before last. Before replacing it I simply peened the joints and they were tight as new. I went ahead and replaced the co-pilot u-joint and if the holes are not drilled correctly the yokes will be cock-eyed. I bet that is where the difference comes from.

Everett
1949 A model,
49 EC
TQH

[Brad Brady]

OK,
Once again I don't want to sound anal....but when the NTSB comes to the accident sight......is your insurance company going to give your wife.....or if she is with you, your children, what is coming to them with your demise? ....You won't know or care.....The idea is making sure your aircraft is in the best possible shape it can be in.....just don't cut any corners.....It not only makes you safer but insures your prodigy...Brad

[n2582d]

Mismatch at wheels if not due to wear would of course be cable rigging. I've placed a piece of rubber tubing over my joints to keep them clean ,lubed and most importantly to provide support.

I sure hope that rubber tubing was PMA'ed like the one pictured here!

MC6183 -mas.jpg (33.04 KiB) Viewed 11984 times

Get hosed here.

[170C]

Are these short sections of radiator hose, fuel hose, water hose or whatever they are legit in our certified aircraft? Do they actually accomplish anything? I can see the theory of keeping the u-joints free of dust, etc and maybe helping the lubercant to stay on them, but I am not aware that not having these hoses causes any problems. Just curious or are they like George's MMO One of mine, obviously the left/pilot one, has a bit of play in it and many times I have considered replacing it or at least pulling it off and brading it a bit as someone suggested several years ago, but just haven't gotten around to it. I only notice it when I am in smooth air, just sitting there with not much to do but look for things to put on my squak list.

[GAHorn]

I recommend leaving them exposed as Cessna intended. (Not to mention they will be easier to inspect and lubricate per the Service Manual recommendations.)
<Edit: McFarland requires their U-joints to be covered. They do not want their OEM lubrication added-to. They also expect the "hose" cover to prevent migration of the u-joint pins. This info is contained in McFarlands instructions rec'd with new U-joints in 2018.>

click to ENLARGE

[blueldr]

The IDENTICAL U Joints can be bought at either Grainger or McMaster-Carr for less than half of the price at Spruce. Keep the company invoice for traceability.

[ronjenx]

Regarding installing used u-joints for the control yokes:

The chances of getting a used one that is drilled correctly for your shafts are pretty slim. As some have mentioned, the yokes may be cocked off. Another problem is the sprocket end play will be too much, or the yoke will bind up to varying degrees. The attach bolts may not even go all the way in due to hole misalignment. If the holes need more than very slight chasing with a drill bit, start with a new u-joint.

No one in this thread has addressed sprocket (and yoke) end play yet. George hinted at it on page one.
I have looked for an end play specification, but haven't found one.
Sprocket end play is adjusted with thin washers of various thicknesses (see note below), placed over the sprocket shaft before the u-joint is slid on.
Install the u-joint and bolt, note the end play, add or remove shim washers as required. I adjust to get no binding, and just a very slight amount of end play, perceptible at the u-joint, but not at the yoke. The yoke misalignment is easy to fix with the turnbuckles.

NOTE:
The 170 and 170A parts books are unclear on these washers.
The 170B parts book, fig. 61 and 61A, index 11, shows part number AN960-A816L, quantity "AR".
This is a thin aluminum washer.
On the 170A I work on, there were two different thickness washers on each sprocket shaft. The pilot's side had three washers, the co-pilot's side had four washers.

[n2582d]

The chances of getting a used one that is drilled correctly for your shafts are pretty slim. As some have mentioned, the yokes may be cocked off. Another problem is the sprocket end play will be too much, or the yoke will bind up to varying degrees. The attach bolts may not even go all the way in due to hole misalignment. If the holes need more than very slight chasing with a drill bit, start with a new u-joint.

It appears that the new ones are pre-drilled so I think your chances for correct end play are as good with a used one as a new one. Here's a picture of one from McFarlane:

MC0411257 -mas3.jpg (33.51 KiB) Viewed 20616 times

MS20270-B10 is the light duty universal joint and MS20271-B10 is the heavy duty universal joint. These univeral joints are made by Apex (Cooper Tools), Belden and probably others. Here's a link to their catalogs: See pages 18 and 19 of this Apex (Cooper Tools Catalog, Belden MS20270 light-duty universal joints, and Belden MS20271 heavy-duty universal joints. The heavy-duty one can take five times the axial tension and compression loads. Notice in both catalogs that the heavy duty one shows a boot on it and on the light duty one the boot is absent (although one can buy boots from both companies). I wonder if McFarlane is selling the light-duty MS20270 u-joint as MC0411257 (for $236) as they show it without a boot? The light duty u-joint is significantly cheaper than the heavy-duty one. At the bottom of this page it is only $19.80.

I recommend leaving them exposed as Cessna intended. (Not to mention they will be easier to inspect and lubricate per the Service Manual recommendations.)

According to Belden, "Boots play an important role in protecting the joint and keeping it fully lubricated. Lubricant retaining boots will prolong the useful life of an assembly by a factor of as much as five." Granted there is a difference between sealed boots and a slice of hose. But newer Cessnas use a 1.12" section of hose over the universal joints.

Hose.jpg (16.17 KiB) Viewed 20616 times

#21 is p/n S1495-10 which has been superseded to R221609, a bulk item. $4.59/ft. My U-joints had badly deteriorated boots on them. I thought they were original but I guess not.

The IDENTICAL U Joints can be bought at either Grainger or McMaster-Carr for less than half of the price at Spruce.

McMaster's p/n 6443K46 might fit. At $28.34 the price is right. This one for $45.45 from Grainger would probably also fit. But I think it's a bit of a stretch to say that these are IDENTICAL u-joints. Ya think with a brand name like "LoveJoy" it might be made in China? If you install these make sure and use the hose over them--the hose will help keep the roll pins from falling to the floor during flare. A primary pitch and roll control part is probably not the place to pinch pennies. I'll be installing two new MS20271-B10 universal joints on my project.

[Brad Brady]

I use Mcmaster Carr and Granger (along with craftsman...their U-joints are unbelievable) for many parts in the Experimental aircraft I Build. But I work on the assumption that they are experimental. I would never use them in a certified aircraft. (just my opinion) The proper parts and part numbers are the only things to be used in our aircraft........Brad