ronjenx wrote: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 21008 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.
gahorn wrote: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 21008 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#21 is p/n S1495-10 which has been superseded to R221609, a bulk item.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.
blueldr wrote: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.