PTFE Lined Rod Ends and Spherical bearings

[ggl205]

I purchased several new rod ends that are lined with PTFE Nylon 12. Nice bearing but far too much stiction. I would like to loosen these bearings up a little but not quite sure of the best way to accomplish this. I originally thought to heat oil and dump them all in, let them soak there for a while, then work them by hand. The hope is hot oil would draw in between ball and liner. Suggestions?

John

[manta22]

John;

What brand & model number rod end bearings are you using? I've never seen any with enough friction that it would cause a problem. These bearings have a Teflon/Kevlar lining and are a good all- purpose choice for most applications.

https://www.speedwaymotors.com/Precision-Carbon-Steel-RH-Male-Heim-Joint-Rod-Ends-5-8-Inch,29655.html

The price is right, too. Of course, if you need a chrome-moly rod end for higher strength, you need to make another choice.

Regards, Neil  Tucson, AZ

[ggl205]

Neil:

I got my rod ends from Jegs. They are 4130 steel, nylon lined and cost a bit more than Speeway rod ends. There are eight of these on four front axle trailing arm links. Combined stiction from all eight holds the axle in any position without dampers installed (and my axle is heavy). I normally use high strength Aurora bearings or, if my budget can stand it, NMB. I used to be able to get low stiction bearings from Aurora but can't find reference to them now.

I really don't want to replace my new rod ends with others but may have to if I can't fix what I have.

John

[manta22]

Wow, that's lots of friction! I guess you might rig up a motor to spin the ball within the race for a while to "wear it in".

A little bit of history on rod ends- early on there were only a few companies that made good ones, mainly for the aircraft and aerospace industry (Heim, AST, New Hampshire, etc) but they were $$$. In the late '60s or early '70s, Aurora entered the commercial market but their rod ends were el cheapo; they certainly have re-positioned themselves in the market since those days. In about the same time frame, NMB (Nippon Miniature Bearing) was just exploring the US market and they were uncertain what to charge for their rod ends. NMB provided me a sample or two for a Sable sports racer that I was building and their US marketing manager asked me what price they should be selling them for!

Regards, Neil  Tucson, AZ

[ggl205]

In about the same time frame, NMB (Nippon Miniature Bearing) was just exploring the US market and they were uncertain what to charge for their rod ends. NMB provided me a sample or two for a Sable sports racer that I was building and their US marketing manager asked me what price they should be selling them for!

Regards, Neil  Tucson, AZ

Oh, so it was you who told NMB to brake my bank (lol)?

John

[Interested Observer]

Are you sure you haven’t inadvertently created a geometrical binding in the suspension linkage?  Disconnect one link and see how it moves.

[manta22]

In about the same time frame, NMB (Nippon Miniature Bearing) was just exploring the US market and they were uncertain what to charge for their rod ends. NMB provided me a sample or two for a Sable sports racer that I was building and their US marketing manager asked me what price they should be selling them for!

Regards, Neil  Tucson, AZ

Oh, so it was you who told NMB to brake my bank (lol)?

John

I low balled my answer but eventually they wised up. 

Regards, Neil  Tucson, AZ

[ggl205]

Are you sure you haven’t inadvertently created a geometrical binding in the suspension linkage?  Disconnect one link and see how it moves.

Rod ends are out of the car. The ball is very tight in the nylon insert (all eight).

John

[WOODY@DDLLC]

John, try some silicon plumbers grease - Lowe's or Homeless Depot! $3~$4
Probably a bit of an interference fit? 

[ggl205]

John, try some silicon plumbers grease - Lowe's or Homeless Depot! $3~$4
Probably a bit of an interference fit? 

Woody, I have some of that silicon plumbers grease around the house and gave it a try on a single rod end. It did reduce friction some but not enough. Then I read in the Hirschmann tech sheet that no lubrication on PTFE bearings should be done as it prevents a "smoothing" effect of the lining material. The smoothing effect yields a uniform fitment between lining and ball thus reducing stiction. Anyone interested should look at this tech sheet as it is very comprehensive. The PDF file is too large for me to attach but just search Hirschmann bearings and you should easily find it.

Looks like I am back to Neil's recommendation of spinning the ball, being careful not to generate too much heat.

John

[Joe Timney]

John,
What size?

[ggl205]

John,
What size?

Joe:

Ball hole diameter is .500"
Threaded stem is .625"
Ball width is .625"

[WOODY@DDLLC]

John just run it at Elmo - the dust there should bed them in naturally! 

[ggl205]

John just run it at Elmo - the dust there should bed them in naturally! 

Hah! Probably right, Woody.

John