Thread: Tow Balls - Why So Awkwardly Complex?

Massive point pressure on a tow ball so I use a grease with lubricating solids, e.g. Moly as the hydrodynamic film will fail and galling will start.
Never had an issue with wear, the film at the base of the ball stops contaminants working higher into the wear areas IMO.

Originally Posted by rick130

Massive point pressure on a tow ball so I use a grease with lubricating solids, e.g. Moly as the hydrodynamic film will fail and galling will start.
Never had an issue with wear, the film at the base of the ball stops contaminants working higher into the wear areas IMO.

The tow ball itself isn't an issue when using grease, Its all the "Crap" that gets stuck up in the hitch itself that can cause problems.
Tow balls are cheap and easy to replace, The hitch itself Not so much.
The Only place I put grease when towing is in the bearing buddy's

Originally Posted by Slunnie

Tightened until it loosened!

Made me smile too.. An old Fitter and Turner I encountered during my apprenticeship days (50+years ago) used the term TTPS

Two Turns Past Stripped

Originally Posted by onebob

Made me smile too.. An old Fitter and Turner I encountered during my apprenticeship days (50+years ago) used the term TTPS

Two Turns Past Stripped

AKA,

crank it till she snaps then back off half a turn

Correct torque for this application is 'two grunts and a sigh'. Which is a little bit less than 'tighten it up til you strip the thread then back it off a 1/4 turn'.

I would be more worried that the threads were cut by a machine shop that couldn't even get the flats on the nut parallel.

Originally Posted by POD

Correct torque for this application is 'two grunts and a sigh'. Which is a little bit less than 'tighten it up til you strip the thread then back it off a 1/4 turn'.

I would be more worried that the threads were cut by a machine shop that couldn't even get the flats on the nut parallel.

Nuts are normally machined from bar stock but may be they are forged (which would explain the slight taper).

Strange that the nut has an Imperial hex size, so I guess still an imperial thread ?


Colin

Ah made me remember my only "failed to proceed " when my D2 **** its fuel manifold at El Questro.
Called NRMA who organised the Kununurra RACWA agent to tow us in.
The truck arrives and has a very grotty towbar insert.
The McHitch depends on the towball sitting flat on the flange so the driver must have used the turn it until it loosens philosophy. It has to be down flat so the pin can pass through the groove as in the photo. The ball is stainless steeel.
I wondered why later when they bought my camper to the caravan park on the tilt tray.
Any way I wanted the car moved to the Thrifty dealership and while talking to the first mob , they said "oh we have been trying to get you a new towball "
I said why and was handed the towball in which the top small thread was stripped. I said no worries we can helicoil it.
Er no the big thread on the bottom was also stripped.
This took real talent.
I carry a spare now.

Regards PhilipA

Originally Posted by gromit

Nuts are normally machined from bar stock but may be they are forged (which would explain the slight taper).

Strange that the nut has an Imperial hex size, so I guess still an imperial thread ?


Colin

It is a while since I have bought a new towball, but I am sure I have bought one in the last ten years - and I have never seen one with metric sizes. I suspect the reason is either that the thread is specified in ADRs, or simply that the ones sold on the Australian market are made in China (or Taiwan) for the US market (which still runs largely on Imperial threads and spanners).