Tow Balls - Why So Awkwardly Complex?

**DirtDigger** · 30th April 2020, 10:34 AM

Originally Posted by Lionelgee

Hello All,

I went to fit a 3.5 Tonne tow ball to my vehicle. I found that the tow ball nut is tapered. The nut is 32.5 mm and only fits "tow ball nut spanners" one way. They should also be torqued to 250 Nm.

According to an online conversion a 32.5 mm socket is 1 inch and 4/16ths; accessed 26th April 2020 Conversion mm to inch and inch to mm with fraction
This may convert down to 1-1/4 inch socket.

This I learnt from experience:

I only have a 32 mm and a 33 mm socket, and these are impact sockets
I have two torque wrenches - neither of them el-cheapos and they both only go up to 200 Nm
There is no ability for tow ball nut spanners to read torque
There is no notification which way the taper should go? Is it thickest side to the tow tongue? Or is it the thinnest side of the taper to the tow tongue?
The car parts supplier I went to only has on stock torque wrenches that go up to 200 Nm.

I found only one supplier of 32.5 mm sockets on eBay and that was available in England. The Imperial version is more readily available at 1-1/4 inch in Australia.

So how many people buy the specialist Tow ball nut spanner and have a guess what the torque setting is? Or they grab a big shifting spanner, or a set of stillsons. To the extent that there may be more non-manufacturer's specification towballs fitted travelling on the road then there is up to specification ones.

So off I go with special tow ball nut spanner in hand to have a guess about taper directions - my guess is thicker to tongue, and what I can crank out on a cheap single purpose pressed spanner. This will have to last until I can take the tow ball into a specialist to see if they have a torque wrench that goes up to 250 Nm and has a 32.5 mm socket and get them to test my work.

Next time I follow someone towing a trailer I will wonder how close to manufacturer's specifications their towball is fitted to?

P.S. I now have a 350 Nm torque wrench and a 1-1/4 inch deep socket on their way via Australia Post.

Kind regards
Lionel

No Mate. Never ever seen a HR tapered tow nut. I use 11/4 standard impact socket and a breaker bar .tighten up hard. No need for torque wrench. You are somehow overcomplicating it.? Why.

**4bee** · 30th April 2020, 10:41 AM

Originally Posted by DirtDigger

No Mate. Never ever seen a HR tapered tow nut. I use 11/4 standard impact socket and a breaker bar .tighten up hard. No need for torque wrench. You are somehow overcomplicating it.? Why.

I suppose it could be down to worn dies on the press.

**pedro54** · 30th April 2020, 12:55 PM

On a 3.5T towball the thread is 7/8" UNF, spanner size is 1 5/16", though I have used 3'4" Whitworth simply because I have it.

Below is an extract from a table of various spanner spanner sizes I created as I needed to fit nuts on an old machine tool. I you look on Ebay most of the large spanners can be found over time at reasonable prices.

Jaw Size Millimetres	Jaw Size Inches	Spanner Metric	Spanner AF	Spanner British	Common Nut/Bolt (*=non-preferred)
32	1.26	32mm			M22*
33.02	1.3			3/4 W; 7/8 BSF
33.34	1.313		1-5/16 AF		7/8 UNF
34	1.339	34mm

Peter

**JDNSW** · 30th April 2020, 02:59 PM

Originally Posted by pedro54

On a 3.5T towball the thread is 7/8" UNF, spanner size is 1 5/16", though I have used 3'4" Whitworth simply because I have it.

Peter

That is a big spanner! Sure the three feet doesn't refer to the handle length?

The toolboxes in my 2a and tractor both have 3/4"W spanners (with the jaws eased slightly with a file) that live there for the purpose of removing and refitting balls - which live in the respective toolboxes when a pin rather than a ball is being used.

**slug_burner** · 30th April 2020, 05:56 PM

I am most surprised that fastener torque for heads and other mechanical components aren’t just listed as; FT, 4 foot cheater bar, just put your foot up against it and pull like hell on your 15” shifter, like purgatory with a 18” shifter or longer.

Come on people, what we do and what is written might be two different things but give Lionel a break.

Don’t bust his balls (ha ha!). I can just see the Hayman Reese representative in the dock saying, “we instructed the purchaser to do it up F..king Tight (FT) my Lord”

**Slunnie** · 1st May 2020, 04:22 PM

Originally Posted by slug_burner

I am most surprised that fastener torque for heads and other mechanical components aren’t just listed as; FT, 4 foot cheater bar, just put your foot up against it and pull like hell on your 15” shifter, like purgatory with a 18” shifter or longer.

Come on people, what we do and what is written might be two different things but give Lionel a break.

Don’t bust his balls (ha ha!). I can just see the Hayman Reese representative in the dock saying, “we instructed the purchaser to do it up F..king Tight (FT) my Lord”

I bet more mechanics could feel FT better than they could 250Nm.

**Blknight.aus** · 1st May 2020, 09:06 PM

I maaaay have been known to accept being told "do it up FT, it doesn't matter" as a challenge to see what fails first my FT or the yield strength of any part of the assembly thats about to get FT'd.

I have on more than one occasion taken said busted part back to the advisor and gone "No, FT is apparently too T and this is now F, got a replacement for me?"

**Slunnie** · 1st May 2020, 09:51 PM

Originally Posted by Blknight.aus

I maaaay have been known to accept being told "do it up FT, it doesn't matter" as a challenge to see what fails first my FT or the yield strength of any part of the assembly thats about to get FT'd.

I have on more than one occasion taken said busted part back to the advisor and gone "No, FT is apparently too T and this is now F, got a replacement for me?"

Tightened until it loosened!

**rick130** · 2nd May 2020, 06:28 AM

Originally Posted by trout1105

I Never grease up the towball because it will pick up grit/sand and will prematurely wear down the ball, The balls are usually brass anyway and don't need lubrication.
If the ball comes undone due to "Friction" then it wasn't tightened up enough in the first place

Brass is brittle, it'd snap quickly under a minor shock load and not something I would use in that situation.

And as for the old grease vs no grease, I've always been firmly on the side of greasing.
Never seen wear from using grease, and when I was an apprentice we were towing a 1 tonne rated tilt trailer all the time for work.
I was also one of those weirdo's that lubricated a cattle crush.
I wanted the bloody thing to work with minimal effort the next time we were drafting/weighing/tagging/marking!
I had to fight the ex-FIL on that one, but I was the one using the crush, he always had farm hands having to put up with a partially seized machine during a draft.

**PhilipA** · 2nd May 2020, 09:28 AM

My Mc Hitch "ball" says not to grease it. I use grease in the UJ on the McHitch as the trunnions are sealed. The chrome coating on the ball is plenty to stop wear and lets face it they are cheap even if they do wear over say 5years.

Grease if used on dirt is a magnet for dust and then becomes grinding compound so IMHO never use it if travelling on dirt.

I do not se grease anywhere where dust is likely eg the rear door lock , side door locks etc

Never had a D2 rear door lock fail, jamb, stick etc even on GRR and long dust hauls.
I use dry teflon lube.
Regards PhilipA

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