Vertical link/stub axle nut and washer

[Dennis Nicholas]

Another detail query.
The stub axle is held onto the vertical link by a nut with a plain washer under it.
The now dished washer is 0.091 inches thick. (by micrometer)
Vertical link hole is 0.821 inch (By digital calliper)
1/2 UNF nut is 0.7475 inch across the flats and 0.8545 across the points.

It can be seen that in picture 1 the washer has been dished into the vert. link hole by the tightening of the nut on the stub axle. The bright ring witness ring marks on nut and washer where the two mate can be seen in picture 2.
Picture 3 clearly shows that the across the flat measurement of the nut is less than the diameter of the vert. link hole which is why the washer has dished in.

DSCF1070.JPG (301.36 KiB) Viewed 1101 times

Nut with washer standing on edge to show dishing

DSCF1069.JPG (328.47 KiB) Viewed 1101 times

Nut and washer showing witness marks where dishing and nut face correspond.

DSCF1071.JPG (211.06 KiB) Viewed 1101 times

showing nut across flat measurement smaller than stub hole diameter.

This seems poor engineering. Should there be a much thicker washer that will not dish, or even better a specially larger across flat sized nut?
Using a digital calliper seems to show that, with the stub only pushed in hand tight, there would only be room for an extra thickness of 0.0095 on the washer before the end of the thread. This would give a washer thickness of 0.1605......could probably allow a bit thicker with stub pulled tighter onto taper.
I am a bit concerned since (only on one occasion) I had a stub axle come loose. I had not done any work on that car so not due to me incorrectly torquing down nut. Mindful in view of the battering we now get from potholes!

Dennis

[Old and Slow]

Here's a dimensional diagram from the TR4/4A manual.
Not very helpful as it doesn't give the exit hole diameter nor the taper angle.

TR4A_suspension.docx

(177.95 KiB) Downloaded 36 times

[philhoward]

I don’t know the exact relative positions of mating faces but I see one of 3 possibilities:

1. The shoulder of the stub axle sits below the back face of the vertical link, so the washer and the stub axle shoulder shouldn’t touch. Gap exists between washer and stub axle.

2. The shoulder of the stub axle protrudes through the vertical link a little, so the washer should fit over the shoulder of the stub axle.

3. Someone has in the past had play in the stub axle and instead of replacing it (or the vertical link), just wound the nut up tighter and tighter? It could after this exercise (and not getting rid of the play) the faulty part was replaced but not the washer?

Once tightened, all the stresses will be on the taper - over-tightening the nut will achieve nothing (apart from distortion) so I don’t think there’s an engineering issue, just a bad mechanic issue in the past. Replace the washer with the same and assemble it correctly and it will be fine.

[Dennis Nicholas]

Here's a dimensional diagram from the TR4/4A manual.
Not very helpful as it doesn't give the exit hole diameter nor the taper angle.
TR4A_suspension.docx

Afraid it does not show the washer and nut in question either, or stub axle.

[RonH]

Hi Dennis
What is the inside and outside diameter of the washer?
Also what is the thread spec of the nut or stub axle?

[gtcse8]

Replace the washer with the same and assemble it correctly and it will be fine.

I would agree Phil

No need to tighten a nut to the point of bending the supporting washer, the tapered stubs are just as prone to sticking as the rear hubs on half shafts.
Dennis I am looking at your request for the parts, but been a bit busy with Dr`s and hozzy`s.
Mark

[JoeySully]

I replaced the same nut and washer recently and torqued it to the correctly as per the WM. I removed it the day after and found the new washer was bent too.
All 4 i have removed have all been bent. the stub axle does not lie flush with the rear of the upright. If it did then it may rotate when tightened up.

[Dennis Nicholas]

Hi Dennis
What is the inside and outside diameter of the washer?
Also what is the thread spec of the nut or stub axle?

Measuring with digital callipers. all in inches
Washer I/D 0.506
Washer O/D 1.115
Thin end of stub axle taper 0.833
Vertical link hole diameter at thin end 0.8215.
Thread is half inch UNF 20 TPI.

DSCF1072.JPG (277.47 KiB) Viewed 953 times

Showing stub pushed in hand tight....shoulder below link surface.

DSCF1073.JPG (232.9 KiB) Viewed 953 times

nut and washer in place (nut not screwed down)

Dennis

[Dennis Nicholas]

I replaced the same nut and washer recently and torqued it to the correctly as per the WM. I removed it the day after and found the new washer was bent too.
All 4 i have removed have all been bent. the stub axle does not lie flush with the rear of the upright. If it did then it may rotate when tightened up.

This seems to be the norm then?

Dennis

[JoeySully]

This seems to be the norm then?

Yes it does seem to be the norm. I doubt it matters, because as the stub axle is pulled into the upright they instantly seize together so well that the only way to separate them is to wallop it whit a big hammer and destroy the threads !

[justfur]

Pretty sure his was standard fitment as when removing the stub axle from the vertical link, so as to not destroy the threads, a socket or pipe is placed over the threads to make contact with the stub axle inside the vertical link.

[JoeySully]

ahh that's what I'm doing wrong. makes sense. They are very soft.

[Dennis Nicholas]

This seems to be the norm then?

the stub axle is pulled into the upright they instantly seize together so well that the only way to separate them is to wallop it whit a big hammer and destroy the threads !

Lucky enough to have a hydraulic press. I put an old plain nut on end flush and pumped away.....big bang and stub release, unfortunately sooner than expected so did not see what pressure on gauge. The stub/nut was free of the press mandril by a gap so the mandrill did notactually push the nut down into the vert. link, BUT it was noticed that the nut had been fired about halfway down its length into the opening with 6 neat little ears poking off the nut corners will try to remember to watch gauge when doing drivers side.

[Old and Slow]

Afraid it does not show the washer and nut in question either

Other pictures in the TR4 Manual show the nyloc nut and washer to the rear of the upright, but they appear screwed up tight and don't take us any further.
I'll look to see if a torque setting is quoted.

[Old and Slow]

Here's a copy of the relevant page, hope it is useful!

TR4A_suspension_2.docx

(212.32 KiB) Downloaded 22 times

55-60 Lbft is the figure, probably the same for all later models using trunnions etc.