TA Front Axle Question

[Rob Reilly]

Cleaning my TA1271 front axle today, I found some stamped numbers.
Mean anything to anyone?

[Steve Simmons]

1546 should be the serial number. The others are a mystery.

[Rob Reilly]

So 1546 is perhaps a serial number of the axle. The 10 and 9 could be the king pin and brake assembler and the inspector.

New question, there are what appear to be steering bump stops on both sides, but they are not the same.
Anybody know about these? Is one broken and the other in backwards?

[Steve Simmons]

The could be inspection numbers, measurements, etc also. I've seen similar numbers elsewhere but everyone has a different opinion about what they might be.

The top photo shows the correct steering stop. The one on the bottom seems to be missing, which is not good. The stop is also the cotter which holds the king pin in place! I've done a write that touches on this in one of the TCMG newsletters. See pages 10-11 here: http://www.tcmotoringguild.org/chassis/20MayChassis.pdf

[Rob Reilly]

Thanks Steve.
I see they are pins that hold the king pin in place. Cotter is a confusing name as I am aware of now 3 different items that go by the name "cotter pin". I bet a guy named Cotter invented all three.
And they would have to be also a steering stop, otherwise there would be no reason for the hex head bolt in the knuckle.

I removed the smaller nut on the one, thinking it was like a shoulder bolt, then tried to drive the pin out, no luck. Tried unscrewing it and discovered the larger hex end is another nut, 5/16" thread but 3/8 BSF hex size. And the end of the thread was mashed out. Ground off the mashing and got the 5/16 nut off. So it is a 3/8" diameter pin with 5/16 thread on one end and 1/4" thread on the other end.

The pin on the other side is just smashed out on both sides, nothing left of threaded ends. I tried driving it out with a hammer and punch and got it to move about 1/8 inch. From the bit I can measure with a dial caliper, it does not seem to be tapered. Is that correct, is it straight? Or is it tapered, and if so, which way?

The king pins are not worn, so I don't intend to take them out. I just want to replace these "cotter pins". I think I'll put in shoulder bolts, so that hex head bolt on the knuckle will have something substantial to bump against.

The stub axles are left and right hand thread like the wheel nuts, but I stamped letters L & R on the left and right spring saddles just for added assurance.

[Steve Simmons]

Brits and Americans use different terms, but in the British manuals you will see these as cotters. What we usually call a cotter pin here in the states is called a split pin in the UK.

The large nut is only a stop and serves no other function. It doesn't hold the pin in place or anything. It goes on last. The small nut is what holds the pin in place. It's uncommon to get an old pin out without destroying the small threads, so make sure you have a new one on hand before trying!

The pins are a straight 3/8" bore, but one side has a taper machined in. So the hole in the axle is straight, but the pin is angled on one side so it "wedges" in the hold to secure the king pin in place. So unfortunately a regular bolt will not work. Because of the wedge, be sure you're removing the pin in the correct direction or you'll just tighten it more. If it was installed properly, it will drive out to the rear. So you're hammering on the small nut side (which should be on the front of the axle).

[Rob Reilly]

Well, I got one out, the one that still had threaded ends. I hit it on the 1/4" thread side, and that just mashed down the threads, so I cut the stub off and set the axle on the ground, used a 3/8" punch and 8 lb. hammer and it took about 200 hits to get it out.

I see the wedge is only cut part way, so you have to know ahead of time which way to drive it out.

The other side with no threaded ends I can't tell which way to go. I drove it out a bit and then I could see the flat, so that one was put in the other way. It is really tight, worse than the other one. Some DPO used a big hammer on it on both sides. Oxy/Acetylene torch didn't help. When it cools off I'm going to start drilling it.

BTW if this had a head we would call it a wedge bolt. These must be wedge studs.
The British can't seem to make up their minds what is a cotter pin I guess.

[Steve Simmons]

Be careful not to use too much heat! The axle is heat treated and you don't want to ruin that. When aligning axles, it is recommended to do it cold. You could try a press to remove the pin if the axle is off the car. Drilling may be a better option though.

Bummer about the second one being in backwards. I've seen that before, which is why I felt I should use the disclaimer "if it was installed properly" when talking about removal.

[Rob Reilly]

Got it out. Center punched both sides. Drilled from both sides, starting small and up to 3/16" before they met in the middle, then increasing 1/64th at a time until the pin was nothing but a thin wall tube. Then with a flat nose punch I collapsed it in on itself and got it out.

[Duncan M]

An illustrated lesson from the bicycle world on hammerless cotter removal.
http://rougeriverworkshop.blogspot.com/ ... moval.html

[ROGER FURNEAUX]

Unfortunately Duncan, this method is no use to us...our cotters have to be removed (not that this is often required) rearwards, and the 1/4" thread is too weak to accomplish this! They can be extracted by unscrewing the large head, placing washers under it, and screwing back on. Even then, because they are so tight the extreme measures noted above are required. I make these cotters, eBay #154194945465 (although they might not be on all sites, you can buy purchase them at Fromtheframeup, among others.

To sum up, the raised lettering on the axle beam is usually facing the rear (not always: it is best to check the caster angle with rods through the eyes, which should lean backwards), The stamped numbers have no known meaning (also on the back axle case). The stub axles are installed with the 5/16" threaded hole for the bump-stop bolt (with 3/8" BSF head) to the rear. This will put the spindle threads on the correct side to ensure the nuts are selt-tightening (LH thread on the LH side, i.e the opposite to the wheel spinners)

Roger Furneaux

[Duncan M]

Here is a picture showing the one sided taper of a factory TC cotter made of hard steel. It is removed in the same direction as the bicycle example. Probably best for the home mechanic to try less destructive methods before resorting to torch and sledge.

Sort of like removing the differential pinion and carrier (to replace the pinion bearings) while the differential is still installed on the car. I cannot be the only TC owner to ever do that? The mechanical advantage of the screw!

IMG_0789.JPG (23.9 KiB) Viewed 2829 times

[Rob Reilly]

Thanks Roger.
The stamped (not raised) number 1546 on my axle can be read from the rear.
My bump stop bolts are in front of the king pins.
My "Instruction Manual for the T Midget" says nothing about orientation and alignment of the front axle.

Malcolm Green in "T Series Restoration Guide" page 35 says, "The stub axles have a left hand thread on the near side and a right hand thread on the off side. On both, the steering stop bolt is to the rear, to engage with the head of the king pin retaining cotter on full lock."

He couldn't say that near side is left side, and off side is right side....

The idea is that if the split cotter pin sheared off and fell out, the rolling force of the hub would tend to tighten rather than loosen the slotted nut inside the hub. The nuts are 5/8-14 BSF thread, one left and one right hand.

The king pins are 3 deg positive caster, like the fork in a bicycle frame angled 3 degrees, so the top is somewhat to the rear of the bottom.

Now if I have described all this correctly, then comes the bad news. I have discovered that my stub axle knuckles are on the wrong sides.
DPO!!!!
Doubly D because he hammered in those cotter pins like there was no tomorrow.

[Steve Simmons]

The raised letters on the face of the axle should be on the rear. But the main thing is that the castor is the correct direction regardless of where the letters are. There are rumors of some axles having the letters on the front, but I wonder if those axles were straightened after an accident and the shop didn't know which way was which. The mounts are symmetrical after all.

The bump stop bolt definitely goes to the rear!

[Rob Reilly]

Oh, those raised numbers on the knuckles. Mine are on the opposite sides from the bump stop bolts and mostly illegible.
I see a raised M5 on the front face of the center axle.
I got the king pins out with my Harbor Freight 6 ton press. One was fairly easy, and the other took more force. I found it's a bit chewed up with divots, hard to imagine how the DPO managed to do that. The king pin steel is much harder than the cotter pin steel.

[Steve Simmons]

I didn't even notice those numbers. I think they are just part numbers. THe numbers I'm talking about that go to the rear are these...

[Rob Reilly]

Ok mine has nothing on the back, nothing at all raised but M5 and it is on the front. Another variable I guess, a different set of axle dies in the forge from '37 to '49.
Caster angle leaning back. Knuckles on the correct sides, left hand thread on the left, right hand thread on the right. King pins polished up and pushed back in "without the use of tools" as per the Instruction Book. Knuckles swing easy.
Ready for paint.