Firstly you need to make sure the axle eyes haven’t bell mouthes, In other words in cross section it would look a bit like an hourglass.
The only thing restraining he stub axle whe brakig is the eye on the end of the axle, And after a while it tends to open out the hole , top and bottom in mainly a fore and aft direction
I notice in the manual Jaguar talks of oversize king pins.
And even before than one need to check the axle beam for alignment . Ove the last 70 years it’s likely someone has kerbed it or towed the car with a tow rope around the end of the axle beam . The details are shown in the workshop manual.
There should be absolutely NO play between axle and kingpin. It should be a tight press in fit . Not hammered in as that will crack the case hardening on the pin , but pressed in with a garage press,Basically the thing to remember is that the weight of the car is resting on the bearing.
The raised section on the kingpin at one end goes at the top and it is not hardened AFter assembly a n engineers felt washer isplaced over the end of the pin and a shaped washer which is supplied with the kingpins is placed over that to hold it in place aand the " soft’ tit on the end is peaned over to hold it in place.
In the centre they have a flat , This is to engage the cotter pin flat that prevents the kingpin rotating.
The bushes need to be installed so that the hoe on the grease groove lines up with the hole in the stub axle.
However , if the axle eyes are bell mouthed , which is what we usually find. WE have the eyes machined out over size to the minimum need ed to get a parallel hole . The make new king pins from case hardening [ not through hardening] steel. Made about .010" bigger than the hole An extra section on the top end to grip wwhile grinding and a cut most of the way through adjacent to this , so it can be removed using a cut off wheel at the end. After Heat treating at a professional heat-treater the axle and pins are given to the macheg shop and the king pins ground down to an interfence fit
An alternative to using over sized king pins is to drill out the axle eyes and fit bushes in them. This has proved satisfactory on a number of our cars.
The only thing I worry about is that it involves removing metal from an area that has proved to be weak .
It wasn’t such a problem with SSs m because they had single leading shoe brakes and so not a s much braking load on the eye .
What I have done on the SSs is to drill down the top of the king pin and tap it for 3/8" thread , Easy to do with the pin in a lathe as the ntit bit is not hardened Then insert a bolt to retain a cable [ with turnbuckle] back tot a bracket on the chassis near the trunnion housing .
It takes all the load off the axle eye and means that under braking the correct caster settings remain correct .
With cycle guards , I could see te top of the king pin move forward alarmingly under braking.
It was a’ done’ thing ’ in the 30s with racing cars . LIGHt , cheap and effective win , win ,win as they say .
I agree, your torque reaction wires are a good idea. Especially in a racing special. I’m not so convinced in a car that only clocks up 1000 miles a year that has only once needed attention to its axle eyes in its 75 year life and in which I generally give myself a slap on the wrist if I fail to read the road ahead such that more than very light braking is required.
I think there must be more to this than I understand. If I remember correctly I only needed the offside eye bushed. The near side was perfect without any attention. Perhaps I had a slightly chattering cotter pin on the offside but not on the near side?
I think SS with single leading shoes don’t have the same load put on them.
I remember Jim Wilson in the old days saying he would carry around a new king pin at swap meets, and if he saw a MK IV axle would hold the pin up to the eye and put a light behind it, in those days more likely a cig give than a torch , but said almost all the time could see light around it , indicating a gap.
The cable acts in much the same way as the angled bar on the front of a MK v/Xk 120 in controlling caster , so even on a saloon it keeps the caster correct if braking into a corner
People tend to check King pins on the car by holding the top and bottom of the wheel and pulling in and out , where as the wear is often better detected by locking the brake up and trying to rotate the wheel.
That’s the direction the majority of the force has been applied in .
A yes, the other Ed Nantes said something similar. I must confess that my SS does have TLS on the fronts. …That doesn’t mean that I ever use their full stopping power though!
Thanks for all your comments, I would like to add one that DavetheLimey sent to me off line. He mentioned that thrust washers are non load bearing & they should be placed on top of the axle eye & there should be no play between the axle & kingpin.
I like Ed’s idea of a cable running rearward to take the load off the top of the kingpin under braking.
I have checked my axle eyes & they are slightly bell mouthed. I have a set of std new kingpins but no oversize .008" which would able to take up the wear in the axle eye. My machinist suggest having my std kingpins hard chromed & then ground to fit the newly bored axle eyes. Unfortunately this can’t be done till Feb 17 as Australia has already shut down for Christmas.
Ed, you mention that the axle eye is a weak part of the axle, does this mean that it can crack at this point?
Is it possible to have axle eye bored to take a thin walled steel sleeve machined to press & Loctite into the axle eye & then ream/mill it to take the std kingpins?
I just went out to check , But the thrust bearings are on the bottom so they take the weight of the car , Well , at least here in the antipodes, But the water goes down the plug hole in the opposite direction so maybe thrust washers are different in the northern hemisphere.
In the early [ i.e good old.] days SS1s didn’t have thrust bearings , but just a top hat bronze bush , so the weight of the car was on the lip of the bush . AS cars got heavier , doubtless owners complained and the steering ratio was changed and also with the pushrod engines the weight was taken on the bearings , for less resistance.
Putting them on to p [ non load bearing] would be a bit pointless as they would only become [ expensive] spacers.
Unfortunately doing a proper job on a front axle is a long complicated process. When new it was just assembling new parts , now we have to repair and make appropriate replacements to suit. I have always rebuilt a spare axle and then done a change over. Steering boxes fall into the same category.
Both involve various processes in tandem that must be sent out and done by specialist companies.
In the case of the axle …
checking the alignment , If in melbourne there is an excellent place in Clayton , the owner is in the VSCC and has a vintage Vauxhall , so understands what you need.
Boring the axle eyes , someone like Cranky’s in Blackburn , you would have to supply the settings from the workshop manual.
Making new king pins , Not hard to do your self if you have a lathe , but important to get the correct steel and important to remember the flat for the cotter and to make them over size to allow material for grinding to size.
take to heat-treaters. Take to grinders.
Then you’re at the stage where you have the pats needed to start work.
I wonder whether hard chroming will result in a better job , or not and whether it will be particularly cheaper
I think there is some confusion with terminology here! As stated, the thrust BEARING, which supports the weight, goes below the axle. The washers, shims, spacers (call them what you will)would last longer when placed ABOVE the axle. It would be easier on assembly to locate the king pin and thrust bearing, then fill the gap adjacent to the bearing with suitable spacers. I made that mistake many years ago. Unfortunately in a “Mill” environment many operators will drive a machine until the wheels fall off. Hence my nickname- "Oh, a wheel fell off, better call “The Limey” Or-
“You buried it in a snowdrift?” Better get The Limey. Etc, etc.
Sometimes there was so much damage that I would have to saw off the end of the axle, make a new end from a block of steel, bore it slightly undersize, then weld it on.The welding meant distortion, so the hole for the king-pin would have to be reamed to size.Many hours of work. The welding also meant taking into account the camber and caster, too!
I, too, like Ed’s cable idea, and sleeving your axle might be good, too. At least that would keep your alignment somewhere close to where it should be. I have enjoyed this conversation!
G’day, mates. Dave. (You didn’t get it stuck in the snow AGAIN. What is wrong with you??)
