The cars weren't supposed to last this long, but after a few decades of kingpin swaps the grease never reaches the bottom bush, but leaks out all over the top!
There's no need to spend a fortune on fixing this - a few years ago I did it this way, with a tenners' worth of materials (plus a new KP set when necessary).
Here's the article I did in 2CVGB:
It works that well that on our Dyane that if you grease it too much, the steering stiffens until you let some grease out!A-Series kingpins.
Unless we are extremely lucky, this is something we will have to tackle at some point. I know that some have done zillions of miles, and still have their original kingpins because the owners conscientiously grease or even oil them frequently, but, for most of us, that is just a dream.
The problem
When the car was new, things were not too bad, but the main problem is now that the kingpins have probably been replaced one or more times, and the welch plug fitted at the top of the stub axle and bashed into position with a chisel, leaks grease, so the upper smaller bush gets no lubrication; the grease seeks the least resistance. The pin corrodes severely at this point, and inevitably develops play. MOT failure, here we come!
One solution
Quite a few years ago I realised that if I could find a less brutal method to seal this plug, and possibly the lower threaded plug that needed to be peened over, then I should have grease-tight kingpins that could be swapped if necessary without needing parts of them needing a hammer to reassemble them! That was the theory, anyway.
This was tried originally quite a few years ago, and worked fine on our 1971 Dyane – it was written up in the 2CVGB magazine then. Someone immediately wrote in about it – the gist of the letter was that “it would not work … Citroen would have done this if it was needed … it was not proper engineering.”
I replied saying it did work, QED, and if “proper engineering” is hitting your stub axles with a hammer and chisel, there is nothing more I can really say! Don’t think it was Mrs Trellis from North Wales.
OK – enough waffle. The design was modified a bit, and is now fitted successfully on two cars, many miles later.
Tools
Apart from normal hand tools including 10mm ¼ square drive socket, and the means of removing and refitting the kingpins, you will need access to a lathe, or someone else to do this (boring a hole in the screwed plug and machining edge of welch plug on each side) You will also need recourse to heat for brazing, and an M6 tap.
A set of wad punches for making washers will be needed – about a fiver at most Sunday markets!
Materials
• Length of 6mm steel studding (threaded rod)
• 6mm nut
• 6mm fibre washer
• Piece of nylon or PVC about 2mm thick – I used a lid from a stainless steel bowl, but anything like this will do – do not use very soft plastic like washing-up liquid bottles.
Here we go.
Remove the kingpin as normal, and discard the two plugs. Take extra care to clean up any damage around the welch plug seat, and the bottom of the stub axle, where the thread is. Both must be absolutely flat. You may have to devise some sort of a reamer if the recess on the top has been mangled too much by the aforesaid “proper engineering”. Reassemble and fit kingpin in usual way without the plugs.
First, modify the welch plug. File the sharp bottom edge so there is about a 2mm witness all around it – this is to avoid cutting the washer that we are going to make, and to give a bit of surface area to seal the washer.
Then, drill and tap the centre of the plug 6mm. Make sure it is perpendicular – a drunken thread will give problems! Screw the studding on to it flush , convex side on the end so it is like a mushroom, (not a chanterelle!), and braze the thread so it cannot unscrew and that it is sealed.
Screw a couple of nuts on it up to the top, and turn the outside to (a) centre it and (b) to make the plug a slack fit into the recess on the axle.
We now need to make a couple of washers from the plastic using a wad punch. The top one needs to have about a 10mm hole, and the outside the same size as the welch plug. The bottom one’s hole should just fit tightly into the threaded plug. The outside diameter is not crucial on that one – a few mm larger than the flange on the plug, maybe.
The next thing to do is to drill a 6.5mm hole in the bottom plug, and to bore a recess in it. The diameter needs to be 1mm larger than the diameter of your 10mm socket, and the depth the height should be the height of your 6mm nut, plus the thickness of the fibre washer. The important bit is not to make the recess so deep that the top of the plug is too thin, or so shallow that the nut protrudes and fouls the edge of the wheel – corroded wheels with curly edges will do that without any encouragement, anyway!
Now, the slot for turning the plug will have disappeared, so we need to file a couple of small flats at the edge so a spanner will fit on it for screwing it in – clean off any burrs so the washer is not damaged.
Reassembly
Put the washer on the bottom plug, and screw it in tightly. Put the other washer on top, and drop the mushroom in, ensuring that the welch plug drops in cleanly and easily.
Now, you will see the end of the studding protruding at the bottom. Put a mark on it, take the mushroom out and run a nut past the mark. Saw it off and clean up with a file. Remove nut.
Put it back on, add fibre washer and nut, tighten. Yeah – I know – why not measure it first? If you remember to do that, fine. If you are doing both sides, make a note of the studding length.
That’s it, apart from greasing it – you may find that either the bottom plug or the nut will need another tweak or two, but beware of breaking the bored hole out.
On one we did, we could apply so much pressure to the grease that the steering was noticeably tight until we unscrewed the grease nipple and let some out!
I also put a second grease nipple at the top and drilled the bush on one car, but found that this was unnecessary after doing the mod – the grease came out of both bushes quite easily.
Mike Phelan © 2006
