Technical Weekend discovery - a stub axle/king pin question

[AndrewRL]

I'm afraid I am after your expert opinions, advice etc again :worship:

I thought I ought to grease the king pins (new stub axles/king pins fitted about 2000km ago). I jacked up the car and managed to get my grease gun to work. I started with the offside and eventually got grease into the nipple (rather than just around it!). Now the Haynes book says to pump in grease until it appears around the king pins so I carried on until I could see a thin thread of grease coming out at the bottom of the stub axle just above the connection to the leaf spring.

I then did the same on the nearside but instead of a thin thread a large grease "plug" appeared out of the bottom of the stub axle. I went to wipe this away when I realised that there was a convex metal disk on the end of this grease plug . Looking at parts diagrams I assume this is supposed to sit at the bottom to hold in the grease (??). So I went back and checked the offside and gently poked my finger up from the bottom and found that there was nothing there and I could reach 2-3cm up

My obvious questions are:
- when you grease these nipples where do you usually expect to see excess grease appearing?
- am I right that there should be this disk at the bottom of the stub axle?
- if the disk should be there - how critical is it (stops grease escaping? keeps dirt out?)?
- if the disk should be there - how is it attached? Is it something a novice can fix (or does it involve major work removing the hubs, stub axles etc)? the only reference I can find seems to imply that it is peened in (so hammered in I assume but that couldn't be done in situ)

I may well have the wrong descriptions so attach a diagram - red arrow where I saw grease emerging and the "plug" appeared; black arrow showing what I assume is the disk.

Any help gratefully received

 

[Toshi 975]

The original stub axles had a screw in sealing cap on a very fine thread and are worth keeping if you find any of these intact. With a replacement King pin kit a core plug is usually supplied which you fit like any core plug with a good bash to the centre of the dish assuming that you fit them the right way around. Not as good as the original but normally do the job. On one set I rebuilt some one had actually used some silver coins they had staked in there. Sounds to me like you do not have any sealing device at all. You should at least be able to fit core plugs in situ otherwise the King pins will not last too long.

 

[AndrewRL]

Thanks Toshi. That is what I assumed (sadly). Are you saying the disks (core plugs) can be fitted in situ (long story but I think I may have a couple)? I'd have to look again but I am not sure there is enough room to bash them in the centre especially as I assume they need a fair wallop to wedge them in (1-1.5cm gap between the stub axle and leaf spring?). I assume by the way that "the right way round" is curved side downwards? Any suggestions on how to fix these in would be most welcome as I am not sure I am up to dismantling anything major

 

[Paolo66]

Toshi is right but so are you. There’s not enough space to bash the discs in in situ. The idea being that you deform the centre so it flattens the disc slightly which then becomes an inteference fit. You have a couple of options its up to you which, if any, you choose?
You can disconnect and lower the leaf spring one side at a time which should give you more room to bash them in. You would have to have the front on axle stands to do this and lower the leaf spring in a controlled way with a trolley jack.
You could try holding the discs in place with some JB Weld. You would have to tape them in place until the JB Weld hardened but that should work.
You could replace the metal discs with a suitable rubber bung.

Damian

 

[Vitesse]

Toshi is right but so are you. There’s not enough space to bash the discs in in situ. The idea being that you deform the centre so it flattens the disc slightly which then becomes an inteference fit. You have a couple of options its up to you which, if any, you choose?
You can disconnect and lower the leaf spring one side at a time which should give you more room to bash them in. You would have to have the front on axle stands to do this and lower the leaf spring in a controlled way with a trolley jack.
You could try holding the discs in place with some JB Weld. You would have to tape them in place until the JB Weld hardened but that should work.
You could replace the metal discs with a suitable rubber bung.

Damian

I would go with Damian’s suggestion of a rubber bung if I was in your position. It’s the simplest and least hassle free fix. IIRC the King Pin diameter is just under 16mm? Someone correct me if I am wrong!

The rubber plugs on this link would be perfect, maybe hold them in place with some JB Weld to make sure they don’t drop out. Nice and cheap fix as well.

https://www.vital-parts.co.uk/body-...MI88359snO2wIVB57VCh0MxAhcEAQYAiABEgIyS_D_BwE

 

[fiat500]

Rubber plugs are a great idea for keeping dirt and water out and creating a tidy finish. But unless the plug, whether rubber or steel, is really secure the grease will always push around the sides and more often will push them out. So I think that rubber doesn't stand a chance. Personally I would follow advice seen elsewhere and put a few welds to keep the steel disc in place. The grease needs to meet an obstacle at the bottom when it exits the central drilling of the kingpin. It is thoroughly blocked at the top because of the silentbloc. Therefore the full grease gun pressure is needed to force grease into the (should be!) tiny clearance gap between kingpin and bush. If you can push in a rubber plug by hand the grease can easily push it out again.

 

[Vitesse]

Rubber plugs are a great idea for keeping dirt and water out and creating a tidy finish. But unless the plug, whether rubber or steel, is really secure the grease will always push around the sides and more often will push them out. So I think that rubber doesn't stand a chance. Personally I would follow advice seen elsewhere and put a few welds to keep the steel disc in place. The grease needs to meet an obstacle at the bottom when it exits the central drilling of the kingpin. It is thoroughly blocked at the top because of the silentbloc. Therefore the full grease gun pressure is needed to force grease into the (should be!) tiny clearance gap between kingpin and bush. If you can push in a rubber plug by hand the grease can easily push it out again.

Yeah but that’s all well and good but I think Andrew is suggesting that his mechanical ability is limited “Any suggestions on how to fix these in would be most welcome as I am not sure I am up to dismantling anything major”. Therefore I find it highly unlikely that he going sparking up the mig welder any time soon! Also I did say secure it using something like JB Weld.

I totally agree a long term fix would be preferable if everyone was clocking up the sort of miles you do on a yearly basis but for the average classic 500 it barely sees the rain, may see one weekend if it’s sunny in the winter and is predominately is used on nice warm sunny days. What’s the suggested maintenance interval? Probably something like every 2000-3000 Miles? It’s not like it’s a weekly occurrence.

 

[fiat500]

Good point... I'm not actually answering the actual question. ?. In any case, you can grease the kingpins till the cows come home and they'll still wear out and even if they do, does it really matter? ?

 

[AndrewRL]

Many thanks all for the helpful suggestions. One day I may feel confident enough to disconnect the leaf spring etc but for the moment I will pursue the rubber bung/jbweld suggestion (like most things it sounds simple enough...although I may regret saying that when I have two rubber bungs permanently stuck between my fingers ).

At the moment I am only doing 1-2000 kms a year but hope to do a lot more...if I didn’t keep finding issues to solve (so you just know more questions are coming ). Did a 170 mile round trip on Sunday and all went well although I hope I haven’t caused more serious damage to the king pins!

That just leaves one question...when the bung is in and well fixed and I pump new grease in...where does this infamous “excess” appear so I know to stop?

Thanks again

 

[the hobbler]

As Peter to wisely pointed out--if you can push a runner 'bung' in with your hand, the grease-gun will push it out very easily as the 'bung' will be the point of least resistance when you try and grease the king-pins, with the result that NO grease will actually get to and round the king-pin.
As difficult as may initially seem, the lack of blanking-disc in the bottom of the king-pin carrier has to be rectified properly. The simplest way to achieve this is to remove the king-pin carrier (which if one is careful can be achieved without disconnecting the brake hydraulics) and properly fit a new blanking-disc. It is fitted, like any 'core-plug' (which effectively is what it is) by having the 'dome' of the disc facing OUTWARDS so that by flattening the disc, it expands out into its aperture. If I remember correctly, there is a groove at the bottom of the king-pin carrier into which you expand the disc. One reason that the discs fall out is that when they are removed, prior to replacing the king-pin and bushes, the disc has not had its centre drilled out, which would allow the disc to collapse enough that it doesn't break the outer lip of the groove off as the disc is pushed out when the king-pin is driven out. If the outer lip HAS been broken off, it might be sensible to hold it in place (after it has been flattened) with a rim of "JP Weld"--make sure that ALL surfaces that are going to come into contact with the "JP Weld" are VERY clean AND grease-free--clean with a spirit.

 

[Vitesse]

Many thanks all for the helpful suggestions. One day I may feel confident enough to disconnect the leaf spring etc but for the moment I will pursue the rubber bung/jbweld suggestion (like most things it sounds simple enough...although I may regret saying that when I have two rubber bungs permanently stuck between my fingers ).

At the moment I am only doing 1-2000 kms a year but hope to do a lot more...if I didn’t keep finding issues to solve (so you just know more questions are coming ). Did a 170 mile round trip on Sunday and all went well although I hope I haven’t caused more serious damage to the king pins!

That just leaves one question...when the bung is in and well fixed and I pump new grease in...where does this infamous “excess” appear so I know to stop?

Thanks again

It normally squirts out at the joints where the two main parts of the king pin assembly rotate. Don’t worry about pumping too much in, sometimes it will pump out one side first and not the other, just rotate the steering around a bit and it might help until it comes out both joints.

A 170 mile trip on bone dry roads is not going to cause any problems. I must be missing something are you planning a world trip?

 

[fiat500]

A 170 mile trip ............ I must be missing something are you planning a world trip?

...you could start with Scotland, ?

 

[AndrewRL]

If I may try your patience a bit further ...

I measured my spare plugs/disks this morning and they are 22mm I think. So if I go the rubber bung/jbweld route I assume that is the size to go for. Of course, having had another look this morning, I guess even getting a rubber bung in may be tough (plus jbweld, removing the grease to allow this) but it sounds like a less challenging option.

Going back to Paolo's suggestion - is this reasonably feasible for a comparative novice? If I understand correctly (another photo attached...I am a visual person ) - it is a question of getting the car on axle stands (supported usually at the point with the red arrow...hopefully correct ) and undoing the leaf spring at the blue arrows and, presumably that will allow the wheel/hub to be swung out enough to get access to hammer in the plug. It sounds fairly straightforward but I guess my concern is how easy it would be to do this and, in particular, how easy to get things back correctly!

And Hobbler - your "remove the king-pin carrier" - how complicated is that? I feel reasonably OK with following simple instructions but don't really want to dismantle the hubs, or require special workshop equipment etc.

I did feel round the bottom of the king pin carrier and there does seem to be a groove so if I can get access I can give it a go. How much hammering does it need? The plugs seem pretty thick

As for journeys...no, I wasn't planning a world trip. I am just aware that I don't really drive the car very far (usually just round the Cambridge ring road) so planned a journey to Forzalive at the weekend. I confess I missed the announcement that it was cancelled so ended up driving the route anyway. I had intended to go to le Mans classic this year but am away at that time so that may have to wait until next time. Scotland sounds a good idea...just need to sort out my king pins first!!

Anyway, many thanks for your continued help

 

[Vitesse]

If I may try your patience a bit further ...

I measured my spare plugs/disks this morning and they are 22mm I think. So if I go the rubber bung/jbweld route I assume that is the size to go for. Of course, having had another look this morning, I guess even getting a rubber bung in may be tough (plus jbweld, removing the grease to allow this) but it sounds like a less challenging option.

Going back to Paolo's suggestion - is this reasonably feasible for a comparative novice? If I understand correctly (another photo attached...I am a visual person ) - it is a question of getting the car on axle stands (supported usually at the point with the red arrow...hopefully correct ) and undoing the leaf spring at the blue arrows and, presumably that will allow the wheel/hub to be swung out enough to get access to hammer in the plug. It sounds fairly straightforward but I guess my concern is how easy it would be to do this and, in particular, how easy to get things back correctly!

And Hobbler - your "remove the king-pin carrier" - how complicated is that? I feel reasonably OK with following simple instructions but don't really want to dismantle the hubs, or require special workshop equipment etc.

I did feel round the bottom of the king pin carrier and there does seem to be a groove so if I can get access I can give it a go. How much hammering does it need? The plugs seem pretty thick

As for journeys...no, I wasn't planning a world trip. I am just aware that I don't really drive the car very far (usually just round the Cambridge ring road) so planned a journey to Forzalive at the weekend. I confess I missed the announcement that it was cancelled so ended up driving the route anyway. I had intended to go to le Mans classic this year but am away at that time so that may have to wait until next time. Scotland sounds a good idea...just need to sort out my king pins first!!

Anyway, many thanks for your continued help

It’s not difficult.

I would jack the car up with a trolley jack in the centre of the leaf spring, as you say place the axle stands where your red arrows are, they normally fit on the leaf spring mounts really well. You then need to use the trolley jack, to jack up where the leaf spring is bolted onto the king pin, where your blue arrow is. You jack it so that it allows you to take the weight of the spring tension that is pushing downwards on the jack. This allows you to undo the bolt securing the leaf spring to the king pin. Then you lower the jack down slowly, taking the tension and leaf spring end with it. I would take the wheel of first as it will give you better access.

My only concern is that as you will be attempting to hammer the plug in with the king pin holder attached to the backplate still, it would be a lot easier with the wheel off but then I would be concerned about hammering upwards with the car just sitting on axel stands in case it slipped off. Ideally you would want to take the whole king pin carrier off the car but then you would need a ball joint splitter to remove the track rod.

Hence why I suggested a rubber bung fix if you really aren’t confident in your own ability. The thing with the 500 is nothing is too difficult, you just have to have the confidence to go for it and next time it will be a breeze and there are plenty of people to help if you get stuck?

 

[Franko500]

If you need a couple of metal core plugs then send me your details via private message and I will pop a couple in the post.


Both of my cars had the screw in covers of which I re-used. So I have some spare later type ones from the kits I bought.

 

[g8rpi]

There is no way a rubber bung of the type shown and epoxy (JB Weld) will stay in place while you pump grease through the king pin. You really need a metal plug. You might just get away with a solid hard rubber plug and epoxy if there is enough depth in the king for it to be longer than it's diameter.


Robert G8RPI.