Technical Kingpins (again)

[RDS]

Hello all


the question of kingpins once again raises its ugly head.

I have read with interest the sticky on the site and was about to this job with a friend using a pair of assemblies obtained from a mechanic in Italy. I was hoping to remove the existing assemblies and re-fit the replacements directly.

However before doing so I would appreciate some advice as to distinguishing whether those replacement kingpins are indeed adequate for the job without further work or whether I need to have the bushes etc, changed for them anyway. In other words, is it possible to determine when off the car, whether a kingpin assembly has good play within tolerance rather than excessive play. I have a feeling that the answer is going to be that the leverage exerted on the stub axle is not possible to replicate in practical terms at home.

The replacement kingpins do appear to be packed with heavy grease and are very stiff to turn by hand.

Thanks in advance.

RDS

 

[the hobbler]

You are correct---you won't have enough leverage when the hub assemblies are off the car to ascertain how much play there is. Without stripping the new units (which somewhat negates the point of getting new units) it is impossible to see how they have been put together. It is, unfortunately, a case of "suck and see".
Fit the new units and see how it goes. Just as a matter of interest, do you new units have just 1 grease nipple or have they been improved by having a 2nd grease nipple fitted? Whatever, make sure you keep it well greased---if you haven't got a 'lever-arm' grease gun, get one (as soon as you are allowed to)and keep the units well lubricated.

 

[RDS]

Many thanks Hobbler, i suspected as much!

yes two nipples on each. The annoyance is that with grease guns either they do not allow the grease to enter the assembly (even if the nipple is cleaned) rather than squirt outside the side or you can't get the gun off again after.....especially as it is now greasy on the handle....

RDS

 

[fiat500]

Many thanks Hobbler, i suspected as much!

yes two nipples on each. The annoyance is that with grease guns either they do not allow the grease to enter the assembly (even if the nipple is cleaned) rather than squirt outside the side or you can't get the gun off again after.....especially as it is now greasy on the handle....

RDS

I have that same problem with one of the two nipples on one of my replacement assemblies. I've tried everything, bar dismantling, to get grease through, including trying to inject the grease with the steering at all angles and removing and cleaning the nipple and hole. I thought it might improve as it wore in...nope! I assume whover did the work didn't take care to ensure there was a route throught the brass bush which also aligned with the groove in the kingpin.

 

[RDS]

I thought the same with the alignment. On another car i did have some success by continually pressing the ball and compressing the spring on the nipple to admit some grease.

 

[the hobbler]

And people wonder why I hate 'pattern' parts with a passion! Surely it cannot be beyond the wit of the assembler to drill the hole through the bush PRIOR to fitting the king-pin in place and assembling the unit---but sadly it seems that it is!

 

[fiat500]

Surely it cannot be beyond the wit of the assembler to drill the hole through the bush PRIOR to fitting the king-pin in place and assembling the unit---but sadly it seems that it is!

...the problem is that the bushes are plain and the spiral groove is on the pin. So even if a hole is drilled in the wall of the bush which successfully aligns with the new tapping for a grease-nipple, the chance of this ever being in alignment with the grease-groove on the pin is very random. If it doesn't do that the grease will be blocked by the tight fit of the pin in the bush. I'm not even sure that all of these aftermarket kingpins even have the grooves.

The original design, with the longitudinal drilling with side feed-holes to each bush is the best so long as the welch-plug at the botton of the steering-pin is securely fitted.

 

[F123C]

Hi RDS,

To test for excessive play in the new assemblies, you could clamp each one in a bench vise, temporarily fit the hub/brake drum, tighten the hub bearing nut to eliminate all free-play, fit a road wheel and use this as a lever to check for excessive free-play in the kingpin. But as 'the hobbler' has said it's difficult to do an accurate test, but this is probably better than nothing.

As regards the grease just squirting out the side, as others have suggested, there may be no clear path for the grease to where it's needed. I'd suggest removing the grease nipple and use a *modified drill bit just a little smaller than the grease nipple thread to bore a hole through the bush if there isn't a hole present.
*to modify a drill bit, grind it flat (i.e. straight across at 90 degrees to the drill length) on the pointy end, then grind a chamfer on each web to approximate what is on a standard drill bit - essentially you are creating a rudimentary end mill. This should cut through the relatively soft brass? bush but not harm the king pin (which is a very hard material). Clean out the hole, then refit the grease nipple and try greasing it.

To remove a grease gun from the grease nipple, just (gently) swing the gun in an arc, it should just pop off the nipple.

What Peter (fiat500) says about there likely being no groove on the king pin in line with the grease nipple is very true, but it is possible to cut a groove in the bushes before/after fitting - there even used to be a type of chisel for cutting these grooves (standard practice for Fitters, back in the day). Nowadays, I suppose a Dremel type tool with a suitable rotary burr could be used to cut a spiral grease groove.

(One mechanic I knew, used to grind a slight spiral groove at each end of a new kingpin before fitting it, his reasoning was that this allowed grease to get to where it was needed)

Al.

 

[RDS]

Hello Al

thanks yes, replicating the entire assembly as if on a car would be an idea, but as you say not perfect. I think we are effectively left with "fit and see".

cheers again

RDS

 

[Toshi 975]

I don't think I have ever seen 500 stub axle assemblies with the two grease nipples, they were only standard on later 126 models. I have however seen ones that have been "reconditioned" with grease nipples fitted in places where grease is never ever going to get to where it needs to be.

 

[Bigvtwin996]

...the problem is that the bushes are plain and the spiral groove is on the pin. So even if a hole is drilled in the wall of the bush which successfully aligns with the new tapping for a grease-nipple, the chance of this ever being in alignment with the grease-groove on the pin is very random. If it doesn't do that the grease will be blocked by the tight fit of the pin in the bush. I'm not even sure that all of these aftermarket kingpins even have the grooves.

The original design, with the longitudinal drilling with side feed-holes to each bush is the best so long as the welch-plug at the botton of the steering-pin is securely fitted.

Didn't Sean cover the problem in his Franko rebuild thread?

 

[fiat500]

Didn't Sean cover the problem in his Franko rebuild thread?

I think Sean had an odd problem in that he had to machine the outside of the bushes to get them to be a very tight fit in the stub-axle. This gave him a very good fit of the kingpins in the bushes without reaming. I don't think he did any groove machining; life's too short anyway.