New king pin fitting

[Oxford Jack]

I have a feeling the answer is staring me in the face, possibly sniggering at my discomfort, I am stumped and asking for guidance please..
I am rebuilding a Girling front axle. I have stripped, cleaned and readied the axle for new bushes and pins etc. I put the new king pin bushes in and have reamed them with the correct tool. The pins were a nice firm push fit, the axle eyes seemed ok. The o/s stub axle fitted with the 2.5mm thrust washer supplied, once I had thinned it a little on a diamond stone to about 2.3mm. I tightened the cotter pin and all was well. The core plugs went in and I was content.
The n/s similarly went together quite happily but there was a little up and down movement, which I reduced with a shim but there is still a little movement. As  I tightened the cotter pin however the stub axle became stiff to move and is obviously not a happy fit.
I understand that the king pin is probably moving in the axle eye as the cotter is tightened but I dont get why it then binds? With the cotter loose and taking a firm grip of the stub axle I cannot feel any movement between the stub axle eyes and axle eye, which suggests to me that the king pin can only be moving to the side rather than tilting? 
Any clues or suggestion would be welcome please, thanks in anticipation.

[Tony Betts]

hi oxford,

there can be a number of things.

first did you use a kingpin reamer, or a standard reamer?

i know many use a standard reamer on girling, but if its not gone through straight. the hole will pull the reamer to the hole. then when the pin is tightend, it goes tight in the hole.

also are you saying there was NO wear in the eyes at all? if so you do the kingpins.

tony

[Bob Culver]

Even with perfect bore in axle kingpins bow slightly as the cotter is tightened. 
If too sriff car will wander until free and there is a risk of bushes turning in the axle assembly.

[Oxford Jack]

Hello Tony,
I used the correct reamer, bought from yourself, so I think it is done correctly, certainly one side has worked out. I found the pin would not at first go through the axle eye, so I used a straight 1/2" reamer to remove what I think were a couple of burrs, easily removed. Once the pin was though the axle eye I could not detect and side to side movement. I had an axle like that a while ago and had the eyes shrunk by welding to cure it, the wear was quite evident in the bell-mouthing of the axle eye.
Thanks for the thought

[Tony Betts]

Hi oxford,

Have you checked to see if it is tight in the stub before fitting in the axle.

If the axle eye has no wear, then the kingpin shouldn't bend the cotter then pushes it up against a flat edge. Unless you put a huge amount of pressure on the cotter.

Often the stub will go tight and loose when turning, because the surfaces between the bush and axle are not flat.

[squeak]

Tony asks "Have you checked to see if it is tight in the stub before fitting in the axle ?"

If it is then likely the kingpin is rotating in the axle end , until prevented by the tightened cotter. The stub will then struggle to turn.

[Ian Dunford]

It's important that there is at least some up and down movement,and it is only possible for one of the bushes to rotate as the other three are locked by the steering arms.
I'm sure you must have used the reamer when all 3 are tightend up with their nuts and lock washers.?

[Oxford Jack]

Tony asks "Have you checked to see if it is tight in the stub before fitting in the axle ?"

If it is then likely the kingpin is rotating in the axle end , until prevented by the tightened cotter. The stub will then struggle to turn.

Hello Tony and Squeak,
The pin was a push fit, but not an interference fit in the stub axle. I understand about the cotter preventing the king pin from rotating if it is too tight, I dont think it was but something to check. I think there was sufficient vertical movement, more than 5 thou. The stub axle is binding as soon as the cotter is tightened in any position so I dont think it is due to horizontal surfaces being out of true, but I will check.

---

It's important that there is at least some up and down movement,and it is only possible for one of the bushes to rotate as the other three are locked by the steering arms.
I'm sure you must have used the reamer when all 3 are tightend up with their nuts and lock washers.?

Thanks Ian,
Yes there was vertical movement at least 0.010", which was more than the other end of the axle. I fitted the steering arm, by filing the bush where it shows, however I removed the arm before I fitted the pin. I reamed the two pin bushes in line, but not the axle eye at the same time. The pin is a press fit, slightly more than I can do by hand, ie light taps with a soft hammer. I will take it apart and check rotation of the pin in the bushes.
Thanks
Jack

[Howard Wright]

Hi Jack

Just a thought.

Is there 10 thou vertical clearance at all positions of the stub axle?  It is easy to make the shim washer wedged by accident and or have the bearing face of the king pin eye not completely flat and 90 degree to the eye.  If so the shim will bind at some points but not others.

Cheers

Howard

[Oxford Jack]

Hi Jack

Just a thought.

Is there 10 thou vertical clearance at all positions of the stub axle?  It is easy to make the shim washer wedged by accident and or have the bearing face of the king pin eye not completely flat and 90 degree to the eye.  If so the shim will bind at some points but not others.

Cheers

Howard

Thanks for the thought Howard. There seemed to be similar clearance in all positions, when the kingpin was in place but before the cotter was tightened That thrust washer I had not thinned, so it should have been flat as supplied. 
Regards Jack