Lower ball joint adjustment

I took my 40 to the vehicle testing station last week to get a new warrant of fitness (NZ equivalent of MoT). It was rejected on the grounds that there was slight play in the lower ball joints. The tester said it might be OK, but they did not have any records on file saying what the allowable play for a GT40 should be (surprise, surprise). So, does anyone have a reference for amount of play allowable on original cars (my setup is as original).

If I do need to make a slight adjustment, I'm assuming that removing the split pins and just tightening the retaining nut (in picture below) a fraction would be sufficient. Any thoughts?

 

[Michael]

Interesting that they can be adjusted, first I’ve seen like that. I’d agree that a light snugging to remove the little bit of play should be sufficient.

 

[David mono]

I took my 40 to the vehicle testing station last week to get a new warrant of fitness (NZ equivalent of MoT). It was rejected on the grounds that there was slight play in the lower ball joints. The tester said it might be OK, but they did not have any records on file saying what the allowable play for a GT40 should be (surprise, surprise). So, does anyone have a reference for amount of play allowable on original cars (my setup is as original).

If I do need to make a slight adjustment, I'm assuming that removing the split pins and just tightening the retaining nut (in picture below) a fraction would be sufficient. Any thoughts?

View attachment 138875

The same problem came up on a SPF and tightening the nut was the solution.

 

[Randy V]

It would have been interesting had the balljoint pin been factory offset a few millimeters so that rotating the housing would allow caster/camber fine tuning…. I have seen something like that on some replacement balljoints for 4wd vehicles..

 

[Devin]

It would have been interesting had the balljoint pin been factory offset a few millimeters so that rotating the housing would allow caster/camber fine tuning…. I have seen something like that on some replacement balljoints for 4wd vehicles..

You are exactly right Randy…Ford Super Duty trucks in particular are the most popular vehicle using this design and have an offset shim (hole within a round peg essentially) of varying sizes that also can be used to fine tune the camber alignment. Not a bad design but a pain to get a different offset shim in/out if it’s out of tolerance.

Brian, I am crossing my fingers for you that it is a “simple” matter of tightening it one position to the next hole to stiffen the movement you are having. Just be careful about using too much torque and making it too tight, however if there is play in it already there probably is room to tighten it up. Does it look like it is serviceable with grease? Wonder if it was packed properly or just needs servicing with a grease gun?

 

[David mono]

Lower ball joint cup from one of the vendor's.

 

Yes - those lower ball joint cups are exactly what I have on mine. Repacked with grease and turned the cups up a smidge and she has passed with flying colours. Thanks for the input everyone.

 

[David mono]

Could the ball joint cup be drilled and taped for a grease nipple.

 

Could the ball joint cup be drilled and taped for a grease nipple.

I don't see any reason why it couldn't, apart from the fact that the nipple would be fairly exposed to damage from rocks/stones etc.

 

[Ryan L]

Can you feel any difference when driving it Brian? The free play/space is on the unloaded side of the joint, so I'm doubtful anyone would be able to tell.

 

No - I can feel no difference whatsoever.

 

[Ryan L]

I'm sure the inspector will sleep better at night though.

I guess it is up to you as the owner to inspect for wear and be cognizant of how much this has been adjusted over time. At some point a joint will like this will fail with the ball pulling through the top of it and the upright separating from the sprung mass of the vehicle. This is primarily what the inspection is trying stop happening. If an owner just keeps tightening up the joint to remove the play, even though the top side is wearing away and getting thinner, then the inspection is not really focusing on the key metric. This would also apply to the ford super duty trucks mentioned above.

 

Quite right Ryan. The ball pins actually looked to be in very good conditioned and I suspect any play was largely as a result of the grease consolidating or some grease leakage. However, I have ordered a new set of ball pins to have on hand should wear become an issue at any time in the future.