Re: 200,000 Mile Oil Change Intervals

I guess the convenient thing about the old style ball joints is that they were self-centering (vehicle weight = no play). I remember my amazement when I was a teenager and I read in the shop manual on the International Travelall (the Chevy Suburban of that day) that I drove that the lower ball joints were acceptable with as much as (IIRC) 1/8" of up/down play with the front end jacked up off the ground.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

And the new one's aren't?

Matt

The difference is that the spring force is transfered thru the control arm and lower ball joint into the steering knuckle with the typical spring or 9as in the case of the vehicle I had) torsion bar suspensions of that era (certainly there were exceptions), whereas with the typical strut suspension system of today (again - certainly there are exceptions), the lower control arm and ball joint is not involved in transfer of the spring force into the knuckle - it only controls geometry and radial forces. The net result is that, with axial spring force into the ball joint of the older system, it tends to be self-centering (i.e., tends to dampen/reduce/eliminate side play from most normal road situations). Without that axial spring force into the ball joint (as is the case in a typical McPherson strut suspension), if there is wear (play) in the lower ball joint, the ball joint is pretty much free to flop and clunk from sidewise forces. That's all I was saying.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

The first time the joint moves, it squeezes a bit more grease out, and then relaxes. Trust me, they DO re-seat.

Well hell, I *could* buy a new car every 2 years and throw away a hell of a lot of money like most people I know. But I'd rather not be so wasteful. Since I enjoy working on cars, 8 hours spread over 30 years is just a little periodic recreation.

It depends on which ball joint in the system, how the suspension is designed, etc. On my older Mopars, the lower joint is weight bearing and therefore self-centering, but the play spec is WAY less than 1/8", but still fairly loose. The upper joint is not preloaded in any way, so ANY looseness will allow play in camber and caster (and a bit in toe because the centerline thru the upper and lower BJ will move relative to the tie-rod end.) That will make the car super-sensitive to wheel imbalance, make it handle funny, and make the steering sloppy.

Exactly.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

But are you taking into account the extra stress of front wheel drive on those sealed joints?