Rear Wheel movement and Radius Arm Bushing play

[cazman]

As I was working on my rear suspension, I noticed that when the rear tires are off the ground, I can hold the top and bottom of the tire and move it slightly (same motion to diagnose bad ball joints - in other cars). The movement can be seen in the Radius Arm Bushing. However the bushings are new and secured to the mount fine. Is there supposed to be play here? I cannot find anything in the manual that discuses this play. It is the same for both sides.

[jbcollier]

There should be no play.

Terminology can be an issue.  The "radius arm" is the long, sheet metal arm that attaches to the chassis up by the firewall and to which the uprights are inserted and bolted.  The arm from the transmission to the lower part of the upright is a "lower link".

Is it the lower link that has play?  If yes, inner or outer joint?

The rubber bushings are from an MGB upper a-arm to king pin joint.  Not a great choice for the Europa's lower link.  I would either fit polyurethane replacements or adjustable links.

[Pfreen]

I have found that the movement is usually in the universal joints. Many joints are not precision enough to prevent a small amount of lateral movement.  I really don't know of an application where a universal joint is used for rotational movement and lateral support.  Drive shafts typically just accommodate misalignment while transmitting torque.

[jbcollier]

GKN and SKF make good u-joints.  GMG are crap right out of the box.

Another example would be the Triumph Spitfire.

[cazman]

JB - the terminology I used is correct, as the play seemed most obvious on the Radius Arm bushing. However now that you all have given me other points to look at (using two people), I see most of the play is coming from the Lower Link outer bushing. Which I am not happy about since, some may recall that I am using the Banks Lower Adjustable links and had trouble with them from the beginning. The outer bushing is poly and is already worn or was too big to begin with. I will sleeve it or make new ones from scratch.

Pfreen - I just replaced one U joint - a Moog. I see another may have slight play though. Probably acceptable.

Thanks for the help - at least I know that the movement should be tight (which I suspected). 

[BDA]

I would replace those bushings with real good quality spherical rod ends. Problem solved.

[cazman]

I know, but I got into this mess because the vintage race group that I am getting ready for won't allow them.

[TurboFource]

Can use something like Global West’s Del-A-Alum bushings?

You could make your own with some machine work and Nyliner bushings.

[BDA]

You could also get replacements from Lotus Supplies.

[Pfreen]

That's terrible, because the stock setup camber may be way off, as mine was.  Especially if you lower the car.

[jbcollier]

The radius arm bushing is flexible as wheel camber changes with suspension travel.  You are seeing the radius arm bushing flex but the source of the play leading to the flex is elsewhere.  Play is most common in the u-joints and also lower link bushings, poor shimming, bad wheel bearings, etc.

[cazman]

I am reviving this because I have found another "play" point that we have not talked about here concerning rear suspension play. Over the past couple years I have replaced my u-joints, radius arm bushings, lower links, and hub bearings. I still have some play when I try on move the rear wheel/tire. So, the last culprit I have found is the bottom hole in the rear aluminum bearing housing - it is worn and that is where I still have play.

Question - has anyone successfully bored out that hole (the one that the 1/2" bolt goes thu for the shock and lower link) and bushed it? Seems like there is meat there.

[BDA]

If you have play for the lower link/lower shock mount bolt in the upright, that is very serious. The remedy would be to sleeve the hole with something but that should be a rare occurrence I would think. I think normally, any play there would come from the rubber bushes in the lower link and the lower shock mount bush. Looking at your previous posts, unless the rubber bushes are in obviously poor shape, they wouldn't be the cause of the play you experience at the wheel.

The thing you haven't mentioned is the shims between the inner u-joint and the tranny. Is that properly shimmed?

[cazman]

Shims are good. This is the last piece in the system that I never looked at closely. Every other part is new and in spec. I suspect that this was worn all along and the other things were just normal maintenance. The wheels have done this since I have had it.

Why do you say it is so serious - because the housing are hard to get and expensive? As far as the play, it seems on par with a worn bushing as far as safety/performance goes.

[BDA]

I say it's serious in that it is unusual (I'm unaware of anyone else complaining about that hole being worn) and could denote a problem such as being hit or improper assembly/disassembly. That 1/2" bolt shouldn't rotate or otherwise move once installed. I've had mine in and out several times and they still require a hammer and punch to get them out of upright.

Of course, that's not to say that it can't be worn (or that the next time I have to take mine apart, it might won't be worn!) and if yours is, I would certainly have a bush pressed in. I think I would have an aluminum bush pressed in. Given that the bolt should be tight in the hole (bush) I might worry that the steel bolt might "grab" a steel bush and when pounding the bolt in or out, it might tend to drive the steel bush with it. On the other hand I might be worrying about noting and steel would be fine. I would consult the person installing the bush.

I would also always use anti-seize when installing the bolt and I would always back it up when tightening or loosening the nut on it.

In any case, checking the condition of the hole should be easy enough and if you've done everything else, it would be a good next check.

Have you checked the condition of your stub-axles? I found one of mine was worn from the bearing (see attached picture). I would expect that you would notice something like that when you changed the bearings but it caught me by surprise.