Spherical Joints - Ideas ?

Peter D · 09-14-04, 11:03 AM

I was hunting down suspension noises the other day & figured that some of them were coming from the rose or spherical joints - specifically, from those that can "float" like the ones at each end of the pushrods. When I had everything dead level, there was no load on these pushrods & I could easily rotate them to get a clunk at each end of the travel.

Idea - I fitted some O-Rings (about 2mm larger ID than the bolt diameter) between the washer & the ball on each side. When I tightened things up, the O-Rings expanded & slid out to let the washers bear against the ball as per normal, but the advantage seemed to be that the rotational play was gone & the O-Rings provided a bit of physical protection over the normally exposed parts of the ball - keeps dust & grit out, grease in.

I have only done the front so far, but the reduction of noise from the front end is quite dramatic.

Has anyone else tried this (or a better approach) ?

Kind Regards,

Peter D.

Dan Weilacher · 09-15-04, 12:04 AM

Hi Pete , the inner part of the "heim", "rose" joint should never be allowed to move at all on the bolt that it is intersected by. If it does , it is going to wear that area , instead of all the rotation at the "bearing" area that is designed btwn the inner and outer shell of the joint.I would think you would want to get some spacers/ washers and secure the position of that joint. All the movement should be in the joint and none any where else.
This will also keep your alignment of your suspension in check and stabilize your GT [img]/ubbthreads/images/graemlins/grin.gif[/img] Take care , Dan

Peter D · 09-15-04, 01:37 AM

Hi Dan, the way I set up the joints still has the ball solidly locked between the washers, with no chance of any movement between the ball & the bolt. All the O-Rings did was to expand & slide up over the outer exposed part of the ball. This provides a "dust shield", and stops the outer shell of the joint from swivelling laterally & rattling against the washers.

The assembly order was :

- Bolt head
- Washer
- O-Ring
- Rose joint ball
- O-Ring
- Washer
- Lever Arm
- Washer
- Nyloc Nut

This arrangement works well if the normal full movement of the rose joint is such that the pushrod & shell rotate on the ball as though they were rotating around the bolt. It would probably be too restrictive in applications where the movement is up & down the axis of the bolt (like on the rear joints of an RF's trailing arms).

Hope this helps a bit to explain things.

Kind Regards,

Peter D.

Adam C. · 09-15-04, 08:36 AM

Peter,

Chassis Shop sells "seals it washers" that go over the ball and perform very similar to your o-rings.

Adam

Peter D · 09-15-04, 09:13 AM

Adam - brilliant ! Why on earth do the damn joints not come with these as a standard fitting ?

Stupid question : answer = planned obsolescence !

Thanks for the pointer - I'll see if I get a full set.

Kind Regards,

Peter D.

Gary Gibbs · 09-15-04, 10:15 AM

You can also get these AN washers with rubber boots from Speedway motors and I highly recommend them.

Dan Weilacher · 09-16-04, 05:18 PM

Hi Peter , sorry I misread your post. I must have been tired from working on my car ,heheh [img]/ubbthreads/images/graemlins/crazy.gif[/img]
Those covers are really cool. The only concern I can think of , can any mosture get in under them, and become trapped ? Or do they really seal up the area well from the elements? Dan

Howard Jones · 09-16-04, 06:22 PM

Corosion isn't the real problem. Most of the parts of good rose joints will resist mosture caused corosion. The real problem is abrasive wear caused by stone particles being traped against the ball and held there by oil or some other adhesive. These covers will prevent just that. They shield the ball from dust etc. They are a very good investment.

As a aside. The common rosejoint should be cleaned as necessary to prevent dust/oil combo from dammaging them. Dry clean roads will be a LOT different than wet muddy roads. At some point going back to bushing might even be necessary.

As I mod my GTD I intend to replace the bottom bushings with a better material bushing and then use rosejoints at the top for just this reason. I think that the added compliance of the bottom bushing also would not hurt alinement variance to much and would be a good road car setup.

Chris Notley · 09-20-04, 06:25 PM

It is worth making the point here that in the great majority of rod end suspension applications, a bolt should not be mounted through the plain spherical ball. Instead a pair of top hat spacers should be machined for each joint application and therefore the rod end must be oversize, for example using a 5/16"UNF bolt will require a 3/8" spherical. No washer is necessary, in fact it is undesirable as it may restrict articulation of the bearing.

Malcolm · 09-21-04, 07:24 AM

One disadvantage with rose/heim joint covers, particularly boots, is that unless you periodically check each joint carefully you may miss a suspension joint failure. Even a big joint failure could be missed and this has happened on at least one UK car I know of with rather peculiar handling habits resulting!

Peter D · 09-22-04, 05:39 AM

Thanks guys. What I thought was a simple topic has become complicated (how unusual with these cars !).

I guess it comes down to regular checking of the joints for corrosion (take apart & check under boots), bolt torque, etc. Just something to be added to the regular "spanner check".

Chris - I have these types of spacers (instead of washers) on most of the joints, but space in the clevis's precludes their use in other places like the backs of the trailing arms - there I have no choice but to use thin washers &/or shims. In these spots, I have kept the O/D of the washers/shims to a minimum so as to avoid fouling on lateral movement. On the DRB (GT40 Australia) cars, all of the rose joints are set up to pretty-much roatate around the bolt axis, so lateral movement is quite minor.

Thanks again,

Peter D.