bushing question

[dezerts10]

I am thinking of making some silicon bronze or brass bushins for my lower control arms and for where my 4 link lower links will attach tot he frame. Is the deflection in say a delrin or the wobble in a uniball something that is needed? I want to use silcon bronze or brass because it will wear better then delrin and I dont want to use the uniball set up because of the expense and the fact that the uniball is basically useless becuase of the motion of the link

[Triaged]

You absolutely need a joint that can handle mis-alignment at all of the 4-links pivots! You won't get any meaningful deflection out of Delrin either. A-arms do not need misalignment on the chassis mounts so Delrin/bronze can be used.

[dezertdude]

in my personal experience, yes its needed. Ive seen some people use uniballs and what not for lower arm pivots. But Ive noticed when my front end takes a HARD unexpected hit, the 2" bushings will flex a good half inch+! If those were'nt there to absorb some shock I would certainly think that would transfer to frame fatigue and eventually premature failure.

johnny joints seem to work well as an inexpensive middleground.

[movindirt]

If it were me I would run Delrin AF for both the lower control arm bushings and front (at frame) of lower links.

Link to info on Delrin: http://www.portplastics.com/download/pdf/plastics/BearingAndWear/bearingAndWear2.pdf

[Triaged]

If it were me I would run Delrin AF for both the lower control arm bushings and front (at frame) of lower links.What do you do to the front pivot of the rear lower links to handle the misalignment that is required? Do you oval out the bushings or do you expect the chassis mounts and lower links to flex? Having the chassis mounts and link flex is a huge safety issue! By the time you pay for that expensive Delrin-AF and machining of it you might as well use a proper spherical bearing.

Using a spherical on the inboard side of an A-arm will make it less likely to buckle.

[ErikShallbetter]

I suggest just using a spherical bearing. Big picture it's not really a big expense.

[movindirt]

What do you do to the front pivot of the rear lower links to handle the misalignment that is required? Do you oval out the bushings or do you expect the chassis mounts and lower links to flex? Having the chassis mounts and link flex is a huge safety issue! By the time you pay for that expensive Delrin-AF and machining of it you might as well use a proper spherical bearing.

Using a spherical on the inboard side of an A-arm will make it less likely to buckle.


What safety issue? Really I would like to know.:)

[Triaged]

When the axle articulates (or the body rolls, aka one side in bump and the other in droop) the angle of the link, when viewed from the top, changes. Given a 4" long bolt and a 60" long lower link the link would have a 15:1 leverage over the bolt which is quite a bit. If the bolt, mount, or link fail at the front the shocks will force it down into the dirt which will not end good. A design that I am working on right now will need 13° of total misalignment at the forward mount. Even using a spherical bearing a short limit strap (aka tether) at the front pivot isn't a bad idea (rumors are that CORR will require it)

[1450-ranger]

Go uniball, stronger, easier on your pivots, easy to replace, not much $$ in the scheme of things. The tether is a must IMO.

[Wild bill]

uniball. Not worth the risk to do anything less.

[Paul Jacobs]

On the four link BRONZE bushings will work but you should run a spherical bearing at the housing. BRONZE bushings will also work for the control arms. silicon bronze is a type of TIG rod with a very low melting point. Bronze is a good choice because it has a lubricating quality because of the small amount of lead content it has. Thats why it is used for prop shaft bushings in almost all fixed shaft boats. They will not last forever so you will need to inspect them from time to time. I am almost certain I have seen Penhall use them on his cars.

Good luck

PJ

[Co-Dog]

If you go with bushings, you want bearing bronze. I've never seen silicon bronze used for bushings, it wears well, but I think it's to brittle.