I looks like the timing has worked out better than I’d thought. On Wednesday I belatedly ordered a set of Heim joints for the 4-link from the friendly folks at AED Motorsport, and happily they arrived today so I’ll be able to use them as spacers when I try to assemble the front mounts this weekend.

As the term “Heim joint” is actually a proprietary name, the more generic term is “spherical rod end bearing”, and like its relative the solid rod end, it allows the dimensionally precise attachment of the end of a rod to a perpendicular rod or bolt — in my case, a bolt passing through one of the many holes on each side of the suspension mount. Unlike a solid rod end which only allows a simple pivot along the axis of the bolt, the spherical rod end allows a certain “degree of misalignment” as well, the value of which is part of the specification of the joint. The ones I have don’t have much misalignment capacity, which is okay as it won’t be needed for my limited suspension travel.

Although Heim joints are known for being very strong and precise with no play or slop in their movement, they also have a number of disadvantages. For street vehicles the lack of cushioning or shock absorption can make for a jarring, uncomfortable ride. Perhaps more critically, their sliding surfaces are exposed to the elements and dirty water and foreign particles can enter the joint, gradually eroding it from within. Due to this and eventual deformation caused by the immense stresses they encounter in a racing setting, they’re often considered a “disposable” part. The trouble is, for a good set of 8 teflon-lined chrome-moly Heim joints you can typically expect to pay $400 or more.

So, I’ve decided to try a new product, which seems simple enough of an idea. It’s from a company called Seals-It, and it’s a rubber boot that’s designed to completely cover the joint. At the moment I must admit I’m unsure as to how to actually install these boots, but I’m going to guess that some lubrication will have to be involved. If they don’t work out, there’s another older product from the same company that only seals from the sides, but at least appears straightforward to set up. We’ll see how well this sort of environmental seal prolongs the life of the joints.

I’ve posted a few pictures here.