Hi all, Just stumbled on this discussion and wanted to add a few things. First, thanks to the folks who posted a couple links where I can find or cobble together an oiling tool. I've been looking for one (currently am building the front suspension on my TR4).
My TR4 manuals definitely call for 90W gear oil on the horizontal trunnion shafts (the outer/lower suspension axis, lubed by two zerks on either side), but grease on the vertical screw portion (the steering axis, lubed by the single zerk on the very bottom of the vertical link assembly). TR2 and TR3 v-link and trunnion assemblies are quite similar to TR4. TR4A, TR250/5 and TR6 are slightly different so I'm not sure if this applies, but would guess it does. I also don't have any up close and personal experience with Spitfire trunnions. However, with the TR4, the rule of thumb I've always heard it said that if you can actually get grease into the horizontal trunnion joints, they are worn out and the bushings need to be replaced. The bushings are pressed into the end of the lower wishbones, then honed to fit the horizontal trunion shaft very closely, which is why heavy oil is used instead of grease. Over time, the bushings wear and clearance increases. When this reaches the point where you are actually able to work grease into the joint, it's got excessive wear. I would think uneven and more rapid tire wear would be the biggest problem caused by excessive clearance, in most cases. In more extreme, erratic steering and handling problems migh come up. The previous post is correct. Parts of the trunnion assembly are made of brass or brass alloy, so do *not* use modern GL5 gear oil. Look for GL4 or earlier types. (By the way, TR4 gearboxes, ODs and diffs also have a lot of brass/brass alloy parts, and the same is true for them, use no GL5 oil.) GL5 will gradually degrade the brass parts.