Rear suspension linkage

I've been working on the rear suspension linkages and swingarm. The swingarm operates on the rear shock via 'drop links' to an aluminium casting called a drag link. The drop links and shock are mounted on a hollow steel tube with large hex bolts at either end. I scraped out the (22year old!) grease from this tube with a big screw driver and then flushed it through with parafin.

Once all spick and span, I forced fresh Castrol LM up the tube by pressing it down over the plastic disc that Castrol put in the middle of their grease tubs. Then I refitted the large bolts and gave them a few pumps on my grease gun to finish the job.

I'd previously painted the drag link and was ready to fit it with new needle-roller bearings and seals. I warmed up the casting with a hot air gun to expand it. It was then pretty easy to force the new bearings in with two sockets wound against one another on a threaded rod. Lashings of LM no doubt helped. 

The rear shock's lower mounting had been stripped of its paint by road spray. The shock's spring and damper tube were pretty good.  

The rear shock has a bush pressed into its lower mounting. I couldn't tell what it was made of  but it was in very good condition. There are two rubber O-rings either side of the bush and they'd clearly done their job beautifully. The contrast with the other components was striking to me anyway.  Some drill-and-wire-brush action, primer and Smoothrite treatment later, the whole thing was spick and span once more.

The drag link is bolted to two large steel castings (or forgings - not sure which) that are in turn attached to the frame with the swing arm spindle and two M12 bolts. The castings are listed as 'linkage carriers' in the Triumph parts catalogue. They each have five holes from top to bottom:

• Top hole for the upper engine mounting bolt
• second hole for the swing arm spindle
• Third hole for lower engine mounting bolt
• Fourth hold for the forward drag link pivot bolt
• Fifth hole for the centre stand pivot boss and bolt

These linkage carrier castings had looked pretty nasty at the lower ends to me but cleaned and painted up beautifully - no pitting at all.

So the castings mount the back of the engine to the frame with four M12 bolts. The upper two M12 bolts pass through lugs in the engine's top crank case and a small aluminium spacer before going through the top hole in the steel castings.The lower engine mounting bolts also pass through outriggers of the main frame.

The right-hand lower bolt is similar but longer and fits into a steel sleeve in the frame.

The lower left-hand bolt is trickier all together because it passes through a steel sleeve and an additional aluminium casting for the side stand.However:

• I couldn't fit the side stand yet because it would have made it impossible to refit the sprocket cover.
• I couldn't fit the sprocket cover yet because it would mean I couldn't tighten the drive sprocket.
• I couldn't tighten the drive sprocket because I needed to be able to stop it from turning by hold it still with the rear brake (and engine compression). 

The solution was to do it a bit at a time ...


So I loosely fitted the right hand bolt temporarily to make sure everything would line up properly, knowing I'd have to remove it again later to fit the side stand.

 With the steel castings loosely in place, it was fairly easy to wiggle the drag link's mounting bolt into position. I found it easiest to do this by working from right to left. The factory manual shows it that way around too (bolt head on the left, nut on the right).

It's all starting to look great now, in my humble opinion. Tidy, clean and that bit closer to getting back on the road again. Next... reassembling the swinging arm and installing it in the frame with rear shock.