Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Shock absorbers

Nice big proper rubber bushes on those Spax gas adjustables Richard

I believe SSL has stopped working with Bilstein, not sure why, perhaps the Morgan volumes were not big enough for Bilstein? However, it does seem all the Morgan development work conducted in collaboration between Dan White and Bilstein was completed years ago which is how I ended up with my set of Bilstein rear dampers, it's just they were the last set on Dan's shelf.

I also know Bilstein keeps excellent records on every damper and coil over they've ever built so as long as you give them the numbers on the damper body they're happy to replicate. It's also worth pointing out that Bilstein is not a 'direct to consumer' company, they are a manufacturer so you must buy through a 'reseller' like Ben Lang for TVR or Dan White for Morgan.

Here are the rears I now run....



Damper performance is excellent, the bushes are proper long lasting suspension grade rubber and as you can see they are equipped with giant tapered integral bump stops. Combined with two seater BCC anti-tramp rear springs and a SiFab Panhard rod the Bilsteins have transformed handling of my Morgan and I have not had a single bottoming out incident since the changes, so those giant soft rubber progressive bump stops are definitely doing their job.

Bilstein offers a huge range of bump stops in different shapes and made from different rubber compounds, but always using a proven compound family that's designed specifically for the job. Other damper manufacturers seem to use the same bubblegum polyurethane material for their bump stops as they use for their eyelet bushings, if this material can't even cope with doing the job of an eyelet bush without premature failure I have no idea how the manufacturer expects it to cope with the pounding forces a bump stop must endure!

Very impressive looking dampers with, as you suggest, massive progressive bump stops. I do wonder if they may place abnormal loads on upper shock mount to hoop though.

Have a look at this thread particularly picture link in first post where the the shock mount has torn out part of the hoop! If you scroll down thread Rog has posted images of various MMC hoop designs over the years to accommodate the shock mount bracket which is also prone to break.

I think this may be why many prefer Rog's progressive bump stops acting directly on leaf springs. Food for thought anyway.

+1

It's a funny old game. I've certainly had a couple of rear AVO's bottom out and leak, but Rog's assists prevent that.

I also found the non adjustable original Spax on my Plus 4 to be very good,

So far I haven't had any AVO bushes fail, but I did have one rear metal damper mounting fracture, so at the rear especially, the engineering is a bit marginal. Roger has already highlighted the compromised geometry of the rear dampers in terms of twist under compression. To be honest it's a wonder we don't see more rear suspension fails.

Correct, I had a set of the early Bilsteins and they were very good, although non-adj there were 3 different valvings available at the build stage, my S1 was the Roadster test bed

The Bilsteins for the rear, were the standard dampers for the latest four-seaters. The massive bump stops were referred to as "spring assistors" effdctively acting as progressive rubber springs. I have kept these dampers but found it necessary to add an additional pair of air suspension dampers to cope with the weight of rear passengers and luggage.

Harald

If the damper top mounting point is tearing out of the hoop, the mounting point clearly wasn't made strong enough, this is an engineering failure from the MMC rather than a function of the damper.

Based on personal experience I'd also suggest the leaf springs used by the MMC are the real reason for a lot of these issues, it seems inarguable the leaves were not properly tempered. Mine had gone completely soft in less than 10,000 miles which meant the rear dampers were having to work twice as hard and the loads transferred to damper bushes and mounting points must have been through the roof. When I removed them my AVO dampers were completely shot with zero resistance left in them, in just 6,000 miles the top bushes were also destroyed.

Yes, the bush material chosen by AVO isn’t the most durable as proven by all the reported early bush failures on other cars using AVOs, but I believe the root cause of my short damper and AVO bush life was largely due to soft and poorly tempered rear springs.

I can see how Roger's rubber spring assisters will work well, especially for people suffering the soft spring issue which I suspect is more common than we think. I was tempted to buy a set from Rog but decided to start with properly tempered rear springs and a set of big bump stop Bilsteins before committing. What I found was just as I'd expected, all the bottoming out was eliminated, and the car's composure was fully restored with nothing more than a pair of new properly tempered and correctly rated springs and set of quality dampers.

Let’s not kid ourselves here, Morgan rear suspension is about as basic as suspension gets, a solid rear axle and leaf spring setup is absolutely ancient and extremely well understood technology, it also persists to this day on nearly all light commercial vehicles, and what we know for sure after deploying this arrangement for well over 100 years is......

Get the spring rates and damping right…. and nothing else is needed!

Agreed Dave, the broken upper support shown on the link I posted was of an earlier pattern with support tube welded entirely external to hoop though. Yours I see is of the far superior later design with the support tube welded through the hoop front and back.

I'm guessing my factory 5 link rear relies on a further improvement to a taller hoop formed from heavier gauge tubing , as this accommodates all the suspension loads transmitted by coilovers.

Your 5 link setup has to be superior in many respects Richard, I'd really like to try a Morgan with this arangement.

I have just fitted Spax adjustable shocks. I will let you know how they compare