Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) SSL question

Just one more thing, some chose to leave their damper blades in even when bearings have been fitted as this can help prevent the Malvern steering dance. You could try removing them and if all is well there is no need to have them fitted. I think that your installer just refitted them as they were already fitted but it’s one less thing to service or worry about if you car now works well without them.

Hey guys,
Picked up my car this morning. The suspension is better than it was when I took it back to them last Tuesday. It doesn’t rattle as badly at every bump in the road but it still has a disturbing “bonk” coming off the back side of a speed hump. When I decided to buy this suspension upgrade I expected something a little more elegant. Were my expectations completely out of line?
They did replace the regular nuts with nylock nuts at the lower cross head.
Richard

So, When you say a metallic bonk exiting the speed bump...... at the back, do you mean the back of the car? Ten inch high bump is really going to hit the car underneath, its only got 4" clearance under there! If you are somehow getting overt I'd say the rear chassis member/exhaust are hitting it as the wheels come off the hump.

Got a new computer and can access your pictures fully now.... gadzooks! your SSL set up is all wrong. It's hard to get the full story but apart from incorrect fitting the collet adjusters have made no spring preload adjustment whatsoever. In effect your sliding hub is free to move where it wants with no spring involvement. The main spring and rebound spring are meant to work together so at ride height and under load the main and rebound springs should be either side of the hub, in effect touching the hub seating surfaces. I'm not sure I believe the trotted out belief that you should be able to rotate the rebound spring with the car sitting under load, wheels on the ground, this I feel is a ridiculous way to show that the main spring load is set at rest with the hub sitting supported between the two springs! This will give the softest spring setting. You should have two adjusting C spanners to set and lock the suspension load? And again there is no evidence of the hubs having been greased! Have you got the installation instructions? And I wonder how many bits your fitter didn't think he needed to use.

So, let's get the relevant points laid down here shall we.

The main spring....... in the SSL or suplex system as it was formally called, This spring is a progressive rate spring and has an initially softer response which allows the suspension to absorb the bobbly irregularities of the road surface where a standard spring would just transfer the shock straight to the chassis. Then when asked to absorb a greater shock the stronger element of the spring comes into play. at this point the sliding hub will leave the seat of the rebound spring as it travels up the fixed pin. When the hub returns to normal ride position it is damped by the rebound spring.

Rebound spring....... beyond the above involvement of the rebound spring in the suspensions travel it also keeps the wheel from dropping into holes in the road and damps this movement preventing the obvious issues.

Spring loading........ So as we have ascertained using the previously described setting for the spring loading, this will give the softest setting, what if you want to stiffen up the suspension.... well your rebound spring ain't going to rotate freely by hand now! Yet your suspension will still be working between the main and rebound spring for most of its critical movement. This suspension system was designed as a self damping system and in fact HFC or harry Morgan didn't design it to have shock absorbers fitted but that's another story! But if you were track racing on a smooth surface you would have selected a stiffer setting and your hub would probably never lose contact with the rebound spring!

Firstly you will need the paperwork that came with the set up and you will need to assemble the system as per the instructions. Fortunately the adjustable element of the SSL system makes it much safer to work on the suspension as you can take the load out of the springs by backing the adjuster rings fully off, not something you cannot do with standard length springs .but can I suggest that you have a look at a site called gomog and read the suspension service section as this will help you understand the system better and show you how to work on it safely. When you have the system fully disassembled check the play of the pin in the hub, Ideally you don't want any but the smallest micro movement is acceptable. If you have issues here come back to us and we can address that for you if needed. And finally, you must understand fully the function of a suspension system and just how dangerous it can be to work on, springs under compression can be lethal and if you have no knowledge of how the system works you should not attempt to carry any work out yourself.

Peter Ballard, one of the SSL directors, wrote an article on classic Morgan front suspension some time ago pointing out some ex factory shortfalls. Normally when two springs operate in series (one on top of the other) they dilute the combined spring rate in a reciprocal manner according to each others spring rate. When operating together in parallel (alongside each other) the combined spring rate is simply the sum of their respective spring rates. In the case of Morgan sliding axle pillar front suspension we have two springs in line but each side of the axle which if they are both in play (under tension) works as if they are in parallel. This means that say a 100 lb inch main spring will have the rate of a 350 lb inch rebound spring added to it until the front suspension compresses enough to allow the axle to rise up the kingpin and remove pressure on rebound. This translates to a very hard ride suddenly collapsing when outer wheel is cornering or absorbing a bump. This falling spring rate is the antipathy of ideal rising rate front suspension, particularly important on a classic Morgan with its design limited travel. Unfortunately many Morgans left the factory with either too long or too higher main spring rate and/or too longer rebound spring, putting them both under tension in static condition. Ironically as such main springs wore their reducing rate actually improved the situation by taking static pre-load off the rebound spring as also noted by Peter.

SSL with their RS kit provide a means of adjusting the main spring pre-load to allow the axle to just touch the rebound spring such that it can still be turned. This also allows for readjusting this important setting as main spring settles. On my own car fitted with SSL kit I noticed, several thousand miles after fitting, the front starting to have excessive rebound travel over bumps. A check revealed the drivers side had several millimetres of slack between rebound spring and axle with a lesser amount on passenger side (I usually drive solo). This I was able to correct by increasing main spring pre-load using the locking collars. As well as restoring ride height it also allows the rebound spring to reduce roll at the front as the inner wheel in a tight turn becomes unloaded. The rebound spring has two rolls to play therefore, reducing bounce and checking roll leaving the car more planted in a fast turn.

The point of my above ramblings is to explain and stress how important this setting is which can so easily be maintained with the RS kit. The procedures are shown and explained in the plasticised fitting instructions that came with the kit. No mention has been made by the OP of these, if they are in his possession and most importantly if his fitter has read, understood and acted upon them. Finally the kingpins need regular greasing every 800 - 1300 miles. As noted by others the OP's images show a remarkable lack of grease particularly as the suspension should have been generously assembled with such when kit fitted.

Richard, Happy new year.
& just to say, what an excellent write up explanation. Thank you. I would only add that “in theory” when settling the springs up, it should be done with the usual weight in the seats. As I said in theory.
Bob

HNY Bob and yes a good point which I intended to add but got lost in my ramblings. Some put a sack of potatoes in the drivers seat before setting the static. Another point I forgot to mention, but which is included in the SSL fitting instructions, is the drop test. Here with shock absorbers still removed, the car is dropped from a height of three inches or so by suddenly releasing a hydraulic jack previously supporting it. This to overcome stiction between axle and kingpins as car bounces slightly, and repeated a few times to find a median for adjusting the rebound to axle gap to exactly zero. Obviously the suspension needs to be freshly greased which it should be anyway. In truth it didn't work so well on my Roadster due to wide 205 tyres and kingpin inclination which snubs any bounce as tyres hit the ground. You do get the opportunity to test drive the car without shock absorbers though which is not as dramatic as one might expect given the unique suspension design. Instead of drop test and after adjusting for static zero pre-load on rebound spring, I use a small hand jack to release cars weight on the road by the slightest amount. This should cause rebound spring to lock up as it becomes loaded but turn when jack released.