Talk Morgan

Suspension problem

Posted By: DeeDee

Suspension problem - 16/12/18 09:50 PM

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Sorry this image is on its side and I have no idea how to turn it through 90 degrees, However this is the drivers side front and the lower spring on the vertical pillar has a 5mm gap above it. Is this normal? The passenger side bottom spring is touching the carrier as I would expect. I only ask as we have a steering wobble at 55mph. Currently she up on our 4 post ramp in the garage so just having a look to see if there`s anything obvious before ringing the dealer as she`s still under warranty.
Posted By: BuyBritish

Re: Suspension problem - 17/12/18 06:48 AM

Is the 'gap consistent with the opposite side, many of us use the online gomog resource here to help understand Morgan maintenance

http://www.gomog.com/allmorgan/front.html

Picture right way around below
2cscjg2 by Robert & Ali Davies, on Flickr

Here is a video showing the bottom spring in operation IT DOES MOT CARRY THE WEIGHT of the car merely is there to be a reaction to pot holes etc see video

Posted By: Robbie Mathisen

Re: Suspension problem - 17/12/18 07:08 AM

Ideally, the rebound spring should be unloaded at rest, the top just kissing the axle. So the spring is 5 mm too short, but I am not sure this really matters. However, it should of course be symmetrical, that is the spring on the other side should be the same. One test is to try to twist the spring with your hand. If you cannot do this, the spring is compressed and thus asymmetrical. If you can twist it easily, it is unloaded and the difference might be within the limits of the acceptable. As it is under guarantee, I would have taken it to the dealer for a checkup.
I do not think this is the reason for your wheel wobble. It might be "St. Malvern's dance", a movement inherent of the wheel /suspension geometry of a Mog. They all do that, Sir... At least many, incuding mine. Got better after I balanced the wheels and lubricated the damper blades (which newer cars do not have). So now I can easily live with it, but am planning to install a steering damper.
Posted By: tmg513

Re: Suspension problem - 17/12/18 08:00 AM

If you put a jack under the bottom cross member on that side does the gap close? I'm perfectly willing to be shot down on this but I'd have thought that with the main spring being under tension it should always press the stub axle down onto the rebound spring.
Posted By: Richard Wood

Re: Suspension problem - 17/12/18 08:58 AM

It appears that either the rebound or the compression spring above is too short on the offending side. It could also be the latter is too weak. This assumes everything was factory assembled correctly and steering bearings are present and intact.

If the chassis is jacked up the gap will dissapear as load is taken from the compression spring and it extends, not that it will tell you much.

A complete strip down of both sides will allow comparison of all four springs and an answer to the problem.

As I understand it a static gap on the drivers (r/h) side between stub axle and rebound spring will reduce initial roll resistance as the wheel unloads during right hand cornering and free play is taken up. Clearly though there should be no assymetry.
Posted By: IvorMog

Re: Suspension problem - 17/12/18 09:36 AM

Hi DeeDee,

The perfect setup is for the bottom rebound spring to be just kissing the bottom of the stub axle at rest such that you can just turn the spring by hand. It's tricky to do because of all the slippery grease but if you us a small rag to hold the spring, it can help. It's not always obvious as you can get some binding at the bottom of the spring in the cross head so persevere with trying to move the spring if it does not seem to move easily.

If it still does not move, get someone to sit in the passenger seat and bounce a few times. If the rebound spring length is just a fraction too long the loading of the main spring will just give you a bit of extra clearance and the rebound spring should then be clear to rotate.

The Morgan front suspension has a lot of stiction in the system and I quite often find that when I get out of the car and check underneath, the driver side rebound spring has a few mm of clearance when I've been driving on my own as that is the side that's had more main spring compression and the stiction in the system has not allowed the main spring to settle at the normal ride height.

All I do then is bounce the front end a few times to even up the springs and usually find that the rebound springs are evenly balanced and just kissing the stub axles.

It is not unusual to get that slight mismatch in ride heights with the car in a static situation so bounce it a few times and re-check.

Of course none of what I've said should rule out a thorough check of the front end to make sure there is nothing else going on but a slight mismatch side to side in static condition is nothing to worry about.

BTW, the old set up was for the rebound spring to be in compression. If it is you will never be able to rotate the spring and in that case you could have a problem because to have one spring in compression and one with 5mm free play suggests something is not quite right.

Could just be excessive stiction that needs a good lube or a sagging main spring on that side. If the car is still under warranty and you are new to Morgan suspensions, It's probably not a bad I idea to discuss it with the dealer anyway.
Posted By: Rog G

Re: Suspension problem - 17/12/18 10:30 AM

Check the top bolt holding the kingpin into the crosshead has not loosened and allowed the crosshead to spread open slightly. I have seen this in the past.
Posted By: DeeDee

Re: Suspension problem - 17/12/18 05:39 PM

Thank you to everyone for your time and advice.

My other half has said he'll take a further look at the issue at the weekend. It'll give him an excuse to retreat into the garage, fire up the log-burner and wield the tools if necessary whilst I mash the tea and provide the biscuits. Team work wink
Posted By: Paul F

Re: Suspension problem - 17/12/18 06:19 PM

Once you have this issue resolved, it is well worth fitting a gaiter to the rebound spring to keep road dirt and grit off your King Pin. It will extend the life of the bushes and King Pins substantially. There is a thread on TM on this. You can make the gaiters out of an off cut of Mohair hood material (as per DaveW), by cutting up an old inner tube or by using a short length of car heater trunking.

There is a page on Morganatica about gaiters - the page includes top and bottom gaiters. The bottom ones are the most important - you will find a design sketch etc there.
Posted By: Stringers Best Mate

Re: Suspension problem - 17/12/18 06:21 PM

Originally Posted By Paul F
Once you have this issue resolved, it is well worth fitting a gaiter to the rebound spring to keep road dirt and grit off your King Pin. It will extend the life of the bushes and King Pins substantially. There is a thread on TM on this. You can make the gaiters out of an off cut of Mohair hood material (as per DaveW), by cutting up an old inner tube or by using a short length of car heater trunking.

There is a page on Morganatica about gaiters - the page includes top and bottom gaiters. The bottom ones are the most important - you will find a design sketch etc there.


It's also worth having a butchers here - https://www.wolfperformance.co.uk/rebound-spring-gaiters.html
Posted By: Gambalunga

Re: Suspension problem - 17/12/18 08:27 PM

Because of the nature of the Morgan front suspension you may need to roll the car backwards and forwards a couple of times to get the stub axle to settle into its static position.
Trying to bounce up and down on the front end will not be particularly effective because doing so would try to move the tyres sideways. It is for this reason that, when the car is not rolling, the front end of a Morgan seems particularly stiff if you try to bounce it. If you had the wheels resting on plates that could move sideways it would be a different thing.

When doing this sort of check it is also recommended to unfasten the bottom end of the damper so that that does not have an effect.

A simple way to check whether or not the lower spring is too short is simply to measure both springs. If one is just touching and the other is the same length obviously the lower spring is not the problem and it has to be stiction of the stub axle on the kingpin or a faulty upper spring.

If there is not stiction one of the effects of this would be more body roll when cornering to the left.
Posted By: IcePack

Re: Suspension problem - 17/12/18 09:42 PM

A thread on this a while ago, led me to believe that the rebound spring should just be touching the stub axle, when the car is normally loaded. Have I got this right?
Posted By: Richard Wood

Re: Suspension problem - 17/12/18 10:15 PM

Originally Posted By IcePack
A thread on this a while ago, led me to believe that the rebound spring should just be touching the stub axle, when the car is normally loaded. Have I got this right?

This good advice is based on the fact that any static pre-load on the rebound spring will work initially in parallel with upper compression spring, dramatically increasing spring rate until rebound spring becomes unloaded. A little difficult to get your head around as intuitively the two springs appear to offset each other or work in series. You have to consider they work on opposite sides of stub axle though.

Any rebound spring pre-load leads to the afore mentioned high spring rate which then reduces to a much lower linear rate when only upper compression spring is in play. This leaves initial harsh ride followed by soggyness as suspension compresses further, exactly what is not required.

A rising rate compression spring would be ideal with no interference from rebound spring, but not sure if such are available.
Posted By: Richard Wood

Re: Suspension problem - 17/12/18 10:32 PM

Originally Posted By Gambalunga

If there is not stiction one of the effects of this would be more body roll when cornering to the left.


Would that not be when cornering to the right Peter? since that would unload the right hand wheel where the OP has rebound spring play, reducing roll resistance on that side until the rebound spring becomes loaded.
Posted By: Gambalunga

Re: Suspension problem - 17/12/18 11:05 PM

Originally Posted By Richard Wood
Originally Posted By Gambalunga

If there is not stiction one of the effects of this would be more body roll when cornering to the left.


Would that not be when cornering to the right Peter? since that would unload the right hand wheel where the OP has rebound spring play, reducing roll resistance on that side until the rebound spring becomes loaded.

Oh shoot! You are absolutely correct Richard. I'm so used to sitting on the left when driving I started thinking of the LHS spring as being on the driver's side. What's called a "senior moment" perhaps oldgit

As Richard points out it is when the rebound spring is loaded in cornering it inhibits the rise on that side of the car.
Posted By: Richard Wood

Re: Suspension problem - 17/12/18 11:22 PM

If its any consolation Peter your not the only one suffering from oldgit moments. Had to edit my first post on this thread to change left to right wink
Posted By: Button

Re: Suspension problem - 18/12/18 12:06 AM

I have never really accepted the idea that the rebound spring should just be kissed. I agree with Hamwich that the rebound spring should engage the bottom of the stub axle about 1/2". Every time I drove the +8 I would check the gap. Sometimes it touched the stub axle, sometimes there would be a 1/2" gap. But even when it touched I was always able to twist the rebound spring. I Emailed Mel Rutter who informed Peter Ballard. Peter stated that until I cured the "Stiction" (His term) I would not have a proper installation. I guess I have given up. Seems to ride OK and handle as good as any other +8. Sometime in the past I removed the cut rebounds and installed a new pair of un-cut springs. The ride was terrible. So there is something to Peter Ballards ideas IMO.
Posted By: Hamwich

Re: Suspension problem - 18/12/18 03:36 AM

Originally Posted By Button
I have never really accepted the idea that the rebound spring should just be kissed. I agree with Hamwich that the rebound spring should engage the bottom of the stub axle about 1/2".


I'm not sure I understand what you mean, Button?

I'm with Peter Ballard on this. The rebound spring should be just free to turn when the car is at static ride height with the normal load (ie weight of driver).

If the gap is too big, you get a bit of a nasty 'tip in' effect when you corner, the car seems to roll more than it should until the stub axle settles onto the rebound spring.
Posted By: tmg513

Re: Suspension problem - 18/12/18 08:59 AM

Originally Posted By Hamwich
Originally Posted By Button
I have never really accepted the idea that the rebound spring should just be kissed. I agree with Hamwich that the rebound spring should engage the bottom of the stub axle about 1/2".


I'm not sure I understand what you mean, Button?

I'm with Peter Ballard on this. The rebound spring should be just free to turn when the car is at static ride height with the normal load (ie weight of driver).

If the gap is too big, you get a bit of a nasty 'tip in' effect when you corner, the car seems to roll more than it should until the stub axle settles onto the rebound spring.

I can't get my head round this: when I install a new kingpin I have to jack it upwards so that both springs are compressed before I can bolt it in place. There's no way I'd be able to turn the rebound spring at rest. Are the more modern cars (mine's 1972) different?
Posted By: Richard Wood

Re: Suspension problem - 18/12/18 09:43 AM

Originally Posted By Button
I have never really accepted the idea that the rebound spring should just be kissed. I agree with Hamwich that the rebound spring should engage the bottom of the stub axle about 1/2". Every time I drove the +8 I would check the gap. Sometimes it touched the stub axle, sometimes there would be a 1/2" gap. But even when it touched I was always able to twist the rebound spring. I Emailed Mel Rutter who informed Peter Ballard. Peter stated that until I cured the "Stiction" (His term) I would not have a proper installation. I guess I have given up. Seems to ride OK and handle as good as any other +8. Sometime in the past I removed the cut rebounds and installed a new pair of un-cut springs. The ride was terrible. So there is something to Peter Ballards ideas IMO.


This article by Peter Ballard best explains Classic Morgan front spring characteristics. I have to agree that if you have excessive stiction of stub axle on king pin then the jury is out on determining static rebound spring pre-load or gap.
Posted By: Gambalunga

Re: Suspension problem - 18/12/18 10:02 AM

Since the rate of the of the two springs combine when they are pressing against each other and then suddenly falls when one of the springs (the rebound spring in our case) is fully unloaded the only way to avoid a falling rate system is to ensure that the rebound spring is free at static ride height.

If you want a stiffer suspension the answer is to increase the rate of the main spring. Those with the Suplex or SSL systems have the option of requesting SSL for a suitable spring from the race kit.
Posted By: IvorMog

Re: Suspension problem - 18/12/18 01:45 PM

Originally Posted By Gambalunga
Since the rate of the of the two springs combine when they are pressing against each other and then suddenly falls when one of the springs (the rebound spring in our case) is fully unloaded the only way to avoid a falling rate system is to ensure that the rebound spring is free at static ride height.

If you want a stiffer suspension the answer is to increase the rate of the main spring. Those with the Suplex or SSL systems have the option of requesting SSL for a suitable spring from the race kit.


Also with the SSL you can adjust the height to get the correct level as the springs settle and the new kingpins loosen up slightly.

After a year and 3000 miles my new set up has settled by about 5mm so I will correct that with the adjusters..
Posted By: sospan

Re: Suspension problem - 18/12/18 06:52 PM

My rebounds are just in contact with the hub and can be rotated when the car is at rest on a level surface. This, to me, is the neutral position when the only loading is from the weight of the car. I also think the upper spring should be neutral (or very close) with perhaps just a hint of compression. In this setup when driving, the springs react from neutral to cope with absorbing travel or releasing as the need arises. By having this neutral, just in contact setting there will be no free play that needs to be overcome before the correct effect is met. Balancing spring rates is important, coupled to suitable pitch of the coils. Very simplified I know but it seems a decent base to work from.
I am tempted by the SSL system for the front but would like to try a car with it first.
Posted By: IvorMog

Re: Suspension problem - 18/12/18 07:17 PM

The upper main spring has to be in compression to take the static weight of the car.

If the car weighs 800kg i.e about 1800lbs then assuming 50/50 weight distribution there is 900lbs at the front or 450lbs per corner.

If the spring rate was 150lbs/inch for example, that would need 3 inch compression to just take the weight of the car.

Maybe a bit more with your surge inducing "heavy" V8 lump.
Posted By: Deejay

Re: Suspension problem - 18/12/18 07:23 PM


Originally Posted By sospan
My rebounds are just in contact with the hub and can be rotated when the car is at rest on a level surface. This, to me, is the neutral position when the only loading is from the weight of the car. I also think the upper spring should be neutral (or very close) with perhaps just a hint of compression. In this setup when driving, the springs react from neutral to cope with absorbing travel or releasing as the need arises. By having this neutral, just in contact setting there will be no free play that needs to be overcome before the correct effect is met. Balancing spring rates is important, coupled to suitable pitch of the coils. Very simplified I know but it seems a decent base to work from.
I am tempted by the SSL system for the front but would like to try a car with it first.

Fully concur with views on rebounds BUT as far as uppers are concerned, isn’t this trying to defy gravity? They have to carry the weight of the front of the car and no matter how strong the spring, or how long or short, it will always be loaded by that weight, so can never be “neutral” like the rebound springs can be.
Apologies if I have misunderstood?
Posted By: Rob Thornton

Re: Suspension problem - 19/12/18 08:19 AM

Maybe a naive observation on my part as I don't pretend to be wholly mechanically minded in this area, but all the comments regarding the optimal setting of the bottom rebound spring seem to be based on user experience rather than technically specified factory data.
Presumably the cars leave the factory with all components set to specified tolerances, clearances etc and further maintenance should aim to maintain these settings unless one chooses to deliberately change them for whatever reason?
Posted By: Richard Wood

Re: Suspension problem - 19/12/18 10:08 AM

Have you read the article by Peter Ballard linked above Rob?

It may be backed by his user experience but makes sound technical sense.

Interesting also is that he explains how trad Morgan suspension may improve with age on comfort stakes at least, as the springs shorten with use, particularly the longer compression one, lowering ride height but importantly removing any rebound spring pre-load that may have been present, hence softer linear rate over bumps.
Posted By: IcePack

Re: Suspension problem - 19/12/18 10:24 AM

Rob my car came out of the factory new. The set up was a right mess, so I for one would say do not trust the factory to have set the suspension correctly. They rely on the end user to sort it out using their knowledge & or their dealers.
Posted By: IvorMog

Re: Suspension problem - 19/12/18 12:37 PM

As I understand it, the factory viewpoint has changed over the years.

In the old days the front suspension was set with both springs in compression with the consequent falling rate effect. That's just the way it was then.

What I don't know is if the factory now sets the front up as we describe it or do they still use the old set up.

And if they did adopt the new set up, when?
Posted By: DaveW

Re: Suspension problem - 19/12/18 12:46 PM

The front spring rates have changed a few times over the years. The 2016 set up was with SSL springs.
The 2005 set up was with Eibach.
Peter Mulberry has all the rates in his head.

The 2016 suspension is very well resolved. So much so that I've kept the standard Spax and not even thought about changing them yet.

The rears have changed from six leaves in 2005 to four leaves now. The change was around 2012, which was when the weak leaf spring period occurred.

I can only comment on the cars I've had!

On my Plus 4 there's about 5mm compression on the rebounds. It doesn't bother me as 5mm is a tiny amount. Had there been more thread on the base of the kingpin I'd have added spacers under the plate to eliminate it, but there isn't really enough thread.
Posted By: Rob Thornton

Re: Suspension problem - 19/12/18 04:53 PM

Originally Posted By Richard Wood
Have you read the article by Peter Ballard linked above Rob?

Richard, I have now read the article and the details of the other advice in the thread and begin to understand!
It would seem that, as with many other aspects of Morgan ownership, there is no right or wrong way, just different levels of performance or handling as determined by the owner.
For my part I will clean the assembly and have a good look at the set up out of curiosity now but, as I am more than happy with the handling characteristics of my Plus 8 at the moment, I will leave well alone!!
Posted By: BobtheTrain

Re: Suspension problem - 19/12/18 05:51 PM

Originally Posted By IcePack
Rob my car came out of the factory new.

Most of them do.
Posted By: Gambalunga

Re: Suspension problem - 19/12/18 06:21 PM

When my car left the factory it was an absolute mess. Unfortunately replacing the springs under warranty to resolve the ground clearance problem made the handling suffer to the point that granny with her shopping trolley could get around corners better.

Fitting the SSL systems resolved all the problems.
Posted By: CBY

Re: Suspension problem - 22/12/18 09:59 AM

SSL system is the only solution to be able to adjust easlily the spring clearance in the time. With SSL you get a suspension which works in the right way: soft at the beginning of the compression and with a rate increasing after.
Original Morgan setting with a rebound spring in compression has a reverse working offering a harsh comfort on small deflection, opposite at all the other cars.
Posted By: Button

Re: Suspension problem - 22/12/18 07:59 PM

Originally Posted By Rob Thornton
Originally Posted By Richard Wood
Have you read the article by Peter Ballard linked above Rob?

Richard, I have now read the article and the details of the other advice in the thread and begin to understand!
It would seem that, as with many other aspects of Morgan ownership, there is no right or wrong way, just different levels of performance or handling as determined by the owner.
For my part I will clean the assembly and have a good look at the set up out of curiosity now but, as I am more than happy with the handling characteristics of my Plus 8 at the moment, I will leave well alone!!


I had multiple issues with the SSL on My +8 Bitsa. The SSL is now on My DHC and I quite like it. I also liked it better on My '63 +4-4 Str but not as well as the DHC. I am using the Blue Roadster springs on the +8. I like these better than the Peter Mulberry Thrust Bearing kit with 140 in/lbs. I am getting old and trying to get comfortable and not driving like a looney anymore.
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