Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing How to: Replacing leaf springs.

I have a +4 2009 (Dec), 11000km, 4-leaf springs, wire wheels, and:
195/60-15 at 22 psi
full tank! (this weight difference of plusminus 50kg varies the riding height considerably, 1,5-2cm!)
with spare wheel, full bumpers and luggage rack (another 20kg!)

I think we can only compare our cars if this criteria are specified. New or weared tyres give another 1 cm.

As DaveW measured, the height of running boards (in front of the rear wheels): N/S 21,5cm O/S 20,5cm (LHD!). Measurements on other points give also a difference between N/S and O/S plusminus 1cm.

As Peter (Gambalunga) measured, the rolling radius of the 195/60 R15 tyres averaged to 288 mm (the distance from the centre of the wheel nut to the floor). The height of the lower chassis rail was O/S 155 mm N/S 165 (LHD). However, this all at 22psi and a full tank (incl. Spare wheel, full bumper and luggage rack!

I am not able to asses if this is critical or not, similar to other here. But a significant difference of 1cm between N/S and O/S. If yes, I consider to go for a reshaping a retempering of the springs, instead purchasing new.

But my question is, are the measurement results (Aldermog, Gambalunga, John V6) really a reliable indication of sagging? At least we should measure at the same pressure, full tank, and correction for different tyre size as well additional equipment (spare wheel, bumper, luggage rack). I also could imagine, that a well lubricated contra rusty leafs will make a difference. A reference of a (almost) new car under the above mentioned standardised conditions would be helpful.

However, probably a reliable indicator is if the springs are marked and the wood is flattened due to regular contact, as Dave mentioned (could the shock absorber characteristic have an influence on this?). Probably Dave's riding height is now, with the 4-seater springs, higher than the original height when Bumble was new?

Does anybody know the specs for new 4-leaf springs? What should be the unloaded camber (cm height) of a new 4-leaf spring? What other specifications can/should be provided for reshaping/retempering? Height at a certain load etc.? Is there a source for such data? What is the spec for the (rear) riding height of a new car?

Thanks for comments

Peter

If the premature failure of these springs is down to an inferior grade of steel, I suspect no amount of re setting or heat treatment will give you a long term fix. It’s a lot of effort to change the springs, IMHO if your springs have degraded get a new set.

After talking to Tim Ayres and others the only real "test" is to determine if the car is bottoming out under load.

The evidence is:
a) a horrible banging under the seat as you crash into and out of potholes.
b) damage to the bodywork where the springs pass from inside the cockpit to outside. Not easy to see unless the car is on a hoist. If the body is damaged the springs need to be replaced at some stage.

Shock absorbers have no influence, as Dave found out when the lower mount fractured. They improve ride, but don't control the springs.

I went for a spirited ride in Milligoons Roadster yesterday. Although he has 15" wheels and 65 profile rubber, compared with 16" wheels and 55 profile rubber on Aldermog the overall ride was much better than Aldermogs. Potholes that I'd have felt were passed over with ease.

Another thought: weak rear springs may also degrade road-holding, which on a Roadster, can be an issue!

Out if interest, what suspension has milligoon's car? Suplex or standard and what shocks? I found that the smaller wheel/tyre combination is more comfortable than the 16" wheels, probably part tyre profile but also unsprung weight.

My car has suddenly become much more comfortable. Greasing the springs this weekend, I'd taken the wheels off and thought I'd check the shocks which Williams put on a while ago. You can't get to the adjusters without taking the wheels off and I've been too lazy to date. They were on their hardest setting!

I'll let him answer, but I believe exactly as it left the factory.

The hard setting on your AVOs sounds like Chunky setting you up for a track day!

But adjustble shocks that can only be adjusted with the wheel off isn't helpful. Sounds like another reason to make the parecl shelf easily removable!

Great photos Dave and you will find that it will transform the ride and handling of the car.
I used clamps to remove the old spring but had visions of the clamps firing off through the garage ceiling on trying to compress the new 4 seater spring.
Yes the load on the new spring is that different!
The four seater access is also difficult due to the 4 seater floor.
I found a Hilka spring compressor (£12 from Screwfix) fitted in the gap between the floor and the chassis. This could be located under the cross member and spring mounting and pressing down on the front of the spring and it was very controlled.
Along with the Suplex front, one of the most rewarding jobs I have done on a Morgan.
PS In the photo of your new spring on the bench it looks as if it a 10 thin leaf spring. Stiff or what!!!!!

The power of Denso!

Dave, where did you source your new springs and what we're your options?

John - I went to Mulfab after a fellow TM'er had gone this route. Mulfab have sold a lot of rear springs to correct the weak versions. I went for the 4 seater springs because I want decent luggage capacity without bottoming.
(Other spring suppliers are available).

Just a bit of a postscript to this. Since fitting new springs I have covered around 450 miles whilst carrying a fairly large case on the rack and two people. During that distance I have had a single noticeable spring to wood event. A short deep undulation in the road surface that I hit at speed and caused a bit of a bang. However compared to the old springs that is insignificant. With just two people and no luggage they perform superbly, very pleased. My only regret is that I didn’t fit the 4 seater springs as Dave did. Definitley will next time but for now the spring assits are going back on for that odd occasion.