Wanting to slightly soften the first inch or so of front suspension travel on my 2014 Plus 4 I decided to fit softer rebound springs. I've seen mixed reports on the Suplex upgrade (apart from the huge cost). Tim at New Elms (nice people) came up with a pair of Rutherford special rebound springs slightly softer and shorter than standard (3"x200lbs) at about £40. Fitted them yesterday (see pix, second one compares the springs) not a tough job and tried the car this morning. The difference is not huge but is perceptible -- a little more resilience over ridges and small bumps. I had been running the front tyres at 20psi so now I think I can put them up to the recommended 22psi and keep my fillings in.
Very simple process to change Will, if you have (or access to) a trolley Jack and axle stands even simpler. As you can see in the photo it's a matter of getting some 5/16" studding and half a dozen nuts and a couple of washers. All available from B&Q or similar.
No need to remove the brake discs or calipers etc. Although access is easier, this is what puts a lot of owners off.
1. Remove one of the lower 5/16" nuts and bolts From the lower plate (1/2" AF spanner size or 13mm Metric)
2. Fit the studding to that side, if you note 2 nuts on top locked together as that thread locks them making a very long bolt) then fit the lower nut and tighten to replace the nut and bolt you just removed.
3. Do the same for the other side of the plate, again tighten the studding nut.
4. Undo the central large nyloc nut and set to one side.
5. Slowly, and about 2 complete turns each, undo alternately the studding lower nuts to relieve the rebound spring pressure. Turn the steering from lock to lock if it fouls the lower lug and it will soon pop through.
6. When all tension is off, take off fully the lower studding nuts, remove the lower plate and change over the rebound spring.
7. Reassembly is as they say a reverse of the strip down, just a couple of turns of compression is enough either side, take your time and it will pull up square. Keep alternating until the lower plate meets the lower lug and the rebound Spring is compressed in place.
8. Refit the centre large nut (no need to replace unless you happen to have one), Nylocs are supposed to be good for 6 remove/refits but some obsess about this, your call.
9. Remove the studding from one side and change for the OE nut and bolt, again your call if you want to replace the 5/16 UNF Nyloc? No need to but I always do for customers as I buy them in bags of 50 ;-). Then do the other side.
10. Spin the steering lock to lock just on case (but it will be fine) there is some coil bind and do a final spanner check of all disturbed nuts and bolts.
11. Shot of grease whilst your in there and then the same on the other side of the car and jobs a good un!
I have simply cut 1 1/2 loops from the rebound spring. Mount spring with the cut loop down. I have been doing this on +4's for over 20 years. Bill Fink and The Chief Engineer for Morgan (forget his name) came up with this idea. The "Rutherford" rebound spring is a neater item in that it is finished with a proper loop. Not just cut and installed as I do. Lately, since Peter Ballard explained "Hooke's Law" I have installed the main spring without the rebound spring and let the Morgan sit on all 4 wheels. Measure the space for the Rebound spring. Add a bit (+1/2"?)(Tim Harris's idea) and cut to fit. The main spring is Peter Mulberry's 140 in/lb and thrust bearing. I replaced the Suplex Kit with this system on My +8. My feeling is the engine is too heavy for the Suplex Kit. I will use the Suplex Kit on My DHC with the lighter Zetec engine. I tested the Suplex kit with the DHC and liked the results.
Spanner juggler has almost said it all in terms of fitting. I would say though it is much easier if you remove the caliper and disc/hub assembly. Be sure to hang the caliper with a cable tie so there is no strain on the brake pipe and do not over-tighten the wheel bearing when re-fitting the hub (which is also an opportunity to massage a little more HMP grease into the wheel bearings. the rear 5/16th" nut and bolt on the lower plate is also the anchor for the rear tie rod to the chassis. You will need to loosen the three bolts which connect this to the chassis in order to move the tie rod out of the way (as in my first picture). Hope this helps.
Spanner juggler has almost said it all in terms of fitting. I would say though it is much easier if you remove the caliper and disc/hub assembly. Be sure to hang the caliper with a cable tie so there is no strain on the brake pipe and do not over-tighten the wheel bearing when re-fitting the hub (which is also an opportunity to massage a little more HMP grease into the wheel bearings. the rear 5/16th" nut and bolt on the lower plate is also the anchor for the rear tie rod to the chassis. You will need to loosen the three bolts which connect this to the chassis in order to move the tie rod out of the way (as in my first picture). Hope this helps.
The reason he didn't is as you describe above ;-). It can be done without the hub removal and many owners (I don't get weekly emails but it's close ;-)) struggle to get the hub nut split pin out and then again are unsure on the end float setting procedure to refit it. Of course it's easier with the hub and disc out of the way however it does bring in a range of skills and knowledge that may well be a stretch for some.
Wanting to slightly soften the first inch or so of front suspension travel on my 2014 Plus 4 I decided to fit softer rebound springs. I've seen mixed reports on the Suplex upgrade (apart from the huge cost). Tim at New Elms (nice people) came up with a pair of Rutherford special rebound springs slightly softer and shorter than standard (3"x200lbs) at about £40. Fitted them yesterday (see pix, second one compares the springs) not a tough job and tried the car this morning. The difference is not huge but is perceptible -- a little more resilience over ridges and small bumps. I had been running the front tyres at 20psi so now I think I can put them up to the recommended 22psi and keep my fillings in.
Notice the number of coils in the picture: Top picture has 7 coils Bottom picture has 8 coils
So My guess is the bottom spring has a higher spring rate than the top picture.
