Suspension upgrades - What they are like after 15 years

[Martec]

Hi,

Instead of the usual questions when something has gone wrong I thought I would catalogue what has been a success. I have just repaired and MOT'ed 2 of our cars, the latter being the MkII so had a good look at the suspension for wear.

15 years ago I MOT'ed our MkII after 30 years off the road:

I had fitted poly bushes to all the front suspension except the subframe mountings and bump stops that remained in rubber. The poly bushes (superflex) are still in excellent condition, the rubber bushes have been replaced twice, but were easily accessible.

I also built the front suspension with lemford top and bottom balljoints (sealed for life) and these are still fine and without slack (the other car MOT'ed, a Honda had to have 3 balljoints replaced).

The marples power steering used tie rods with 4 trackrod ends, these have been fitted about 12-13 years and grease several times a years with copper slip and are still fine.

So I'm happy with the feel and longevity of the front end.

The rear was built in rubber and the torque arm bushes cracked and were collapsing after 2 years (rear poly bushes were not available 15 years ago). I fitted a full set of poly bushes (Polybush) but later took out the front and centre spring pads and fitted rubber again. These have been replaced again a few years ago, no hardship. Again I have been happy with the comfort and longevity of these bushes.

I spent 3 years welding new steel sections into the rotten car so everything has been attached to a solid shell. My biggest cock up was not using my vernier gauge and measuring the wire diameter of the front springs (the car was a nodding donkey), and have been replaced with a correctly calculated spring.

With comments from Alec in particular about our car being too low the intension this winter is to gingerly remove the front springs AGAIN and shim them up by 1/4" to raise the front by 1/2" to its correct height and then replace the rear springs with another set of springs (Ken took them off a car as they were cambered too high and replaced them with the correct springs). If my tests of their spring tension match my old springs then this will raise the back to the correct height with the gas tank and petrol tank full.

I am now on my 3rd set of tyres, initially Avon's, then Hankook and now Vredstein. All bought at a reasonable price and all have given good grip.

The car passed its MOT with ease, only needing a front sidelight bulb, but there again this year it has had 4 new tyres, a new battery, rebuilt carbs and pump, new type thermostat and cover and a few new bump stops and front subframe mountings, cheap really.

This is no stiff and hard riding car, it is a comfortable and agile old car that is a pleasure to drive, or as Des who MOT'ed it said 'its a nice old bus'.

Brian

[Martec]

Further to the above assessment I have now raised the back end but not as intended.

I went to see Ken Jenkins (he is only about 30 miles away), it is always a pleasure to chat to Ken but he is very popular so it doesn't last long.

We couldn't find a set of the aftermarket and 'sold by a well known supplier' springs, only one but did find a proper set of high arch springs (by proper I mean the end of each leaf has a forged indent to take a 6mm thick rubber button). I took the three springs home and compared the tension against my own springs (measured the deflection against a set load in my hydraulic press), they all came our roughly the same.

The odd aftermarket spring is a little wider and on cleaning up one of the proper high arched springs (4.5") it was badly corroded and marked so I took them back to Ken. I had been making a set of spacers incase I had to use my own springs which on inspection were in excellent condition.

So using some strip steel 10mm x 25mm I made blocks 2" x 3" by 1" deep which is now bolted onto the spring with narrower strips either side of the spring box to hold bottom plate on. This results in the axle being 2" lower (back end 2" higher).

Which do you think looks best??

Brian

[J44EAG]

The car looks better "propped up" in the second picture, Brian. Gives the impression of having had some recent suspension work done and able to ably carry some rear end load without sagging.

The first pic seems to allow the sills to be level in relation to the ground. That perhaps makes for a more mature suspension visual.

I think I favour the second visual even though I`m a dropped suspension freak.

Mike

[oldtimer]

Hi Martec,
That don't look bad for an 'ole smoker - the boy's done well.
The first photo looks as though the tail is sagging a little.
As for the stance in the second photo - to me, both the front and rear ride heights look perfect.

Now we come to the difficult bit. The rear suspension is not designed to maintain a particular ride height to compensate for variable loads. As I said, the second photo looks the business but you have not mentioned the amount of fuel and/or gas on board.

Clearly, you have mastered the art of adjusting the rear suspension ride height. You are now faced with finding the ride height which is most suitable for the use to which the vehicle is put. Sadly both the petrol and gas tanks are aft* of the axle which aggravates the situation.

On the basis that number two photo has, say 3/4 of a tank of petrol and possibly no gas I would be highly chuffed to accept that setting. With full fuel and even a couple of passengers to the rear then clearly the rear will sag somewhat, but so what. In contrast the thought of the rear being way up in the air with no load would look equally poor.

Well done Martec, it looks a treat

Oldtimer

* Aft is an old seafarer's term which refers to the back of the boat !

[Martec]

Thanks Mike and Oldtimer,

When I was with Ken he showed me two cars he had in and both had the rear end looking like the jacked up picture and said thats what it should look like.

The car is particularly heavy at present as it has almost a full tank of LPG (normal) but also 3/4 of a tank of petrol (usually 3/8 to 1/2 full) its been in since May so needs burning off. With my long legs and the seat bolted further back none can sit behind me and rarely is there anyone but me and Lesley in the car. The gas tank is bolted directly above the axle.

I expected to lift the front as well but the front spring pans are horizantal (correct) so it is staying there. That is the daft thing about these cars, there is nothing in the manual to say what the correct height should be or the correct suspension angles, just setting block and bars to adjust the suspension when its jacked up!!!!!

I was surpised to be able to crawl under the back to check the oil in the axle, never been able to do that before (mind you I have lost a stone in weight).

It felt a bit loose when I drove it today but cornered well, but it needs to settle a bit now.

Aft...............Aft............ I vaguely remember the term from 31 years in the MN.

Brian

[Martec]

Yesterday I had an enjoyable day out with Ron Warren and accompanied him in him XF estate to 'Jones springs' in Darlaston near Wednesbury http://www.jones-springs.co.uk to pick up a set of new springs for his old Rover at £160 plus vat each.

I have previously contacted 'Rossendale springs' http://www.rossroadsprings.co.uk/ and was quoted for an original set of spring but recambered to suit me and the original type forged ends at £290 plus vat and carriage.

Jones springs wanted £325 to standard spec. and yet they quote £160 for XK 120 - 140, why??

So I asked Kev why? Apparently the Jaguar MkII and the Bentley of a certain age used 2.25" wide springs and everyone else uses 2" or 2.5".

To make 2.25" wide springs the 2.5" material has to be machined down, so an extra cost in the production.

This explains the higher cost of quality made springs from quality european steel, it also explains why the odd spring I had looked at from the usual Jaguar mass suppliers looked wider, they are still at 2.5" and I was concerned that they would scuff inside the spring boxes.

We have decided that my old correctly formed springs are probably old original uncorroded springs and Kev recons they can easily be re-tempered cheaper, so that is an option for the future.

I hope this information is of help to others.

Brian
PS Kev says there is a coil spring maker not too far away from him so that is an option for special front coil springs.