Adding a Spring Leaf

The 109 has TI Console (Heystee) parabolic springs.  The rear springs are 4-leaf heavy duty spec, and always have been.  The front springs, however, are only available in standard duty 2-leaf spec.  The extra weight of the 109’s fittings, accessories and trim are a bit much for standard rate springs, but further more, since fitting the anti-roll bar to the rear end, I have found the front corner tucking during cornering.  Additionally, the replacement of the front axle with a Discovery unit (and it’s taller saddles) was going to reduce front ride height.  For all of these reasons, a third leaf has been added.

The first step was to prepare the new leafs (from a pair of springs separated for the same purpose by Drew Wright of Wright Off Road).  The spring eyes were cut off and a countersunk hole drilled for bolting in the leaf clamp (this was done by an engineering shop as the spring steel is too hard for DIY tools).  The clamps were sourced from Martin Hogan at Rocky Mountain.

Next, the existing springs were prepared.  The axle had already been removed for swap with a later type (Discovery), but it could be done with the axle in place on stands over the spring, but the axle must be separated and lifted well clear.  The original wrapped clamps and their rivets were cut away with the grinder and then the centre bolt was removed with mole grips on the head and a 13mm spanner on the bottom nut.  Once removed, the two leaves separate, allowing thorough scraping of all the accumulated muck and mud.  I then painted the bottom of the top leafs, both sides of the lower leafs and the tops of the new leafs with Schutz (it’s flexible, so won’t crack and flake like other paints).  The new, longer centre pins from Heystee were dropped through the leafs from above, ensuring the rectangular shims were in place, and then the new leafs were added to the bottom of the pile ensuring they had a shim between them and the leafs above and another new shim (supplied with the new leafs) below.  With this new sandwich held together by hand (you could use a bottle jack or G-clamp, but it isn’t really necessary), the bottom nuts were wound on by hand/  The nuts were then tightened while making sure all the leafs and shims were parallel.  On completion, the remaining top and new bottom surfaces of the springs were also Schutzed.

It’ll be interesting to see how they affect handling and comfort, but now that the car is again supported on the springs (albeit with the new axle resting on stands rather than wheels), I can see the springs are retaining much more of their resting camber – they were not far from straight with just two leafs, but now have a fairly normal looking profile.

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Comments

  1. Hi Nick, firstly top notch web site, got some good ideas from you.

    Moving on, how are the 3 leaf parabolics holding up. I currently have a bobtailed 109 pick up, wheel base is still 109 but thr rear cross member was brought forward by about 10 inces, not sure why. Anyway I have new GB 3 leaf paras on the back which makes it sit quite high, probably the lack of weight from the crossmember coming forward and also the lift found when fitting paras. The front has paras on but i am not sure how old they are but the front end is a good 3+ inches lower than the rear. Also the spare wheel is bonnet mounted so that wont help matters and 200di fitted by Glencoygn not sure if diesels are heavier than the old 2.25 petrol which was in.

    Option 1 try and source some heavy duty 2 leaf paras or option 2 add a third leaf to the 2 leafs like you did.

    What did your project lift the chassis by, approx. did you try and source some heavy duty 2 leafs or are these not available.

    Thanks Nick

    Ian

  2. Hi Ian,

    Thanks – I’m glad you like the site, it does take more time and effort than people realise to post everything up, but as long as people find it useful, then it’s worth it.

    I’d guess that the 109 was bob-tailed because the owner wanted to increase the not great departure angle of a 109 and didn’t need the full load bay, but did need more space than an 88″ affords. Or perhaps they found that the longer wheel base worked better off road for them – short wheel bases have better turning circles and breakover angles, but struggle on steep ascents and descents more than long wheel base models (centre of gravity gets too close to the down-slope axle, causing scrabbling) and can’t cross ditches or troughs as easily as longer models either. The general consensus is that the ideal wheel base is 100″, which just happens to be the wheel base of the Range Rover Classic and Discovery I, and was one of few credible features of the DC100 concept.

    Parabolics do tend to lift vehicles by 2-3″, and generally lift the rear more than the front. This is especially the case if you have extra nose weight, and bonnet mounted spare qualifies as that. I suspect that the spring rates are typically designed for laden utility or station wagon 109s which have a CoG further aft than an empty rag top or pic-up 109 with a bonnet mounted spare. Diesels are always said to be heavier than petrol engines, but I don’t see much difference – the SIII engines used almost identical heads and blocks, and the injection pump can’t weigh enough to make a difference. The crank shaft may be heavier, being a forged unit, but again, I can’t see it making a huge difference. The Tdi shares many parts with the 12J, which was essentially just a stroked 10J diesel, and the extra weight of the turbo is probably offset by the lighter alloy head, so again, I don’t think there is much difference in the weight. The diesels do have heavier flyhweels to damp out the vibration caused by the higher compression ratio and detonation that diesels have, so that and the other small differences might add up to 10kg difference or so, but I suspect the suspension differed more to cope with the vibration and the greater low down torque of the diesels.

    I don’t know what spring rates are around for parabolics – I only really know of brand quality reputations. I think that the rates are all comparable, all copying the measurements from the original springs made by Santana when LR stopped the SIII, or copying TI Console (now Heystee), who were the sole providers initially. Rocky Mountain and I think also Heystee used to offer three-leaf HD front springs, but dropped them for lack of demand. My springs are Heystee, which are the dearest by some considerable margin, but also the best. They have lasted about 16-17 years now with no apparent trouble, and the front springs coped with a lot more weight than you have for the bulk of that time – I only added the third leaf because of the axle swap and the height of the new axle’s saddles; I was concerned about the loss of chassis height and also the amount of torque the longer saddles would apply to the springs under braking, known as axle wrap, and I wanted to try to retain the previous vehicle stance and stiffen the springs to resist wrap. As a side benefit, the stiffer springs also help reduce body roll on the front end when cornering, the back already having HD 4 leaf springs and an anti-roll bar. They are a little jarring over speed bumps, though, and might benefit from softer dampers like the ES3000s normally supplied with parabolics rather than the 9000s I currently have.

    I don’t think you’ll find existing 3-leaf front springs, but I was advised by Heystee and RM that you could buy just once spring, cutting the ends off each leaf so they match, and using one leaf on each existing spring – they said there would be no appreciable difference in camber, thickness or rate between a top and bottom leaf and that you wouldn’t need to buy two new springs to use a top or bottom leaf only from each, wasting the remaining leafs. I got lucky – that awfully nice man Drew Wright (Wright Off Road) had already done the same mod but had bought a pair of Heystee springs to do it, so I got a pair of identical upper leafs to add for a couple of beer tokens. If you do this, you can expect to gain a couple of inches on the front end, but it does get stiffer, so articulation may suffer off road if the car isn’t heavy enough and you’ll need the softer dampers for sure.

    Hope that all helps.

    Nick.

  3. Hi Nick, thanks for your sharing your knowledge. I have decided to stay with the 2 leaf fronts, I dont think 3 will be necessary. I have since put some 88″ rear shackles on the back and it has helped angle the shackles back to about 45 degrees which I gather is about right and also taken the helper leaf out so it is running on 2 leaf rears. It rides well and is a lot lower. Not sure about the load capacity now but I only throw camping gear in now and then so it should be ok. Once again, thanks.

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