Bushes: Polybushing the Disco

The Discovery has lots of rubber on them: all the linkages and arms on axles and steering ,and the top+bottom of shockabsorbers, have some rubbers to give a bit flexing between the components. This is of the uttermost importance in a 4x4 vehicle, but any car has them. A vehicle used over rough terrain or going off road, will experience fast wear in these components. And Land Rovers will wear these at a higher rate than an other vehicle because oil kills rubber slowly... Polyurethane bushes does not suffer that much from oilstain.

Red Polybush obtained for dampers front and rear. Changed the original rubber bushes rear august 2000. The bushes are of an extremely tight fit in their upper mountings, lower OK. Lower damper bracket needs repairs: the bushing must have been loose for some time, because the hole in lower bracket had been worked to become "keyholed". This rubber bush were renewed 6 months earlier. Check yours - now! This indicates Otto having not only four-wheel drive, but also four-wheel steering: axle is loose due to worn upper and/or lower link bushes. New bushes are needed. Lower axle bracket needs a plate/washer to be welded on. Upper mounting bolt snapped while opening on LHside. Renewed upper bracket.

For whole process of renewing the suspension bushes, go to this page. This is a rather big job, but is very important for the vehicles ride qualities, to reduce clonks, vibrations, etc. You need  a big breaker bar and a large torque key, in addition to plain ordinary tools, but it is not a difficult job: anyone could do it.

Coils and Shock Absorbers If you're contemplating fitting new springs and shockers, give a second thought to the issue of fitting taller springs to be able to fit bigger wheels, obtain better ground clearance, and gain better axle articulation. Read more here. The rear shockers were far beyond renewal date, but the coil springs were OK/so and so. Decided to go for a full renewal to enjoy the benefits of an all new and upgraded suspension setup. Chose Heavy Duty Coil springs from Famous Four , which have dual rated (progressive) rears for Discovery, meaning they are initially soft, but has a stiff feeling when put under pressure - like when cornering or vehicle is loaded. These coils are highly acclaimed (read FFs own description here). They will reduce roll and pitch considerably, and a generally acclaimed for their performance. Forgot to check length of rears, but up front it looks like this:

Also obtained the new Tenneco product line Monroe Adventure shock absorbers. These are gas shockers, and perform far better than OEM both on- and off road. Given very good review in a Land Rover World article summer/autumn 2001. Part# Monroe Adventure Gas Shockers: Front: D6419, Rear: D6440

Mind you: Polybushes for standard OEM shockers will not  fit Monroe Adventures. The spindle is about 10mm shorter than OEM, and no way a standard set of polybushes will fit on them. There's rubber bushes supplied with them, so these has to be used. I managed to put on one poly and one rubber on each spindle-end of the shockers. If it seems difficult to enter all the washers and rubbers, and still be able to put the nut on, try lifting the axle a bit; this will compress one of the bushes, allowing a couple of millimeter more of the spindle to protrude for entering the nut.

There is an article (with some pictures) by Kyle Van Tassel in the Tech-section of the Discoweb on the procedure for renewing shockers and coils. Also LROI August 2001 has an article on changing shock absorbers, and also covers the technology of shockers.

Renewing front coils and shockers

Gas assisted shockers are best renewed together with the turret, as they are pretty hard to compress. Turrets tend to rust heavily, so check these carefully before you start work - maybe this is the time to renew them (as I did), or they can be restored using a wirebrush and painted for protection. Give them a thorough covering of rustpreventing oil, paint or whatever - it's not without reason they tend to rust heavily... Check you have nyloc nuts for the retainer ring, and do get a new retainerring if you suspect any of the bolts to be solid rusted. If any of them break, you can not replace it with a bolt - you'll need the whole ring (they're at ~£6). Soak all nuts & bolts using WD40 or similar some days before actually commencing the job.

It did the job taking one side at the time, i.e. removing only one wheel at a time. Manuals use to specify both front wheels off...maybe I feel a bit assured by having the axle resting on at least one wheel. First took LH-side.

Loosen wheelnut on front wheels  Put blocks in front and rear of rear wheels. Jack vehicle and place axle stands under relevant side of the chassis. Keep jack placed under the axle to be able to lift/lower the complete axle. Remove LH roadwheel.

In engine bay: Remove airfilter and intercooler/turbo hoses (cover the holes to prevent ingress of dirt) for improved access. When doing RH side: Loosen and tuck away the coolant overflow tank  and  dieselheater (if installed).

Remove bottom nut on shock absorber. This is really worst part of the job, the spindle you're supposed to hold onto while removing the 19mm nut, is soft, and nut is corroded - and the shocker will just turn, and nothing firm to hold onto. Cutting away the spindle is difficult due to bad access. I used a big channel lock/vice grip to  hold the shock while trying to loosen the lower nut - and suddenly it gave away. If impossible this way, cutting spindle with a saw is one option, and another would be to drill a hole directly through the shocker, and offer a big screwdriver through the hole to hold. A very long drill would be needed. Anyway: You might run into trouble if the shock absorber are supposed to be put back on and not renewed...

Pic: Discoweb

Remove the four nuts holding turrets (two in wheel well, two in engine bay). Lift the whole unit away. If turret is to be reused, clean and inspect, paint if necessary after having removed the shocker in a vice or something. My shocker were completely bust: when pushing it in it wouldn't press out, and when pulled all the way out, it wouldn't pull in... Also turret was too corroded, and the retainer ring had to be renewed anyway, because one of the bolts snapped (they use to do...). 2 nuts had 13mm head, and 2 had 12mm...You're warned! 

For improved access if rustproofing is needed: Remove the two bolts (17mm) at inside/bottom of springs (for the bottom captive plate). The nut (below/under the bracket) is a captive nut - it's spotwelded.

Jack lifted to compress spring. Clamps put on and tightened. You will have to compress the spring pretty much. It has a free length of about 40cm... If you can't remove the spring, lift jack further up, and tighten clamps. Do not use the clamps for tightening spring without lifting jack: you'll be lifting the axle with your clamps!!!

Lower jack, taking care not to stretch the brake flexible hoses. Turn steering wheel to the right so the brake hoses have some extra length. Remove spring. Carefully release the tension loaded in the spring. This is a dangerous job, so take heed not having any fingers inside the springs, nor any tools.

Now carefully clean spring seats, axle, brackets etc., and do a rustprevention on the area. As soon as spring/shocker is in place, this area will be inaccessible, so allow the time to do it good.

Make a test-fit of the retainer-ring and turret, as it is common turrets sold are not too good fitting pattern parts. Entering the retainerstuds through the turret holes a couple of times before fitting anything on the truck makes everything easier.

Offer up retainer ring, and loosely fit a couple of nuts just to keep it from dropping down. 

Then, compress new spring with the clamps,  Put bottom captive plate onto the coil if you removed ut. When coils are in situ, lift jack until tension is taken off the coilclamps, and remove them. Lower jack. Now the loosely fitted nuts on the retainer ring can be released, as the coil holds it tight anyway. Tighten the two captive plate bolts (use new bolts and plenty of coppergrease).

Assemble the turret, washers and bushes. They must be assembled in the correct order (as described in manual and in a sheet of paper coming along with the shocker. The top spindle was too short to allow polybushes, so polybush used on one side of the turret, and rubber (which are thinner) on the other. Tighten top nut firmly - the bushes shall bulge, but not be totally compressed. Main point is taking up the slack, and it should not be allowed to work loose - the tension bushes make shall prevent that.

Offer shock/turret through the wing-cut out, on with the washers and bush, and try entering the spindle through bottom hole, and the bolts on the retainer ring running into the turrets holes. If the shock is too long, lower jack so you will not need excessive force to be able to put on the nuts onto the retainer ring. Tighten nylocs to specified torque. Put on washers and bush on bottom spindle, and then bottom nut with plenty of copper grease. If spindle seems too short, try lift the jack a bit - this will compress the bush sufficiently to enter the bottom nut. 

Put wheel back on. Lift jack sufficiently to remove your axlestands placed under chassis, then lower jack and retighten wheel nuts to specified torque (129NM). 

RH side is similar to LH side, only that there are other things to remove for improved access to the two inner nuts of the turret.

How much time used for renewing front coils/shockers?

1.side (LH) took approximately 2 - 2,5 hours - everything inclusive (finding tools, jacking, dressing in boiler suit, cleaning hands afterwards, etc.).

2.side (RH) took approximately 1,5 - 2  hours - everything inclusive (finding tools, jacking, dressing in boiler suit, cleaning hands afterwards, etc.).

Renewing rear coils and shockers

It's better to obtain the socalled "isolators" when you purchase your coils. These are  nylon rings to be put on top of the coils, going into the upper coil brackets. They are cheap and you won't run into any trouble being left stranded waiting for another package from your mailorder supplier. Mine did not have these when I removed my old coils - maybe they didn't use them back 1990? Also get a retainer strip - just buy a piece of metal of roughly same thickness and width and it will be far cheaper than obtaining such a strip of metal from Land Rover. If you break one (like I did), you just manufacture you're new retainer in situ.

Loosen wheelnuts on rear wheels. Put blocks both front and rear of front wheels. Jack vehicle and place axle stands under the chassis. Keep jack placed under the axle to be able to lift/lower the complete axle. Remove both roadwheels or on the side you're starting with only. 

Remove shockabsorbers. Carefully inspect the bushes for any signs of wear - if suspect discard and check why they have been destroyed. Typically lower bushes tear, due to movement in the trailing arm bushes. Rectify problem before installing anything new! 

RH side is more difficult than LH side, and problem is the possibility of overstraining the brakeline, running onto top of diff. 

I firstly turned my attention to the retainer, intending to remove it while everything was seated and no clamps were on - i.e. fingers and tools could safely be put into the coils. Then I lowered the axle and released the two bolts on the lower retainer plate. The nut is spotwelded below, so a 17mm socket will suffice. One of the bolts snapped, but it was easy  using an angle grinder to remove the nut and refit using nut and bolt (fairly big washers needed). 

Pull carefully on top of coil to make it unseat from top bracket - use no brute force here, or you're clamps could slip. You may have to tighten the clamps further to make it let go of its top bracket. Best thing is then to lift axle, tighten clamps, and lower again. This is a safer way than working directly on the clamps. 

Having the coil released top, and the retainer already removed, the coil can be withdrawn. Manuals states this is the time to remove the retainer strip. If done this way, you will have to carefully release the tension from the clamps before putting fingers and sockets into the coils.

Having the spring removed, this is the time to brush away rust and dust, and put on some rustproofing oil onto the brackets. New spring should then be put under tension by the spring clamps, and slided in, remembering the nylon isolator up top. If the coils are not identical in both ends, i.e. like Famous Fours coils being closer in one end, put the closer end up top as this will make it easier to put fingers and tools inside the coils to work on the retainer strip. Release tension from the clamps. Put in the retainer and bolt it. 

Put the shock absorbers on, taking care to get the different washers and bushes in the correct order. Refit roadwheel.

The LH side was easier, and neither of the springs (old or new) had to be compressed to be taken out/put in. This is due to the further "drop" on the LHside, because the rubber brakeline is offset. 

So, how is the ride?

During the last 7 months, Otto has had: All new suspension bushes (except from A-frame) (blue Polybushes chosen), all (5) new shock absorbers (Monroe Adventure + Bilstein gas steering damper), and all new coilsprings (Famous Four standard ride height HD springs).

The ride has become substantially firmer, having an improved steering feel, improved high speed road handling and cornering. But also a harsher ride when unladen, initially more bouncy when vehicle is empty (this is pretty much what I'd expected for a Famous Four setup + gas dampers). As soon as the components are being put under stress, i.e. vehicle is loaded or with medium sized potholes and bumps, it feels softer. But then if the hole is deep or bump is high, it gets firmer again. Feels like being initially soft, and then successively harsher. This is probably both due to the rear coil springs being progressive/dual rated, and the shockers also have a valving allowing for reacting differently to "soft" and "hard" bumps. Rolling and pitching drastically reduced. 

But: All shockers were far beyond renewal date, lots of the bushes were no-good or close to shot, though coils seemed to be OK. Don't know how ride would have felt changing from near-new OEM setup, but the new springs are definetly both harder and shorter, indicating that ride should get harsher...so I guess I got what I wanted and what I paid for...

Spring length and rideheight:

Of course I forgot measuring ride-height before fitting new springs, but I feel it now seats lower than on the old ones. The free unladen length of the used front springs were measured: 

Rear ones were difficult to "read", but seems to be this: LH Rear marked PinkRedBlue, RH Rear marked PinkRedYellow. Those are supposed to be front coils, so doesn't quite make sense. . 

Vehicle now sits a tiny bit higher than a 300tdi (on standard springs) I met today, smth like 5mm higher - probably just the difference between new and old springs.

This is the height on the new Famous Four normal ride height springs on Otto, measured with 205-16 wheels, from floor measured through the hub and to the highest point in wheel arch: 

The front ride height is a really bit puzzling, as the springs I removed differed by ~20mm - and RH side shorter than LH side. Suspected it would sit lower on RH, but in fact it sits higher...

Famous Four +1" Heavy Duty Springs

A friend of mine recently renewed his springs, and fitted Famous Four - but then of the +1" type - i.e. a moderate suspension lift. 

On 225/75-16 wheels, he has measured the height from ground, through hub and to top of wheel arch, highest point of wing: 840mm +/- 2-3mm in all corners. 

These springs has in fact lifted the vehicle more up front than rear in relation to the standard ride height Famous Four springs as measured above.

More help and info on suspension

For more help on suspension, check these links:

Discoweb: Go to tech-section: Look for stuff on suspension mods, lifts, etc. (the articles are organized accordiing to the alphabet, which isn't too helpful...)

Also check and especially their article on polybushes and the project 110 article on renewing bushes+springs+shockers

Vibration on coilers: LRs technical bulletin on diagnosis of vibrations

Northern California Rover Club has a pdf-newsletter with an article on changing shock absorbers.