Front and Rear Suspension Rebuild. By Mark Hooper, July 2002

Important Notes.

The suspension of any car can be subject to many different forces during normal everyday use, the loads applied to sports cars can (and probably will) be greater. If in any doubt you should seek professional help. Incorrect adjustment and bad workmanship can at best cause tyres to wear out quickly, the worst case is not worth considering.

I don’t intend to describe in detail how to do the work, you should refer to the workshop manual. I intend to provide some additional guidance based on my experience from actually having done the work.

Why Rebuild?

There will be one of two reasons for wanting to rebuild the suspension on your car:
1. Poor handling
2. Replacement of corroded/damaged components

If like me the reason for rebuilding is corrosion the first thing to do is make sure that you are prepared for two reasons why Lotus cars have a bad reputation, expensive parts and parts that are listed NLA (for those of you who don’t know what this means – No Longer Available). Even for those of you who are simply replacing worn out bushes, you should still prepare for a shock we you get the bill for the parts, some of the bushes can cost £10+ each, and you will require a few.

For those of you who are reading this simply out of interest I suggest that you check your car as described below before you get too comfortable. I was under the impression that my car was fine, after inspection I had to replace all four corners.

Other Jobs to Consider.

As disassembly of the rear suspension requires the brake system to be disconnected upgrading to Stainless Steel Braided Lines could be done at the same time. Possibly extending to a full rebuild of the braking system, including rebuilding calipers, replacing brake pipes, new pads and disks, proportioning valves etc (I did, but that’s another story).

Replacement or upgrade of the springs and dampers, I’d suggest that you replace both rather than just the dampers as the springs will degrade slowly over the years resulting in a lower ride (again I did).

Replacement/adjustment of wheel bearings, I only had to replace one rear wheel bearing.

Replacement of ball joints, check the rubber boots of all ball joints to ensure that they are in good order. Replace front drive shaft boots, check these carefully for any signs of cracks or splits, failure will cause damage to the drive shaft if left for any length of time, also contaminating the brakes and generally spreading grease everywhere.

Check the steering paying attention to the track rods and track rod ends; one of my track rods was worn, resulting in excessive play in the wheel.

Checking you car.

Firstly and most common is corrosion of the rear lower suspension arm.

Places to check are:
1. On the top of the arm just behind the Hub Carrier.
2. On top of the leading or trailing arms.

The Top Link Arm doesn’t seem to suffer from corrosion. If you’ve been lucky now check the front suspension.

Places to check are:
1. On the underside of the main Track Control Arm (see picture)
2. Along both sides of the main Track Control Arm, check where the TCA Strut and spring damper assemblies connect.

Both the upper wishbone and the TCA Strut don’t seem to suffer from corrosion. I’d also suggest that you remove the two plugs on the underside of the Track Control Arm and see if any water or worse comes out. If after checking your car you have managed to transform what seemed like solid lumps of steel into a pile of rust spread around under your car close the garage door and have a couple of beers, go back tomorrow.

Obtaining the Parts and Parts Required.

Now for some really bad news…parts availability, most parts are available to order, but don’t expect to walk in and collect the parts, be prepared to order them. I did however say ‘most’, at the time of writing, front track control arms are NOT available and the opportunistic people who tried to sell me two used arms from a crashed car that was 2 years older than mine with no guarantee for £700 were almost as welcome as the people who tried to sell me the rear brake proportioning valves for £300 each (but that’s another story).

One important point to note when obtaining replacement bolts for the suspension is that the correct specification of high tensile bolts are used.

Rear Suspension Parts

New rear wishbones are available both from Lotus and Midas Metalcraft, however note that only the Lotus parts are galvanised and included all bushes. Both of these options are valuable, galvanised versions should last considerably longer and the cost of the bushes themselves (6 bushes per side) is almost enough to make the Midas Metalcraft version almost as expensive as the Lotus genuine part. The only other problem with the rear wishbones is their cost, expect to pay £300 - £350 each.

Other parts required for the rear suspension are:
1. Two bushes for the Top Link Arm
2. Set of new nyloc nuts (Always replace these type of nuts, it isn’t worth risking re-use)
3. Thread lock

You may struggle to remove/loosen the top two outboard bolts securing the Link End to the Top Link Arm, these need to be loosened to allow adjustment of the Camber angle, soaking with penetrating oil should help. However, expect to have to replace these bolts.

No other parts should be required, adjustment of the rear suspension is achieved by the use of cam bolts.

Front Suspension Parts

I haven’t found a source for new front wishbones, I had to resort to getting my originals re-fabricated by a local engineering company. Unless you are very skilled I would suggest that this is the best route, as the originals are fabricated components and not highly pre-stressed components a competent company should be able to under take this job. The list price (if only available) for the front wishbone is in the order of £300-£350 each.

Other parts required for the front suspension are:
1. Set of bushed (7 per side)
2. Ball joint upper (see below)
3. Set of new nyloc nuts
4. Spacer-upper ball joint (see below)
5. Camber adjustment plate (Later cars) (see below)
6. Ball joint lower (If worn out)
7. Ball joint anti roll bar (see below)

You may struggle to remove the bolts securing the top ball joint to the upper wishbones, I’m afraid that not matter how much penetrating oil or pressure you exert you will fail to remove these bolts. Unfortunately heat will destroy the ball joint itself.

On my car I was missing half of the spacers for the upper ball joint, there should be 8 per side of the car. They are used to alter the castor angle of the steering.

If you have a later spec car you will possibly require different camber adjustment plates, there are 4 different sizes, you will obviously already have one set. Earlier cars use bolts that have integral cams similar to the rear suspension.

Care should be taken when disconnecting the front anti-roll bar that you don’t either pop the ball joint or even worse snap the bolt. If the ball joint does pop, it is fairly easy to reassemble, however if you snap the bolt off you will need to replace the joint. Expect to pay £40 - £45 for a replacement. If the nut is tight and penetrating oil isn’t helping I’d suggest using a nut splitter, a replacement nut is cheaper.

Doing The Job.

Workshop safety first, this is job that definitely requires the use of sturdy axle stands to support the car. Please take care placing the stands correctly, also note that you need to make sure that you can access all of the bolts securing the suspension to the car. Do not work on a car supported by jacks, blocks of wood or piles of bricks etc. It is also important to properly support the car as some of the bolts will be very tight requiring you to exert some force to release.

Disassembly and reassembly of the front and/or rear suspension is straightforward, no special tools are required, not even a spring compressor as the springs and dampers can be removed and installed as single assemblies.

Replacing the bushes will require the use of a press, or some other suitable alternative, it is important to note that there are ‘hard’ and ‘soft’ bushes, and that they should be inserted into the wishbones the correct way round.

I’d always strong advise the use of copper grease when reassembling the suspension, taking care to remove the grease from threads before tightening (grease will adversely affect the torque setting).

The rear top link inboard bolt requires the use of thread locking compound.

Another important point to note is that the wishbone pivot bolts should only be fully tightened when the car is at its normal ride height, failure to do this will accelerate wear of the bushes.

Once complete you need to adjust the suspension geometry.

I can recommend the use of the Dinitrol range of cavity and body wax products and would suggest that all new components (apart from your brakes) receive treatment on a regular basis. This should not only reduce the risk of corrosion but also ease disassembly.