Robert Bentley Z3 Manual - Review (from BMWCC Magazine)

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Mike Fishwick
Joined: Fri 19 Jun, 2009 11:27
Posts: 1991

  Z3 roadster 2.8
Location: Daglan, France

Robert Bentley Z3 Manual - Review (from BMWCC Magazine)

Post by Mike Fishwick » Mon 17 Dec, 2007 17:06

ROBERT BENTLEY Z3 WORKSHOP MANUAL
Book Review by Mike Fishwick

One of the least attractive things about owning a recent BMW is the almost total lack of information which the owner is permitted to have. To be fair, BMW are not the only culprit, with Volkswagen for instance being just as bad. Many owners of course do not really want to know anything about their vehicle, regarding even routine checks under the bonnet as being beyond them, but there are those of us who dislike the cloak of secrecy with which BMW and their dealers surround our cars.

Unless one is very lucky, the only answer is a manual such as are produced by Haynes, but even these leave much to be desired. In the case of the Z3 the only such publication is produced in the United States by Robert Bentley Publishing.

After many years of reviewing similar BMW motorcycle-based books for the BMW Club Journal I have usually found that Haynes and Clymer etc tend to fill their manuals with information which will never be required. Examples are the measurement of crankshaft bearing clearances, rather than providing clear and accurate descriptions of tasks which are regularly undertaken. I was therefore pleased to see that this two-inch thick manual is basically concerned with routine maintenance tasks rather than major rebuild procedures.

The manual covers 1.9 and 2.8 litre models manufactured between the 1996 and 1998 model years, and therefore does not cover the later 2.8 litre engine with its double-VANOS control, differential intake manifold control, twin catalysts and variable-outlet silencer etc. As one would expect it is aimed specifically at US-market cars, but in most cases there are few differences from those destined for the UK. For example, my 2.8 is fitted with the US-market secondary air injection system which is not used on current UK models.

It does, however, give good guidance on subjects as diverse as the removal of door linings, suspension overhaul, bumper removal and other bodywork-related tasks. Replacement of the timing chains is covered in some detail, but no real reference is made to the practical problems likely to be encountered in removing and replacing the timing chest. In the absence of full dealer facilities this is one job I would prefer to tackle with the engine removed from the car!

Gearbox work covers both the Getrag and ZF products, and is limited to replacement of the seals and lever linkage, which is a pretty realistic choice, but it is unfortunate that no coverage is given to the final drive unit. We are however discouraged from attempting anything beyond oil changes, being told that removal of the gearknob requires an upwards force of 80 lbs, rather than the subtle sideways twist which has it in one’s hand without effort. Again, Bentley insists that before removal of the gearlever we must remove the exhaust system, heat shield, and prop shaft – I removed mine from inside the car, using only a screwdriver, in five minutes!

The quality of photographs is excellent, and it is obvious that many of the line drawings have been produced specially, rather than by the usual expedient of lifting illustrations from the BMW Parts CD.

It is an unfortunate fact of life that manuals such as these must be judged by their failings, and in this case there are frankly too many omissions and mistakes for one to seriously accept the claim that these books are ‘Virtual reprints of the official factory manuals.’

Modern BMW cars bristle with electronic systems (‘Over-complex’ do I hear?) but these are probably the most reliable parts of the car, and most problems in later life will be confined to easily-diagnosed brake and suspension defects. However, should one be faced with a problem in the admittedly complex electrical systems of the Z3, it would be good to have enough background information to decide if the cause is to be found in the wiring or an electronic module.

It is unfortunate, therefore, that no operating descriptions are provided for the Body Electronics, Crash Control, or Slip Control Modules, while others are too basic to be of real use.

Although many owners would like a detailed description of the engine management system, they will be disappointed to find that while the description purports to cover both the Bosch Motronic 5.2 and Seimens MS41.1 systems, it is in fact so general that it could apply to any such system! We are informed that they are ‘Similar,’ and are provided with a very simple diagram showing the Seimens ‘black box’ with its associated sensors etc.

Apart from fuel pressure tests trouble-shooting is confined to component replacement, which is neither logical nor economic, and is seldom effective! In my experience most faults with such systems are caused by wiring and connector problems.

I have written far better descriptions of the Bosch LE Jetronic and Motronic systems as applied to BMW motorcycles, and am sure that a professional technical author should do better than this effort.

Against this background it is a welcome surprise to see detailed lists showing which sensors etc. are connected to the pins of the Bosch and Seimens modules. Unfortunately we are not provided with any information regarding the voltages and waveforms which should be apparent at these pins; this is just the type of information which many readers will be looking for. Neither is any information given regarding the meanings of the more common fault codes.

We should not be surprised by these problems, for publishers of such manuals are dependent upon the manufacturers for the supply of information, data, and in many cases illustrations, without which the production of such a manual would be prohibitively expensive. There is must obviously be a quid pro quo that no real ‘secrets’ will be given away, this usually concerning electronic systems. Even some basic matters are, however, inaccurate.

The illustrations show the fuel supply and return pipes incorrectly labelled, while the fuel pressure regulator supposedly resides with the filter, under the floor. Although this may apply to very early cars, it is certainly not representative of Z3 production. The regulator is in fact shown in its correct position on the fuel rail, but is labelled as a ‘Pulsation Damper!’

We are predictably informed that the brakes of a vehicle equipped with ASC cannot be bled by the owner using a pressure bleeder, and can only be treated at a BMW dealership. In fact the only problem is that total fluid removal from the pump body cannot be guaranteed without a vacuum system – but a simple pressure bleeder such as my Gunsons unit is completely suitable for routine bleeding – such as after removal of a caliper, for example.

Even the operation of the handbrake adjusters is shown as being in the wrong direction.

There is certainly enough information provided for an interested owner to at least be able to gain a good idea of how most things work, and where even the smallest items are located. The large amount of detail which is provided concerns the everyday tasks such as maintenance, and more complex operations such as brake and suspension overhauls.
Wiring diagrams and relay location information are provided in great profusion, and are one of the most valuable parts of the book. For example, the ability to find and replace the relay responsible for the supply to the ignition coils or fuel pump would amply repay the cost of the book, particularly if it were to fail on a wet night in the middle of nowhere. It is worth buying the book for this section alone.

As with all such manuals one will only gain the true value by reading it in conjunction with your car, and deciding which parts apply to your particular vehicle. You will always learn something in the process, or at least find something to puzzle over!

In general I would regard Robert Bentley as being no worse than the offerings of Haynes or Clymer, and in spite of its limitations this book does at least provide the Z3 owner with the only model-specific information that is available from any source.

As with all such books it is far from perfect, but its good points are such that the price of £36 will be amply repaid in terms of peace of mind for the owner who wishes to know more about their car than is provided in the Driver’s Handbook.

BMW Z3 Roadster Service Manual – Bentley Publishers (ISBN 0-8376-0327-7)

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