BMW 5 & 6 Series E12 - E24 - E28 -E34 Restoration Tips and Techniques (eBook)

Chapter 2

E28

The E28 arrived in July 1981 as the second generation 5 Series. Various comments about the new car being dated were levelled at the E28 and in many ways it was slightly old fashioned, conservative and very similar looking to the outgoing model. But as Ford found out with the 1982 Sierra, going radical doesn’t always pay off. Not only that, but in the late seventies when the E28 was being designed, BMW was not the big selling multi-factory company that it is today and they could not afford either a total redesign from scratch or the financial consequences if the car didn’t sell. So, for the second generation 5 Series it was a conservative massaging of the original, tidying up details and remedying the faults of the old car - wind noise, dated interior, mediocre fuel economy and tricky on limit handling.

BMW’s objectives were “to maintain BMW’s typical styling and appearance, and at the same time improve economy, interior space and luggage compartment size. To provide more comfort, and higher standards of ‘functionality’, ergonomy and safety. To improve quality and reliability in general”.

Whilst the E28 was the same length as the E12, an extra 1.6 inches of rear leg room was found. The boot was now 16.25 cubic feet in size.

Inside, the E28 was all new and a fine example of BMW’s interior design. All new and made from the highest quality materials, the most basic E28 still looked and felt like the quality item it was. New seats and solid door trims went in along with an all new dash, big clear instruments and the all new service indicator system that stored information about the number of cold starts, engine load and distance to calculate when servicing was needed. Cars with LE Jetronic fuel injection also had an econometer in the base of the rev counter. The E28 heralded a new era for electronics as well as for it’s time, the E28 was pretty advanced. The styling was also very popular and the E28 sold well - whilst Audi came up with the slippery 100 and Ford had the Sierra, neither had the classy and patrician look of the E28.

In fact, whilst the E28 looked like little more than a face lifted E12, much of the car was different and only the doors, roof skin and front and the glass was carried over as well as the basics of the engines.

Starting at the front, the E28 suspension was completely revised and nothing was carried over. The picture on the next page shows that the E28 suspension was very different and was modelled on the design of the E23 front end with double joint technology. This design gave a reduced steering offset for greater stability (particularly under braking) whilst moving the front suspension rearwards slightly and maintaining the E12 wheelbase (just half in inch shorter), and giving more suspension travel. The front anti roll bar was also moved from the front to the back meaning that the front spars of the crossmember could be eliminated, improving accident safety greatly by converting the front end into a crumple zone without touching the suspension at all.

E28 M5 (Dan Kelly)

White 528i rear view dead on (Derin Oloyede)

This revised front suspension meant that the inner wings and chassis legs were also completely new.

At the back end, the semi trailing arm rear suspension was also totally revised - again, not a single component was carried over. The heavy old E12 suspension that was based on the E3 saloon design - was replaced by a new lighter set up with revised trailing arms and less trailing arm pivot axis.

The 528i - now the most powerful model with the M535i discontinued - had a special rear suspension. This had an extra link between the trailing arm outer pivot. This meant that the rear wheel did not just have a circular motion around the pivot axis but instead has a ‘straighter’ motion allowing a raising of the pivot point to maintain geometry and give an anti squat effect.

The braking system was also completely revised. Gone were the twin servos and the single servo on a bracket set ups and in came two new systems. For the 518 and 520i, a simple vacuum servo and single master cylinder was bolted directly to the bulkhead and pedal box (with a cross linkage for RHD cars), and for the 525i and 528i, the E23 7 Series system was used - this was a hydraulic booster taking hydraulic power from the power steering pump straight to a hydraulic ram between the pedal box and master cylinder with a pressure accumulator sphere not unlike the suspension sphere on Citroen Hydropneu-matic suspension. The calipers were now twin piston rears similar to before, but at the front end the old four piston calipers were sadly replaced by single piston sliding calipers - perfectly okay, but just not as ‘nice’ as the old four piston units. The brake hydraulic system was split diagonally. 518 and 520i cars used rear drum brakes, and ABS was an option on the bigger engined four wheel disc brake cars.

White 528i Front On (Derin Oloyede)

The wheels were also restyled - new style steel wheels with circular holes and a stainless steel ‘dog dish’ centre cap to cover the wheel bolts. The 20 spoke alloy wheels remained as for the outgoing E12 but a new addition was the Michelin TRX alloy wheel and tyre option. These proved to be a fairly popular option on the 528i (and standard on the later 528iSE), until the owner found out how much new tyres cost!

E28 Front Suspension (BMW AG)

E28 Rear Suspension (BMW AG)

1982 518 in Pasta Green

The tyres used on the E28 were the 200/60 HR 390 and the TRX had proven quite successful on the Ford Granada 2.8 - they were not nearly as successful on the E28 though.

The engines and gearboxes were another area where BMW’s engineers were busy improving things. The M10 engine in the 518 stayed pretty much as before -although not massively powerful it was a solid reliable old plodder that was never going to be a huge seller. The opportunity was taken to raise the compression ratio from 8.3:1 to 9.5:1 however.

The 520i was a very welcome improvement over the previous 520. Still using the same basic M60 six cylinder engine, the new unit for the E28 used the electro - mechanical Bosch K Jetronic fuel injection system and electronic breakerless ignition. Power was rated at 125 bhp with a 9.8:1 compression ratio, and 163 nm of torque. In common with all E28 engines, the block was cast slightly lighter than the previous E12 units.

The 525i and 528i were also revised. Replacing the original L Jetronic fuel injection system was the new LE Jetronic, an economy biased system with few, lighter parts including a new one piece inlet manifold designed to boost torque and overrun fuel shut off.

The gearboxes were much as before, but with a few changes. The four speed 518 unit was still a Getrag 242, but new to the E28 was a five speed overdrive 245 unit. Similar units with specific bellhousing bolt patterns were also used in the 520i although the vast majority were five speed units. The 242 continued in the 518 until the end, but the 245 was replaced in September 1982 by the Getrag 240 five speed, an all new unit designed for the E30 3 Series.

518i 520i 525e Standard Interior

White 528i, rear 3/4 (Derin Oloyede)

Pasta Green E28 with later plastic wheel trims

As for equipment and specification, the E28 carried on what the E12 left behind. The 518 was a very basic car - plain trim with no rear fold down centre armrest, four speed box, no power steering and a clock. The 520i was sometimes ordered as basic as this but they almost always had a rear centre armrest, power steering and a five speed manual box - very few (if any) cars outside of the German taxi rank were ordered without these extras which were made standard in the UK for example. The 525i was a similar spec to a 520i but normally with central locking and electric front windows, but the 528i had a five speed box, front foglights, alloy wheels, electric front windows and central locking from the word go. The six cylinder cars also had a rev counter with only the earliest and most basic 520i’s having a clock. The 525i and 528i also had better door trims with cloth centre panels.

E28 518 engine bay

The E28 was launched in the UK in October 1981 with the 518 following on in January 1982. Straight away, the new model proved to be a good seller but BMW were working away behind the scenes to improve it further. The first change came in September 1982 when the 520i received a new engine. The K Jetron-ic M60 unit was only ever a stop gap until the new revised M20 engines intended for the E30 came on stream, and the 520i got the engine first. Very similar to the old M60, the engine was basically the same but featured a new cylinder head with bigger inlet ports, revised cam profile and Bosch LE Jetronic fuel injection as well as the revised camshaft belt and drive sprockets phased in during September 1981. The Getrag 245 five speed gearbox was also replaced by the 240 at this point - the 240 was a quieter and more durable unit.

At the same time, the Getrag 265 five speed overdrive gearbox is the 525i and 528i was replaced by the all new 260 unit. This unit was designed to go into the new E30 323i, and BMW chose to replace the heavy and ageing 265 at the same point with this new box in a special M30 casing. The 265 lived on as a close ratio Sport unit in the 528i.

Late 1982 also saw the 518 gain a new electronically controlled Solex Pierburg 2BE (2 barrel electronic) carburettor in common with the new E30 316, plus a viscous coupled fan was finally fitted.

October 1982 saw the launch of the 524td,...