M5 topic (E12-E28-E34-E60-F10)

[Jeroen]

Wonderful! So it's about time for that 2nd video!

[raymondw]

The E34 M5 is the last of the hand-build M5's. This fact alone makes it one of the last true M cars, to which I refer too as a 'classic M'. Proof of that proces has always been rare, but some pictures have been posted on the m5board just recently.

Enjoy:

http://www.m5board.com/vbulletin/e34-m5 ... -more.html

[Jeroen]

Always nice to see how much care and dedication was put into these machines ey?!

[raymondw]

I have created a facebook acount some time ago for which I reworked some raw material from the Ardennes trip of 2010.





New Bilsteins are still available from BMW so I bit the bullet and ordered some to replace the 'cluncking' front-right unit.

[raymondw]

The following picture shows the condition of the left-front jack-stand of BK02837 after removal of the protective BITAC layer. Normally, this protective coating is resistant to shock and thus is even capable of protecting the underlying metal on impact of a larger object; however, this coating ages and can become brittle over time. When using the jack-stand, cracks in this coating will occur allowing water to enter the cavities underneath. When not taken care off, the influence of the environment (oxygen) will cause corrosion which will be heavily accelerated during the winter-season when massive amounts of salt are thrown on the roads.



As BK02837 has always been garaged during the winter-seasons, the sills are well preserved and only show slight surface corrosion on the jack-stands themselves and the mating areas with the front-fenders. The following picture shows the jack-stand after a two hour curing of the etching fluid, but just before applying the first layer of POR15-coat..



After applying the first-layer of POR15 paint. This will be allowed an hour to dry before applying a second layer of paint.



As the lower part of the sill towards the wheel arches were also affected, these got the full POR15 treatment as well. As clearly can be seen, the grey POR15 paint matches to the OE-primer paint very well.



In between the application of the first and second layer of POR15, I had some time to drain the oil from the differential.



The following picture shows the drain-plug just after its removal; the tiny particles in the oil are remnants of friction material from the limited slip plates. This is exactly the reason why LSD’s need regular fluid-changes.



According to the service schemes from BMW, this is required at every inspection II (80k km interval), but IMHO this is too much for LSD’s that are frequently used in LSD-operating range.



I have to admit BK02837’s service records does not show any proof of previous diff-fluid replacements, so it is at least 14years of age when it was serviced by the BMW dealership in Landeck (Austria) for its inspection II at 80k km. With that knowledge in mind, the condition of the old-diff fluid is not that bad. Despite its dark-brown tint, it still is clear and far from sludgy at 191k km.

[Jeroen]

Nice work again. Reminds me to replace some diff oils as well!

[raymondw]

For some time, the rear wheels of BK02837 was a little too low. Although this filled the wheel-arches nicely, the ride was too harsh. This usually is caused by the pressure accumulators of the SLS-system. Each accumulator contains a membrane to regulate the pressure through the shock-absorbers. This membrane is made from rubber that is subject to wear and aging. At some point, the two chambers in the accumulators are connected due to which the shock-absorbers are subject to the full pressure of the SLS system that is fed by the PAS-pump at the front-left side of the engine.



The shock absorbers were replaced in 2006 at a considerable expense, but have been used for no more than 25k km since then so are still new. Besides, their retail price has increased to more than 700 Euro’s each; needless to say that I don’t want to take any risk of ruining them. Besides, I like the composed suspension of the E34 that despite using low-profile 17” tires isn’t overly harsh and thus offers some comfort on long distance trips without compromising on predictability. Next to originality, that was an important reason for me to stick to the OE suspension in July 2006.



The removal of the SLS-accumulators is rather straight forward. These are bolted to the body with three M6 bolts. The access to the rear-bolt is limited, especially on the left side where the exhaust limits space, but nothing that a few extension tools cannot solve. Care should be taken when disconnecting the ingoing and outgoing pressure lines. A simple half-open wrench won’t do as it doesn’t distribute the force evenly around the nut due to which it will just damage. Instead, I used a half-open hexagonal wrench, a much better tool for the job.



Since the pressure hoses between the SLS-accumulators and shock absorbers are replaced as well, I did not disconnect the outgoing connection directly on the accumulators, but on the shock absorbers instead. This requires two 17mm wrenches; one to secure the ingoing connector to the shock-absorber and the other two disconnect the nut from the pressure-hose. The right accumulator just drops out; the left one, requires lifting of the car to gain enough clearance between the exhaust and the drive-shaft.



After removal, the condition of the underlying body can be assessed, which apart from being a bit dirty is excellent. There is no rust and/or damage anywhere which is typical for a car that has never been used as a daily driver and also has never been subject to winter-usage.



Although not really necessary, I replaced the rubber mounts, bolts and nuts as well. The right accumulator is in place; the left one is still a to do item as well as the hoses.



Hopefully, this will solve the harsh ride, but I will know that for certain later this year. I would like to send the steering-box for a rebuild as well and since both systems are supplied with pressure by the same pump, I won’t fill the reservoir for the power-steering until-that is completed.

In between all this work, I found some time to fill the final drive with some new lubricant as well. On Limited slip differential’s such as used on the E34 M5, I prefer Castrol SAF-XJ which is rated with a viscosity of 75W140.



I used to buy this from the dealer, but at hefty price-tag of around 70Euro’s per litre. On ‘fleebay’, the same product is offered for just 12 Euro per liter, which is significantly less, but not always ‘fresh’ as being from recent production. Please note that Castrol recently relabeled SAF-XJ to
‘Limited Slip 75W140’. Despite the name-change, this is the same product.

[uwbuurman]

Nice pics Raymond! When will this great car be up and running again?

[raymondw]

Nice pics Raymond! When will this great car be up and running again?

Hopefully somewhere in 2013, but I am in no hurry:

- Overhaul of the steering gearbox
- Solve oil-leak in front
- Replace front crankshaft seal and timing cover seals.
- Replace sump gasket
- Preventive change of the piston-rod bearings
- Maye replacement of timing-chain etc
- Overhaul of injectors
- Full TB sync
- Reinstallation of original turbine rim-covers.
- Replacement of the rear-tyres (Michelin PS2)
- Assessment of the front suspension
- Repainting the lower door sills