Preparing BK02837 (M5 3.6) for another twenty years.

raymondw · 19th September 2011, 19:53

Although BK02837 has never been subject to winter usage, this doesn’t mean that this car hasn’t seen bad weather including snow. Even in high summer, there is a distinct change of snow in the high Alpine area’s when cold weather fronts occur. Throughout September, the probability of snow rapidly increases as we experienced amongst others during the E34 M5 Alps tours in 2005.

As I do not intend to part with this car for a very long time to come, a closer inspection of the jack-stands and the water drainage channels from the A-pillar becomes a must. This was already on the agenda for the winter of 2010/2011, however the overhaul of the front suspension of my E28 M5 constrained access to the ramp until May last year so I postponed with a few months.

After the removal of the ‘M-technik’ side-skirts, the sills were inspected and at a first glance are in fine condition. As expected, the protective coating has deteriorated a bit exposing the bare metal of particularly the front jack-stands causing some surface rust, but nothing critical.

This also applies to the drainage channels. These are partially blocked by dirt that was collected after twenty-two years. Total absence of winter-usage and limiting wet-weather use have helped maintain them in good condition. The rear-jack-stands appear to be in fine. However, a thorough clean is required to determine their condition and the course of (preventive) action.

Apart from some dirt, the lower parts of the front-fenders are in excellent condition.

My first impression is that the sills need a good clean, followed by the partial removal of the protective coating before preserving the exposed metal areas. The paint of the lower part of the fenders has suffered throughout the years of spirited driving in the Alps though; there are literally hundreds of small spots were the primer paint becomes visible, meaning that the original diamond-black paint must be much less than 100micron’s. Although this is original paint, there should be no harm in a repaint for cosmetic reasons.

Also twenty-two years of age is the sump-gasket. Although the engine has never been opened, the small oil-leak requires attention to avoid the spill. The required parts are already on my project-inventory.

Tomba · 19th September 2011, 22:02

I'm already looking forward to the write up Raymond!

First e28 M5 · 20th September 2011, 00:17

Big Ray,

Since you are keeping this classic E34 M5 I would open the small plastic caps located inside the rear wheel housing and fill with oil or heated/melted grease. This way you will keep the lower panels to rust from inside to outside. On all german cars they have that plastic caps all around the chassis to lubricate and extend the chassis life. When I used to live in EU I did this to my Merdeces W115 220D and never got any problmes.

One thing I hate on cars is rust ! I dont care if the car is 500.000 miles as long is rust free that is what matter for me...otherwise you became "Flinstone"...In sunny california my E24 M6 loves the dry wheater, I dont have even a one dot of rust around the chassis.

Keep us posted

Anri the M6-er

mc hammered · 20th September 2011, 05:30

Thanks for pointing out where to look and I plan to pull off the sideskirts and inspect those areas as well.

Any rust I will clean up and coat with some POR15 and then add this to the annual checkup.

raymondw · 20th September 2011, 21:55

Quote:

Originally Posted by First e28 M5

Big Ray,

Since you are keeping this classic E34 M5 I would open the small plastic caps located inside the rear wheel housing and fill with oil or heated/melted grease. This way you will keep the lower panels to rust from inside to outside. On all german cars they have that plastic caps all around the chassis to lubricate and extend the chassis life. When I used to live in EU I did this to my Merdeces W115 220D and never got any problmes.

Thanks for the tip; I will certainly do so. The first thing I want is an endoscope inspection. These can be bought with a digital imaging sensor with a USB interface for grabs and allow proper documentation before deciding on the corrective/preventive measure.

davidoli · 21st September 2011, 10:32

Great thread and pics , as usual , Raymond ........... A must to do list for those wishing to keep their E34 M5s roadworthy for years to come !

D

First e28 M5 · 21st September 2011, 17:08

Quote:

Originally Posted by raymondw

Thanks for the tip; I will certainly do so. The first thing I want is an endoscope inspection. These can be bought with a digital imaging sensor with a USB interface for grabs and allow proper documentation before deciding on the corrective/preventive measure.

Ray,

If you look at your all 4 door/jams you will notice those plastic caps as well. Also front hood at the end, it worth to look at the sunroof drain plugs becasue throught the years clugs with durt...

I do remmeber when I used to own my beatuful W115 220D I made a phone call to Stuttgard Mercedes dealer and found that they were selling at that time a special Grease for chassis lubrication.

The crease made for chassis lubrication required to be heated and fill to the areas you want, ones cools down gets hard and stays without going outside to make a mess... Even if you look at the owners manual on old Mercedes will require at some miles chassis lubrication... I think in Germany somewere you will be able to find that specail grease. If you want to lubricate the chassis right I would spent some time to fint that grease.

At this moment I also have Cosmoline was for the engine bay. Often you will see valve cover logo BMM M Power in a bad shape because throught the years the wax is gone and the open metal start corrosion and turns into a nasty look... same for the intake. On my E24 M6 I cleaned the valve cover logo and applyied cosmoline was and stay nice and original..

Keep us posted
Anri

raymondw · 4th March 2012, 00:33

It has been some time since the latest update, but as I now have an E39 530i Touring there is no need to complete the work before the summer. In fact, I am taking it easy and only get my hands dirty when I am in the mood to do so.

Some time ago, I removed the left fender to allow a closer inspection of the sandwich construction between the fender and the sills. As can be seen, the inner fenders are in excellent shape. There is no rust and even the welds look like they have been crafted just recently.

The fender itself appears to be in very good shape. The primer-coating still sticks very well….

With the exception of the lower part that mates to the sill on which some corrosion can be seen. Compared to many other E34’s that I have seen, this isn’t really that serious and the fenders will last for a very long time to come, but at some time, the fenders cannot be rescued forcing their replacement at some point. As I’d like to preserve as much as possible from the original parts, these area’s need attention.

Please note that one can expect the fenders of most E34’s to be in a much worse condition as unlike the vast majority of the E34 population, BK02837 has never been used as a daily driver and has always been spared from winter duties so salt is not an issue. To get an impression on what one can expect on most other E34’s, especially when the M-technique side-skirts is fitted, visit the thread about member Robert Kiel’s E34 M5.

Unlike with Robert’s car, the fenders of GD55450 can be restored. However, the thickness of the metal-plate is very thin so there is little margin for errors. The following picture clearly shows the crater-like surface after the first two sanding sessions. Sanding these won’t do much good as it only removes solid metal; the dremel is too risky so I shot-blasted the craters thoroughly. This leaves surface this is far from ideal for normal primer paints.

For POR15 however, this is ideal as its molecular structure works best on rough surfaces. Most automotive enthusiasts don’t know about the existence of this product that originally was developed for marine applications, but it works very well. An important step In the process is cleaning the craters from ferro-oxide.

This is part of the POR15 application process before the final coat is applied. According to its manufacturer, its surface is very tough and elastic once cured so it doesn’t crack. As such it is ideal for application in areas were friction between metal plates occur.

The POR15 paint won’t be the final finish so in adherence to its application instructions a very thin layer of normal primer paint was sprayed on the tacky POR15 layer. This matches to original primer coats color very well.

I will allow this layer to dry for some days before determining the next course of action.

Last but not least; a recent delivery of parts including two pressure accumulators for the rear suspension. These will be fitted once the overhaul of the fenders has been completed.

raymondw · 31st March 2012, 20:13

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.

Sebring NL · 6th April 2012, 02:43

I really hope you can document this thoroughly and with good pictures this time Ray

Was thinking about doing the same thing with the Sebring once I get her up for summer again.

But also need to put all the Powerflex stuff that DickH already provided in 2008 on the car.