So I've owned this car for a couple of years, I bought it to replace my E39 530d touring as it's getting a bit tired and it's value is such that it's not worth spending money on beyond maintenance. I fancied an older and more simple BMW of similar size with superior performance, but also a touring. E34 540i touring was what I went looking for, I was really after a manual, but only found one, and it was not in particularly great condition. I therefore figured converting an automatic with better bodywork would be a better option. I picked up this Ascot green example up with relatively high miles at 196k, but as i was replacing the transmission, diff, and propshaft, I figured it didn't really matter.
The newly refurbished staggered throwing stars were a definite bonus! Those will most certainly be staying.
I spent most of the last 2 years collecting parts, mostly for the 6 speed conversion, but then for everything else. I certainly needn't have bothered about the mileage because there'll be bugger all original mechanicals when I'm done!
But first I needed to sort a few more pressing issues, like a sunroof leak. I don't believe in taking things apart and fixing just one thing, when you can sort out several things, so i figured if the headlining was coming out to sort what turned out to be a blocked rear drain, I might as well take the roof rails off and sort out the flaky paint on those, recover the headlining that was old and saggy, replace the gas struts on the rear glass hatch, replace the dried and shrunken sunroof perimeter seal, and for an added bonus while significant portions of the rear interior are apart, replace the usual wiring hack job towbar electrics with a genuine BMW kit I picked up brand new for a song, along with rebinding and tidying up all the electrical wiring.
First off, the roof rails
Until i took them off, I didn't realise they were fibre reinforced plastic! I had figured they were cast metal, as what was showing under the paint was a dull grey colour. Live and learn huh! Interesting construction technique, the structural portion of each rail is formed of an incredibly tightly folded piece of stainless steel, with four stainless studs that protrude through the car roof. The moulded plastic rails are then held to these with a multitude of short stainless set screws that thread into brass inserts in the plastic.
I didn't get pics of stripping the paint off the rails, or them bare plastic, suffice to say it was a messy process and revealed that some of the inserts and surrounding plastic had been pulled out, but were thankfully not missing, so before I painted them, I refixed them, and reinforced all the others with some JB weld (JB weld will feature later, stay tuned!). I gave the rails a sand with some 240 grit until any scrape marks from the stripping were gone, gave them a coat of plastic primer, and then about 3 coats of plasticote satn black.
Came out pretty nice, and I only had to fish one little fly out of the finish, I'll call that a win! Once they'd dried fully (I left them for a few days out in the sun) I was time to assemble them, and look into the spacers that go between the studs and the roof.
The rust staining around the studs is from the spacers. They allow the rails to be clamped down to the roof without squashing the rubber gasket that fits between the rails and the roof panel. The originals were badly corroded, and the rubber o-rings were pretty shot. New ones were expensive for what they are, and didn't seem from research to come with new o-rings. I decided to make new ones from a couple of stainless washers (M8 and M12) and a silicone rubber washer (16mm ID if memory serves). Thickness came out the same, it fits over the shoulder at the base of the studs nicely. To hold these little assemblies together in alignment, I used a layer of double sided tape.
That sorted, I used the double sided tape to hold the gaskets onto the base of the rails and moved onto preparing the roof in readiness. There was a little corrosion around the holes in the roof, so i bare metalled these little areas, treated them with kurust, and epoxy primed them . The epoxy is some stuff I've used on suspension components, and bonds really well to steal, is water proof, and in this application, where it's going to be covered, needs no top coating. I'd already fitted the perimeter seal on the sunroof (pain in the arse job to get the sticky glue remains off, sorry no pics of that job) so it was time to refit the rails.
All in all, a very time consuming, but satisfactory job, that I'm glad is done.
Next, a seemingly unrelated job!