Project: W124 Recommission

[mj2k]

Following advice on another thread, I'm posting my project thread here, in the hope it'll prove interesting or useful to someone.

I was planning to buy a good W210 in a few months, but as it happened whilst I was researching W210 potential issues, I stumbled across a barn find W124 which was asking to be rescued...

It's a 1990 W124 2.5 normally aspirated diesel with manual box (though it's got a 3.0 TD sticker on the boot for some reason), in black, with vinyl seat covers hiding it's no doubt horrendously shiny cloth seats.

It's been in storage for 4 years and has 315,000 on the clock, so theoretically has plenty of life left in it, though will presumably need a little recommissioning.

Plans for it are:

• Get it running and MOT it
• Check out the interior condition and fit leather if the cloth is done for
• It's had a few MOT advisories for it's worn propshaft so will def need to look at that
• Check if there's any hidden structural rust anywhere
• Once I know it's solid and driveable, look into fitting it with an OM606 turbodiesel
• Potentially uprate the gearbox, and maybe diff
• Enjoy!

Car as I bought it:

 

[mj2k]

Car arrived last Tuesday, and first impressions weren't too good - the brakes seized on the back of the tow lorry, so we had real trouble getting it into my garage. Also it was a non-starter, and the radiator was holed.

First job was having a look at the starting problem. Expecting fuel starvation I cracked open the unions at the filter, and surprisingly found plenty of diesel. But I also found the new battery was completely dead.

24 hours later the battery was still only showing 7.5v, so presumably the previous owner burned it out whilst trying to start it. I borrowed the battery from my Pug 306, turned it over until fuel came out of the filter output, and retightened the unions. I then cracked the unions on the injectors, and repeated the procedure until I saw fuel there.

10 seconds after I'd retightened the injector unions it made a splutter, after another 3 cranks it started and could be revved. It stayed running and I managed to make the car move under it's own power for the 1st time in 4 years

Unfortunately the radiator I'd bought was wrong, and the new rad isn't due until 24th Feb, so I couldn't do any more mechanical work for the time being.

 

[John Jones Jr]

Sounds like you could have a lot work on your hands. What's the body condition like?

 

[mj2k]

Next thing was looking at the interior, under the fake leather covers. It was generally in good condition, but had the usual unsightly driver's seat bolster wear, was filthy, and absolutely stank of cigarettes.

So the below interior was bought off Ebay:

I picked the interior up on Sat, and started fitting it on Sat evening. Front door cards were well and truly stuck, but since I was taking the old interior to the dump on the Sunday (it stank that much!) I ripped off the door pockets, which freed it up. The front door cards had obviously been off before, and then been forced into position which had bet the 'lug holes' and jammed the plastic lugs into weird positions. If you hit the same issue but plan to reuse the door cards, follow the proper door card removal procedure as far as you can, then very gently try lifting the edges of the door panel until you can feel where it's stuck. If like mine it's stuck on the door pockets, you should be able to gently pry them up a little without doing too much damage, and then try gently tapping from below to free them. Probably he same would work with the door handle clips too, important thing is not to bash it too hard from underneath if it's stuck, or you will break clips off.

Next tricky job was removing the rear headrests. This procedure was sort-of followed, but because I had no battery power the headrests were in the wrong position. Carefully prying off the plastic covers from inside the car allowed me to slip a small screwdriver in to push the plastic 'lever' in the below photo (pinched from above thread). No need to pull the whole darned lot out, if you move it in the right direction the headrests just slide out

Next nasty job was one of the captive nuts holding the front seats in place was spinning freely without undoing. This was the biggest / nastiest job of the whole lot. I undid the 3 other bolts and wedged the seat at an angle, to put some extra pressure on the unstuck captive nut. This caused it to become captive-ish again, and allowed it to be undone a few turns, before having to re-wedge the seat. Much fiddling later, it finally came free

I still have to either fit the electric seat loom or attempt to fit the manual seat bases, but apart from that it's all done now:

 

[mj2k]

Sounds like you could have a lot work on your hands. What's the body condition like?

Ah, that's the interesting bit. It doesn't look too bad from first impressions, but it is rotting in unusual places, e.g. on the top of the sill where the plastic kick plate has been rubbing and under the rear carpet, just near the double skinned section on the rear seat base. I can't think of any earthly reason why it'd rot there - it's nowhere near where road muck would get kicked up and the carpets weren't wet, so it must just be years of condensation damage.

I haven't got it up in the air yet (the brakes are still seized and I wouldn't trust jacking it until I've freed them a bit), so I guess I'll know a bit better once I've attacked it from underneath with a screwdriver.

The most scary bits for me would be if the rear subframe mounts have completely disintegrated so I've got nothing to weld against, or if the front spring hangers have rotted through. If either of those bits have gone completely I might have to strip it for the many useful parts and get another shell, but it'd be a shame because I like the colour.

Anything other than that I'd consider a good excuse to get in some welding practice

 

[mj2k]

Final update until the rad arrives - the new battery arrived today. Stuck it in, turned the key, started first time

So it looks like the only issue causing it to be a 'non-runner' was an airlock caused by replacing both fuel filters without bleeding the system.

I bet a great many diesel W124s have had extra unnecessary fuel system work done or maybe even been sent to the scrapyard because of this same issue, and I bet most normal owners' patience would run out after they'd flattened their battery for the 2nd time trying to reprime it. Why on earth didn't Mercedes fit a mechanical priming lever to the lift pump? This problem would be gone with just a little boring finger exercise if it had one

 

[John Jones Jr]

under the rear carpet, just near the double skinned section on the rear seat base. I can't think of any earthly reason why it'd rot there - it's nowhere near where road muck would get kicked up and the carpets weren't wet, so it must just be years of condensation damage.

That could be water ingress. My first suspicion would be a leaking rear screen seal. Have a look under the parcel shelf trim and inspect the shelf from the boot. But as you rightly say it could be just from condensation.

 

[Mike Walker]

Interesting thread so thanks for starting it. I hope that you get the same level of interest and support as Charles Morgan has with his restoration, albeit of a different model of Mercedes.

 

[grober]

The rear subframe front mounting points and the rear of the sill around the jacking point seem to be the most vulnerable points for structural rust. There are many threads out there about this type of repair and it should not be a reason to write an otherwise sound car off---small body sections can be fabricated or sometimes parts from later models can be adapted. Because its a 1990 car it will have been factory painted using a solvent based paint system rather than the later water based paint so I wouldn't be surprised if the bodywork is in reasonable nick compared to cars several years younger.

http://forums.mercedesclub.org.uk/showthread.php?t=99883

 

[mj2k]

That could be water ingress. My first suspicion would be a leaking rear screen seal. Have a look under the parcel shelf trim and inspect the shelf from the boot. But as you rightly say it could be just from condensation.

Thanks, I've had the parcel shelf out to fit the new interior, and there wasn't any signs of water ingress there, but I'll check from inside the boot too.

 

[mj2k]

Interesting thread so thanks for starting it. I hope that you get the same level of interest and support as Charles Morgan has with his restoration, albeit of a different model of Mercedes.

Thanks, doubt it's going to be quite so good, but if I can rescue a reasonably unusual old lady (she's got the ASD rear diff and manual box) from the scrapheap that'd be good

 

[mj2k]

The rear subframe front mounting points and the rear of the sill around the jacking point seem to be the most vulnerable points for structural rust. There are many threads out there about this type of repair and it should not be a reason to write an otherwise sound car off---small body sections can be fabricated or sometimes parts from later models can be adapted. Because its a 1990 car it will have been factory painted using a solvent based paint system rather than the later water based paint so I wouldn't be surprised if the bodywork is in reasonable nick compared to cars several years younger.

W124 rusted rear subframe mounts - Mercedes-Benz Owners' Forums

The jacking points seem reasonably good though I haven't had the sill covers off yet, and the subframe mounts look reasonable, though I'd rather get it through an MOT before poking them too vigorously

Main thing that worries me is if the rear subframe mounts or front spring hangers have disintegrated - it'd make welding it back up without affecting wheel alignment a lot more tricky. Actually removing the subframe doesn't scare me too much, I've just had to pull both subframes on a V6 Alfa, and anything will seem easy after that

 

[John Jones Jr]

Those wheel arch trims would be a concern.

 

[grober]

I never got the chrome wheel arch trims thing. Intended to conceal rusty wheel arches instead they trend to draw the eye. Painted to match the same colour as the body they become virtually invisible to the casual observer. Indeed many "performance " versions of modern cars have them as part of the body addenda deemed necessary nowadays. Unless immediate work is planned to replace / repair the front wings I would rattle can spray em body colour [ preferably off the car] and spend the money on more pressing body concerns.

 

[mj2k]

Yep, no doubt the wheelarches have dissolved behind those trims, presumably they'll have provided a nice moist environment for the rust bug to breed in...

But fixing them is not high on my priority list for the moment, seeing if it's MOT-able has to come first. And tbh I think the black-and-chrome look quite suits the car

Edit: and even more weirdly I can't see any signs of rust bubbles in front of the front wheelarches, so either they've been fillered by an expert, or they're actually intact. If the latter, those wheelarch trims may have actually been added as 'bling' - the car was covered in little Indian god window stickers and bits of fake gold when I got it, so those rust traps may have been added just for the looks.

 

[Charles Morgan]

Most wheel arch trims are there to hide stuff, but occasionally it's just good old fashioned bad taste!

If you ask one of the mods (contact us button at the bottom) they could move this to the project section.

 

[mj2k]

Thanks, done

Must admit I actually quite like them on this W124 - it'd look a little slab-sided in plain black and the chrome breaks up the lines a little bit. Probably a silver coachline (i.e. make sure the lower mouldings have decent silver trim on them) would have a similar effect whilst looking a little less naff, might have to think about that if I can get the trims off without bringing the wheelarches with them.

Or the other option would be to remove the rust traps, black out the windows and pretend I'm a middle-aged gangsta

 

[mj2k]

Quick update - tonight I dared to take a peek under a wheelarch trim / rust trap and at least at the front it doesn't look bad at all. Looks like it may have had new front wings at some point. The rear wheelarches can wait *shudder*.

Also my new radiator arrived. I went for the biggest I could (an E420 rad) because it only cost 10 quid more than the correct one, had a much larger surface area, and had various takeoffs which might come in useful if I do an engine swap. I figured you can't overcool an engine if the thermostat's working correctly, so why not?

A few minutes work with a pair of pliers to snap off a plastic flange which was getting in the way, and it fitted perfectly. Only trouble is - the upper radiator pipe is 7cm too short now. I spent ages looking through parts catalogs trying to find a rad hose of suitable length, then started looking at custom silicone hoses, which would have been overkill at this point. So I started looking at individual silicone hoses, and how to connect them together.

And then I came across an aluminium connector which you could order in various lengths / diameters, with swaged ends. Perfect. I've now got a 20cm long 32mm inside diameter connector on order, and all I'll need to do is cut the original pipe and put this bit in the middle So if anyone else is facing a similar dilemma after buying a non-standard radiator, have a look through Ebay for pipe connectors in the 'car tuning and styling' section - it might well save you a lot of headaches / expense.

 

[mj2k]

Hmm, well today was a mixed bag. I decided to free off the seized brakes and have a good look at the underside while I was at it.

At first things seemed rather good - the spare wheel well's intact, rear flexi brake pipes were as new, the pins holding the pads in came out with ease, and the o/s/r subframe mount appears to be totally intact (no cracking noises under pressure, no signs of underseal cracking or discoloration), so I moved onto the n/s/r. Not so good there - the jacking point is obviously going to need some work:

And the subframe mount has cracks in the sealant which suggests it might well be somewhat crumbly:

Nothing unexpected so far, and the brakes freed off easily at the back. So I moved onto the n/s/f and got a nasty surprise, something I wasn't expecting to see on a W124 - catalytic corrosion. The steel wheel bolts had strongly welded themselves to the alloy wheel, and because of the odd design two of them snapped off whilst I was trying to free them:

The shoulder left sticking out is bound to make drilling them without damaging the wheel impossible, so looks like that wheel's a goner, possibly the hub too. And since I couldn't take the wheel off, I couldn't free the pads or give the wheelarch area a proper inspection.

So, I moved onto the o/s/f. Easy to take off since it's wearing the spare (the proper alloy's still good, but the tyre has a cut in the sidewall), so I was able to quickly free the stuck pads. And then came the 2nd lot of bad signs - the panel under the headlight made ominous cracking sounds, so I gave it a good poke with a screwdriver and got this:

Not totally unexpected, but between the days's earlier findings and the unexpected rot holes in the rear footwells the welding work's building up, and then I found this:

Rot around the suspension arm mount, and similar on the subframe. At this point I was starting to wonder how much other hidden rot I'd find, so I bit the bullet and took off the wheelarch trims (aka rust traps). Both front wings were very good, as was the o/s/r:

That blob at the front's nothing to worry about, just the gunk which was holding the rust trap on. There's some paint damage where the rust traps have been rubbing, but nothing serious. Looks lie I was right - both front wings were replaced. And then I moved onto the n/s/r:

Oh dear. And even worse it looks like the rust trap lived up to it's name and actually caused this damage - when I took it off it carried a large lump of paint and rust with it which would have previously been solid metal, and then I saw rust tracking out from where the metal lugs which held the rust trap on had damaged the paint inside the wheelarch lip. A minute's work with a screwdriver and half the inner wheelarch lip was gone, along with a large section of the outer wheelarch at the rear. So the only way to fix that is going to be with inner and outer wheelarch repair sections.

Also, it's going to need a lot of paintwork - there are numerous scabs beneath the paint like this:

And finally, it looks like the MB job sheet for this car may be incorrect. I may be wrong because I have very limited knowledge of how ASD works, but I'd have expected to see hydraulic lines going into the diff, but I can only see / feel the ABS sensor.

So now I'm faced with a real dilemma - do I make a start on the mountain of welding, knowing there may be further horrors lurking in wait?

Or do I take the good bits off it - the manual box / pedals, rear spoiler, engine (if it's good it'd go straight into a 190d), tank, front wings, interior (of course) and any working electrics, and look for a better base car to work on?

Any opinions gratefully received

 

[grober]

In a way its no surprise that after a much more detailed inspection the car is showing most of the characteristic body corrosion of these models at that age. It is after all 25 + years old having spent its life in the UK 's car unfriendly climate. I would venture that after 365,000 miles? the mechanicals may also be a little past their best. Being frank a manual 2.5 diesel is not a spec that's going to appeal to the bulk of W124 buyers save maybe the veg oil brigade who tend to major on costs anyway. Most cars can be restored if enough money is spent on em but this one is looking more like a labour of love rather than an investment in the longer term. :dk