1991 Mercedes W124 250D Manual

1991 Mercedes W124 250D Manual

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ian316

4,150 posts

107 months

Sunday 7th January 2018
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90-95 seems to be the ideal cruising speed anymore seems noisy and pointless and any less doesn't seem to improve the mpg

SebringMan

Original Poster:

1,773 posts

188 months

Monday 22nd January 2018
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As you say they gather pace rather than accelerate.

They just cruise lovely on the motorway and in a comfortable yet grippy way are a nice drive on country roads.

Speaking of which mine is back out doing the daily rounds. 38MPG was what was had from the last tank. I must have been feeling flush as I have brimmed the tank to the top with V-Power Diesel ; I know the PD diesel I had responded very well to this, to the point of being cheaper to run. While I don't expect any difference here it may clean things out and perk it up a bit, you never know.

It seems to be pulling well enough anyway smile.

SebringMan

Original Poster:

1,773 posts

188 months

Friday 9th February 2018
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Is there much to update?

In all honesty, no. It's been a faithful workhorse since I got it and it's been gathering the miles as I go along while giving me a comfy ride as I go along the way.

However, I bought an Apple CarPlay unit for the M3. Seeing as it is not on my drive and I wanted to try the HU before I kept to committing it I figured I'd try it in the Mercedes. A brave measure I know but it didn't take long to realise that I'd be installing this into the M3:

February 2018 by Charlieboy, on Flickr

You can see why as despite the headunit's single DIN chassis it wasn't exactly a great fit ito the Mercedes, albeit very usable. That's not to say it can't be done.

Mercedes February 2018 by Charlieboy, on Flickr

Soon after the Alpine from earlier on in this thread was reinstalled. This reminds me. I've sold one of the Alpine units and I really should sort out the headunit wiring, which isn't to the standard I would do it.

Speaking of standards the W124 made a friend for 2 days the form of an S205 C350e Estate. It's fair to say that both are unsurprisingly very different. I got the C350e as hybrid technology has intrigued me lately. All I will say I can see the benefits of hybrid technology even though the fuel savings aren't that convincing at all. It's an impressive car for sure with plenty of poke in the mix and usable poke, espeically in town.

That said, the real world MPG between the two isn't miles apart.

Mercedes February 2018 by Charlieboy, on Flickr

Mercedes February 2018 by Charlieboy, on Flickr

Mercedes February 2018 by Charlieboy, on Flickr

Mercedes February 2018 by Charlieboy, on Flickr

Mercedes February 2018 by Charlieboy, on Flickr


SebringMan

Original Poster:

1,773 posts

188 months

Wednesday 14th February 2018
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There are times when sometimes you see your life flash before your eyes. While that didn't happen to me, I probably wasn't far away from it. Why? I lost braking power approaching the Princethorpe crossing on the Fosse Way!

I tried an ambitious overtake (read, any overtake) in the W124 where some sleepy woman was doing 35-40MPH in an NSL limit! Bailing out of the overtake was fine but it wasn't for when I came to stop for the Princethorpe crossroads! The first pedal stroke went to the floor with little braking with the second pump was fine. Oddly, if I let the car cool down the brakes were fine again for 15 minutes but then I'd need a second pump to get meaningful/normal power out of the brakes. I can only assume one of three things

1)The master cylinder was iffy - It did however look to have been replaced recently and the fixings have been disturbed on it previously too
2)The brake fluid had boiled due to a high water content ; given its lovely brown colour this is a likely scenario.
3)The level dropped during the overtake which is what introduced air into the system. The reservoir is not the easiest thing to read off and it can be misleading.

Out of the above the latter two scenarios seemed likely with the boiling of the fluid looking possible ; I did manage to syringe out the brake fluid after all. The annoying thing? The brake fluid was on the list for being changed but once the weather had begun to warm up. It was fair to say that the priority of this changed somewhat very quickly!

With the Eezibleed and the spare tyre deflated to 20PSi I was able to bleed all 4 calipers within an hour and a half. It involved me taking the tyre valve on an off the tyre as my 15 year old Eezibleed was leaking air slightly from the bottle cap! It did however allow me to get the job done well.

Mercedes Brake bleed by Charlieboy, on Flickr

Mercedes Brake bleed by Charlieboy, on Flickr

What was the end result like? A pedal that was much firmer than it ever has been in my ownership! With the vacuum source depleted the brake pedal is tricky to press down now. Once the engine is running the brake pedal biting point has risen towards the top of the pedal ; it previously wasn't miles away from this but there is a marked improvement from before. Maybe the system wasn't bled properly before, who knows?

What's the moral of the story? Change your brake fluid kids! Besides having superior and more dependable braking it should also extend the longevity of the braking system too! This car has only done 3-5000 over the last few years as well!

Now that I have managed to change my underwear and the car has now been pushed swifly back into service it's time to update the other thread. Maybe the W124 got envious of the C350e I had for a few days last week!

JakeT

5,466 posts

122 months

Wednesday 14th February 2018
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Just read this thread and thought I recognised the car. Then realised I saw it at roadkill! You were parking in front of my mates 190. Pic is stolen from his insta. smile


MJK 24

5,648 posts

238 months

Wednesday 14th February 2018
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I note your spare is a 15 hole Alloy and your road wheels are steel. You'll need some different, much longer bolts to fit the spare should you ever need to use it.

SebringMan

Original Poster:

1,773 posts

188 months

Wednesday 14th February 2018
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JakeT said:
Just read this thread and thought I recognised the car. Then realised I saw it at roadkill! You were parking in front of my mates 190. Pic is stolen from his insta. smile
Aha, so you were one of the 3 or 4 guys in that car? I remember discussing whether you wanted to switch places given how low your friend's 190E was! It was good to bump into a fellow Merc owner there. The RoadKill event was a great thing and IMHO a bit of a signal to what is possible over here, MotorTrend after all have been like Bauer Media in the States for a very long time now.


MJK 24 said:
I note your spare is a 15 hole Alloy and your road wheels are steel. You'll need some different, much longer bolts to fit the spare should you ever need to use it.
Cheers for pointing that out smile.

I saw the Spare on Monday as I planned to bleed the brakes then. However, it did occur to me yesterday that for now the alloy wheel is indeed a lovely paperweight in the boot of my Merc. I'll possibly keep an eye out for a steelie.

I really need to check the spec of my Merc. I always thought it was a strange spec. In short it has:

-Full Walnut trim inside including the doors
-Height adjustable lights
-Auxiliary water pump
-Chrome strips on the door handles
-Electric Windows all round.

The steel wheels on it don't really fit with that specification even if mine is a 250D and is missing leather and AC from the above list.

r129sl

9,518 posts

205 months

Wednesday 14th February 2018
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Brakes and gears are very interesting without vacuum. So is switching the engine off.

My vacuum pump failed 100miles into a two week touring holiday. We managed.

SebringMan

Original Poster:

1,773 posts

188 months

Wednesday 14th February 2018
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r129sl said:
Brakes and gears are very interesting without vacuum. So is switching the engine off.

My vacuum pump failed 100miles into a two week touring holiday. We managed.
I've only once had the no vacuum scenario whilst driving but yes it does get interesting. This is the probably about the third time I've had the long pedal problem however. One of those times was bringing the car back from a garage after a brake caliper swap!

That must have been interesting for you given how much runs off the vacuum system in a W124!

Are the gearboxes on W124s vacuum controlled like the W123s? I was under the impression only the W123s were!

r129sl

9,518 posts

205 months

Wednesday 14th February 2018
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The gearbox is vacuum modulated. Shifts are very hard without it. The brake servo depends on the vacuum pump, too. And of course there is the central locking although that wasn't an issue in the far north. Without vacuum you can only switch off the engine by going under the bonnet and interrupting the fuel supply.

I did have the long travel pedal (on a separate occasion); it always came back up on the second press. That was a bad master cylinder.

JakeT

5,466 posts

122 months

Wednesday 14th February 2018
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I was not one of them, I had to rock up earlier with a mate in his Fire Engine laugh

When we came to leave he had to wait for you to leave before he could get if off of the pavement. It still rides well being so low though!

RK was a good event, I felt bad the lads had to just sign autographs all day, and the burnouts were done on the most grippy surface there I think.

You're right there, TEN have done well really, with some great car content online. I wish MTOD was a little more compelling for the money, as it seems to offer more for American subscribers. I still try to support the stuff they make by purchasing some merch though.

SebringMan

Original Poster:

1,773 posts

188 months

Monday 19th February 2018
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JakeT said:
I was not one of them, I had to rock up earlier with a mate in his Fire Engine laugh

When we came to leave he had to wait for you to leave before he could get if off of the pavement. It still rides well being so low though!

RK was a good event, I felt bad the lads had to just sign autographs all day, and the burnouts were done on the most grippy surface there I think.

You're right there, TEN have done well really, with some great car content online. I wish MTOD was a little more compelling for the money, as it seems to offer more for American subscribers. I still try to support the stuff they make by purchasing some merch though.
Ah yes, I remember him saying that he'd be there for the entire day as I was hoping he'd switch spots with me!

You have to give your hat off to Freiburger and Dulcich ; that must have taken alot of patience! But OTOH I get the impression that they as well as MT massively underestimated just how popular they were over there. They were saying in their Q&A session that alot of their viewers come from the Middle East as well as pockets of Europe, with us being one of those pockets. DF was saying some blokes from Dubai were treating them like rockstars at SEMA!

That said, there is something in their contract which I suspect makes them sit out to do the autographs.

What I found strange was seeing a queue this long, and yes it goes outside of the photo!



It was surreal to bump into the cigar smoking Big Time Drag Racer Jeff Lutz! He had a few people meet him but nowhere near as much as the RoadKill hosts. The best thing? A few of us had a regular chat with Jeff and it's refreshing to see someone at a show with a very down to earth nature, sharing his experience and generally having a good time with the rest of us! That was one of the highlights of the show for me!

r129sl said:
The gearbox is vacuum modulated. Shifts are very hard without it. The brake servo depends on the vacuum pump, too. And of course there is the central locking although that wasn't an issue in the far north. Without vacuum you can only switch off the engine by going under the bonnet and interrupting the fuel supply.

I did have the long travel pedal (on a separate occasion); it always came back up on the second press. That was a bad master cylinder.
The 300D had the solenoid ruptured for turning off the engine. That was a fun job to continuously turn it off!

It's interesting to see they stuck with the vacuum modulation for this one!

As for the brakes mine are still working spot on! Maybe it's a sign of mission creep but I scored a bargain on a pair of Coupe 4 pot calipers! Will they go on? We shall see.

Edited by SebringMan on Monday 19th February 17:47

SebringMan

Original Poster:

1,773 posts

188 months

Sunday 25th February 2018
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You would have thought with the updates going on with the M3 thread this old girl was being neglected! Well, not so fast!

The truth is this has been my daily runner! Yes the rust on the driver's wing is getting slightly worse but overall it's been earning its keep and it's been doing a sterling job there! With that in mind it was time to deal with a few of the niggles. Most of which I dealt with today!

The first was to test drive yet another car! This time it was a fully electric car ; a BMW i3S!

Untitled by Charlieboy, on Flickr

OK, it's older and not an i3S! What were my impressions? Firstly electric cars are quite an experience to drive; Intuitive and easy to pick up but generally great ; the response was literally electric! Overtaking in it was like nothing else I've been in ; you can see why people love these things! The second thing is that it's quite a quirky thing! However, there is something about the W124! I'll be honest. When I went from the S205 C350e back into the Merc I did miss the C350e ; It's a great machine with super splendour and class! The i3 simply didn't do that for me! The W124's charm won me back upon driving it away! It was strange as I was so enjoying the drive of the i3! Like an old dog it has a few external warts and so on. But it is utterly faithful and has a real grandeur about just rolling up and down the roads in great comfort, German style! It has a sense of Americanness in its steering and comfort levels without being wayward or ill handling!

Anything, that's enough mission creep there! The few issues I had were as follows:

-A diesel leak from the fuel thermostat area
-No rear fog light
-A driver's door barrel that was a jackpot as to when it decided to work
-Tidying it up!

The first thing to deal with was the diesel leak! I don't need to tell anyway how slippery diesel can be out on the cold wet roads! While it wasn't gushing out the problem did need fixing! With that in mind a local RRer fixed me up with some decent Cohline fuel hose. As you probably know even R6 fuel hose these days is very poor quality and not always fuel resistant ; I know of a few cars that have gone up in smoke thanks to crap piping! To add further complications some of my fuel hose had been changed already!

Initially I thought it was the hoses going to the diesel thermstat. A couple previously (the R6 ones) were cracking at the ends! I then replaced the thermsotat hoses with the new items and new jubilee clips the old clips had gone weak. However, the R6 lines then started to leak! With that happening I then changed those! At this point I saw the plastic outlet of the fuel thermostat twisting! Since I'm not sure if it is meant to move I figured it was best to bypass it as many people elsewhere do. However, should it ever be needed I looped a bit of hose around to preven the inside of it getting dirty but also so that it can be plugged back in again for an emergency. In the meantime I'll be keeping my eye out for a replacement thermostat (they can stop being a thermostat/heater) or getting a rebuild kit from Mercedes, which is an O-ring and a plastic outlet although mine seems fine on the latter.

by Charlieboy, on Flickr

The wetness on the block is the carb cleaner I used. It's always nice to clean things up! The plumbing of the fuel pre-filter was also tidied up and put more into the factory position ; the extended hose previously was quite messy and rubbed on just about everything in comparison to now!

The second issue was the rear fog light not working. This was down to the light switch knob falling off when it was pulled! To be honest it was very tired looking and when a new one from Mercedes is only £2 it made no sense to persist with the old item! It really freshened up the interior on that side of things! I didn't take a photo of this as I was running out of time and I had one final thing to do.

Finally there was the matter of the door barrel. The central locking does work on this car thankfully but you can only utilise this by opening and closing the locks from the boot and passenger door lock! The driver's door would only lock and open a handful of times. Cleaning it out didn't do much! What solution did I have? A new key? A new door barrel I hear you ask? No. I went a little leftfield but also down a well trodden path:

by Charlieboy, on Flickr

In case you are wondering the yellow vacuum lines going to the box are is the vacuum pump for the central locking. What I did was add on the smaller box to give remote central locking, using the existing vacuum pump as it is! The kit I had was relatively inexpensive and didn't take too long to install at all! I did have to buy one that could work with pneumatic locks however; they required a 3.5 second pulse in order to activate the vacuum pump for long enough! And in truth it works like a charm and really makes life easier. Not just for opening the driver's door but for also getting to the boot with your hands full! Yes, the purists may not like it but it does add a great touch of convenience to a retro daily driver! Oh, and circumvent the driver's door lock issue. It was easy to wire up too! I interrupted one of the existing wires going from one of the door lock switches and then made a subloom up to go in between the vacuum pump's power plug. This way I cut a minimal amount of the car's wiring and the wires in the subloom could be soldered for a more long term reliable connection!

And I gained a keyring too! OK, I lied. I gained a keyfob!

Who said an old retro couldn't have modern convenience features? This one almost has the lot!

There is more that should be coming but for now it's time to hit the hay.

by Charlieboy, on Flickr

ian316

4,150 posts

107 months

Sunday 25th February 2018
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What is the kit and where did you get it from please?

SebringMan

Original Poster:

1,773 posts

188 months

Sunday 25th February 2018
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ian316 said:
What is the kit and where did you get it from please?
I got the kit from Amazon! It was £25 delivered to my door.

It came with two wiring diagrams. The original diagram is correct and the seller's are not. I made a mini loom to go in between the Vacuum pump power plug and the pump itself. This provides the power to the RCL box. It also meant that I didn't have to cut any of those wires.

You will however have to cut one of the wires on the round plug; it interrupts that signal which is why it works. Most people go with the looser of the two green wires to do it, which I did. One of the green wires will work, the other won't apparently. Mine had 12V once the door was opened and 0V the other way which was the correct wire. W126s don't have this issue as they only one one wire per door as opposed to the W124's two per door. There will also be two yellow wires (the boot) and two blue wires (the driver's door). They also have the same principles as the green wires but simply operate another part.

https://www.amazon.co.uk/Universal-Remote-Central-...

If you want a better quality kit the Toad A101CL will do the same thing, but that's around £80.

https://www.ebay.co.uk/i/312052680097?chn=ps&a...

Edited by SebringMan on Sunday 25th February 18:37

SebringMan

Original Poster:

1,773 posts

188 months

Sunday 25th February 2018
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I forgot to say, there was one thing I left off my day of W124 caring. The headlight knob.

Mine could put on the front foglights but it could not do the rears at all; it kept on slipping off the end, probably from the rear foglights never being used! Of course, this would never help it to pass the MOT! Let's be honest, being an older daily it's probably also more likely to be pulled over and checked for things. This car thankfully had great tyres all round and is sound where it counts. Visually it could be better! Since a new knob was £2 from Mercedes it seemed crazy not to change it. It looks a little out of place but then the old one was quite an eyesore too!

W124 Feb 2018 by Charlieboy, on Flickr

I also went on my travels to the Pistonheads Sunday Service at Ginetta. I have to say that I loved driving up in the old girl. It was a wonderful place to tour the Ginetta factory. The staff clearly have a passion and were certainly more inviting than the folk at ProDrive, that's for sure! Many props to Ginetta for taking their time to do their stuff over the weekend.

Ginetta Tour by Charlieboy, on Flickr

One of the two jigs used for building the cars

Ginetta Tour by Charlieboy, on Flickr

Ginetta Tour by Charlieboy, on Flickr

A Ginetta G40 spaceframe

Ginetta Tour by Charlieboy, on Flickr

And its powerplant ; a Zetec 1.8

Ginetta Tour by Charlieboy, on Flickr

You have to love the older stuff they made! Uncompromising yes! Stunning, however, they most definitely are!

Ginetta Tour by Charlieboy, on Flickr

A built-up G40

Ginetta Tour by Charlieboy, on Flickr

Will you survey the magnificence!

What did the Mercedes average on the fuel run up there? With me not exceeding 80 I somehow got 43MPG with 3 people on a bit! TBH I wonder if it did more given that the fuel was pretty much to the top of this fuel cap, and that last time it wasn't despite using the two click method. A bit of a result for the old Mercedes for sure!

ian316

4,150 posts

107 months

Wednesday 28th February 2018
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Thanks for the reply on the remote

SebringMan

Original Poster:

1,773 posts

188 months

Wednesday 28th February 2018
quotequote all
ian316 said:
Thanks for the reply on the remote
No worries, but I can do better. With a shoddy diagram wink:




ian316

4,150 posts

107 months

Thursday 1st March 2018
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SebringMan said:
ian316 said:
Thanks for the reply on the remote
No worries, but I can do better. With a shoddy diagram wink:

Wow a wiring diagram I can follow cheers for this, when I've looked into this before only the more expensive one was available thanks again

SebringMan

Original Poster:

1,773 posts

188 months

Tuesday 27th March 2018
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ian316 said:
Wow a wiring diagram I can follow cheers for this, when I've looked into this before only the more expensive one was available thanks again
Anytime, it's good to see a cheap but easy way to add convenience.

You'd have thought with me doing things on the M3 that the Mercedes was being neglected. Far from it. The car did admirably well through the snow and really was a great companion!

250D & snow by Charlieboy, on Flickr

However, since the M3 needed to be sent away for a short while the Merc strangely went back into storage. This is just as well as I have a plan to take it to the Laon Historique. But the car is not quite ready. The first thing is I'd have to make it safe!

It has a few issues I'd like to deal with. The one I really wished to fix was the braking issue. It still wasn't fixed! There I was going down the M69 and the car started to vibrate alot, as if the driveshaft was going to escape! When I came to brake, it went back to having the pedal on the floor again! This time I pulled up prompty, with more of a clue this time. There was a distinct burning smell coming from the rear of the car. When I went to check the rear right wheel was hotter than the rest by quite a way, enough to boil the water I put onto the wheel! It's funny as the wheel trim itself has always had more brake dust staining than the other pads. It was looking like the caliper was at fault.

The first thing to do was to lift the back end up. Despite the car rolling nicely being pushed once the handbrake was off on the ground the offside rear wheel was hard to turn by hand! It would eventually free off, but it took its time! I've normally always had brakes notably dragging on a car if the calipers are shot, so this was interesting.

Rear brake calliper swap. by Charlieboy, on Flickr

With the cause found I set about stripping that side down. Once the caliper was off it was clear it had seen better days. One piston was just about going back in, but the opposing side had the outer rim looking like it had lived in the ocean! It would explain why the brakes were being random!

Rear brake calliper swap. by Charlieboy, on Flickr

With that in mind it was time to assemble the new brake hose and refurbished brake caliper:

Rear brake calliper swap. by Charlieboy, on Flickr

Unfortunately the copper brake pipe put up a fight with it turning with the union. Eventually I managed to work around the the issue and had the union spinning nicely again. It's one reason why I don't like Copper brake pipes; it's not the first time it has happened to me. The pipe is now straight but I may well replace it; Mercedes want £30 for a new pipe and my flaring tool isn't all that; for peace of mind I may well take that avenue:

Rear brake calliper swap. by Charlieboy, on Flickr

Rear brake calliper swap. by Charlieboy, on Flickr

Once that was all sorted I went to fit it to the car. Pushing down the brake pedal 40mm or so, and holding it there helped significantly in minimising the brake fluid loss.

Rear brake calliper swap. by Charlieboy, on Flickr

And there it is, all finished! Note the light coloured rust staining; I've seen this before with a seized caliper so it does look like the cause has been found. The other side surprisingly is in good condition.

That's one thing down. If I am fussy I could do the bodywork but I do like the lived in look of the car strangely!