W124 - Bumper Fitted & Started LPG Servicing

[DeanH]

Thought I'd dip my toes into the W124 world with the example offered by RobT recently. First impressions are good, it drives really well and ate up the 250 mile journey back from London. Everything feels to be the wrong way around, which felt very odd at first but I'm slowly getting used to it!

It's got a reasonable list of jobs to chip away at:

1. Dash lights don't work (broken potentiometer on the back of the cluster?)
2. Lamp failure warning bulb comes on with the lights (related to the above, or wrong bulbs used elsewhere in the car)
3. Cruise control doesn't work (brake switch mentioned in the sale thread)
4. Central locking actuator has been removed as it was stiff
5. Broken insert on rear bumper (replacement came with the car, cheers Rob!)
6. Handbrake doesn't work (I probably broke it as I can't get used to the foot operated brake!)
7. Noisy bearing in engine bay (sounds to be from the aux belt, think it's the water pump).
8. Cracked windscreen & dull paintwork on the front end (doubt I'll bother, maybe one day!)

Other stuff I have remembered or that has made itself known:

9. Occasional grinding noise from the brakes (sounds like ABS kicking in to me, may be related to cruise control).

10. Boot only locks/unlocks from inside.

 

[320touring]

Well bought - great cars and a grand seller!

 

For #1 on the one I had, wiggling the dash light dimmer (it's the trip counter reset I think) brought them back.

[DeanH]

18 minutes ago, 320touring said:

Well bought - great cars and a grand seller!

 

For #1 on the one I had, wiggling the dash light dimmer (it's the trip counter reset I think) brought them back.

Couldn't agree more!

My plan was to get the clocks out and have a clean of the contacts on the potentiometer and see what happens. But getting the clocks out seems like it could be a bit of an ordeal, so wiggling might be better!

[HMC]

The dash light is the potentiometer, I removed the cluster to look  and a bit of solder has come away, so would be a simple fix.

[DeanH]

Just now, HMC said:

The dash light is the potentiometer, I removed the cluster to look  and a bit of solder has come away, so would be a simple fix.

Had seen the big dollops of solder on the potentiometers online, thought they could be a bit suspect. Will revert to getting it out instead of wiggling then, thanks!

[320touring]

Only 7 to go!

[HMC]

Also to get the clocks out just grab the plastic surround round the border of the Perspex and gradually pull from each side. The speedo cable is quite tight at the back so you have to feel around when the cluster is out and Unscrew it which gives you a bit more space to pull the cluster out further and get access. 

[jaypee]

Well bought! 

[DeanH]

1 hour ago, HMC said:

Also to get the clocks out just grab the plastic surround round the border of the Perspex and gradually pull from each side. The speedo cable is quite tight at the back so you have to feel around when the cluster is out and Unscrew it which gives you a bit more space to pull the cluster out further and get access. 

The videos I watched showed some MB tools. I was having visions of fashioning my own from coat hangers, your method sounds easier.

[Soundwave]

Looking good!

[DeanH]

Two birds with one stone today, fixing the dash lights has cured the lamp failure light.

Getting the cluster out is a bit of an ordeal, there isn't much slack on the speedo cable (and putting it back on was worse!), but got it out eventually.

Flip it over and the offending article is the white block with the broken solder joint as @HMC said.

Soldered it back together, looks rough but I'm happy enough with my first attempt at soldering.

And now we have lights! Ignore the christmas tree on the bottom row, hadn't switched the engine on but at least you can see that the lamp warning isn't on.

Cruise control next I reckon, or maybe the rear bumper...

[DeanH]

@Talbot (or anyone else for that matter) would you have any advice on how to test the brake light switch before I buy a new one?

There are only two pins on it but four wires go into the connector. Presumably the pins each act as in/out for the two circuits. If so I'm struggling to understand how it can be a silent failure as the resistance will be the same across the pins for both circuits. Will probably be clear if I manage to get it open but that's easier said than done!

[HMC]

Well done on fixing the dash lights, nice one!

[Talbot]

Interesting.  That's not a duo brake switch, just a single circuit, so if the brake lamps are working, the switch is fine.  It's unlikely to be the issue in this case.

Or... I wonder if someone has fitted a single circuit switch when a duo one should be fitted.  Does the connector have spare connection points that aren't being used by the current switch?

[DeanH]

3 hours ago, Talbot said:

Interesting.  That's not a duo brake switch, just a single circuit, so if the brake lamps are working, the switch is fine.  It's unlikely to be the issue in this case.

Or... I wonder if someone has fitted a single circuit switch when a duo one should be fitted.  Does the connector have spare connection points that aren't being used by the current switch?

It not being a duo switch was my first thought when I got it out to be honest. I was expecting two plungers but never seen one before so didn't know for definite. I'll have another look at the connector and mechanism later on.

[DeanH]

Had another look and taken some pictures.

4 cables

2 pins

Bracket only ever designed for one plunger (not sure whether this is relevant)

Could it be that each pin makes/break contact in a separate circuit? I can't see how this would work though...

[DeanH]

I've been slacking slightly with progress on the W124 as I thought I had better focus my effort on preparing for the looming MOT.

First of all tried to bodge together the broken rear light cluster, that was a spectacular failure so a new part was required...

After that I turned my attention to the handbrake that didn't work, so that saw new discs, pads and shoes go on the rear.

Happy to see that the Merc uses mechanical adjusters rather than the V70 system that I found fairly useless the other month.

Forgot to take many pictures so here's one of the new shoes, I'm not great at these threads as you might have gathered.

And today was the big day, the big day of failure...

But the nice man put some tape over the bumper

And that got me a pass! 12 more months of fettling and fun.

Slightly worried by the corrosion but I'll get underneath and have a proper look at some point.

[richardmorris]

If the oil leak gets worse it will help the rusting issue.

[DeanH]

3 hours ago, richardmorris said:

If the oil leak gets worse it will help the rusting issue.

MOT man did make that comment 😂

[stuboy]

well done with the mot

[DeanH]

A day off work saw some work to the brakes before the weather turns for the worst.

Asbestos free is a rather odd claim to fame in 2021.

Plenty of meat left on the pads despite the wear indicators flashing on the dash and the increasingly frequent grinding noises from the front.

That'll be because the discs are jiggered and the lip is making its way through the wear sensor.

One of the wear sensors decided to snap when pushed back into the new pad, bugger! Surprisingly cheap and easy to get hold of though.

And of course the reservoir was now overflowing. Decided to try and find a turkey baster to suck a bit of fluid out, none to be found in the three big supermarkets here. Had to resort to a Calpol syringe, 5ml at a time!

Fluid looks more like oil, could do with some attention once I have built up the courage to touch the bleed nipples.

Quick test drive and all is well, much quieter when coming to a stop. So, that'll be number 9 crossed off the original list. Back to the cruise control and central locking next I think.

[DeanH]

Lacked motivation through the poor weather so whilst it was good last weekend decided to whip the bumper off and fit the insert that Rob gave me with the car. Of course I didn't get round to putting it back on til today when it was pissing it down again!

Before...

And after.

Also started servicing the LPG system as the car started hunting when coming up to temperature. Quite enjoyed this as the filter cartridge needed splitting down, new seals and a filter insert. A bit more involved than a petrol filter is. Certainly needed changing...

[dome]

4 hours ago, DeanH said:

 

Also started servicing the LPG system as the car started hunting when coming up to temperature. Quite enjoyed this as the filter cartridge needed splitting down, new seals and a filter insert. A bit more involved than a petrol filter is. Certainly needed changing...

Shit, that filter has been there for a long time! I've done a few LPG services but never seen one as bad as that. Noticed any difference in how it drives?

[DodgeRover]

Check for a magnet in the bottom of the first gas solenoid with a filter under it under the bonnet, they can get surprisingly clogged.

[DeanH]

8 hours ago, dome said:

Shit, that filter has been there for a long time! I've done a few LPG services but never seen one as bad as that. Noticed any difference in how it drives?

I've only done one of the filters so haven't filled it up with gas again yet. Hoping it works as I don't want to dive into the vaporiser, they seem quite fiddly.

[DeanH]

8 hours ago, DodgeRover said:

Check for a magnet in the bottom of the first gas solenoid with a filter under it under the bonnet, they can get surprisingly clogged.

Is that the thing with the brass bowl that contains the small filter? That's next I just need a small spanner to be able to undo it. Couldn't quite contort my hands into the gap.

[DodgeRover]

Yes that will be it, make sure the tank is turned off either physically with the valve or make sure the solenoid is working as the line upto it will be full of liquid LPG and it will take a short while to depressurise.

[mat_the_cat]

14 hours ago, dome said:

Shit, that filter has been there for a long time! I've done a few LPG services but never seen one as bad as that. Noticed any difference in how it drives?

A lot of folk seem to only take their LPG car in for a service when it starts misbehaving!

[DeanH]

7 hours ago, DodgeRover said:

Yes that will be it, make sure the tank is turned off either physically with the valve or make sure the solenoid is working as the line upto it will be full of liquid LPG and it will take a short while to depressurise.

Tank is already turned off. Must admit I gingerly disconnected the other filter and unclenched when it didn't shoot gas in my face!

[DodgeRover]

It's amazing how long the had just in the pipe takes to vaporiser off!