Mercedes SL320 R129 - Part 2

Mercedes SL320 R129 - Part 2

Author
Discussion

Yogioes

Original Poster:

100 posts

44 months

Monday 5th August
quotequote all
Thank guys.

Prices for these are all over the place. They seem to be advertised anywhere from £3k to over £20k.
I think I paid a fair price for it and I hope to get that back although I have added nearly £1,500 in parts.

Part of the reason I chose the R129 was the comments I had read about how the Mercs of this era were built.
I have enjoyed working on a car that was not built with a short life and disposability in mind.
I know that most buyers don't care what happens to their brand new car after three years so why should a manufacturer build for long life.
It might seem odd, but it's wee things that appeal to me - even after 19 years, the brake back plates are still in excellent condition.
I have had other cars where at 10 years old you can wiggle off the last crusty remains of the back plates.
It would appear that they had not heard of the term "value engineering" when these were built.

Johnny Raydome

545 posts

53 months

Wednesday 7th August
quotequote all
Used to keep an eye out but never saw your car about. I'm not a million miles away.

Good luck with your sale, is there a link? I can't seem to find it.

Also, I'm glad to see you made it out of Quarriers in one piece. Place gives me the heebie-jeebies!

I know it's not really possible to compare open-top motoring with biking but was there a specific reason you didn't like the driving experience of an open top car?
For example - raw speed, danger, feeling 'at one' with the machine etc etc.

Genuinely interested.

Yogioes

Original Poster:

100 posts

44 months

Thursday 8th August
quotequote all
I have advertised it on PH and Car & Classic.
Only had one email asking if I am flexible on price.

Quarriers is an unusual place. Friends used to live there in one of the converted houses and I like the Three Sisters Bake Coffee shop / Restaurant.

Why is the convertible not for me?
I'm embarrassed to admit it but I feel a bit conspicuous and self conscious when I'm in it. I tend to avoid towns where possible and head for the country roads which it is well suited to. A bit daft really as quite frankly, who cares.
I don't drive it that fast apart from the odd burst of acceleration or powering up a hill. It does drive very well.
Initially, the steering feels light but you soon adjust to it and it feels great through the bends. Equally, the brakes are quite confidence inspiring.
Each tank of fuel has worked out at 31mpg.

I can't recall if I mentioned it but it does not roll back on a hill when in drive. A very handy feature and all the more so since my modern 8 speed auto Discovery does roll back. Is that called progress?

If you do see me out and about in it, be sure to wave or flash the lights.

And, any excuse to add a picture. Just along the road from Coulport.


Yogioes

Original Poster:

100 posts

44 months

Sunday 11th August
quotequote all
A very pleasant run to Inveraray on Saturday evening for a fish supper.
On a sunny Saturday or Sunday the roads can be extremely busy but in the evening they get very quiet and you can mostly have the road to yourself.




Yogioes

Original Poster:

100 posts

44 months

Thursday 29th August
quotequote all
New issue with the car.
Back around April when out for one of the first runs after doing the rear subframe refresh, the BAS / ESP amber light illuminated.
I switched the engine off, restarted it and it has been fine since then. I had forgotten about it.

Saturday evening, while out for a 100 mile round trip, the BAS / ESP light came on again.
I carried on driving and some other issues appeared.
At first it was fine, but after about 10 miles the cruise control started switching itself off. I could reset it and it would be okay for a while but the frequency of resets increased until I stopped using it.
Also, for a split second the gauges dropped to zero. It happened very quickly and only a few times so it was hard to be completely sure what happened but I think I saw the petrol and oil temp gauges drop momentarily.
Then, when braking firmly, the three adjacent lights came on. Two ambers and one red.
I carried on with some caution as I was nearly home.
After about 5 minutes the three additional lights went off again.
I garaged the car.

The next day I took it out and washed it. The obvious thing to do when a car has a fault.
I took it for a short run to dry off the brakes. Initially there were no lights but before I got home the BAS / ESP light was on again.
It's back in the garage while I consider my options.
I have an OBDII scanner that I have never actually used.
My car does not have an OBDII socket but has the 38 pin port under the bonnet. I have ordered an adapter cable to see if that works.

Other options ......
Get the correct scanner - Seems to be a lot of confusing options, choices and misinformation.
Get the local Indy to read the codes to see if that answers the question or gives a clue.
Get under the car - I was not entirely confident in the way the rear ABS cables connected in the plug that is under the rear seat. Might be worth a wee look.
More time reading multiple post on the internet.

Picture of the offending lights. The first three are amber, the last one is red.


Deefor62

104 posts

96 months

Friday 30th August
quotequote all
Yogioes said:
New issue with the car.
Back around April when out for one of the first runs after doing the rear subframe refresh, the BAS / ESP amber light illuminated.
I switched the engine off, restarted it and it has been fine since then. I had forgotten about it.

Saturday evening, while out for a 100 mile round trip, the BAS / ESP light came on again.
I carried on driving and some other issues appeared.
At first it was fine, but after about 10 miles the cruise control started switching itself off. I could reset it and it would be okay for a while but the frequency of resets increased until I stopped using it.
Also, for a split second the gauges dropped to zero. It happened very quickly and only a few times so it was hard to be completely sure what happened but I think I saw the petrol and oil temp gauges drop momentarily.
Then, when braking firmly, the three adjacent lights came on. Two ambers and one red.
I carried on with some caution as I was nearly home.
After about 5 minutes the three additional lights went off again.
I garaged the car.

The next day I took it out and washed it. The obvious thing to do when a car has a fault.
I took it for a short run to dry off the brakes. Initially there were no lights but before I got home the BAS / ESP light was on again.
It's back in the garage while I consider my options.
I have an OBDII scanner that I have never actually used.
My car does not have an OBDII socket but has the 38 pin port under the bonnet. I have ordered an adapter cable to see if that works.

Other options ......
Get the correct scanner - Seems to be a lot of confusing options, choices and misinformation.
Get the local Indy to read the codes to see if that answers the question or gives a clue.
Get under the car - I was not entirely confident in the way the rear ABS cables connected in the plug that is under the rear seat. Might be worth a wee look.
More time reading multiple post on the internet.

Picture of the offending lights. The first three are amber, the last one is red.

I had all dash lights come on and all gauges (except temperature) on my albeit older 500sl intermittently then constantly.
Unusually and fortunately I discovered it was a really simple issue by way of a slightly loose positive terminal on the battery.
Yours sounds as though it could be a voltage drop with so many things going at the same time, and if lucky, a simple fix like mine.
Good luck

tobinen

5,574 posts

93 months

Friday 30th August
quotequote all
On my 210 and 140 I had this and it was fixed with a new brake light switch. About £15 from MB

sbk1972

216 posts

24 months

Friday 30th August
quotequote all
Ditto above. I have a ML55 and had similar lights come on. Was the Brake pedal switch. Replaced it twice now.

Also, i have one of the lights comes on and my OBD read mentions the steering wheel sensor. I haf to go full left to full right to reset it. This one always happens once you disconnect the battery, or replace it.

Did the R129 have a wiring loom issue ?? I think that was earlier cars 90/93. might want to look that up on a proper SL / R129 forum.

I use my ODB code reader all the time, saved me 100s of times.

Simon

tobinen

5,574 posts

93 months

Friday 30th August
quotequote all
sbk1972 said:
I had to go full left to full right to reset it. This one always happens once you disconnect the battery, or replace it.

Simon
Yes, good point. Turn the sterring lock to lock after you fit it. It's a straightforward DIY job.


Yogioes

Original Poster:

100 posts

44 months

Friday 30th August
quotequote all
Thank you for the tips.

I had come across the brake light switch suggestions and at that price it's probably a good idea to fit a new one to eliminate it.

While I don't like having problems, I do like to hear the solutions and how they were identified.

How does the car know that the brake light switch is not working?
It would need to know that the brakes have been applied and also that the brake light switch has not been activated. Clever.

I have not been back out to test it, but I wondered if the extra three lights came on as an extra warning when I braked firmly.

It would be good to have access to one of the programmers who setup the logic for all the circuits on these cars. It can seem complicated but is probably quite simple when you know what is actually going on.

An example being when my roof stopped going up or down. It was because the window mechanism had stripped some teeth.
At first that might seem odd and not relevant but when I found out that the roof controller needs to know where the windows are before working that made perfect sense.

I believe the 129 did suffer from decomposing wiring problems along with other models but it was around 95. My car should not be affected.
Just checked, the battery terminals are all tight.
Next time the light comes on I will try the steering full left to full right tip.

As an aside on OBD's, from what I have found it appears that a US 129 at the age of mine, 2000, would have the OBDII port under the steering column but it was not introduced on UK SL's until the R230.
From what I have read, the 38 pin OBD port under the bonnet on my car is using the same comms language as OBDII so hopefully my code reader will work.

Yogioes

Original Poster:

100 posts

44 months

Sunday 1st September
quotequote all
OK, so I got the cable to connect the under bonnet round socket to my OBDII cable. It appears to have worked.

This is the first one which looks like something to do with the connections to the transmission.
I have come across a few threads about trans fluid in the electrical connector.




And the second one - Appears to be a transmission speed sensor and may, or may not, be connected with the above possibility.






More time required trawling the internet.

I don't want to risk disabling the car at the moment as I will need to be able to get the motorbike out this week to swap it for the new one.

Wills2

16,235 posts

123 months

Sunday 1st September
quotequote all
I love these cars and like to see a thread about them, reading this one makes me remember my old SL320 I had it back in 2000 it was a 1997 model with the M104 I6 so not that old the time but still and gave me no end of trouble, I still love them though.

Your facelift is lovely I remember someone having the same a few doors down from me and I was jealous of the facelift, best looking one I think.







Edited by Wills2 on Sunday 1st September 23:05

Yogioes

Original Poster:

100 posts

44 months

Monday 2nd September
quotequote all
Hi Wills2
"no end of trouble" from a three year old SL must have been irritating and disappointing.
It might also explain the lack of any other Mercs in your car history.

Wills2

16,235 posts

123 months

Monday 2nd September
quotequote all
Yogioes said:
Hi Wills2
"no end of trouble" from a three year old SL must have been irritating and disappointing.
It might also explain the lack of any other Mercs in your car history.
Yes it was my first and last, but loads of memories and lots of lovely trips away there is something about an SL, I think I had a Friday afternoon car sometimes you're just a bit unlucky.







Yogioes

Original Poster:

100 posts

44 months

Monday 23rd September
quotequote all
Well, I got my new bike on the 4th and it's already over 1,500 miles.

I think the Merc has taken a bit of a huff as the only use it gets is being moved out the garage to get the bike out.
The first sign of trouble was when nothing happened when turning the key to start the engine. It happened once but started fine at the next turn of the key. I thought I had imagined it or turned the key incorrectly.
Over the next few shunts in and out the garage it became obvious that there was indeed a problem. All the ignition lights come on but nothing happens when turning to the start position.
It appears to be linked to the gearbox limit switch as moving the gear lever has so far always allowed it to start.
On one occasion it seemed to have quite a bump when selecting reverse or drive but was back to normal the next day.
I should stop playing with my new toy and get it sorted.

The new toy - a bargists version of a motorbike - electric window, heated steering, heated seats front and rear, cruise control, remote central locking.


Yogioes

Original Poster:

100 posts

44 months

Thursday 3rd October
quotequote all
A little update......

DOH

The car was sitting in the drive while I was out on the bike and it rained while I was away.
Not wanting to put the car away with lots of standing water on it I decided to use the rubber blade of an ice scraper to sweep most of the water off.
It worked a treat.

Until a short time later when the sun came out and I could see that I had created a thousand little scratches straight down the bonnet at right across the boot lid.

DOH

I gave the car a wash and dried it off properly and put it back in the garage.
I used Autoglyms Paint Renovator which helped a bit but I think I used too much and was too heavy handed as that removed the scratches but created some new finer ones.
I went over it again a bit more carefully before finishing it off with Autoglym Super Resin Polish.
It feels lovely now and almost all the scratches have gone.





When viewed in daylight it may have a little haze in the colour .... or that might just me my paranoia.


Back to the BAS/EPC warning light.
It had added a few other issues.
Occasionally it will not start. The dash lights up but nothing when I turn the key to start the engine. If I move the gear lever it then starts so I assume there is an issue with the inhibitor switch.
It's hard to spot, but occasionally while driving, some of the gauges drop for a split second. It happens very quickly and is hard to spot. It's not advisable to stare at your gauges while driving!!
On two occasions over the last hundred miles it has given one or two hard gear changes. Very random.

Based on the error code and the fact that it has had an odd hard shift when selecting reverse or drive to get it in and out the garage and with guidance from the internet ....... I decided to change the conductor plate in the gearbox.
I collected together the parts and got on with it. A slightly messy job not helped by the fact that I could not shift the drain plug.
I decided not to persevere with that and just removed the sump pan to drain the oil.
As I don't have a parts washer I decide not to mess with the solenoid valves and just swapped over the conductor plate.
I also fitted a new wiring connector. There were no signs of oil leaking into the old one.

I do like the way the bonnet opens right up,
The bonnet pad may be past it's best.




The old conductor plate and plug




Put it all back together and took it for a test run .......
No difference whatsoever!

With the collection of small issues I am wondering if they are all connected.
So, I took it to the local Indy specialist and it is booked to go in for a check later this month.


In the meantime.
On my test drive I had the hood up which is not something I normally do. I noticed that one of the little vibration rattles was louder than usual which prompted me to investigate.

I found that this bit of plastic was partially detached.




Out with the Araldite and assorted clamps




All sorted and that little repair has been one of the best improvements that I have done to the car!!!!
I was aware of the rattle before and it seemed to be a minor irritation but was hard to spot when driving with the roof down.
It has brought a whole new level of calm to the driving experience.
There are still the odd noises here and there but for the most part, it is remarkably peaceful even with the roof down.

I hadn't really looked under these flaps before but I am guessing that somebody else has been trying to stop rattles as there is what looks like one side of a velcro fastener stuck to these flaps on both sides of the car? Doesn't look factory.




It was a lovely but cold day yesterday so I put the dog in the passenger seat, turned up the heating and went to Largs for a walk along the front. Ideal.

Please excuse the lamp post and bin in the picture. It's all about the composition.


TR4man

3,461 posts

122 months

Thursday 3rd October
quotequote all
I wonder if these gremlins are the car's way of telling you it shouldn't be sold?

Yogioes

Original Poster:

100 posts

44 months

Tuesday 22nd October
quotequote all
TR4man may be onto something there ....... or, have you seen the film Christine?

From the start of Sept when I got the new bike I had not had a single journey where the BAS ESP light had not come on.
As mentioned above, I had tried a few things with no success and had booked it into the local Merc indy specialist.

Well, on the way there ..... no BAS ESP light. The journey was certainly long enough to have triggered it based on the previous six weeks journeys.

I left it with the garage and went back later that day to collect it.

They gave it a good check over, read all the codes, cleared the codes and took it for a test drive.
No BAS ESP light and no new codes showing.

Obviously, my code reader is of very limited use on this car.

Here are the reports showing the stored codes.





It's very detailed, even including the problems with the CD player.
The guy talked me through it.
The Canbus issues and the gauges dropping will be hard to resolve. May even need a new instrument cluster which is not available from Mercedes.
He suggested that the most likely source of the BAS ESP light was the OSR ABS sensor / ABS ring. He noted that the ABS ring was lifting a bit due to corrosion.
He suggested the ring was around £30 but that the ABS sensor is no longer available from Mercedes.
He also pointed out that one of the front strut top mount rubbers was cracked.

I called Mercedes parts.
The ABS ring - Not sold as a separate item - That only comes with a new driveshaft. £800!!!!
I had a look at the car and to my amateur eyes it still looks quite clean and neat. Not sure what to do about this as yet.

I ordered two new front top mounts.
I also ordered a new throttle position sensor. I think I mentioned before that there is a VERY slight stickiness in the throttle pedal. I find it a wee bit irritating as the car is quite sensitive to a bit of throttle.
I have already changed the cable which helped a bit so I am hoping that this cures it as it is £190 wasted otherwise.

The car had several good runs on Sunday and Monday, still with no BAS ESP light, I didn't see the gauges drop and not a single bumpy gearchange. A self healing car?

On Sunday I was at the Lochwinnoch car show. They had a lovely day for it and had a good turn out.

On Monday I went to get a quote for getting the wheels refurbished. They are in fairly good condition with only minor scuffs and some corrosion under the paint but as two do not hold pressure and as all four tyres need replaced I decided to get them tidied up.

I also went to a local trimmers for a quote to get the three plastic windows replaced. There are some very minor cracks that will only get worse and they are a bit opaque making it quite hard to see through.
My attempt at repairing the section of broken stitching has convinced me that a full DIY replacement is not a good idea.
The trimmer told me that he will remove the rear section from the car to do the work. I didn't know it was in two sections.
I will probably go ahead with the repair when I can get it organised.

Priority is the front strut mounts, wheels & tyres and an MoT due within a month.

The other code that I was interested in is B1706-002 which mentions the rear window defroster. When I got the car the hardtop was attached and I remember thinking that the heated rear window did not work.
However, I have no idea how to "Check control line to component N10/2" ........ or what N10/2 is ...... or what is a control line.
Pesky Canbus stuff.
This did have me looking at the Stags at the show, envious of their simple old 12V electrics. Obviously, the two that were there were not rusty wrecks like quite a few of them are.

In other news, some of the plastic trims along the top of the screen were cracked.
I'm struggling to justify £36 for each sun visor hinge cover so I had a go with some superglue.

OS before




OS after




NS after (no before picture)




I tried to do this centre trim in situ but without success




Did I mention the film Christine?
For the first 11 months that I have owned the car, opening the centre cubby was a two finger job. One to press the button and the other to push the lid up at the same time.
Well, it has sorted itself ...........




The car is probably still for sale but don't let it know!!
Probably the wrong time of year and it's due an Mot.
The advert on PH disappeared (I assumed wrongly that it stayed until I cancelled it) and I have deleted the advert from C&C.

r129sl

8,129 posts

151 months

Wednesday 23rd October
quotequote all
I had a run of similar problems. My symptoms were cruise control and speed limiter functions intermittently dropping out, speedo needle wobble, hard power cut at about 144mph and occasional illumination of the ESP/BAS light. I had the same fault code pointing to the transmission conductor plate, replaced that, no joy. In the end, I replaced the ABS reluctor rings on the rear driveshafts and also the front hubs, the latter because the ABS rings are part of the front hubs.

Changing the nearside front hub solved the problems: this is where the vehicle gets its speed data. The grooves on the hub had corroded such that they were no longer distinct, leading to speedo wobble and then total confusion at high speeds. The car compares this data with the data from the transmission output shaft for the purposes of the ESP system, but where there is a mismatch the fault code points at the transmission not the hub.

I still have a bizarre issue whereby on start-up the cluster lights only illuminate for a fraction of a second before extinguishing and leaving only the ESP/BAS light lit. This then goes out as normal when the engine is fired. The ESP and BAS systems work fine. I've no idea what the cause of that is.

Deefor62

104 posts

96 months

Wednesday 23rd October
quotequote all
Yogioes said:
TR4man may be onto something there ....... or, have you seen the film Christine?

From the start of Sept when I got the new bike I had not had a single journey where the BAS ESP light had not come on.
As mentioned above, I had tried a few things with no success and had booked it into the local Merc indy specialist.

Well, on the way there ..... no BAS ESP light. The journey was certainly long enough to have triggered it based on the previous six weeks journeys.

I left it with the garage and went back later that day to collect it.

They gave it a good check over, read all the codes, cleared the codes and took it for a test drive.
No BAS ESP light and no new codes showing.

Obviously, my code reader is of very limited use on this car.

Here are the reports showing the stored codes.





It's very detailed, even including the problems with the CD player.
The guy talked me through it.
The Canbus issues and the gauges dropping will be hard to resolve. May even need a new instrument cluster which is not available from Mercedes.
He suggested that the most likely source of the BAS ESP light was the OSR ABS sensor / ABS ring. He noted that the ABS ring was lifting a bit due to corrosion.
He suggested the ring was around £30 but that the ABS sensor is no longer available from Mercedes.
He also pointed out that one of the front strut top mount rubbers was cracked.

I called Mercedes parts.
The ABS ring - Not sold as a separate item - That only comes with a new driveshaft. £800!!!!
I had a look at the car and to my amateur eyes it still looks quite clean and neat. Not sure what to do about this as yet.

I ordered two new front top mounts.
I also ordered a new throttle position sensor. I think I mentioned before that there is a VERY slight stickiness in the throttle pedal. I find it a wee bit irritating as the car is quite sensitive to a bit of throttle.
I have already changed the cable which helped a bit so I am hoping that this cures it as it is £190 wasted otherwise.

The car had several good runs on Sunday and Monday, still with no BAS ESP light, I didn't see the gauges drop and not a single bumpy gearchange. A self healing car?

On Sunday I was at the Lochwinnoch car show. They had a lovely day for it and had a good turn out.

On Monday I went to get a quote for getting the wheels refurbished. They are in fairly good condition with only minor scuffs and some corrosion under the paint but as two do not hold pressure and as all four tyres need replaced I decided to get them tidied up.

I also went to a local trimmers for a quote to get the three plastic windows replaced. There are some very minor cracks that will only get worse and they are a bit opaque making it quite hard to see through.
My attempt at repairing the section of broken stitching has convinced me that a full DIY replacement is not a good idea.
The trimmer told me that he will remove the rear section from the car to do the work. I didn't know it was in two sections.
I will probably go ahead with the repair when I can get it organised.

Priority is the front strut mounts, wheels & tyres and an MoT due within a month.

The other code that I was interested in is B1706-002 which mentions the rear window defroster. When I got the car the hardtop was attached and I remember thinking that the heated rear window did not work.
However, I have no idea how to "Check control line to component N10/2" ........ or what N10/2 is ...... or what is a control line.
Pesky Canbus stuff.
This did have me looking at the Stags at the show, envious of their simple old 12V electrics. Obviously, the two that were there were not rusty wrecks like quite a few of them are.

In other news, some of the plastic trims along the top of the screen were cracked.
I'm struggling to justify £36 for each sun visor hinge cover so I had a go with some superglue.

OS before




OS after




NS after (no before picture)




I tried to do this centre trim in situ but without success




Did I mention the film Christine?
For the first 11 months that I have owned the car, opening the centre cubby was a two finger job. One to press the button and the other to push the lid up at the same time.
Well, it has sorted itself ...........




The car is probably still for sale but don't let it know!!
Probably the wrong time of year and it's due an Mot.
The advert on PH disappeared (I assumed wrongly that it stayed until I cancelled it) and I have deleted the advert from C&C.
N10/2 is likely to be the relay that controls your heated rear window/intermittent wipe/indicators and hazard warning lights.

By all accounts, these are notoriously problematic as the solder cracks and cause various issues. In my case, it was the self parking and intermittent wipers that packed up. Replacements (including used ones) are quite costly, and so I took the steps of taking it apart to see if there were any obvious cracks in the solder on the base plate. Fortunately for me, I only had to clean the contacts of the individual relays, and the wipers now work as they should.
My car is an early 500SL, and the N10 is located on the nearside of the engine. immediately in front of the scuttle, and which contains a whole load of other troublesome relays (OVP - I'm looking at you here).
The N10 is removed by sliding a little lever forward, which lifts it out of the holding block.
Hope this helps.