Pillow's C216 CL600 Project

pillow

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Joined
Feb 19, 2019
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133
Location
Hampshire
Car
W216 CL600
A bit late to the party with this one, considering I have owned it for nearly 2 years now.

But I have just been browsing google photos and have enjoyed reviewing all the photos I took of my CL at various stages of my ownership/repair so feel like maybe some folk would like to see the qualms and costs of owning a fairly high-mileage V12 Mercedes!

A bit of a foreword then about things:

So prior to purchasing a CL I had a BMW 630i. Very enjoyable, reliable car, good enough poke, rare manual gearbox version, interesting styling, very comfortable long distance cruiser. I love BMWs and had to own probably the last best naturally aspirated straight-6 they produced.

lKxaOONQDhSG7OK5rudizSWdmUryHUETZkljAeWWtMFIJ6nfgJaptEGpPjuwg35A4TNZ94pE75xLjAIa_3IsRs4NO1DwChPl-F0iyjYR6-ybv81khUdUclHZf_WIVRmR0SZ6aiMtDQ=w600
JgjrCoK7_GqtglVOnQt98yJmaNLfhuJdmFgluiWsEhkYAV69_EDyAA-KMwOOUFV5oVhS416jEeEgoh4J_Kb5x0knsOY4YVyGh2Uf2TelrAUAt_nZb109nF16U3WSEgKYkQ6LZy0kHA=w600


I finally got to a point (new job) where I could potentially afford something in a higher class and began the search for something I could replace it with. The criteria was fairly simple: bigger, more powerful, more comfortable, 12 cylinders. It's at this point you realise how few options there are that can meet these criteria. The three car shortlist winded up being; a CL600, a Bentley Continental, an Aston Martin DB9.

To cut a long story short all three powertrains had weaknesses - the CL600 and it's infamous coil packs, the Bentley needs the engine out to do pretty much anything (vacuum lines on the top of the gearbox?!), the DB9 has it's timing cover leak (engine out job).

The CL600 was going to be the most pragmatic choice. And so the search began. 10 months later and I found what I was looking for - a CL600, black exterior, black interior, black piano trim. 110,000 miles, no major issues. Well, except the owner had owned it for only 5 months and was selling it because he "could not afford to run it".. at a hair over £10k I thought I had gotten a great deal on a lot of car. Not the prettiest/most exciting looking, and the black paint was showing it's age, but it's all stuff that I could remedy.

71MOx1SUKj9O38p-pusjzETMOB37pvPdkzpj_mvnsVNnq6zDqLMy4TEcV_qkz2GXxH6g8hhyiAUfRqdmFcvsJZOiX4HoW3iqgjHFXFDbv2LMQ8dZOAVnzuYaXtbmbuL46Bp_JGmVbQ=w600


The drive home was incredibly enjoyable. The previous owner had gutted the mufflers (something which would later come to irritate me) but having just purchased the car it was a dream hearing 12 cylinders purring away on the uneventful drive back.

More tales of the subsequent 2 years to follow....
 
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pillow

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Feb 19, 2019
Messages
133
Location
Hampshire
Car
W216 CL600
The first problems

So there were a few issues I knew about off the bat - amplifier was dead, centre console armrest was stuck shut, cold start would wake the neighbourhood up..

I haven't got any pictures but I managed to figure out that the amplifier lived in the boot, left side of the car and was easy enough to whip out. Remove some boot trim, pull the carpet away, unplug a light and you have full access to unplug and unbolt the amp. Had a peek at the board myself (comfortable with building computers so happy to work with electronics) but saw no obvious faults. Likely a duff component/s on the board itself and without a means to diagnose and test efficiently I decided to send off for repair.

BBA-REMAN (despite the terrible reviews) was where I decided to send it off to. Long story short, within about a week they claimed to have fixed the problem and sent it back to me. I can't complain about the service I received but I am still wary about the reviews out there. Total cost: £300. Not bad as a new amp runs about £1200 I think.

The centre console armrest was an odd one which took a while to work out. The entire armrest mechanism (dual hinge thing) is inside the armrest, and it is glued together. Fortunately you can pry off the buttons on either side and can access a small portion of the mechanism and here I found the problem with how the hinge was locating. Essentially it was not attached to the spring and was thus staying engaged and not releasing when you pressed the button. Lucky break really.


After a week or so I ran into my first really troubling issue. The car would, on occasion, not start. Foot on brake, press the start button, smooth-as-butter starter would whir into life strongly, but then nothing. Wait a bit, try again and maybe it would work. Sometimes it would work reliably when hot, sometimes only when cold. There was no real discernible pattern. There were also absolutely no issues once started, it would drive perfectly, idle perfectly, never shut off or stall out or anything you could consider strange. At this point I knew I needed 2 things - a specialist who might be able to help, and some form of diagnostic system (having used INPA for my BMWs I needed an equivalent for Mercedes). For this first step I decided to order the iCarsoft MB II, something which to this day lives in my glovebox just in case.

I also was fortunate enough to have a really good specialist just a short walk from where I worked in Fleet. (Anyone in the north Hampshire area, I can highly recommend Huxley's in Fleet, Liam is incredibly helpful and Stu is very friendly). I had it booked in with them but their suggestion was to see how old the batteries were and swap them out as they can cause all sorts of strange gremlins. So the next stop was to check the batteries - each 11 years old.. ok time to visit the dealer to get a pair of genuine replacements. About £400 lighter and a little while later I had two new batteries fitted but the problem persisted. (Irritatingly the car worked flawlessly for a few hours after fitting the batteries before the issue reared up again (and reaffirmed to me that the problem was not with the batteries). Right, what else could I pre-emptively replace? Camshaft and Crankshaft sensors were next on the list - About £110 for a Bosch camshaft sensor, and a Hella Crankshaft sensor. A little trickier to fit these two, the crankshaft was not too bad as you can remove the top portion of the firewall panel which gives decent access around the rear of the engine. The camshaft sensor is where I experienced my first baked plastic = very fragile moment.

JI448AgMvLDj0RcQJmPLtLRTODjcylAlB5eGyaltO6ldiEz8_kLUTO-Xtxl5Mabnw-YNyqiAAipk9ZLhdFUSfhf4khHgj1Y3skejQRjxwGy4xo8nB9K71AjxCLEHjwW4o5i8TODS6w=w600


The connecter broke rather unhelpfully. Fortunately fairly cheap and easy to get a replacement plug housing from the dealers, and the pins simply push in from the rear of it. New sensors installed, problem persisted.

At this point I was at a bit of a lose end. I feared perhaps there was an issue with the ECU which would require ££££ remediation.

Unfortunately I don't know what exactly caused the next, ultimately stoke-of-genius, action but I decided to investigate the Front SAM a bit. Without much understanding about what the relays were responsible for I decided to see what they looked like.

icLPySJbfwukP-6qY4-y7kpIW-0mTcheCzJQABbKCPk0XjYViCrmWyRC9Apwq-dDdSpY9uSn-mzS5S21UHsH7kiIDgsyrOXfxK86tZAB1ans98SmlePCm1okGP3eoQnK3T6v0VLk1w=w600


Things didn't look too bad. I took the entire thing apart having read stories about corrosion and saw nothing untoward (this thing is incredible if you do take it apart. It's like a really thick printed circuit board with loads of metal layers and pathways that trace out the different electrical paths). The only thing of note is that relay E had a very small amount of corrosion on the base of it's pins.

Look it up -> Terminal 87 relay, chassis

Could this be a problem? I decide to swap it with relay A, the Air Pump relay (for secondary air injection I believe) and see how it goes.

Sure enough the car now starts every time. Still not sure exactly what this relay controls but clearly it's something quite important.

£10 for a replacement relay.. ~£550 out of pocket for the sensors, battery and replacement relay. A couple weeks in and we are already £850 down.

I knew it was going to be an expensive few months :D
 

merc85

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£850 down in the 1st few weeks, I'm glad i'm not the only one who has bought cars like this lol.

Good work getting this issue's resolved ;)
 
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pillow

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Feb 19, 2019
Messages
133
Location
Hampshire
Car
W216 CL600
So week 3 rolls around next. Having solved the starting issue and with an appointment booked at Huxley's I decide to go ahead and have them get the car on the ramp to poke around, plug it in, have a scan etc.

Only minor things to add to the list;

window modules are reporting an issue (but they said a software update would almost certainly fix it)
rear alloy is cracked (but not leaking) and a few of the others have been welded
bit of play in the inner tie rods
couple of exhaust rubber hangers are perished
thermostat is stuck open

Hmm ok, interesting. So I decide to let them update the modules, and sort out the inner and outer tie-rods (decided I might as well have the outer tie-rods done as they aren't really much more expensive). I also decided a gearbox service would probably be a good idea as occasionally the shift from 1 to 2 was a bit harsh.. normally not an issue as I use C mode most of the time but better to be safe than sorry. Another £500 gone.. a trip to the dealer later and it turns out the thermostat is only available as a full housing, which includes one of the valves for the secondary air system.. £400 please.

nzaDKZqs8israone2sq_K5TNX4AG62jp7O905ZqJlbPvDxYGIio0cIs9vaVaAJ_WItg3QcbXvGV9qvabkn3SKdYWbtTOSvI2JTT7aWR9q1yf4gpvBmDLJjxUlLXqfdxVBBWp2r32Ik2iwLqmM716vPTrn17lMk6Ujdl6vf2np8axiJ-_-eHMP_vx6VCuoj7QG7vfWz4ZUrJz4_vOdzzCWFWmDnTITNP0bs2wdzz3ShjL_Zf8a418lEssfKdyWg2StuStQcWTBN_PKdqju7K_A8RXXRnY_zsEpm6DBQtN4nJWUb5uRamixIlexA01IizgLFyuo8pI5xKraur_AIMY6IFC7DOdVbklhMv9O6GE4bfYr4PxxkUH8LGRv4YdlN801FPzCwbzjNroI7eHUdc2DRBKDWB6M4uUEB5moZ3WN_AfrdB0qnon-aj9jmcnM3WBDzLq__vIltFD-J_VIKXb2DBsZp3vr06vYY6yEGTVTyr0zo2QWRRSBu0CF7xqzcX_toRKGY-xD8zsYcUeUdGRuHpgH5YaIcPfmMWOc4fbB5zRdcE_skPJYfOHPRCJw0Lu7jvE8jOzeN-P5UIZFQw3NeelYnQsBUEkaiDR3fm7pAYfD3NripmZ2kXNp-W5JqVlmkI7tRGjWIdYjR_fNws0rvJ0NissYdl_jjpbpVM9QE5lRM3SL183calxPJ2a1Q=w600
s-l1600.jpg


Fortunately the thermostat is on top of the engine and easy enough to fit. Not much of a silver lining but at least it's something.

So here we are 3 weeks into ownership and the running total is near £2000.. To be totally fair this was expected (and a reason I got a very reasonable deal) so I have kept some money aside to deal with all of this.

I can see from the timestamps of my photos that the car behaved itself fairly well for the next 4 weeks.. that is until I realised something was looking a bit wrong..
 

merc85

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This thread reminds me of my "Brutus" Project lol Good work :)
 
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pillow

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Feb 19, 2019
Messages
133
Location
Hampshire
Car
W216 CL600
The tale picks up several weeks after the thermostat replacement, about 1-2 months after purchase. Following the replacement of the thermostat a new problem transpired; the coolant level just kept dropping.

I disliked the fact there was no bleed screw on the cooling system so appreciated that after draining and re-filling the coolant there would be an element of needing to top up, but unfortunately this was a persistent problem. Could I have mucked up something when re-installing the thermostat? The gaskets are on the underside as you join everything back up and bolt it back on.. could I have nicked one of the gaskets causing a slow leak?

Well I decided the simplest solution is usually the best to start with, and considering I had just changed the thermostat perhaps this was the reason for the coolant loss. New rubber seals from the dealers were reasonable (~£10) and the removal and reinstallation of the thermostat is also reasonably easy as it's located up top. I quickly remove, check the old seals (which were new on the new thermostat) they looked ok. Oh well, threw them away and installed the new ones, carefully positioned it and re-nipped up the bolts. Refill the coolant and see how it goes.

Unfortunately a week later and the level was still dropping. At this point I was fairly confident I hadn't mucked up re-installing the thermostat. I checked underneath the car to see if I could see any coolant drips - absolutely nothing. Ah man.

Thankfully google came to my assistance. A lot of mentions of "100k" "coolant loss" "turbo". These all pointed towards the coolant outlet hose from the turbo, specifically the o-ring that seals it to the turbo. Apparently, (and unsurprisingly), these dry up and leak coolant out. You never see the coolant on the floor because they just evaporate off the turbo housing.

A little bit of reconnaissance was in order. It is impossible to see the turbos without removing parts from the top side of the engine, however I was able to precariously slide my phone down one side of the engine and snap some pictures. Of those that were not blurry I got a good look at what was going on;

EEBlcoS.jpg
jvHPL5W.jpg


Well that looks pretty conclusive to me. Time to get stuck in.


This was my first time really digging into the engine and bar one bolt snapping in the head (just 1 of the 4 that secure one of the intercooler coolant lines so not vital) it was rather an enjoyable experience.

OFclBAe.jpg



QqA5ndj.jpg


110k of oil build up, as it happens the cyclinder head cover had a tiny chip which allowed all of this. Sorted with some QuikSteel filler to ensure the gasket was seating properly. I would need to do the rocker cover gaskets soon anyway as they dry up to a plastic like consistency. The snapped bolt still resides to this day in the little arm right in the centre of the image. All of this got a liberal spray of brake cleaner and the toothbrush treatment to clean it up.

And what do the turbos look like?

9M61sAe.jpg
nAcriDC.jpg



Jackpot, still moist from having run the engine earlier in the day. A couple of quid for the o-rings and the oil line seals and a short time later and we had some nice new o-rings in place. Reassembly was thankfully unremarkable. Coolant refilled and time to see how she goes.

Spoiler alert: It worked
Spoiler alert 2: Something expensive broke in the following week...
 

MrGreedy

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Ah, spend on a 'blind buy' of an older car (i.e. one not backed up with a massive folder of receipts and a knowledgeable previous owner) is always a very real possibility.

If you're keeping the car, a lot of the stuff you are doing is basically sensible maintenance and consumables (batteries, transmission, thermostat), so don't sweat it.

It could be worse. I bought an Insignia for £4k, and in my 2 years over ownership, I spent about £8k on repairs. This was only as low as it was because I did nearly everything myself. If I'd paid Vauxhall, it could have easily been £16k. But even after 2 years, I felt there were many more expensive problems quite possibly around the corner, so I got rid of it.

I just wish I'd spent £12k straight off the bat on something much nicer
 

Kass1

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Apr 8, 2015
Messages
6
Car
Mercedes CL500 W140
Hi (Pillow) I have recently acquired a 2007 CL600 C216 myself. Reading your post I noticed you have had your gearbox serviced due to a jerky gear change between first and second. Did the service make this issue go away. Mine is doing the same thing. Thanks, look forward to the reply.
 

Kass1

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Messages
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Mercedes CL500 W140
So week 3 rolls around next. Having solved the starting issue and with an appointment booked at Huxley's I decide to go ahead and have them get the car on the ramp to poke around, plug it in, have a scan etc.

Only minor things to add to the list;

window modules are reporting an issue (but they said a software update would almost certainly fix it)
rear alloy is cracked (but not leaking) and a few of the others have been welded
bit of play in the inner tie rods
couple of exhaust rubber hangers are perished
thermostat is stuck open

Hmm ok, interesting. So I decide to let them update the modules, and sort out the inner and outer tie-rods (decided I might as well have the outer tie-rods done as they aren't really much more expensive). I also decided a gearbox service would probably be a good idea as occasionally the shift from 1 to 2 was a bit harsh.. normally not an issue as I use C mode most of the time but better to be safe than sorry. Another £500 gone.. a trip to the dealer later and it turns out the thermostat is only available as a full housing, which includes one of the valves for the secondary air system.. £400 please.

nzaDKZqs8israone2sq_K5TNX4AG62jp7O905ZqJlbPvDxYGIio0cIs9vaVaAJ_WItg3QcbXvGV9qvabkn3SKdYWbtTOSvI2JTT7aWR9q1yf4gpvBmDLJjxUlLXqfdxVBBWp2r32Ik2iwLqmM716vPTrn17lMk6Ujdl6vf2np8axiJ-_-eHMP_vx6VCuoj7QG7vfWz4ZUrJz4_vOdzzCWFWmDnTITNP0bs2wdzz3ShjL_Zf8a418lEssfKdyWg2StuStQcWTBN_PKdqju7K_A8RXXRnY_zsEpm6DBQtN4nJWUb5uRamixIlexA01IizgLFyuo8pI5xKraur_AIMY6IFC7DOdVbklhMv9O6GE4bfYr4PxxkUH8LGRv4YdlN801FPzCwbzjNroI7eHUdc2DRBKDWB6M4uUEB5moZ3WN_AfrdB0qnon-aj9jmcnM3WBDzLq__vIltFD-J_VIKXb2DBsZp3vr06vYY6yEGTVTyr0zo2QWRRSBu0CF7xqzcX_toRKGY-xD8zsYcUeUdGRuHpgH5YaIcPfmMWOc4fbB5zRdcE_skPJYfOHPRCJw0Lu7jvE8jOzeN-P5UIZFQw3NeelYnQsBUEkaiDR3fm7pAYfD3NripmZ2kXNp-W5JqVlmkI7tRGjWIdYjR_fNws0rvJ0NissYdl_jjpbpVM9QE5lRM3SL183calxPJ2a1Q=w600
s-l1600.jpg


Fortunately the thermostat is on top of the engine and easy enough to fit. Not much of a silver lining but at least it's something.

So here we are 3 weeks into ownership and the running total is near £2000.. To be totally fair this was expected (and a reason I got a very reasonable deal) so I have kept some money aside to deal with all of this.

I can see from the timestamps of my photos that the car behaved itself fairly well for the next 4 weeks.. that is until I realised something was looking a bit wrong..
Hi, love the whole post and thanks for mentioning your journey with the mighty CL600. I have just purchased my CL600 2007 which also has a bit of a jerky gear change from 1st to second. I wanted to ask you if yours got sorted after the gearbox service. Thanks
 
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pillow

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W216 CL600
Hi, love the whole post and thanks for mentioning your journey with the mighty CL600. I have just purchased my CL600 2007 which also has a bit of a jerky gear change from 1st to second. I wanted to ask you if yours got sorted after the gearbox service. Thanks
Not jerky, but harsh. It felt like it was just dropped into gear and there would be a single knock when it engaged. It resolved itself about a month after the gearbox service.
 

Kass1

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Apr 8, 2015
Messages
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Mercedes CL500 W140
Not jerky, but harsh. It felt like it was just dropped into gear and there would be a single knock when it engaged. It resolved itself about a month after the gearbox service.
Ah right okay. Thanks for the reply. Mine is getting done next week full gearbox service including torque converter oil. Will let you know how I get on. Cheers
 
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pillow

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W216 CL600
Right it has been a couple of weeks since the last update because I had to go out and take a few pictures for this update. April 2019 when this next update covers I only have one picture of the incident:

pOqJtz7.jpg



About 15 seconds after starting the car and just pulling out of the drive the steering goes heavy. White ABC warning on the instrument cluster.. A slight sense of trepidation.

I ease the car back into my parking spot and pop the bonnet up. I'm greeted with an odd smell and oil pretty much everywhere. I'm a bit less worried at this point because there being oil everywhere tells me that it is likely just an ABC hose that has ruptured, and indeed that was the case. A quick check of the ABC oil level - low but not detrimentally so. A quick start of the engine with the bonnet up and clear as day I could see a thin stream of hydraulic fluid getting sprayed out from the middle of the hose. Considering there is supposed to be 200 bar of pressure in this hose I was surprised at how feeble the stream of oil coming out of it was.

Anyway, a quick call to the dealer highlighted that this hose was a £400 part... jeez! A few days later the replacement hose turned up - for good measure I ordered a replacement pulsation dampener (black sphere that sits on the ABC/PS pump) and a pair of accumulators to cover the front and rear axle valve blocks.

Here are some pictures I've just taken this morning to show the areas of interest:

The front valve block can be found behind the left fog light/in front of the left tyre (although if you come at it from the tyre side you have the washer bottle in the way. The way you get to it is from underneath, where it is clearly visible.

l43ZDwr.jpg


zHmNwAV.jpg



You can see 4 hydraulic lines going into the front valve block but in total there are 6 (there are 2 more just below the image). 1 is the main high pressure hose that comes from the pump (the one that blew for me). This one carries 200 bar of pressure to the front valve block. Another of the lines here carries hydraulic fluid to a radiator at the front before returning to the reservoir. A pair act as the feed to the rear and the return line from the rear, that makes 4. The remaining 2 feed the front two struts.

Here is a more complete picture from an ebay listing:
Blok-zaworow-ABC-przod-Mercedes-W221-A2213200258


The front accumulator is screwed into the rear side of this valve block. As you can see here the front accumulator is a screw on type with a nut at the neck of it:

feb-starpartz-063.jpg


As you can imagine getting the right size spanner in the tight space between the washer fluid bottle and the valve block is difficult, however a chain strap around the sphere makes really light work of it. Installation is simply the reverse of removal.


Installation of the high pressure hose is a bit more challenging. At the pump side access is mediocre - not terrible, but not great. Removing the airbox from this side of the engine is all that is needed but when removing the pulsation dampener you need to be mindful of a large AC hose, and these AC hoses are not really flexible at all. You might be able to see if poking through in this image:

W23NDoz.jpg


but if not, here is a closeup:

xgwqCPx.jpg


Note the pulsation dampener (with the nut on the top of it), and the high pressure hose (which is held into the pump by two small torx bolts. Removing the pulsation dampener gives move space to remove the high pressure hose, and then it's just a case of unbolting it where it is mounted to the block.

It loops around the front of the heads, and then curves down towards that front valve block. Secured here at the head with 2 e-torx bolts:

co4aVNs.jpg


Further down it is secured in with one of the mounting bolts of the AC condenser. This was the biggest pain in this operation. Anyone who has done alternator/AC compressor work knows that the bolts that hold these in are VERY long. The bolt goes from one side of the accessory right the way through and then into the block. They are easily near 6 inches long. The problem with this was I had to remove one of these bolts to get the hose out. Unfortunately with about a quarter of an inch of the bolt to go (when pulling it out) it comes up against the subframe. Incredibly frustrating considering it comes out about the 5-6 inches it needs to except this tiny little bit left. No amount of pulling/pushing/jiggling would get it to come out just a little bit more. This mean I had to undo the engine mounts and lift the engine up a little just to pull the bolt out. Then it's just a case of unbolting it from the valve block and negotiating it out of the space. Reverse the procedue to re-install the replacement hose.

The rear accumulator is not too difficult to replace. As you can see from the following picture:

s-l300.jpg


Instead of being screwed into a thread, there are three bolts that secure this rear accumulator. There is then a hose that joins this to the rear valve block. The top of the rear accumulator can be seen by looking right next to the spare wheel well under the boot carpet. You can't really do anything from this side as the nuts that secure it in connect from underneath the car. Access is reasonable but you need a universal joint or a wobbly socket.

Top up the reservoir with fluid, clean up as much of the mess as possible and have another go at it and we're all good. If the hose was original then it's done pretty well for over 10 years and 110k miles. The other hoses in the system do not carry as much so should be fine.

Total cost?
Hose: £380ish
Accumulators: £360 (for the pair)
Pulsation Dampener: £220

so all in with the replacement fluid needed the total spend was about £900. Another painful week...


However, following this things remained pretty quiet. The next set of documented pictures came from the start of July, so I got a good couple of months of trouble free bliss :D.

The next failure was the inevitable one though. The one thing I had already braced myself for before purchase..
 

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