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Discussion Starter #1
Overall this is probably not for everyone and the main motivation behind doing this myself is the fact that nobody else has done a DIY on this.

Main challenges:
  • Need to put APMU into maintenance mode - still trying to figure out what that exactly does. The job of APMU is to maintain a desired pressure inside the system (steering/suspension). There is 3 circuits controlled by 3 separate magnetic valves. These valves are controlled directly by the PCCM. Couple ways around it, you can manually drive the valves or you can figure out how to talk to the PCCM via can to make it do that for you. Currently #2 is proving to be more challenging than expected, so will most likely go for #1.
  • Extra tooling required - not too big of a deal, basically you need to pull 30hg-in of vacuum out of the system, then cut the vacuum supply and deliver the new fluid in place of said vacuum. Not any different then filling the coolant system. ~50$ worth of parts and material
  • QD adapters required - I believe these might be sold by McL, need to consult the McL SPC
  • Need to vent system prior to service - you could do it the crude way and just loosen the valve but given that the system is rated for 40Bar I have opted to make a small valve (on the qd side) and a tank to vent the system.
  • Will not be able to perform APMU calibration so I might still need the dealer...
Like I mentioned earlier, this isn't a project for everyone. The dealer is charging around $3000 for parts and labor; so your definitively not saving yourself a ton of money however the parts can be had for cheap (<800$) and I need a hobby to keep me sane.

Anything wrong with my plan? Am I crazy or what?

Tom
 

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I'm excited by your DIY on this topic... I believe you can do it all yourself and the system should re-pressurize automatically after you re-energized the system. Be sure to disconnect all electrical power during the process.

This system is nearly identical to the Mercedes ABC (Active Body Control) suspension system used on millions of Mercedes vehicles over the past 20 years (and a host of other brands as well) and you can find a lot of information online regarding replacing the nitrogen filled accumulators for those vehicles. The good news is lots of people have successfully changed those themselves.

Looking forward to lots of pictures and a nice DIY write-up when you do this!
 

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Discussion Starter #3
interesting, I have not seen anybody else do this on a mcl.

I think you are spot on on all points. The system looks very similar to the benz one which people do not bleed at all. The concern there is that any air trapped in the system might cause cavitation/air pockets in one of the critical components which is going to produce an early failure hence why I think vacuum bleeding the system seems like a good investment.

The APMU control is very simple, 5v + a current limiting resistor will take care of controlling all the valves. I bought a set of connectors (DJ7062A-1.5-11/21) to make a harness. The system has 3 operational modes, of which we are only interested in 2. One is inactive which I believe opens the pressure and vent valves, allowing to release the ridiculous pressures out of the system. After that we just need to open the main valve to the suspension and keep the fill/return and steering valve closed (since were not trying to bleed that part).

Valves are easily accessible so the only remaining part is to figure out the QD fittings.

Seems a lot easier than people make it out to be. On another note I scored a PCCM for dirt cheap off ebay so I should be able to do some work on it.
 

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I'm excited by your DIY on this topic... I believe you can do it all yourself and the system should re-pressurize automatically after you re-energized the system.
I'm sorry to say this is not the case. it has to be recalibrated at the dealer through software. The dealer forgot to do that step after replacing my accumulators a few years back. Two weeks later I was getting PCC errors. Unfortunately this is something you will not be able to accomplish without the dealer recalibrating.
 

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Discussion Starter #5
I'm sorry to say this is not the case. it has to be recalibrated at the dealer through software. The dealer forgot to do that step after replacing my accumulators a few years back. Two weeks later I was getting PCC errors. Unfortunately this is something you will not be able to accomplish without the dealer recalibrating.
Good info, I have a few things in the back pocket. The backup plan is to just do the calibration when the car is for airbag service.
 

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Discussion Starter #6 (Edited)
Spent a bit of time with the car tonight, the fittings look like regular zerk fittings. Looks like I just need to remove the check valve out of a regular grease gun coupler and give that a shot. I was expecting a low loss valve of some sort.

My damaged PCCM got here... it still works :) now for some overnight parts from japan^H^H^H^H^Hchina..
 

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Man I hope you figure this out before mine need replacement. I'd love for this to be a DIY procedure! There is an APMU for sale on eBay if you're looking for one to bench test. Subscribed and thank you.
 

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Spent a bit of time with the car tonight, the fittings look like regular zerk fittings. Looks like I just need to remove the check valve out of a regular grease gun coupler and give that a shot. I was expecting a low loss valve of some sort.

My damaged PCCM got here... it still works :) now for some overnight parts from japan^H^H^H^H^Hchina..
looks like a brake bleeder type of valve.turn it to open and let us know.
i may be wrong but system is pressurized by the pump,so means fluid should circulate and therefore self bleeding over a short period of time,especially if just replacing the accumulators and not draining the system.
 

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Spent a bit of time with the car tonight, the fittings look like regular zerk fittings. Looks like I just need to remove the check valve out of a regular grease gun coupler and give that a shot. I was expecting a low loss valve of some sort.

My damaged PCCM got here... it still works :) now for some overnight parts from japan^H^H^H^H^Hchina..
zlykopt,
Any updates on this? hopefully you have been driving and enjoying the car since this project was started?
 

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I had mine done by a none dealer, without the supposedly necessary equipment and it's been great!
 

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Discussion Starter #11
I have not done mine yet, been driving the car "daily" so I can't afford the downtime... should get addressed over winter season.

While I agree that most of these systems will bleed itself (like the Benz cars), there is some risk of air being trapped in the system and causing damage. The plan is to vacuum fill the system.

Most of my hobby time is spent on making a MDS like replacement which would make things easier...
 

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interesting project.
I change around 8 accumulators already. First of all. you can make it very very cheap by changing the accumlators yourself. on p11 is very easy and it takes less than 2 hours. and you bring it back to dealer for the suspension bleed. which cost around 350. and you are good to go. It is too much trouble try to bleed the system by yourself.
 

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That seems like a good idea. Where do you order the new accumulators from?
(I'm new the McLaren ownership, and not sure where to source replacement parts when I need them.)
 

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Subscribed! I have a new-to-me 650S that is throwing PCC errors occasionally. The expensive warranty I purchased does not cover these Accumulators so I'm looking for a DIY option :). Can't wait to see how this thread progresses.
 

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Subscribed! I have a new-to-me 650S that is throwing PCC errors occasionally. The expensive warranty I purchased does not cover these Accumulators so I'm looking for a DIY option :). Can't wait to see how this thread progresses.
OK I've been digging around and it seems I can get 4 accumulators for the 650s for about $1400 delivered. My local dealership was also nice enough to offer to match this price if you can believe that. I've also heard/read that the installation of the accumulators is very straight forward, and that there is very little residual pressure in the suspensions hydraulic system if the car is allowed to "sleep" for some time - meaning the accumulators can be removed without any huge release in pressure. But obviously I don't know this for a fact (so don't quote me lol), and information is very sparse on this.

As mentioned numerous times on this forum, the bigger challenge is bleeding the suspension system after introducing air by removing/replacing the accumulators. The dealership seems to have a monopoly on this process, and I was quoted roughly $600 for the suspension bleeding/computer adaptation process. That brings the DIY cost to $2000 give or take assuming $1400 to DIY the accumulators and then $600 trip to the dealer for the bleed/adaptation portion.

Now here's something that hasn't been mentioned so far (or I totally missed it). If the dealer does the entire job from start to finish, the parts are then covered by a 2-year warranty. This means if they go bad again within a 2-year period, the replacement is free. That's what my service writer told me. If that really is the case, then perhaps a DIY is not such a great value if the whole job at the dealer is under $3,000. Anyone else feel the same way?
 

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XPRD on here can beat that price i think.contact him first.
as far as changing them,there seems to be different stories.a member here says he just changed them out and didn't need to do anything other than adding a little bit of fluid to make up for the slight loss he experienced.
others here have said that only dealers can do this because of the high pressure involved and the bleeding required.

i tend to believe the dyi is a viable option if you don't let the system drain out.and even then,there are bleeders on the system that i would think would allow us to do it without the "magic" machine dealers have.
 

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XPRD on here can beat that price i think.contact him first.
as far as changing them,there seems to be different stories.a member here says he just changed them out and didn't need to do anything other than adding a little bit of fluid to make up for the slight loss he experienced.
others here have said that only dealers can do this because of the high pressure involved and the bleeding required.

i tend to believe the dyi is a viable option if you don't let the system drain out.and even then,there are bleeders on the system that i would think would allow us to do it without the "magic" machine dealers have.
Yes, XPRD has been great so far ;-)
 

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I can’t wait for someone to actually try it with no dealer visit involved and then report back on the results. Mine aren’t bad at the so I’m not that guy at the moment.
 

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You could do the replacement yourself... Do all 4 at once since you don't know beforehand which is bad.. Or all... Normal pressure is just over 20 bar... Watch out for your ccm, cover with plastic... Officially should bleed with vacuum machine... Repressurizes on startup if not in maintanance mode... Check for slight shaking when turning on active mode set on track... If you feel movement in the car there is air in the system and get it bled! If not, good for you :p.

Sometimes however you guys amaze me that you spend a lot of money on a great car but cut corners if it comes to service or repairs. No disrespect though:geek:
 
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