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Discussion in 'Maserati' started by thecarnut, Jan 11, 2009.
Thanks Ivan, for this usefull info.
Ah yes that clarifies things: thank you!
So, just to be absolutely certain about the procedure (I need to be spoon fed on things like this ):
To replace the main accumulator on the Merak, one simply has to unscrew the old one (with the engine not running of course), and then screw the new in place. Voilá!?
Any O-ring or gasket that should be replaced as well?
Yes there's an O-ring and be sure you seat it on there properly and carefully tighten the accumulator. There are proceedures for bleeding the main circuit BEFORE you do anything else. The headlamps are recirculative so just putting themm up & down bleeds that.
On the Bora at least the main feeds feeds the braking accumulators hence the need to bleed th main circuit first. Once that's done you bleed the calipers and done!
A few more questions:
- I plan to replace the main accumulator only (i.e. the one in the engine bay), not the two smaller brake/clutch units up front. If I understand the Merak manual correctly, supposedly only the regulator needs to be bled; but, where is the bleeding nipple? Have I seriously misunderstood something?
- As far as I understand, the clutch system is really a sub-system of the braking system, so only the braking system needs bleeding; is this correct?
I don't know what they did on your Merak for the clutch but it's my belief that ONLY the Khamsin got a LHM system clutch actuation. On the Bora there's a separate reservoir for the clutch and it's brake fluid.
The air bleeds naturally out of the recirculating portion of the system but as for bleeding the regulator I'm sorry I don't remember. It's been about 10 years. I know you have to get the main circuit clear first. I'd wait a day before bleeding the braking system so as to let any bubbles generated to settle out of the fluid from the main system tank.
Because of the LHM system's extreme pressure it will compress any air rather quickly and still leave you with plenty of power to stop. But, you will also notice that the brakes seem to grab and be even more touchy than normal.
FWIW, on my Merak - which is still new to me, so I'm certainly no expert by any means - I did have one occurrence where I felt the brakes want to lock up sooner than I expected... in doing some homework on this model, though, I did note that this seemed to be a characteristic of this type of braking system. It wasn't a problem, and it was easy to modulate the brake pedal the moment I felt it start to occur, but it was definitely... ummm - "unusual" the one time it happened.
They ARE naturally sensitive and if you've just jumped into the car after driving a car with a standard braking system then it's a bit of a jolt. You have to train yourself to not immeadiately hit the brakes hard in an emergency. My new Jag is the same way. Wet streets can be a challenge for new drivers. But if you've got air in the system or worse is Nitrogen from a leaking accumulator you'll know it. It's very different.
The new accumulator usually comes with a replacement o-ring. The old accumulator can sometime be very difficult to unscrew. I have had cars where it is easier to remove the pressure regulator/accumulator assembly to unscrew the accumulator in a bench.
Why are you only servicing the main accumulator? Where the brake accumulators rebuilt within the last 5 years? If they have not (or worst, you do not known when they were last done) I would strongly recommend that you do all three at the same time and then write the date with a Sharpie pen on the accumulators. It is best to have the brake accumulators rebuilt and a new diaphragm installed. To rebuild an accumulator is not that expensive (approx $100 each) and many bad things happen if this is neglected.
On the body of the regulator is a nut that opens with a 12mm wrench. With the engine running, slightly open the nut to purge air. After 15 seconds close the nut ... your done.
And when Ivan write slightly, he means just that, half a turn maybe. Otherwise you may find yourselves searching for a small spring and a steel ball somewhere in your garage.
Ivan and Bob: Many thanks for these instructions!
Marius: If anything goes wrong, I'll invite you to my garage to help me search for whatever gremlin part that might have escaped!
Good point Ivan. I wanted to change the main one precisely because I don't know when it was last replaced, and my car doesn't meet the diagnostic criteria for sufficient reserve pressure. For example, the headlights only raise 2-3 times with the engine off.
I have had the car since June 2006, and the seller told me that the other accumulators had recently been replaced... but, see now that I should seriously consider changing them as well while I am at it...
Try the test proceedures first. I they pass then don't worry about them.
OK, a question about the main accumulator - you guys have stated that the headlights should raise perhaps 10 or so times with the engine off... what if the car hasn't been driven either regularly or hardly run at all recently? It seems logical that the accumulator shouldn't be able to hold pressure literally FOREVER, so if my car has only been run for brief periods recently, is it possible that the accumulator hasn't had enough time under pressure from the pump to actually build up the reserve pressure it needs?
Just curious - obviously, once I get some other things addressed, I will let it run for awhile to test this out, but I also don't want to knee-jerk assume that I may need a new or rebuilt one if in reality I may not.
The accumulators are filled with Nitrogen. Time, more than miles, is the reason they need to be recharged and/or rebuilt. Some of the Nitrogen will leak through the diaphragm and the diaphragms themselves will disintegrate over time. Life expectancy of a diaphragm is about 10 years. I have seen them last much longer, but you will take taking a risk.
It should only take about 10 - 15 seconds for the pump to charge the accumulators if things are working properly. Running the car for a longer time is not going to make any difference.
10-15 seconds with the engine running, you mean, or 10-15 seconds with the ingition key in the "on" position, but not having started the car, or with the engine running?
The system is driven by a pump that is in turn turned by the engine. So in answer to your question, engine running.
Ivan has described the system brilliantly. Search on Enrico's Maserati website and you will find further hints and tips.
I've had some 'fun' with my Khamsin over the past 5 years, trying to work out where the LHM was dripping from. Turned out the headlight switch and a junction box on the A post were the culprits. But as described by others, the drivers footwell carpet is now shot.
As I'm unable to match the faded grey to what is available I'm going to have to do the whole car and am inclined to go black.
Currently I've had the engine removed for a rebuild and the three spheres and main pump have been rebuilt. However the garage didn't send off the regulator portion and I questioned that. As the car is apart I'd rather everything is done now so have asked that it is sent off as well as the clutch slave cylinder. I know my car hadn't been touched for over 20 years so I was living on borrowed time as they say.
In the UK the specialist who does this work is Pleiades, contact info I posted on the Khamsin thread. I'll try to find the link if I can.
My experience with a 1972 DS21 bears out Marc's contention about the pressurized hydraulic sytem in the Citroen. It was perhaps the only system that did not give me trouble. Other things kept happening often enough that the car was in the shop every 3 months or so during the time I owned it.
With regard to Rolls Royce, however, a well-known mechanic and restorer in New Jersey warned me to stay away from the modern Rolls Royces with the self-leveling suspension. When something went wrong, one had to trace the problem throughout the system, with the cash register ringing the entire time.
are the later meraks brakes without the Vulcan blood hydraulics much better? i always wonder how many early meraks were converted to the later brakes back in the day.
presumably you would have to add headlamp motors (x19?) also ...
A brake master cylinder with a vacuum booster as well. It DOES intrude upon the front luggage space.
I would guess very few early Meraks have been converted as the cost would be rather high. Much less expensive is to simply fix/maintain the Citroen system. If a non-Citroen Merak is what you desire then the later SS model is the one to get.
In the USA with the later Merak you also get the Bora style interior (really nice) and the big rubber bumpers (not nice at all).
My Merak SS is on the tail end of the production line. I can tell you there is almost no give in the brakes, they are extremly tight. I have never driven a LHM car, but I suspect the two would be very close. Once steel braided lines are put in, I suspect it will be difficult to tell the 2 systems apart.
George, we need to get you in a properly setup Merak with LHM or a Bora.
Trust me, they are very different feeling. For one thing the are very powerfull which is great at high speeds. I suspect a lot of the trouble with peoples experiences with the LHM system is that they don't get a chance to become acclimated and they probably haven't driven a properly sorted example. It's my contention that LHM systems should be bled a bit more regularly than most people do. As a consequence, they have a bit of air in them and that causes them to grab more than is normal. It's a hard system to modulate properly under such conditions.