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Discussion Starter · #1 ·
Everything You Always Wanted to Know But You Where Too Afraid To Ask ;)


What is this about:

The Cambiocorsa gearbox/clutch has an F1 pump which primes when there is not enough pressure in the CC system. You can clearly listen to the F1 pump when you open the drivers door.


So whats the problem:

The F1 pump gets power from a relay (more about relays) which after long term use, gets stuck open and fries your F1 pump.


Whats the solution:

As preventative maintenance, you can change your relay once every couple of years. The Maserati Part Number for the relay is: 155437.

In the early cars, the relay was of gray color, made by TYCO and looks like this:



In later years, once they realised that the relay failed occasionally and caused a lot of damage, it was replaced by a newer/better one. The new relay is of black color and it is made by BiTRON and looks like this:




How can I get one of those?

I tried Eurospares, but they only have the older gray types. Eventually, I went to my local Alfa Romeo dealer and got one from there, since the same relay is used in many other brands/cars.

Just ask for a: BiTRON relay 46520419 B047 50A

For example, here is one you can order online from Germany:

Alfa Romeo Fiat Relais 46520419 Bitron B047 50A - ..:: alfacarparts Online Shop ::..


Questions and answers:

- How frequently does the relay gets stuck?

Unknown, it depends on its use. We've never seen a "black" relay get stuck, so far we've only seen gray ones get stuck.

- In "another" forum, we were told that a 40A relay works fine, why is the new relay 50A?

Yes, a 40A will work but has a shorter lifespan, its stupid to use a 40A with a shorter lifespan when you can get the proper 50A which is within the specifications. If you can find a higher rated relay than 50A then that would be even better, but so far we haven't seen a compatible one (12V with the same contacts).

- Will it fit my car?

I know that my GS came with the newer black relay. I tried the gray one from Eurospares, it seemed to work for a while but at some point it failed because it didn't "sit" well.

I asked around and I was told that older cars may have a different relay base. One tech told me that he buys a relay base from VW and uses that to convert old relays into new ones. This still isn't clear to me, but I will soon take a look at a 2002 car so I can compare. I'll let you know what I find.
 

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You mention lifespans of a 40amp vs. a 50amp. Do you know what those lifespans are?
Many of us are changing them annually as preventive maintenance.
From my post yesterday the 50 amp at Ricamabi is $38 the 40 amp from NAPA is $10
 

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Discussion Starter · #3 ·
There is no measurement. A 50A relay is more powerful and can withstand current for longer than a 40A relay.

For example, when the 360 Modena came out, it had a 30A relay which got stuck so frequently that may Ferrari clients complained. Eventually Ferrari replaced it like Maserati.

My GS has had the same black relay since 2006, so I can't really see the point of changing the relay annually, if it was such a risk then it should have failed in those past 5 years.

I'd say, go for the 50A relay.
 

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But I imagine IF (when) it does fail, your F1 pump will fry. $10/year is very cheap quasi-insurance against that possibility. To me, common sense says spend the $10 annually.

Thanks for your post. It's informative.

I have included the other two choices as well - Red 50 amp from Ricambi - Black - 40 amp from NAPA
 

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Discussion Starter · #5 ·
True, I have to agree with you.

Once thing I remember, is that when the relay is about to fail, it gets stuck for more and more time, eventually it gets stuck open permanently.

But, when its about to fail and gets stuck for more time that it should, then its possible to predict the failure because your pump will run for more than 5 seconds all the time. I've never seen this happen, so I could be wrong.
 

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One thing to note is that fuses and relays are placed within a circuit to keep current operating within normal operations. The fuse will blow or relay breaks it circuit when it detects an overload in the circuit. The fuse blows once and it is useless and circuit is broken. The relay circuit breaks but gets reset.
An overload protection relay can withstand surge currents up to three times normal power for up to 30 minutes, protecting the circuit in normal operation. If a temporary overload occurs, it can be reset, quickly putting the motor back in operation.

So when this occurs frequently the problem is not the relay or the fuse but the motor itself or something is causing the circuit to overload ie. frayed wired touching another power source. Something is causing the motor to overload and create a temporary overload to the circuit.

The lifespan of the relay is variable. Mine has lasted since later 2004. MY2005
 

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MaseratiBlue - a greatly informative post. Thanks much. Confirms what a Maserati Tech told me about the relationship between the relay and F1 pump failures. I was looking to find a pic of the blade configuration on the BiTron to compare to the NAPA part but wasn't able to find any. Do you happen to have a pic?
 

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Question:

If the F1 Relay is in good functioning shape, what is the likelihood of F1 Pump failure from other causes? Is there evidence to believe that a regularly replaced F1 Relay would prolong the life of the Pump, so that we don't see Pump failures within 15k-25k miles?

I recall reading here on the forum that the F1 Pump motor was a poor quality electric motor, but I am no judge.
 

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a) how would us non-techies know it's in good functioning shape?
b) there is a lot of evidence of pump frying because of bad relay
c) it's only $10 and easily replaced (no tools required). If it were $100 or more I'm sure we would feel differently.

I am not interested in arguing the point, just passing along what I consider to be a VERY practical tip (courtesy of Vincenzo and Don Lorenzo)
 

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One thing to note is that fuses and relays are placed within a circuit to keep current operating within normal operations. The fuse will blow or relay breaks it circuit when it detects an overload in the circuit. The fuse blows once and it is useless and circuit is broken. The relay circuit breaks but gets reset.
An overload protection relay can withstand surge currents up to three times normal power for up to 30 minutes, protecting the circuit in normal operation. If a temporary overload occurs, it can be reset, quickly putting the motor back in operation.

So when this occurs frequently the problem is not the relay or the fuse but the motor itself or something is causing the circuit to overload ie. frayed wired touching another power source. Something is causing the motor to overload and create a temporary overload to the circuit.

The lifespan of the relay is variable. Mine has lasted since later 2004. MY2005
Relays are used to allow a small current to switch a large(er) current on and off. The starter-solenoid in cars is a form of relay. It uses a small current from the ignition switch (low power) to control the connection (really high power) from the starter motor drive to the battery.

In the failure mode described here, the problem is that over time, the contacts within the F1 relay that switch that larger pump current get pitted slightly by the arc that occurs when the circuit closes or opens - the DC current jumps the small gap as the contacts almost touch, much like the way a sparkplug works.

At some point after numerous cycles, this pitting and arcing can cause the relay contacts to weld together, meaning that the circuit won't open (e.g. - switch off) when it needs to, thus constantly applying power to the F1 pump and likely burning it out. For the F1 pump, I assume that the car computer cycles it on and off to maintain some range of pressure in the hydraulics. When you open the door, the car computer runs the pump briefly to build the hydraulics back up to operating pressure in anticipation of you starting the car.

Note, it's also possible for relays to fail "off" if the relay coil itself fails, keeping it from closing the contacts, meaning that the pump won't run (but also won't burn out).

The main amperage rating on the relay is the amount of current it can successfully switch. Using a higher-rated relay usually means that the contacts are stronger/tougher/thicker and should be less prone to welding together.

Circuit-breakers detect an overload on a circuit and turn it off, typically by having a bimetallic strip that heats up and bends, which physically moves a switch to open the circuit, or by using an electromagnet that at excess currents becomes strong enough to physically move a switch to open the circuit.
 

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Well done, thanks
 

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Flushing the F1 fluid wouldn't kill you....

The F1 fluid takes a beating I would flush once a year it seems by 18k that fluid is Orange/Brown originally Green. So Flush :thumbsup:
 

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f1 fluid and f1 relay

Hello from Nh usa, where is best place to get f1 fluid and how much is required. Also is there a thread on how to go about changing fluid. My unit appears to be leaking slightly, and looking at it are there 6 f1 motors looks life 3 and 3? Where would be a good source for the relay as well. Thanks a bunch.
 

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Can someone explain the replacement procedure for the relay? Easy access? Pics would be great. After reading this, I have an 05GS that has never has this replaced. Mild panic has set in on a Sunday am.
 

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great- thanks. I have always struggled with the search engine on this site.
 

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It's easier to do the search on Google. which will direct you to a post. Try it next time.
 

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not sure but i think Maserati Cambiocorsa gearbox/clutch F1 pump should be the same as Alfa Romeo Selespeed gearbox/clutch pump...
 

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Discussion Starter · #19 ·
There are two bumps, the old one is exactly the same as the Selespeed pump, but the newer one is not.

If you are changing your pump, you can either buy the cheaper Selespeed since its the same as the old Maserati one, but you should be aware that it has been made obsolete for a better pump. Its your choice.
 
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