Maserati 3200GT 1999 Brake Servo replacement.

[Julian Hall]

High pitch whistle noise in the cabin was determined to be faulty Brake Servo. Purchased 2nd hand replacement from Eurospares.co.uk and fitted by an independent mechanic. Noise continued! !!
2 years on and a few 'experts ' guessing other potential causes but no solution.
Visited another local independent yesterday and the mechanic confidently advised the replacement Brake Servo was at fault and needed replacing!
I am prepared to try again and need to source a replacement I can be confident will not be another faulty component. Any suggestions / recommendations / thoughts are welcome.
Attached pics confirm the Brake Servo specs requ I red.
Thanks

 

[Zep]

I would ask how they reached the conclusion. If they removed the hose to the servo and plugged, plugged it and the noise stopped then the diagnosis is almost certainly correct.

Then you have the decision to make about risking another second hand part.

 

[Oneball]

It’s quite easy to test a brake servo off the car. You just need to see if it holds a vacuum

However Eurospares list a new servo at £250. Is it even worth buying a s/h one?

 

[davy83]

well this is one of two things here. its either not the brake servo and just so baffling that you have not worked out whats causing it, or the brake servo has a weakness that makes it fail like this and the second hand one you bought had already failed. This is one of the inherent flaws in 2nd hand parts is that if a part has a particular weakness, most of the 2nd hand ones were removed from cars because of this already and so are already broken. I see this all the time with second hand pedal sensors which are all more or less already broken but its hard to tell so they get sold as working.
Is it only when the engine is revved up? could it be a vacuum leak in the same area? The vacuum hoses around the brake servo are pretty complicated.
Is there any fault in the rest of the braking system that would make the brake servo behave like this? A blocked pipe maybe, or one of the wheel rotary sensors not working properly? Would a stuck caliper piston cause problems?

 

[Lozzer]

Hi, it could be that dreaded Kaiser valve if it has one, the later cars don't have a non return valve fitted to the brake servo so when the Kaiser fails it can pressurise the servo. It's worth checking, the servo might be ok and the noise you're hearing is air being blown into it.

 

[alfatwo]

Hi, it could be that dreaded Kaiser valve if it has one, the later cars don't have a non return valve fitted to the brake servo so when the Kaiser fails it can pressurise the servo. It's worth checking, the servo might be ok and the noise you're hearing is air being blown into it.

I'd go with the Kaiser valve too, that sound is typical of the one way valve failing

If the brakes work fine it wont be the servo!

Dave

 

[Julian Hall]

Thank you all for your feedback, much appreciate. The mechanic did say when he tested the car under acceleration with the noise occurring it went away when he applied the Brake pedal as he accelerated.....hence his opinion that it is the servo. I have the original servo , can this be tested?