A couple of times recently I've found that the first time I use the brakes, usually after only a few metres of driving, the servo vacuum dies away, leaving a solid pedal and needing a mighty shove to even hold the car stationary (3200GTA)! Then all is back to normal, no further problems while driving. I'm thinking maybe a failed non-return valve on the inlet vacuum somewhere? Any ideas or similar experience?
Loss of brake servo vacuum
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mchristyuk
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Yep.. mine had it's Kaiser valve on the way out and did similar things.
You have 2 options.. replace the Kaiser valve or "delete" it and place a normal one way valve in the line instead. Eurospares website shows the alternative plumbing depending on which way you go.
I couldn't get a new, or second hand, Kaiser valve anywhere. However I did find the Volkswagen/Audi group use an almost identical part (suction jet pump) on their turbo cars. The nipples are a bit bigger than the Maserati item so it was a bit of a @£$! to get pushed into the pipework but a bit of silicone spray got it together. Both parts are made by Bosch and look identical apart from the nipple sizes. Since putting the Audi one on mine the brakes haven't gone ******* me again.
As I said your other option is to remove the vacuum pipe from the airbox and instead run a pipe straight from the brake servo to the plenum, however you will need to put a one way valve in there somewhere.. ideally the original 3200 item right in the servo.
Mark
You have 2 options.. replace the Kaiser valve or "delete" it and place a normal one way valve in the line instead. Eurospares website shows the alternative plumbing depending on which way you go.
I couldn't get a new, or second hand, Kaiser valve anywhere. However I did find the Volkswagen/Audi group use an almost identical part (suction jet pump) on their turbo cars. The nipples are a bit bigger than the Maserati item so it was a bit of a @£$! to get pushed into the pipework but a bit of silicone spray got it together. Both parts are made by Bosch and look identical apart from the nipple sizes. Since putting the Audi one on mine the brakes haven't gone ******* me again.
As I said your other option is to remove the vacuum pipe from the airbox and instead run a pipe straight from the brake servo to the plenum, however you will need to put a one way valve in there somewhere.. ideally the original 3200 item right in the servo.
Mark
SteveM
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I take it you havent had the inlet manifold off recently? If so, I have heard of the hose that connects underneath the inlet plenum not being re-secured tightly and causing the problems you are experiencing. However if its as described I am leaning towards failing Kaiser valve.
Witout Kaiser Valve very early 3200 have been delivered maybe first 50..200 or so.. . Intention of the Kaiser valve is to improve vacuum.
However I have some doubts that the Kaiser Valve fails, as typically all hoses around the Kaiser valve are altered (re-clamped) or exchanged (as they are stone hard after 15 years) when the Kaiser Valve is changed so the true cause in my opinion stays unclear. At least I could not experience any differnce on my "collection" of Kaiser valves when testing outside, but I exchanged the hoses around.
Maybe I am wrong but I just have some doubts as a Kaiser valve is a passive part (Venturi Valve). Kaiser is the Manufacturer. So if someone could point out how detect that a Kaiser valve is defective I will check mines. All the other one way valves are quite simple to check.
By I agree using an Audi one (once fitted) does it as well. Depending on the 3200 VIN you will experience different diameters in the hoses around the Kaiser valve which simplifies or complicates adaptation.
However I have some doubts that the Kaiser Valve fails, as typically all hoses around the Kaiser valve are altered (re-clamped) or exchanged (as they are stone hard after 15 years) when the Kaiser Valve is changed so the true cause in my opinion stays unclear. At least I could not experience any differnce on my "collection" of Kaiser valves when testing outside, but I exchanged the hoses around.
Maybe I am wrong but I just have some doubts as a Kaiser valve is a passive part (Venturi Valve). Kaiser is the Manufacturer. So if someone could point out how detect that a Kaiser valve is defective I will check mines. All the other one way valves are quite simple to check.
By I agree using an Audi one (once fitted) does it as well. Depending on the 3200 VIN you will experience different diameters in the hoses around the Kaiser valve which simplifies or complicates adaptation.
mchristyuk
Junior Member
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Phil,
I'll take that as a hint then!
Getting my car back from the garage tonight, but then away all weekend. Will look to do some words and pictures next week.
Mark
I'll take that as a hint then!
Getting my car back from the garage tonight, but then away all weekend. Will look to do some words and pictures next week.
Mark
mchristyuk
Junior Member
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Lol.. just as well I have a high resolution monitor!
mark
mark
Well it is definitely the Kaiser valve. I felt around the back of the engine and the valve fell in two as soon as I touched it. Now it doesn't sound like a very Italian part, so I suspect the Maser has rejected it . Anyone know where I might get a replacement? BTW it's really hard work to get at the thing - should I be able to replace it without taking the plenum off?
. Anyone know where I might get a replacement? BTW it's really hard work to get at the thing - should I be able to replace it without taking the plenum off?
mchristyuk
Junior Member
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- 668
Wink
Yes you can. You will graze your knuckles though!
Mark
Yes you can. You will graze your knuckles though!
Mark
Well it is definitely the Kaiser valve. I felt around the back of the engine and the valve fell in two as soon as I touched it. Now it doesn't sound like a very Italian part, so I suspect the Maser has rejected it
Ok falling into two parts makes it shure that ist broken..To my knowledge a Kaiser valve with the correct connectors can be obtained only from Maserati (or a used one form a breakers yard). Other Options are the Audi "Saugstrahlpumpe" or for the UK market suction pump but those have differnt diameters at the connectors so this might need stretching the vacuum hoses or using adapters.
The upper is the Audi one, and especially the left connector has some relevant derivation form the lower original part (the other two should fit quite well)
To replace the Kaiser valve.. this depends a bit on what was the last time the hoses around have been disconnected. If they are sitting there untouched since 1999 they are pretty hard and it`s difficult to get them loose. However untightening all vacuum hoses in the area (and also to open the cable holder) gives typically enough room and play to work.
Good news is that replacement valve is fitted, all is well again, and the idle is better too, so maybe there had been a slight air leak before. No idea why Maserati decided to squeeze this component into the least accessible gap between cylinder head and bulkhead, but I still have a few surviving knuckles. Thanks to all for the help.
jluis
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Was your idle "bad" only when cold or also when hot?
Mine has trouble keeping idle and having power when starting at cold for about 60 seconds.
After hot it stays ok, so I guess it's an air leak that only affects the engine while running on open loop
No, idle wasn't really bad, but it hunted up and down between 1000 - 1300 or so, both hot and cold. Replacing the throttle pedal pot with davy83's contactless upgrade made a big improvement, and replacing the kaiser valve has improved it further. Now it's sitting at just under 1000rpm, with only slight hunting of about 100rpm range when in N.