vacuum unit JS578

Talk about the E-Type Series 3

Topic author
carlv12
Posts: 55
Joined: Wed May 20, 2009 1:39 pm
Location: Valencia
Spain

#1 vacuum unit JS578

Post by carlv12 » Tue Feb 15, 2011 12:04 am

Hello,
I have a problem with my vacuum unit JS578 for my E Type V12.

I have been talking and testing with my mechanic hours today - the result:

my actual JS578 vacuum unit does NOT work correctly, it does not hold the vacuum. The problem is that the part is 1,5 years old and even another new JS578 from a friend does NOT work correctly. Under vacuum the shaft must be pulled to the outside, this happens for only a moment, then the vacuum is lost and the shaft pushes again to the inside.

We have compared with a vacuum unit from XJ-S Lucas, JLM519 and this unit holds the vacuum. Here, the shaft is pushed inside with vacuum and it holds the vacuum. I understand that the vacuum unit for E Type JS578 pulls the shaft outside under vacuum pressure and the XJ-S Lucas unit pushes the shaft inside under vacuum pressure, they work the same way, but opposite directions. BUT the vacuum must be hold, if NOT there is a failure.

The only reason for this failure is that many parts suppliers sell "new old stock" where the inside membrane has little leaks.

What is your experience with these JS578 vacuum units?

I don't know what to do? Should I disconnect the vacuum unit?


Thank you and best regards from Valencia

Carlos

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