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  #1  
Old 09-18-2014, 08:31 PM
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Intermittent Vacuum Problems

My 83 300D is having occasional complete loss of vacuum. When it goes, I lose everything- brakes, door locks and shut-off. I've measured the vacuum near the pump during these episodes and it's zero, nada, ziltch.

But the next time I start the car it'll be fine for quite some time. Then, like today, it goes again. Only to be good for the drive home.

Anyone else experience a similar situation? I've only had the car 6 years but I don't think the vacuum pump was ever replaced. Should I replace the whole unit? Rebuild kit?

Thanks for any help. I've read all the threads I can on this. I'm not sure how to proceed.

Rich
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  #2  
Old 09-18-2014, 08:50 PM
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The odds are about 10:1 that the check valve in the nipple on the pump has failed. The typical scenario is that the retainer plate fails due to corrosion, then the valve components rattle around in the pump inlet and cause intermittent blockage.

Disconnect the hard line at the pump, then remove the nipple from the pump. If the nipple is empty, fish the spring, plunger and retainer plate out of the pump.
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Old 09-18-2014, 08:54 PM
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Thank you! I will look tomorrow and post my findings.
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  #4  
Old 09-19-2014, 12:08 AM
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Quote:
Originally Posted by tangofox007 View Post
The odds are about 10:1 that the check valve in the nipple on the pump has failed. The typical scenario is that the retainer plate fails due to corrosion, then the valve components rattle around in the pump inlet and cause intermittent blockage.

Disconnect the hard line at the pump, then remove the nipple from the pump. If the nipple is empty, fish the spring, plunger and retainer plate out of the pump.
X2 on the check Valve except that when My Check Valve was gunked up I still had partial Vacuum.
I cleaned it with WD-40. Don't clean it with Brake Cleaner as it sometimes makes Plastic Parts sticky.
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Old 09-20-2014, 10:02 AM
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OK the nipple was empty. I found the spring and plate in the pump but not the plunger. Any suggestions on getting it out? Can you describe it?
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  #6  
Old 09-20-2014, 10:33 AM
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The missing piece is plastic, close to the size of a pencil eraser. You might try a vacuum cleaner.
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  #7  
Old 09-20-2014, 10:33 AM
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Nevermind, I got it

I figured that vacuum sucked it in, so I used my shop vac to suck it out.

Fighting fire with fire...
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  #8  
Old 09-20-2014, 10:34 AM
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Tangofox, our posts crossed, Thank you for your help!!!
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