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'85 300TD vacuum pump prob? Could it be?

Old 08-23-2016, 07:12 PM
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Default '85 300TD vacuum pump prob? Could it be?

Greetings. New poster to forum.

I am experiencing some apparent vacuum issues all of the sudden with my son's '85 300TD (inherited from me). Recharged the a/c Sunday and started having problems with shutoff and hard brake pedal. Research suggests vacuum prob. All lines are connected and no breaks or visible leaks. (Have replaced most all the rubber ends and the brake booster main vac line previously).

Put vac gauge on one the lines prior to recharging a/c and was pulling about 10 lbs. I realize that is low, but car was shutting off and no brake issues. Last night I could not get any reading on gauge. Tonight I disconnected the booster main vac Line at the booster, and could feel a little vacuum when I raised the rpms. Blocking off that end and putting gauge directly on nipple shows me about 5lbs with raised rpms. This is not enough to turn the car off.

Some web research says it could be the vac pump itself, or maybe a check valve on the pump, but I am a bit skeptical as vac has never been high, but it's been adequate for the most part. (I've owned the car for almost 15yrs and it only has 165k on it).

I have not connected vac quite direct to the pump yet, but if I guess I may have to try to find hose/adapter to do that maybe?? Hoping someone on this forum might have some insight or troubleshooting suggestions.

Thank you in advance for any help you guys may be able to provide.

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