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Old 01-25-2001, 08:28 AM
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Join Date: Nov 2000
Location: Dushore, PA, USA
Posts: 18
Follow-up from my post of 11/21/2000.... Had lost most control of climate control system - all air blown came out defrost vents regardless of control head settings. Also was hard to start (new glowplugs last yr), & hard to stop engine by key (mechanical stop on engine worked fine).

W/ myriad of rubber connectors in the vacuum lines on these models, they have to be inspected carefully for cracking & replaced as needed. If you live in the boonies, as I do, you'll find it hard to obtain metric parts. I was able to use 7/64" rubber fuel line/vacuum hose to make new connectors, & 1/8" plastic fittings (tee's, Y's, crosses, etc.) where needed.

As BenzMac had suggested I checked the main vacuum line from pump to brake booster. Was pleasantly surprised that the line was clear, & had fast recovery. Once I got a diagram of the vacuum system, I used a curved Kelly clamp (surgical tool like curved locking needlenose pliers w/ scissor grip) to systematically clamp off or isolate individual vacuum flap actuators under dash. There are 5, each one a different part #. One, which controls defrost vent, is 2-stage. As soon as I clamped off the hose going into the side of the defroster canister, my defroster vents closed, & the floor vents opened up for the 1st time this winter! My toes may yet thaw out!! & I still have defrost capability.

As for starting & stopping the engine, both problems resolved when I fixed the vacuum leak. Fixing the leak was expected to solve the engine stop since it has a vacuum actuated shutoff. Everybody I talked to, though, didn't think it would solve the hard start. The vacuum shutoff is actually a needle / plunger pin that blocks fuel flow through the injector pump. The key switch has a vacuum supply line coming off of the vacuum manifold/tree in engine compartment. When key is turned on it allows vacuum to retract shutoff diaphragm, pulling back needle valve & allowing fuel to flow. 10 deg F. this AM, & started immediately!

Question for forum - are the vacuum flap actuators rebuildable, or must they be replaced? Defrost element (of course) is the most expensive, @ $45

FYI: a decent vacuum tester avail @ Pep Boys $40..... same one at AutoZone $25
'83 300TDT Wgn
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