Dave, Harbor Freight has Mighty Vac for about $39 bucks or they have an off brand, U.S. General, on sale with online coupon for $17.95. These are both manual vacuum pumps but many here have used the Mighty Vac and they work just fine.

I sometimes think the electric vacuum pumps are difficult to control and can create too much vacuum and actually may ruin seals.

In fact, I would baseline your vacuum at the intake manifold and only use that amount of vacuum to keep your testing as close to real world for your engine as possible.

cc

 

Thank you, I agree. Been using a hand operated vac pump to test but it won't supply enough vac to test entire system. Had to pump like a mad man to get 10 in of vac in holding tank to test. I plan on putting a "T" into line coming out of manifold and using gauge on hand operated pump to make sure I don't go over 20.5 in (my baseline) At this point I don't know what else to do.

 

So have you tested each component individually to see if they hold vacuum?

Actuators front and back

Relays, green outlet with red outlet capped then red outlet with vacuum applied to control port and green outlet capped

Wiper door safety valve

Reservoir with all ports capped

Also, is your wiper switch getting electricity? If your small gauge bezel is broken you may not be getting ground to the switch as it is supplied through it.

cc

 

Most all Vacume System problems end up being a Vacume Leak. The easyest way to find them is to listen only problem is You can't hear anything with the engine Running. So get a long hose and run it outside Your shop to a vacume pump or a Minivan or whatever hapens to be parked in the driveway. Hook this up to where the Vacume Line goes to the Manifold and now youn can open and close everything a Listen for Leaks. You will probably hear a Hiss in no time.

 

Yes, I have tested everything except headlight switch and tach solenoid. Gauge bezel is broken, but if I open wiper door manually, wipers work on both high and low. Have a friend that has a vac pump used to evacuate AC systems. Gonna see if that will power up system before resorting to another vehicle running to supply vac.

 

Since the door opens with the override switch, it's a pretty good bet the relay and the wiper arm safety valve are working ok. Do you know for sure the solenoid electrical connector is securely connected to the solenoid and that it is correctly oriented?

cc

 

Door does NOT open with overide switch or wiper switch. Won't open at all. Elec on solenoid is secure and correct.

 

Oh, sorry I misunderstood.

Then I suggest the following procedure:

First, let's test your theory about having a leak on the wiper side. Disconnect the yellow striped hose for the wiper relay at the T near the vacuum tank and cap the T off. Now start then engine and see if the headlights work.

This essentially isolates the wipers from the headlights leaving only the headlights functional.

If the headlights work you have found the system with the leak, the wipers as you suspected.

If they do not work, reverse the test and reconnect the wiper hose and disconnect the headlight hose from the T and cap that end. You will also need to disconnect the hose at the tank that provides vacuum for the left headlight and cap the tank nipple.

If the wiper door now works the leak is in the headlight system.

If both tests fail, test the tank for leaks by disconnecting all hoses and capping off all ports except the one with the solid black hose coming from the check valve. You will need a vacuum gauge and T connector for this test.

cc

 

Thank you very much! I will do exactly what you say. Unfortunately I won't be able to get to it till middle of next week at soonest. I will report my findings.

 

OK, I snuck in a little time after all. Disconnected and plugged yellow striped hose for wiper relay at "T".. headlights now work just fine, so it's definately leaking on wiper side. What do you suggest next? Can't tell you how much I appreciate you help!

 

There are two components on the primary vacuum circuit, the relay and the actuator.

I would take the yellow striped hose you disconnected and hook it up to a vacuum source by itself, the other end goes to the center port of the relay so disconnect the green striped hose from the relay and cap the port. Disconnect the very small diameter heater line at the T in the yellow striped hose to the relay and cap the T. Then run your vacuum test.

If it maintains vacuum move on to the red striped hose and do the same thing but this time you will need to apply vacuum to the small control port on the relay to move the valve to the position where it should block vacuum to the green hose and pinch the hose with a clamp to keep the valve in place. The control diaphragm is spring loaded and will return to rest if vacuum is lost at the control port.

If vacuum is retained on the red striped port the relay is ok. If either port fails to maintain vacuum replace the relay.

Move on to the actuator.

Test the front port by connecting your vacuum source to it and pump it up and see if the front of the actuator maintains vacuum.

If it doesn't, there are two places vacuum can escape, the rubber plug and the diaphragm. If it's escaping at the diaphragm, replace the actuator.

Repeat the test on the rear port. Again, there are two places vacuum can escape, the diaphragm again and the actuator rod seal. The seal can be replaced if you find the leak there. Once again, if the diaphragm is leaking replace the actuator.

If neither of these components leaks, we need to move on to the control circuit.

cc

 

Can't tell you how much I appreciate your sticking with me! Should get some time tomorrow

 

OK, first part of this test passed. Tested yellow hose to center port of relay with the T capped off... held vacuum. The 2nd part I'm a little confused on. If I apply vac to small control port, then pinch that hose off to retain vac, how do I then see if vac is retained on red hose?? If I apply vac to small control port, then pull off red hose, vac is retained.
On actuator, vac is retained front and rear only if I cap off opposite port. If I simply remove front hose, leaving rear hose attached, I can't pump any vacuum in. Whaddya think Coach?

 

The small port moves a dumbell shaped valve up when vacuum is applied. In this position, the green port on the bottom of the relay is cutoff from vacuum and vacuum is instead fed from the center yellow striped port to the top red striped port. The yellow striped hose supplies vacuum at all times, the valve position determines whether the red hose or the green hose gets the vacuum.

As I mentioned before, if vacuum is lost at the small port, an internal spring will push the valve back down so that vacuum is again applied to the green port.

What you are testing for here is to see if the valve is leaking in either position. Vacuum can escape through the bottom where the filter is.

cc

 

On the actuator, the front and back should be sealed off from each other. The side towards the front of the car keeps the wiper door shut unless either the override switch is pulled or the wiper switch is moved to one of the speed positions.

The side toward the windshield opens the door when vacuum is removed from the small control hose on the relay thereby connecting the yellow vacuum source to the green vacuum hose.

cc

BTW, it works that way so that if the system should fail to maintain vacuum at all, it will open both the headlight doors and the wiper door and allow the use of those components all the time. The default in the event of a vacuum failure is open. That is the purpose of the springs in the relays.

 

I forgot to answer your last question...if neither side of the actuator will hold vacuum unless the opposite port is capped, then the diaphragm is bad and you need to replace the actuator.

cc

 

OK, I'll check all these things out and report back. Sounds like actuator is toast for sure, I'm still leary of relay tho. Thanks again!!

 

If you disconnect the hoses from the wiper door actuator, if you put a hand vacuum pump on one lead then the other the door should open and close it. If it doesn't the diaphragm is shot in that actuator 100-125 bucks.

Good luck.

 

OK, wiper actuator is ordered. Will let you know what happens.

 

There are several of the imported actuators that do not hold vacuum even when new so test it when you get it.

cc