Bergerboy

Anyone have a good picture of the proper alignment of the vacuum switch that detects that the wipers are in park before allowing the door to close?
I believe mine is on its way out, ordered a new one, and I want to make sure it aligns properly so that the plunger is pushed in enough to switch the vacuum path and allow the door to close.
There doesn't seem to be a good flat surface on the wiper arm to interface with the current switch, and it appears to be pushing it in at an angle, which may be the cause of the failure over the years.
I'd like to start the new switch off with a proper alignment, and all I see are slots in the mounting bracket that don't appear to affect the angle.
What is supposed to actually press on the switch? And shouldn't it be pressing in-line with the plunger?
Thanks!

Alan 71

Hi b,
There's a short 'lever' (3") that's part of the wiper transmission that depresses the plunger on the vacuum switch when the wipers move to the park position.
The wiper arm doesn't contact the switch.
Regards,
Alan

The position of the small bracket that mounts to the cowl is adjustable, as is the position of the switch on the bracket.

69Vett

the switch should be depressed all the way in but, leaving about 1/8" of switch travel.
so the switch does not bottom out when wipers are parked.

Dave J

Bergerboy

Thanks All, and especially Alan once again - pristine pictures of a pristine car!
It appears from your pix that the contacting part of the transmission, that 3" lever, as you call it, depresses on the switch button at a bit of an angle, no?
That's how mine is hitting also, which I thought might be a mis-adjusted situation. I can't imagine that this is good for the longevity of the valve seals inside (being cycled with an off-center force repeatedly).
Is there a good view of the parked system, sighting straight down on the lever and switch?
Mine is pretty mangled anyway, so for $30, I'll go ahead and replace it. But now I'm not convinced that is has failed yet. I need to continue root causing the vacuum issue that has recently turned into an intermittent inop of the wiper door, and then the wipers of course.
Also - the availability of replacement switches is in question. The $50 unit from Ecklers is out of stock, and the $30 from C.C. is also on backorder due to "production difficulties from the supplier". Ecklers does show availability of (what looks like) the same unit - pictured above - as what C.C. says is in delay.

fever1

Is there an adjustment for the switch on my 69, with the wipers in the rest position on mine it is barely touching the wiper lever and my door opens on start up and stays open I don't see an adjustment, Thanks so with them in the rest position the plunger should be almost all depressed correct.

Alan 71

Hi F,
Yes, there's some adjustment possible.
The small bracket that is mounted on 2 studs in the wiper bay has a little adjustment.
The point at which the valve mounts to the small bracket has quite a bit of adjustment possible. Not the 2 slots in the bracket that the captured nuts can slide in.
On my 71 the lever isn't perfectly perpendicular to the plunger but is close as the photos I posted earlier show.
Regards,
Alan










The lever is QUITE perpendicular to the travel of the plunger.

Dave J

Yes, there is an adjustment. The base mount has slots rather than holes for the mounting bolts. The nuts can be hard to adjust if they're rusty. The safety valve must be adjusted up so the vacuum path is allowed to go through the valve when the plunger is depressed.

0Willcox Corvette

If you think your valve is not working properly, test it with this video before you purchase.

If you are buying the valve you show in the picture above.... we'll you might pass... it's imported and won't work properly. The import valves leak when the wipers are on and leak down when the system is off.

I have the US made relay in stock.
https://willcoxcorvette.com/corvette...t-really-works

69-72 Wiper Arm Vacuum Relay testing.

7T1vette

One of the problems with this aftermarket part is that the relative position of that switch may not be correct once it is assembled to the car. The mounting holes in the plastic flange are NOT elongated; but they may need to be elongated to assure that the switch is "made" when the wiper depresses it.

When I replaced this on my car, I found that if I just bolted it down as it came, the contact button would not be depressed enough to pass vacuum. So, I had to elongate the mounting holes with my Dremel so that the switch would work properly.

fever1

Man you guys are of great help, can' get any plainer than this, I do have the import valve since it has the white plunger I've tested both of the ones I have and neither holds vac, I'm going to remove the bracket and elongate the holes etc. reinstall and see what happens on the car, if doesn't work I will buy the American one for sure Thanks and Ill get back.

Alan 71

Hi f,
I hope you don't elongate the 2 holes in the switch body.
The adjustment is intended to be made in the elongated holes in the small bracket.
That's why the 2 nuts are captured on the small bracket in the way they are.
Regards,
Alan

0Willcox Corvette

The issue is that the company that makes the imported switch, made it work in a fashion indicated in the "incorrect" video found on the internet. When he did this he made it block vacuum on the lower nipple and not the middle.

If you have the imported valve.. you can elongate until your blue in the face... the valve will not work. When the wipers are in operation the valve will leak vacuum and when the arms are parked the valve will leak down.

7T1vette

I didn't purchase this item from Willcox. In fact, it was purchased years ago. Maybe I didn't know how to adjust it properly, but I couldn't identify another way to reposition it relative to the wiper without elongating the holes.

Just sharing what experience I've had with that item.

fever1

Thanks to Alan 71,69 vet Dave with all of the info you gave after messing with this switch etc. for a month or so I got the vac. working as it should, the switch has the white button, I removed the bracket cleaned and lubricated the sliding nuts to where I could get the adjustment as needed for the switch, also elongated the holes in the switch just a bit for more adjustment with 1/8 inch before the switch bottoms out and the door works good, no vac leak down at all, I have learned a bunch about the vacuum system on these old vettes which has been a pain but very interesting, Thanks to all

0Willcox Corvette

Raise the wiper door, and stop the arms in the upward position with your center dash switch. Then pull the middle nipple hose off and put a vacuum gauge on the nipple, with the wipers open the imported valve will almost always leak vacuum. Actually I've not seen one that didn't. (unless they finally fixed the valves and if they did it would have been very recent).

Please post back if you don't mind.

Willcox

Dave J

7T1vette

Apparently, fever1 had the same results that I did...which required elongating the mounting holes regardless of 'normal' adjustment feature on the car.

These aftermarket parts are made to LOOK LIKE the original parts. There is little done by the aftermarket folks to understand the function of the part and/or to specify reasonable dimensional measurements. Worse yet is the poor quality of materials used to fabricate them; the materials used are cheap substitutes for those used with the original parts. Even if you can get the replacement parts to function properly (with some "adjustments" normally required), they don't seem to have the durability and lifespan anywhere close to the factory parts. But, this is what happens when the customers are buying primarily based on PRICE. Shame on us, too.

{Note: Re the above discussion, I am referring to the manufacturers of the aftermarket parts...not (necessarily) the vendors. The vendors are basically reacting to what the buyers want [that's US]. If we want to pay for better quality parts, we have to REJECT the cr@p and be willing to pay for better quality products.}

ajrothm

I agree 100%... ALL of the repro switches/valves are complete junk.

A few years ago, I installed one of the "good"/"non imported" wiper switches to replace my original 44 year old switch that was leaking by...(but still worked)... I head out on a road trip, hit bad weather, and soon figure out that my new "good" switch is not working and slamming the wiper door down on the arms. I had to use the bypass pull down for the rest of the trip.

After I got home, I pulled the new "good" switch and figured out that it sticks when in the parked position. It had a crunchy spot in its travel. My dad had an old original switch off of a 69' thats been sitting for decades. I slapped it in, door works perfect..

Unfortunately I couldnt return the "good" switch because I had already had it for a year before I installed it.


I've had similar issues with the relays, one of which I still have a problem with....

fever1

I'll check it, do I do this with the car running or stopped with the vac pump to the center nipple and the red hose plugged or with car stopped and trying to pump vac to the valve?