tristan69:

The first thing I would try is to run a vacuum hose directly from the check valve's smaller port (on the side with the 2 ports) to the top port (the small one) on the vacuum relay for the wiper door. With apologies to Willcox Corvette for using their excellent on-line vacuum connection diagrams, the wiggly blue line in this image is where I would run the hose:



Be sure to block off the open ends of hoses you disconnect.

Go for a drive.

If the wiper door stays down, then your problem is in one of the hoses or one of the components (circled in green) you have bypassed. If the door does not stay down, test the relay, the actuator, and the related connecting hoses for leaks. My original post in this thread has a link to tests you can perform those components.

Since my 78 doesn't have a wiper door, I can't test this approach on my car. Nor can I tell you how to test the valve in the upper left corner of the diagram or the green-circled component (switch?) near the right side of the diagram. So if the approach I've outlined here doesn't locate your problem, post another entry and maybe someone with wiper door vacuum system experience will chime in.

Good luck!
Jerry

 

All the vacuum hoses in my 70 are original, I know because I've owned it for 40 years and never replaced anything. My headlights and wiper door are not functioning properly so I suppose it's time to go through the whole system. I know Mid-America and other suppliers sell hose kits. Is there a preferred vendor for such parts. I know when I redid my whole suspension a few years ago, Van Steel and Baer were the ones to go to for parts and rebuild services. How about hoses, actuators, etc?
Thanks

 

I think the last thing I would replace on the system would be the hoses. Get your self a Mityvac and test the actuators and the relays first. Make sure these components work properly, if not then the new hoses will be all for naught. If you are concerned about original hoses sealing, you can always trim off a small bit on each open end to take away the 40 year old flare. You can also check each seal on each end of the hoses by connecting one end to a component, and hooking up the Mityvac to the other end of the hose when you test. I happen to like the look of original cleaned up hoses.

 

There are no preferred vendors that I know of. I do remember reading that Doc Rebuild's hose kits worked OK. I originally reported in this post that,

I also asked that anyone should, "Please correct me if I'm wrong and I'll edit this post accordingly." Well, I stand corrected. Please see posts #52, #53, and #54 below for comments from Zip Corvette and petes74ttop.

I sincerely apologize to Zip and to all of you great forum members for passing on some bad hearsay, and I promise to do my best to NOT do it again.

For hardware, I have no experience other than recalling some have not had good luck with some reproduction items; and some have suggested using OEM items, but they are pricey if you can find them. When you find a part that needs to be replaced, do a search on this forum specifically for that part. You might find experiences others have reported.

Sorry I can't be more helpful. Hopefully, others will chime in with more info for you.

 

Hi everyone, I am new to the forum and wanted to say how much great info you all have to give. Thanks for such a great guide!

 

I had the same problem..check the wiper door valve for the drivers side wiper arm..mine leaked and would pop open the wiper door when driving..good luck on the paint!

 

The article on Corvette-101.com is fixed

 

Where is the best deal to get the complete hose kit for this application. Dr Rebuild want $50 for the kit and I think that is too, too high. Any suggestions?

 

That's great! I've edited my original post on this thread and the .pdf tutorial file to reflect that the hose diagram on Corvette-101.com is no longer wrong.

Not at this time. Overall, experiences with Willcox as reported on this forum seem to be pretty good, but I don't know specifically about hose kits. Check 'em out. If you're not satisfied, they'll make it right.

BTW: I'm not connected with Willcox in any way.

 

Wow!

If you decided to, you could become the Bill Gates of Tech Writing for anything on earth that's technical.

Do a background check on anybody that asks you to explain nuclear weapons to them!

J/K

-jim

 

Thanks! Now if the $$$ would come with that...

Can't do that, but I am a mechanical engineer with some experience in aircraft and space hardware development programs.

 

I would beg to differ with that. It depend on what context that statement about the larger hose is taken in. If you compare them to a 68 car then yes our hoses are larger, our hoses match the 69L and up. They still work fine and they are on hundreds and hundreds if not thousands of cars. This is something that he said on his website and like I said is taken out of context. I have lots of originally hoses here and they match the OD within thousandths. That is going from and old hose to a new hose. I don't know where Wilcox gets their hoses from, but I can tell you we supply most every Corvette shop out there directly or indirectly. By the way, I really like your diagram of how the system works, give me a call.
Justin

 

I've installed vacuum hoses from Zip and other vendors and Zip's work just fine! That BS that Zip's hoses have a larger OD and therefore won't fit is just BS.
On the headlight relay the red, yellow and green are a tight fit, but they do fit.

 

The red, yellow and green are not supposed to be lined up. Here is a pic off a very original 71. You will notice where the plastic is faded and where it is still looks new. That is where the hoses were originally.
[IMG][/IMG]

 

Posted above by Zip Corvette:

Thanks to you and petes74ttop for setting me straight. I have edited my post (#44 above) accordingly.

My sincere apologies to Zip and to the best Corvette forum on the web for passing on some bad hearsay. That was not fair to Zip, and I promise to do my best NOT to do it again.

Jerry
78IndyPace

 

I have chased all of the hoses, replaced the switch in the dash. When I hook up the system, the lights pop up (nice and crisp) but never go down. To manually make them go down, I have to disconnect the hose that runs between the check valve and the tank, disconnecting that hose, and pull down the headlights manually.

I have replaced one of the relays that had a broken nipple with a new one. Could the other be bad and if so, could a faulty relay cause this type of symptom?

Thanks...

 

One more question. What is considered the top of the actuator and what is considered the bottom? Which color hose connects to which wide of the actuator?

I realize I've probably just embarrassed myself. There is a certain feeling of freedom since I have also come to realize that it won't be my last time.... ;-)

 

Look at Post #1
The relay gets 4 hoses-
Top (Metal) gets White
Next (Plastic) Red
Next (Plastic) Yellow
Next (Plastic) Green

The Actuators-
Red from relay-goes to rear
Green from relay goes to front

For your problem- With the headlight switch off, and Override switch UP do you get vacuum to the TOP (metal) on your relay?

 

Jerry,
No issues, just setting the story straight.

 

thanks a lpt I just found this I have been most of the day trying to get headlites to work will try again tomorrow thanks