I have a 1976 and the relay valves were bad. I've seen quite a few posts about this issue I tried fixing them and I have plenty of vacuum they open even when the lights are shut off. I will manually close them have the lights off and soon as I start the car they come up!! Is the relay valve stuck? If I need to buy them any suggestions on where to get them? I've heard stories about new ones not working and I don't want to pay 200 dollars to get the OEM replacements unless I have to.

 

If they open with the lights off you have a vacuum leak in the control circuit. This is a thin hose that goes from the intake manifold to the headlight switch and then to the relays up front.

To test your relays: With engine running connect a hose to the small port on the relay and suck on it. If the headlight closes the relay and actuator are good.

 

EDIT: Just saw you already tried to repair. Maybe info will be useful to someone else.

Use this link to verify all the components vacuum troubleshooting. I just rebuilt my relays. I agree, $200 is a lot!!! Rebuilding doesn't cost much, so what do you have to lose. In my case, the diaphram worked fine, so piston was moving up and down as it should. Problem was the rubber piston was not making good enough seal to "switch" the vacuum between ports. I took two approaches; on the first one, I used a dremel to cut the binding ring off to separate the two halves of the relay. Cut and remove carefully because you are going to reuse these. Cleaned everything up good and hit the metal top with a fresh coat of paint. Then I repaired the rubber piston. You have to remove the piston from the shaft; the end is stamped to hold the washer on the shaft, carefully remove enough of the metal until you can slide the washer and piston off the shaft. If you look at both ends of the piston, they are really just cups. Buy a couple of o-rings that will fit in the cups, just big enough to slightly spread the cups outward (sorry I don't remember size), you can get these in the plumbing section of the hardware store. I used weather strip adhesive to secure them. Then put everything back together. Use vasoline to lube piston before reinserting. I used JB Weld Steel to secure pison back on shaft (I broke end of shaft when trying to recrimp the shaft end ). The binding ring can be soldered on, but I used the JB Weld Steel again to secure since I didn't have the right setup to solder.

On the second one, I did not cut the binding ring. I just removed metal from shaft end and slide the pison out. Cleaned, painted, repaired piston, lubed and then JB Welded the piston back on shaft. The first one works perfectly. The second one still had a slight leak. After tearing it back down, I found that one end of the piston (the cup) had dry rot and cracked. Now I just need to find another piston.

Anyone know where I can source just the rubber piston?

This will give you and idea of the process. Not hard at all. Do an advance search on vacuum relays and you'll see a lot of info and different ways the repair has been done.

 

Here are some more good links:

http://forums.corvetteforum.com/c3-t...ay-valves.html

http://forums.corvetteforum.com/c3-t...tem-works.html

 

Redman, it sounds a lot like you and I did the same thing when rebuilding the vacuum relays. I cut the first one and had a hard time getting the ring to hold the halves together on reassembly. On the next one, I just pried the ring off all the way around the top halves and it worked nicely when reassembled. As far as the o-rings in the pistons, I just slipped the o-rings over the piston till I got above the piston. Then I used the weather strip to hold the o-ring in the piston. This one worked so well, I just picked up a couple of cores at the next corvette expo. So if you need another piston you can always try picking one up at a corvette show. I have another leak in the system and it is the vacuum reserve. I have thought about just bypassing the darn thing because the only time the lights come up anyway is with the motor running and driving anyway.

 

Eddie, thanks for the suggestions. I initially tried putting o-rings on outside of piston first, but the could not get back into bore. I may play with that again or look for skinnier o-ring. I had thought about just using the one working relay, but I hate to bubba if I don't have to. Never thought about removing all together . . . hmmm.

 

I have thought about using one relay also. I seem to remember some using just one relay and it working correctly.

On the other hand, I have bought electric motors from a saturn, headlight control module from a firebird and the headlight motor mounting kit from 69myway. I just have not taken the time to do hardly anything to my vette in the last couple of years. I have cleaned it up a few times and driven it about 500 miles each of the last summers.

 

Are we talking about the "O" rings and the dogbone? If so the "O" rings go into a "cup" on the end of the dogbone not on the outside of the dogbone.

I tried rebuilding the relays but had no luck and ended up buying new ones.
Now everything works properly.

 

Yes, was talking about the o-ring and dogbone. I did put on the end of the cup like you are talking about, but found out later that the cup on one end was cracked and would not seal properly. We were talking about putting on outside as an alternative to get a good seal or at least I think that's what we were talking about.

Sorry Cherokee, didn't mean to highjack your thread.

 

Where did you buy the relays?

 

Where did you buy the relays?

 

I got them from Willcox.

 

i also got the best price from willcox

 

I made a new dogbone (pistons). I bought a 3/8" aluminum dowel at home depot. I chucked it in a drill press and ground the outside to the same shape as the dogbone except put a groove in each end for an o-ring. Then I cut it to the length of the dogbone, drill a hole through the centerline for the shaft. I reinstalled with a little lube and recrimped the shaft (I think I added a little JB weld to be safe). It has worked flawlessly for years.

 

would this work?
if so, why did GM install 2 relays, or is it so u spend more on replacement parts?

 

Wilcox has new valves for $34.00. I would think Wilcox would stand behind the product if it doesn't work for you.

http://willcoxcorvette.com/product_i...ducts_id=26643