Hi, all. Could anybody explain an easy way to find a vacuum leakage. If I turn off the engine, I can not close the doors, open the trunk, or operate the headlights after 30 sec. Also, how long is it expected that the vacuum should hold in the tank? It is a Riviera 68. Regards, Per. :beer :beer
Sounds like you have the vacuum power locks. There's alot of rubber hose and switching when you have this option. It bends back and forth when opening the doors=lots of chances of cracks/breakages. I think you're doing pretty good with it holding for 30 secs if original hoses. It's a battle to replace all that in the doors(hope you have small hands) Me-I wouldn't mess with it unless you have a complete break-which you may be able to hear leaking-good luck
i'm not familiar with vacuum operated remotes but typical trouble shooting procedures call for simplifying / isolating as much as possible. with that in mind, can you pull the lines off of the main vacuum reservoir and test that seperately to be sure that it's got integerity? after that, reattach your lines one at a time until you've verified which ones do and do not leak. hoses that are subject to constant flexing will be the most likely to crack so i definitely agree with lapham that tubing into the doors would be a good place to start looking.
Hi Per 30?? You should be glad, my system holds about 10 seconds Since I've replaced all the hoses/stuff concerning the headlights I believe my leaks are cause by something in the heating system (vacuum-operated vents). Do you have the cruise-control?
Thank you for replies. Bjorn, how is good old Norway? Have been looking at your "winter project". What winter are we talking about? I would imagine that a system like this, (when new), should be able to keep the vacuum for at least 24 hours. (On my Benz, the auto vacuum door lock/opening system still operate a month after parking it). A real bad vacuum leakage would also effect engine performance. I t is just a pain to find it. (Have Auto Climate, door & trunk opener, but no cruise control, have to do that myself :grin: ) Regards, Per. :beer :beer
Norway is fine, no winter yet, but the car is parked for the winter (the salt is already on the roads.. ) It was last winter originally.. I got the car in september last year but still did not finish it so it will be this winter hopefully The cruise control is vac operated, and I suspect mine is a bit leaky in addition to the vents - that was why I asked I'm kinda glad I don't have the vacuum door locks.... would only be more hassle - theres enough vaccum on our cars as it is!!
A common cause of vacuum leakage is the tank inside the left fender. On my 68 the tank was leaking at the seams. I had to remove the left fender to get to it though. Also look at the vacuum lines going to the headlight cans. They tend to split slightly at the ends. A bunch of parasitic leaks equal one big problem on these cars as you know. My lights operate with the engine off even after 24 hours....but only once! Jason
Also, the vacuum cans themselves are a major leak area. Do any of your headlights "droop" after shutting off the car?
After a week or so, my car tends to "wink" at me. One headlight comes down. But, I expect this to be normal. I dont think even when new they held vacuum for too long. My buddy worked at a Lincoln Mercury dealership prepping cars. He used to tell me the headlight doors would open by themselves when they sat for a period of time.
My car doesn't wink, even when all the vacuum is gone, but I guess thats mostly because I replaced the cans with Camaro ones and made my own linkage for them, so they are a bit non-standard
I don't have any problems with "winking", but I have also used Bjorn's Camaro RS cannister modification. I just found in the "Fisher 1968 body manual": Vacuum door lock diagnosis chart, that it is considered a fault if the vacuum does not hold for 48 hours, and in the "1968 Buick features sales manual" that the headlights should operate 2 - 3 times with the engine off. I am sure to have a lot of "fun" getting those figures. Maybe I should just forget about it & :3gears: Nice week-end to all. :beer :beer :beer
Even if you had cruise control, it couldn't cause problems with your door locks since it doesn't use the vacuum reserve (it doesn't need it since it operates only when the engine is running). The Automatic Climate Control, manual Climate Control and even the standard heater use vacuum in these Rivieras but they do have an independent vacuum reserve. Neither of these could cause problems to the vacuum door locks, unless someone changed the vacuum hose routing... If the car was a 66-67, the problem would likely be the vacuum reseve itself or the power lock hoses or switches (less likely the trunk release). 68 and 69 models could add the vacuum headlight system and the plastic manifold connectors on the firewall to the list of potential leaks... First thing to do is to try to isolate the problem. I wouldn't be surprised if many leaks were found. Find the vacuum source for the door locks and trunk release, disconnect it and plug the connection (be careful if you touch the plastic manifold, it is very fragile, it might even have been replaced with "T" connectors...) If there is still a leak, you'll know that the vacuum reserve or headlight system are bad. Check the vacuum reserve alone to see if it holds vacuum, if it doesn't you'll have to replace it... If it does, try to find the vacuum leak to the headlights. I do not own a 68 and never played with the vacuum headlights so someone else might help you more with it. I'd strongly recommend you to have a 68 shop manual for it. I have one if you need a few pictures of the system. If the vacuum reserve is OK and if the headlight system is fine, reconnect the door locks and try to locate the leaks. If the headlights also leak, disconnect them to isolate the door locks. As I said earlier, the trunk release is on the same circuit as the door locks. It is rare that it looses vacuum but it is possible. The first thing to do is to disconnect the larger hose on one switch and plug it. If there is a leak in the switch you removed, the vacuum should last longer. if nothing changed reconnect it and try the other switch. When reconnecting the switches, you might want to cut a part of the hose (and hope it is not too dry!) so it won't leak at the connection. If removing the switches haven't changed anything. You should next remove the same hoses, one at a time on the vacuum control valve behind the dash. I don't know where it is located on a 68 but if it is at the same place as it is on a 67, it is hard to reach! I think that it has been relocated on the passenger side on 68's but the shop manual doesn't illustrate it. If there is still a leak, the vacuum control valve itself might be responsible for it or the vacuum source to the control valve. Don't mess with the small hoses on the switches or the door lock actuator circuits since the vacuum is applied to them only when the switch is pressed. This means that there is only one hose in each door to look at if the system works fine whenth enine is running. If you find the big leak and your system holds air for few minutes, you might want to find the smaller leaks by using a homemade tool. A Mason jar half-filled with water and two vacuum hoses passing through small air tight holes in the metal cover. One hose goes at the bottom of the jar in the water and the other one at the top of the jar above the water. You can disconnect the hoses where you suspect leaks and connect them to the hoses in the jar. Always connect the vacuum source to the one at the top of the jar and the one where vacuum is applied to the hose at the bottom. Then, start your engine to see if there are any bubbles. If there are none, no vacuum leaks where the vacuum is applied. If the water seems to be boiling, you know there is a big leak there or your new tool doesn't work! If the water level drops, you have connected the hoses in the wrong direction and your engine is drinking it! ou: This trick isn't one I imaginated, it is explained and illustrated somewhere in a Buick shop manual! I just don't remember which one (if somebody else saw it, tell me the page and year!) and I'll take a picture of it! It worked for me and my Riv now keeps it's vacuum overnight! I did the same on my former 68 Wildcat to which I even added remote door locking/unlocking system! About the Mercedes, does it use engine vacuum? My parents had many 80's and early 90's Volkswagens with power door locks and they used a vacuum/pressure system and an electric pump in the trunk. When the driver's side door was locked or unlocked, the electrical pump made pressure or vacuum to lock or unlock the 3 other doors, the trunk door and the fuel door. It was much simpler and more reliable than the system in 60's GM cars!
Thank's Phil. I have both manuals, but it might help to read them. Found the "jar" in the 68 book also. Anyway, your description is very good and clear :TU: I am sure you also helped many others in the same boat. Regarding the Benz, you are probably right there too. Just thinking.......could I possibly install a Benz system on the Riv? Per. :beer :beer
