: vacuum problems? any ideas please?

03-11-07, 09:36 PM
ok guys, im not online all the time but i always swing by to see whats up here,haha. and ive got a problem hopefully someone may have some insight to. i simply assumed ok vacuum leak, but ive got a 81 fwb, the thing is idling really high now (ive occasionally chirped the tires just putting it in gear without the brakes on!!!) but along with the high idle ive also got a constant, 100% of the time defroster running, i just turn it to hot or cold depending on the weather since it cant be turned off, and when i need to make a pretty quick stop (like when exiting the highway coming to a stop sign for example) the brakes will get hard, for normal driving and casual stopping like normal in a big ole cadillac its fine on the brakes, its only when i really need to get on them do they get hard like that.

im not too sure how to check my vacuum pump or anything, so im not sure if its that, but i have checked the car over several times spraying all the vacuum lines with starting fluid looking for a leak and i couldnt find one, im tired of burning up so much gas cause of the idle, and now that its warming up outside the ever present defroster is driving me nuts too! haha.

i would much appreciate any help or advice, thanks a lot guys! and hopefully i can properly introduce myself soon with some pictures!!

03-12-07, 12:43 AM
Sounds like the off button on your panel for the defroster is broken.

And if you've been spraying the vacuum lines with starting fluid, no wonder you're english is so broken. Jeeze man, you must be really high, lol.

Hit the 5.0l subforum, plenty of info there about the emissions systems. Your caddy should have 5. Otherwise, pick up a haynes manual and go nuts.

03-12-07, 10:21 AM
haha, yeah the internet these days, my typing is nowhere near correct, so when im typing papers for school ive got tot ry real hard and remember.

but spraying starting fluid on the vacuum lines will pin point a leak, if there is a leak in the line it will suck the fluid into the intake and cause the motor to rev, so the second you hear the motor rev you know that you have a vacuum leak in that spot, ive been told the best way is to use a propane bottle with a small tip hooked up to it, but i never felt like making the line and tip,ha.

and its got the 368 not the 5 litre, ill go search around some more though.

03-13-07, 12:55 PM
When the climate control system looses vacuum it will switch to constant defroster mode, so look under the hood again for a hose off close to the firewall that goes into the dash. You have all the classic symptoms of a large vacuum leak. Also I think you have a vacuum storage container on this car, maybe inside an inner fender? maybe that hose is off or the container leaks?

The Ape Man
03-13-07, 08:02 PM
Try pinching off vacuum lines one at a time to see if the idle drops. The brake booster itself can spring a leak. Sometimes you hear it under the dash when that happens. Without proper vacuum all hell will break loose as you know.

03-19-07, 03:16 PM
thanks guys, i thought the heater valve, (im not sure the correct name, connects 2 heater lines with the vacuum line in the front might be part of A problem, its very corroded, but im gonna try to follow that line because it goes down and back into the firewall like you said, and also this car does have a canister, im not sure how to check it for a leak to be honest, my brake booster is fairly new, roughly 2 years tops, when i first bought the car it was bad, but i checked the vacuum there and ive definitely got some good suction so i know its not the pump now, but im sure the booster it self could leak somewhere, so im still checking.hahaha.
im gonna try pinching off some lines and see what i can find also, appreciate all the pointers, im the only person who has ever worked on this car since ive owned it and id like to keep it that way. thanks guys.

07-02-07, 12:51 PM
I have a 1966 cadillac coupe deville and I am having the same exact problem. My brakes are always hard and it ideals high. My heat is always on as well. I think I found the vacuum it kinda looks like a big black can of pork and beans laying sideways with a hose out the top. I have new brakes, new master cylinder amongst other things but I can find anything that doesn't look right on the brakes.