cruise control vacuum lines
06-14-2015, 12:56 AM
#1
Racer
Thread Starter
cruise control vacuum lines
where do the two vacuum lines come from and go to? I can see the one dives under the power brake booster then disappears from there. both my lines need changed. thanks in advance.
chad
95 Lt1
chad
95 Lt1
Last edited by chadk; 06-14-2015 at 12:57 AM. Reason: include year
06-14-2015, 05:39 AM
#2
not 100% sure on an LT1 car, but on my 85, there are two lines - one 5/32" hose that connects to a "tee" just under the master cylinder. one side of the "tee" goes to the fuel vapor emission system at the far-forward LH side of the car. not sure where the other side goes, but I'm thinking somewhere to the intake manifold. the other line is a 7/32" line that goes through the firewall just under the brake booster. on the interior side of the firewall, I have no idea where the 7/32" hose goes, but i'll soon be finding out. I'm replacing most of the vacuum lines on my 85, and that 7/32 hose is fairly deteriorated at the cruise control module, although I may do a splice repair since most of the hose looks to be in fairly good condition. just not cherishing the thought of getting under the dash of my 85 just to replace a piece of vacuum hose. 
Last edited by Joe C; 06-14-2015 at 05:44 AM.
06-14-2015, 07:27 AM
#3
I just did my 94 and did it the hard way pulled the bottom of the dash and the seat also the battery.
Now the easy way. The line that goes threw the firewall goes to a switch on the brake pedal.
Don't take anything off or out. Just reach up under the dash and grab the hose most likely still in good shape there if so cut it in a easy spot. Then cut it in half long ways about six inches. Then run some bailing wire in the hose a fair bit. Then use electric tape to hold it make it tight. Then lube up the hose and pull it out from under the hood. Put your new line back in revese. Then cut flush and put a connector to the hose to the switch. Or pull the car apart and lay on your back and cuss trying to get the hose off and on the switch.
Now the easy way. The line that goes threw the firewall goes to a switch on the brake pedal.
Don't take anything off or out. Just reach up under the dash and grab the hose most likely still in good shape there if so cut it in a easy spot. Then cut it in half long ways about six inches. Then run some bailing wire in the hose a fair bit. Then use electric tape to hold it make it tight. Then lube up the hose and pull it out from under the hood. Put your new line back in revese. Then cut flush and put a connector to the hose to the switch. Or pull the car apart and lay on your back and cuss trying to get the hose off and on the switch.
06-14-2015, 07:32 AM
#4
I just did my 94 and did it the hard way pulled the bottom of the dash and the seat also the battery.
Now the easy way. The line that goes threw the firewall goes to a switch on the brake pedal.
Don't take anything off or out. Just reach up under the dash and grab the hose most likely still in good shape there if so cut it in a easy spot. Then cut it in half long ways about six inches. Then run some bailing wire in the hose a fair bit. Then use electric tape to hold it make it tight. Then lube up the hose and pull it out from under the hood. Put your new line back in revese. Then cut flush and put a connector to the hose to the switch. Or pull the car apart and lay on your back and cuss trying to get the hose off and on the switch.
Now the easy way. The line that goes threw the firewall goes to a switch on the brake pedal.
Don't take anything off or out. Just reach up under the dash and grab the hose most likely still in good shape there if so cut it in a easy spot. Then cut it in half long ways about six inches. Then run some bailing wire in the hose a fair bit. Then use electric tape to hold it make it tight. Then lube up the hose and pull it out from under the hood. Put your new line back in revese. Then cut flush and put a connector to the hose to the switch. Or pull the car apart and lay on your back and cuss trying to get the hose off and on the switch.
06-15-2015, 08:49 AM
#5
Don't forget to lube up before install
10-24-2016, 01:29 AM
#6
I just did my 94 and did it the hard way pulled the bottom of the dash and the seat also the battery.
Now the easy way. The line that goes threw the firewall goes to a switch on the brake pedal.
Don't take anything off or out. Just reach up under the dash and grab the hose most likely still in good shape there if so cut it in a easy spot. Then cut it in half long ways about six inches. Then run some bailing wire in the hose a fair bit. Then use electric tape to hold it make it tight. Then lube up the hose and pull it out from under the hood. Put your new line back in revese. Then cut flush and put a connector to the hose to the switch. Or pull the car apart and lay on your back and cuss trying to get the hose off and on the switch.
Now the easy way. The line that goes threw the firewall goes to a switch on the brake pedal.
Don't take anything off or out. Just reach up under the dash and grab the hose most likely still in good shape there if so cut it in a easy spot. Then cut it in half long ways about six inches. Then run some bailing wire in the hose a fair bit. Then use electric tape to hold it make it tight. Then lube up the hose and pull it out from under the hood. Put your new line back in revese. Then cut flush and put a connector to the hose to the switch. Or pull the car apart and lay on your back and cuss trying to get the hose off and on the switch.
10-24-2016, 05:12 AM
#7
Hi antfarner. I'm trying to repair/replace the line that goes through the firewall on my 96. Got under the dash and located the 7/32 hose that goes through the firewall. There is a large 2" grommet plug that is very tight and I can't dislodge it, and the hose will not push through or pull through. I thought of cutting the hose and using a 3/8 socket set to link it to the new line and push/pull it through the Firewall and connecting tho the controller, but could not get the existing line (which is good under the dash) through the grommet. Any ideas hos to get the grommet loose or to get he hose to slide through? Not much room to work under there, can omly get one hand in there laying on my back....too many wiring bundles, other junk in the way.
Last edited by antfarmer2; 10-24-2016 at 05:14 AM.
10-24-2016, 09:00 AM
#8
JimmyC - a fellow here locally generally uses a "hard-tube" to feed through the existing hose that's in the grommet. Requires little or no lube to accomplish and you do hose on either side to complete the connection. I've never needed to replace a pass-through for vacuum but I believe it's what I'd do.
10-24-2016, 04:29 PM
#9
Thanks, I'll give it another go...tomorrow. After spending almost two hours taking the seat and lower dash out and laying on my back struggling with the stuck line, this 71 year old needs a little recovery time.
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azmusclecar (08-13-2020)
10-24-2016, 04:42 PM
#10
Do not mess with the grommet just the hose.