Red89'-L98

I have a 1989 corvette and my cruise control is not working at all. I saw on another post about something else it could be cause by vacuum line issues, is this true?

If it is, can anyone give me some info on where it would be and how hard it would be to replace/fix it?

I am also wanting to replace all the vacuum lines on the car because before I got it, it sat for probably 3 or more years the previous owner said without ever moving. I fixed all of that though, just replaced all fluids and flushed them and new fuel pump and a tune up.

Some of the vacuum lines look like if I touch them wrong that they will crumble which is not good. Does anyone know where to get maybe a set of all the lines from, or the sizes for them? I also noticed on some of the vacuum lines like in the picture below they have like a special tip on them that connect to the vacuum check valve, but only 2 out of the 3 have it.



Any help on where to get the lines from or how to fix the cruise control would be appreciated.

I am going out of town soon and cruise control would be a nice luxury for the long drive

EDIT: Go to last post and I have recent updates on my cruise control problem with more information.

Thanks, Stephen

Red89'-L98

I have not seen any response yet and would love to get this fixed before I go out of town and to replace most of the vacuum lines.

Again, any and all help is appreciated.

Thanks, Stephen

leesvet

All these lines are just generic vac hose. That fitting in the pic is a check valve. Thats generic as well. ANY auto parts store will have all these pieces.

The cruise control may or may not be vac related. Thats just one of many possible reasons why its not working. Look at the lines and if it looks bad, it may be worth fixing the vac hose. Next would be the brake pedal switch that deactivates the cruise when the brake is applied. If that is out of adjustment you cannot get the cruise to engage. Thats also comes from the brake pedal laying against the switch. Try to engage the cruise while lifting UP on the brake pedal with your left foot. That switch is adjustable.

Red89'-L98

I honestly never would have thought about it possibly being the brake pedal on the cruise control that could be the problem, I will be checking that very soon.

Now onto the vacuum hoses Do you know what size they are? Are they all a common size other than the larger more obvious ones, because I know of at least 2 lines that are bad on mine and they are both coming off the air check valve. So would any place I go to like autozone or such places have the vacuum hoses even the ones with the different looking connectors?

Also, thanks a lot for the help.

leesvet

ANY auto parts store. There are different size but they can match them. You'll need to buy a roll of hose, and maybe the 2nd size. There's plenty of places to use it. Any hard lines can be replaced with hose. Look at the fittings and buy a vac kit if you will need some connectors or unions to fit onto what was a hard line.

slickfx3

for a quick fix nip the connection ends of those hoses half to an inch, on all the hoses, it usually are the bad spots, cause they flare over the t fittings and stretch and develop cracks...after 100 years of c4 baking heat

go under the brake pedal and push the cc switch back into the pedal after you take the hush panel off, this way the vacume switch does not think you are stepping on the brakes and turning itself off.

mine started working fine after this exercise, i bumped the switch installing the booster for the 4th time.

and it's cool that you are taking care of the little things, over time the car will have everything worked out, the duty of a c4 owner

Red89'-L98

Haha yeah, I like everything to be perfect on a car so I try and fix everything needed when needed and the cruise control has not worked since I got it. I am going to replace vacuum lines for it and the vacuum lines for anything else that looks bad and I am going to check the brake switch like mentioned by you and lee and I might replace the vacuum reservoir in the front of the car by the drivers side headlight along with the vacuum check valve as mine looks really rough.

Thanks for the help, Stephen

c4cruiser

Vacuum line checks should be made first.

There is a fuse for the cruise control. Have you checked it? It could also be the multi-function lever (turn signal) has a problem

Is your car an auto trans or a manual? There are different and separate switches.

The FSM has all sorts of diagnostic procedures to follow; vacuum, cables, and electrical things to check. If you don't have an FSM, maybe somebody could post up scanned pages from an '89 FSM so you can follow the diagnostic procedures and look at the electric schematics.

Red89'-L98

The car is an automatic and I will be heading to autozone soon to get some vacuum hoses.

I am going to get the vacuum hoses in 1/4", 1/8", and 5/32" probably 2 of each since they are only 3 feet long and start with that and the switch behind the brake.

Do you think that those 3 hose sizes will cover my needs, or should I look somewhere else that has more sizes or maybe even those sizes in longer lenght than 3 feet?

I wish I had an FSM but I do not and will hopefully be getting one very soon.

haroldb007

If it set up for 3 years, did you have to do anything to the battery?On my 96 the vacume line is right near it and hooks to a diafram over the battery. I broke this hose putting on a battery tender last year, but did not know it until trying to ingage the cruse controle.You might check this,the hose will be smaller then the others and seems to be of poorer quality the larger ones,so if it is loose or broke it should be easy to see.

Red89'-L98

Yes, I did change the battery as there was no hope for it as I did try to charge it. And yes, I have thought about those 2 vacuum lines and figured I would replace the vacuum line to it along with the dump line on it.

Thanks for the information, Stephen

leesvet

IIWM,
I'd get more like 10 ft of hose in the common size, (easy to see and match up) and just return any unopened packages...better to have it than to need it. You'll be amazed at how fast 3 ft gets used when looping around things and wrapping around others...

Not sure if they will have the hard line. Some have straight hard line, some stores don;t.
usually the hard line can be reused if you cut off any bad sections or ends. Just be sure to install each line exactly where it was. There are some things that use metered vacuum, others use manifold vac thats higher. That check valve is important.Get that in right. That handles your a/c vents inside, the cruise, and I think it also supplies part of the vapor system? not sure on that one..the line runs from that check valve to the firewall for the a/c then across to the booster area where it goes to the cruise solenoid and cabin. Seems like there is another junction around there but I could be mistaken..

Red89'-L98

Ok, I was thinking I would need more than that. So are those the 3 sizes I should get? or are there any others that would be needed.?

leesvet

I do not believe there is much 1/4 in there but I would get them to look and match up the sizes. I think its 5/32 and 1/8...mostly.

Red89'-L98

Ok, thanks for all the help, hopefully I can get this fixed.

Red89'-L98

Actually, I have one more question are there any brands that you would recommend to buy for the vacuum tubing?

Like is this the right kind, or am I looking for a different kind?

http://www.autozone.com/autozone/acc...dentifier=4942

nutz4c4

That should work..

leesvet

its all generic...brand makes no difference.

Red89'-L98

Yeah, I figured that, I just wanted to make sure.

Thanks a lot to everyone that helped. Hopefully this will fix my problems.

Red89'-L98

Ok, haha was doing some research and was wondering which is better silicone or rubber vacuum hoses/tubing. Both are about the same price just the silicone is more easily attainable in the length and size I need from what I have found so far.

Thanks, Stephen