C1111toro Posted April 16, 2020 Share Posted April 16, 2020 Hi Everyone, I’m trying to get my cruise control working again. I just bought my first Comanche in Nov. 19. I have done all the electrical tests and it seems like everything checks out ok. Then I noticed that my servo is missing a vacuum line. I cannot find the line. Could someone please upload a photo that shows where the smaller vacuum line originates? I have an 89 4.0. Here is a pic of my truck along with a close up of my servo as well as another photo that I sourced from Comanche Club showing the smaller vacuum line in question. Link to comment Share on other sites More sharing options...
Big Dan Posted April 16, 2020 Share Posted April 16, 2020 If memory serves correctly, it goes directly to the vacuum ball. Sent from my Pixel 2 XL using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 16, 2020 Share Posted April 16, 2020 That small Vac line traces from where the servo is all the way to the other side of the passenger bumper(the side facing inward). Should be a foot ball shaped cannister and one of the lines goes to the blower controls and the other to the servo. I think I have an 87-90 servo. Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 Thanks Dan. Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 1 minute ago, eaglescout526 said: That small Vac line traces from where the servo is all the way to the other side of the passenger bumper(the side facing inward). Should be a foot ball shaped cannister and one of the lines goes to the blower controls and the other to the servo. I think I have an 87-90 servo. Thanks eaglescout526. I'll check it out in the morning. Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 16, 2020 Share Posted April 16, 2020 No problem. Let us know what you find. Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 I have two that run along the passenger side from the vacuum ball. Both terminate on the firewall. Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 16, 2020 Share Posted April 16, 2020 3 minutes ago, C1111toro said: That's your servo vac harness. It is on a evap box stud. Smart place to put it from further damage. Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 Thanks. So should I disregard the first photo of my servo that appears to be damaged? It appears as though the vacuum line was attached there at one point. I don’t know, I just asking. I appreciate everyones advice. Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 16, 2020 Share Posted April 16, 2020 No I wouldn't disregard it. But I would try to fix that if you can by maybe snugging a hard vac line into the hole and then putting the vac line on and test it to see if it works. If it doesn't work, like I said I have an 87-90 servo that won't work with any of the wiring harnesses I have. Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 Thank you guys! You were both correct. eaglescout526 You da man! It was the vacuum line attached to the stud on the firewall. I just need to repair the servo where the plastic nipple was to reattach the line. I'll try to find a tiny brass fitting that will self tap itself into the plastic body of the servo. If not I will source some smaller diameter hard line to make a coupler. Two thumbs up! Thanks again, Chris Link to comment Share on other sites More sharing options...
Big Dan Posted April 16, 2020 Share Posted April 16, 2020 Glad you got it and glad that eaglescout was able to be much more descriptive than I was. Sent from my Pixel 2 XL using Tapatalk Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 16, 2020 Share Posted April 16, 2020 No problem glad to help! Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 I took a jet from a carburetor that I had and drilled it out with 1/8 drill bit(the pic of the jet is prior to drilling out with 1/8 bit). Then I used a 11/64 drill bit to drill out the plastic opening in the servo. I then self tapped the brass jet into the plastic. Worked like a charm. I will test it tomorrow: Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 SOLVED! FUNCTIONING! I tested my repair with the drilled out jet today and it was a fail. I decided to take the Servo off and take it apart. The plastic 90 degree vacuum fitting that exists the plastic Servo housing had broken off further inside the housing than I had expected. My fix was to use a Dremel with a mini cut of wheel to reshape the 90 degree plastic fitting that is in the housing. I then used some chainsaw fuel line. I heated up the end just enough to get it to fit onto the newly formed nipple. The fuel line which is now an air line exits the Servo through the pre-existing hole that the factory plastic 90 degree fitting existed. The fuel lines exterior diameter was a perfect match for the black vacuum line to fit over and seal. I hope this helps everyone. Please feel free to ask any questions. Check out the pics. Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 16, 2020 Share Posted April 16, 2020 Way to save a servo! Link to comment Share on other sites More sharing options...
C1111toro Posted April 16, 2020 Author Share Posted April 16, 2020 Thanks. The final step at the end was to cut the fuel line to length and install the factory vacuum line onto it. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now