Command Trac Vacuum issues - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > Command Trac Vacuum issues

Bds fox ipf 2.0 racing series shocks now available at rockYukon Ultimate 35 axle kit for c/clip axles with Yukon ZipANOTHER Rockridge4wd Creation!! Spare Tire Carrier Delete

Reply
Unread 04-14-2013, 08:00 PM   #1
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
Command Trac Vacuum issues

Ok. I can not get this YJ to shift in to 4X4 at all. When I pull the lever up, I can tell that the front drive shaft is trying to help. I can turn it free hand when in 2x4, then can't when I shift to 4X4. But when spin the tires in teh dirt the front ones do not spin or act like they have any drive power to them.
I checked the vac lines to the shift motor. They are all fowled up. I am going to have to re run all of them. I am not really to up set about the light coming on,but may fix it as I go through this.
But my main problem is this.
The Red line that is supposed to come from the vac canister is really hooked up to a line that has 3 or 4 other tee's in it. So I don't really feel any vacuum at the place that it is spliced with hose.
PO put a lift in it and just added hose in the middle. And not a very good job of it. So I am going to cut out more of it and run it to the motor from the switch on the transfer case. But I am sure that I am not getting enough suction to the switch. I haven't had time to put a vac gauge on it yet. Maybe tomorrow. SO what should I expect to see as a good number for vac?? and where is a better or best place to get this from. I am thinking of running a hose closer to the canister and putting in a tee but I want to find a line that has enough for me first.
Thanks

ad-man is offline   Reply With Quote Quick reply to this message
Unread 04-14-2013, 09:42 PM   #2
Anticanman
Follow me
 
Anticanman's Avatar
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,250
Read this

http://www.jeepforum.com/forum/f12/t...80/?highlight=

Pay attention to the thread linked inside there
__________________
Luck Favours The Prepared
[SIGPIC][/SIGPIC]
Anticanman is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 11:36 AM   #3
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
Thanks. I read all of those but they all seem to want to get rid of the vac setup. I do not want to leave it in full time 4wd. I really want it to work right. I read in a nutter thread that it needs to be hooked up to a "non ported" vac line. I am thinking that i should be able to find a line that will give me a certain amount of vac that will run as it should.
ad-man is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 11:42 AM   #4
pete1991YJ
Registered User
1991 YJ Wrangler 
 
Join Date: Mar 2012
Location: Niagara Falls, NY
Posts: 1,659
Quote:
Originally Posted by ad-man View Post
Thanks. I read all of those but they all seem to want to get rid of the vac setup. I do not want to leave it in full time 4wd. I really want it to work right. I read in a nutter thread that it needs to be hooked up to a "non ported" vac line. I am thinking that i should be able to find a line that will give me a certain amount of vac that will run as it should.
On mine, the vac actually comes right off the manifold and no canister.

BUT -

Just because you can put solid shafts does not mean its in full time 4WD. If you do eliminate the vac disconnect, it still stays in 2-wheel until you shift the t-case. Just like the modern jeeps do.
__________________
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"
pete1991YJ is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 12:03 PM   #5
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
Ok i understand that. But wouldn't that wear things out quicker? I guess the axles are always turning and now the shaft would be turning. But just free wheeling with the wheels.
Where on the manifold are you getting your vac from?
ad-man is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 12:09 PM   #6
pete1991YJ
Registered User
1991 YJ Wrangler 
 
Join Date: Mar 2012
Location: Niagara Falls, NY
Posts: 1,659
Quote:
Originally Posted by ad-man View Post
Ok i understand that. But wouldn't that wear things out quicker? I guess the axles are always turning and now the shaft would be turning. But just free wheeling with the wheels.
Where on the manifold are you getting your vac from?
Actually it does not wear noticably since its just freewheeling - there isn't any load on it. When you lock the t-case in 4WD *then* it has a load and starts to wear normally. Like I say, all the late-model jeeps do it this way since 1997 or so. No probs at all.

On mine anyway, the vac is taken from the top of the manifold near the back of the engine. Same spot the MAP sensor goes into.
.
__________________
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"
pete1991YJ is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 01:21 PM   #7
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
Ok i am going ti try to see if i can get it to work from there, if not its getting flipped. I mean my god, what is the point of a jeep without 4x4 really?
ad-man is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 02:06 PM   #8
pete1991YJ
Registered User
1991 YJ Wrangler 
 
Join Date: Mar 2012
Location: Niagara Falls, NY
Posts: 1,659
Quote:
Originally Posted by ad-man View Post
Ok i am going ti try to see if i can get it to work from there, if not its getting flipped. I mean my god, what is the point of a jeep without 4x4 really?
You could just run all new hose, prolly more reliable. But best of all like we've been saying, is to just eliminate the vacuum disconnect altogether preferably with a set of XJ axle shafts. $50 cheap at the junkyard and the 4x4 is *guaranteed* to work after that. It has no choice since its been replaced with solid steel, its gonna work.
__________________
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"
pete1991YJ is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 02:21 PM   #9
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
Thats something to think about. I have been in the front end of my 89 xj to replace seals. Its not to intimidating. I need to read more on it. Plenty of axles in the JYs around here if xjs. I know that all the hoses are very brittle and the light is not hooked up so. Probably.
ad-man is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 04:20 PM   #10
Anticanman
Follow me
 
Anticanman's Avatar
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,250
Or you can just lock the clip over which takes about twenty minutes.
__________________
Luck Favours The Prepared
[SIGPIC][/SIGPIC]
Anticanman is offline   Reply With Quote Quick reply to this message
Unread 04-15-2013, 09:00 PM   #11
pete1991YJ
Registered User
1991 YJ Wrangler 
 
Join Date: Mar 2012
Location: Niagara Falls, NY
Posts: 1,659
Quote:
Originally Posted by Anticanman View Post
Or you can just lock the clip over which takes about twenty minutes.
^^^^ this
__________________
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"
pete1991YJ is offline   Reply With Quote Quick reply to this message
Unread 04-17-2013, 08:59 PM   #12
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
Well I finally got to it to night. Just replaced the green and yellow line as far as i could. Plugged the port for the light for now. Its working fine. But i do think I need to get the shaft balanced. A little rough sounding. But its working and some day when I am bored I may find out where the light hooks up. Just a bare ended wire out of the switch right now.
Now foe the next problem. ;-)
Damn thing jumps out of gear in third when I am let off and the gas. But that is a new thread.
Thank you to everyone for the help.
ad-man is offline   Reply With Quote Quick reply to this message
Unread 04-17-2013, 09:19 PM   #13
pete1991YJ
Registered User
1991 YJ Wrangler 
 
Join Date: Mar 2012
Location: Niagara Falls, NY
Posts: 1,659
Quote:
Originally Posted by ad-man View Post
Well I finally got to it to night. Just replaced the green and yellow line as far as i could. Plugged the port for the light for now. Its working fine. But i do think I need to get the shaft balanced. A little rough sounding. But its working and some day when I am bored I may find out where the light hooks up. Just a bare ended wire out of the switch right now.
Now foe the next problem. ;-)
Damn thing jumps out of gear in third when I am let off and the gas. But that is a new thread.
Thank you to everyone for the help.
was gonna say, jeep never balanced the front shaft at the factory. They're *all* a little rough in 4WD at speed.
__________________
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"
pete1991YJ is offline   Reply With Quote Quick reply to this message
Unread 04-17-2013, 09:26 PM   #14
ad-man
Registered User
1989 XJ Cherokee 
 
Join Date: Nov 2011
Location: las vegas, nv
Posts: 263
I got a good drive line shop near the house that has great prices. Plus I will just go ahead and replace the u joints for fun. Thanks again.
ad-man is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.