CTIS going low after sitting for a while
#1
11-27-2018, 10:59 AM
CTIS going low after sitting for a while
Hey everyone,
I have a 2000 H1 that runs and works great. It is a car that I use infrequently and if it sits for a while the front or rear tires will go completely flat. It hasn't happened that both back and front go down, just one or the other. Currently it is just the front. When I get in and air it up, they stay up and work fine, but if it sits for a while it will go down again.
Is this an air hose thing that I should get replaced in the CTIS? I just got it back from the Chevy dealer who replaced the PMB, batteries and went through the rig and said it was clean. It only has about 20k miles on it and is garage kept.
Thanks for your help, not sure if I should take it back to the dealer for this work or find someone more local. I'm in Austin, Texas.
I have a 2000 H1 that runs and works great. It is a car that I use infrequently and if it sits for a while the front or rear tires will go completely flat. It hasn't happened that both back and front go down, just one or the other. Currently it is just the front. When I get in and air it up, they stay up and work fine, but if it sits for a while it will go down again.
Is this an air hose thing that I should get replaced in the CTIS? I just got it back from the Chevy dealer who replaced the PMB, batteries and went through the rig and said it was clean. It only has about 20k miles on it and is garage kept.
Thanks for your help, not sure if I should take it back to the dealer for this work or find someone more local. I'm in Austin, Texas.
#2
11-27-2018, 06:01 PM
That is pretty normal. As they age the seals and valves get dry and brittle, especially on a truck that isn't driven much. First pop the disconnects at the wheels after the tires are aired up to proper pressure. If the tires still leak down then do the soapy water test. Start at the CTIS disconnects at the wheels. They are easy to check and replace. Spray the disconnects and look for bubbles. Spray the rim also. This should isolate the leak to a specific wheel/tire if the leak is at the wheel. If no bubbles move on and spray the lines and connections back to the pump looking for air bubbles.
If still no air bubbles or leaks found you can disconnect the CTIS line leaving the hub. Put the end in a container of water and if you have bubbles you need to replace that hub seal. You can also have a CTIS leak at the control valve that allows you to adjust pressure front to back. If you have two piece wheels the O ring between the two wheel halves can also leak.
Typing this quickly so I may have left a thing or two out but that should get you started.
There is a really good H1 mechanic in Houston. David Long is his name. I will PM you his number.
If still no air bubbles or leaks found you can disconnect the CTIS line leaving the hub. Put the end in a container of water and if you have bubbles you need to replace that hub seal. You can also have a CTIS leak at the control valve that allows you to adjust pressure front to back. If you have two piece wheels the O ring between the two wheel halves can also leak.
Typing this quickly so I may have left a thing or two out but that should get you started.
There is a really good H1 mechanic in Houston. David Long is his name. I will PM you his number.
#3
11-27-2018, 08:35 PM
Thanks, I appreciate it. I'll give that a shot this weekend and see what I can find. I'll make sure to keep David's information on file too if I need it in the future.
#4
08-04-2020, 06:05 PM
That is pretty normal. As they age the seals and valves get dry and brittle, especially on a truck that isn't driven much. First pop the disconnects at the wheels after the tires are aired up to proper pressure. If the tires still leak down then do the soapy water test. Start at the CTIS disconnects at the wheels. They are easy to check and replace. Spray the disconnects and look for bubbles. Spray the rim also. This should isolate the leak to a specific wheel/tire if the leak is at the wheel. If no bubbles move on and spray the lines and connections back to the pump looking for air bubbles.
If still no air bubbles or leaks found you can disconnect the CTIS line leaving the hub. Put the end in a container of water and if you have bubbles you need to replace that hub seal. You can also have a CTIS leak at the control valve that allows you to adjust pressure front to back. If you have two piece wheels the O ring between the two wheel halves can also leak.
Typing this quickly so I may have left a thing or two out but that should get you started.
There is a really good H1 mechanic in Houston. David Long is his name. I will PM you his number.
If still no air bubbles or leaks found you can disconnect the CTIS line leaving the hub. Put the end in a container of water and if you have bubbles you need to replace that hub seal. You can also have a CTIS leak at the control valve that allows you to adjust pressure front to back. If you have two piece wheels the O ring between the two wheel halves can also leak.
Typing this quickly so I may have left a thing or two out but that should get you started.
There is a really good H1 mechanic in Houston. David Long is his name. I will PM you his number.
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