C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Lumbar pump repair

Old 06-02-2011, 02:49 PM
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craneman61!
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Default Lumbar pump repair

I have been looking at threads and researching this all morning. For some reason my DA can't find what i need. I have a 1996 with the controls that switch from driver to passenger. I need help with the lumbar pump. All i get is a clicking noise when i operate any of the lumbar controls. Where do you think the problem lies?
Old 06-02-2011, 03:02 PM
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tlong
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Take the seat cushions off and look for unplugged wire harnesses. All the stuff is under the passenger seat.
Old 06-02-2011, 03:03 PM
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Steve731
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Have you removed the passenger seat cushion and removed the air pump? I think it has one pop rivet that has to be drilled out before you can remove the pump? Mine (94) did the same thing. It turns out that the little air pump was locked up. Hook up 12 volts to the connectors to see if pumps purrs. I took the pump apart. Lightly!! sanded the rotor and reinstalled. It worked for me. Otherwise you will have to get another pump.
Old 06-02-2011, 03:19 PM
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craneman61!
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I have the pump out. Do you have to take to motor apart? I don't see anything in the pump part that looks likes it is not right.
Old 06-02-2011, 03:37 PM
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Steve731
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Will the pump work if you apply 12v across the pins on the outside of the housing? It will pump with +/- hooked up one way and suck with +/- hooked up the other way. Hence inflating and deflating the bags.
Old 06-02-2011, 04:58 PM
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Churchkey
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You probably have a ruptured diaphram in the end of the pump.

Found the how to fix link for you.

https://www.corvetteforum.com/techti...=181&TopicID=2
Old 06-02-2011, 06:14 PM
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Red Dwarf
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Originally Posted by Churchkey
You probably have a ruptured diaphram in the end of the pump.

Found the how to fix link for you.

https://www.corvetteforum.com/techti...=181&TopicID=2
When I pulled the pump on my 95, expecting to see a rubber diaphram, I found the pump is a centrifugal type with vanes that extrend when the pump is activated. IIRC there was a problem putting it back together, so make sure you note the location of what you remove. Didn't solve my problem as there was a bad connection in one of the connectors. Still comes & goes.

Last edited by Red Dwarf; 06-03-2011 at 08:50 AM. Reason: SP
Old 06-02-2011, 07:47 PM
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anciano
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When I pulled the pump on my 95, expecting to see a rubber diaphram, I found the pump is a centrifugal type with vanes that extrend when the pump is activated.
And my '94 is the same design. I thought the thing was acting up and took it apart, finding nothing wrong or hung up. Turns out I was expecting a more dramatic inflation than that puny little pump could put out. Sitting very still and waiting patiently I could feel the airbags slowly inflating. It's not exactly a huge effect. I'd rather have a permanent lumbar pad under the seatcover, and I may put one in there.
Old 06-03-2011, 12:50 AM
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Mine is the design that does not have the diaphram. I was wondering what I was missing (other than my sanity) because I could not find a diaphram. The pump runs on the bench. I will look at this again tomorrow. I'm glad others have the desigh without the diaphram and explained it to me. I thought I was really losing it.
Old 06-03-2011, 01:13 PM
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Does your pump work smoothly in both directions on the bench? If it does and works the same when you push the appropriate side of the lumbar button then the problem must be in the manifolds. Each of the buttons cycles the pump to either pump or evaculate - depending on which side of the button is pushed it also opens one of hte solenid valves on the manifold to allow the air into or out of the bladder- that action keeps the bladder inflated at the desired level. There is a manifold for each seat. With a little trouble shooting you should be able to figure out which parts are not working. Hope this helps.
Old 06-03-2011, 08:43 PM
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I took the pump and cleaned all the bakelite ? pieces good with finger nail polish remover. I put a light coat of sewing machine oil on all the pieces incluning the wings that slide in and out when the motor is running. Put it all back together and it works great. It pushes and pulls and the motor runs much better now than before. Now I have to see about the bags in the seats. Thanks for the input and instructions. I was going nuts looking for that diaphram.
Old 06-03-2011, 09:12 PM
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I thought I was through for today but just couldn't stand it. Went back out to check the seats and see what wouldn't work. Everything on the passenger and driver seat works. If I could I would buy everyone a beer. THANKS GUYS
Old 06-03-2011, 09:38 PM
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Persistance pays off. Good for you!
Old 06-04-2011, 11:02 AM
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tlong
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Good job. You saved a wad of money. These are among the best seats Chevy ever made. The side bolsters trip my friends out.

I replaced standards with sports-wiring and everything. It was like a miracle when they worked and have been fantastic since. The standards were almost as comfortable and found a good home in a Louisiana vette. Keeping them going can be a challenge, along with the rest of the vehicle...
Old 06-04-2011, 11:15 AM
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xphnmn
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Hate to sound like a complete dummy but I'm new to vettes. How do the seat cushions come off? My lumbar pump doesn't seem like it runs at all.
Old 06-04-2011, 01:03 PM
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Red Dwarf
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Originally Posted by xphnmn
Hate to sound like a complete dummy but I'm new to vettes. How do the seat cushions come off? My lumbar pump doesn't seem like it runs at all.

http://forums.corvetteforum.com/c4-g...reference.html
Old 06-04-2011, 01:24 PM
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The plastic (bakelight) nipples were broken (one on each seat) where the hardened tubing attached to the pump. I went to the Hobby Shop and got some aluminum tubing that was the correct od to slip into the pump housing and the broken off nipple. Then they were reattached with some serious two part epoxy so the mend could take the pressure. I dipped the hardened tubing into a cup of hot water to soften them and reattached. Worked great.

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