Vacuum Part Mystery December 09, 2020, 12:20:49 pm 1990 Chevy G30 5.7lThese are vacuum hoses I am replacing. The thin white one is what I cannot identify and local parts store cannot either.
Re: Vacuum Part Mystery Reply #1 – December 09, 2020, 12:44:08 pm Do you have a manifold vacuum gauge mounted in your cockpit? That would be my guess, and not oem for a G-30...Stevep.s. might be labelled 'fuel mileage' or similar. 1 Likes
Re: Vacuum Part Mystery Reply #2 – December 09, 2020, 01:41:44 pm Yours appears to be a Chevrolet, check your vacuum heater controls in the dash. See if they are working.Jon 2 Likes
Re: Vacuum Part Mystery Reply #3 – December 09, 2020, 05:12:24 pm Try asking (ask to send pictures) to Auto Shop | Glendale, AZ | Scott Repman's Truck and Auto Repair in Phoenix AZ area. They might ask for a small fee for their time since you are not a customer but they might do you a favor. Extremely knowledgeable and very good as locating older parts.Worked on our Chevy chassis and really knew their stuff (specialize in trucks and RVs including older ones).Jane 1 Likes
Re: Vacuum Part Mystery Reply #4 – December 09, 2020, 05:35:52 pm Quote from: Jane and Scott - December 09, 2020, 05:12:24 pmTry asking (ask to send pictures) to Auto Shop | Glendale, AZ | Scott Repman's Truck and Auto Repair in Phoenix AZ area. They might ask for a small fee for their time since you are not a customer but they might do you a favor. Extremely knowledgeable and very good as locating older parts.Worked on our Chevy chassis and really knew their stuff (specialize in trucks and RVs including older ones).JaneUnfortunately I live in NorCal. I'll call. Maybe I get lucky.
Re: Vacuum Part Mystery Reply #5 – December 09, 2020, 05:36:44 pm Quote from: Steve - December 09, 2020, 12:44:08 pmDo you have a manifold vacuum gauge mounted in your cockpit? That would be my guess, and not oem for a G-30...Stevep.s. might be labelled 'fuel mileage' or similar.No gauge, but thanks.
Re: Vacuum Part Mystery Reply #6 – December 09, 2020, 06:45:14 pm Quote from: Steve - December 09, 2020, 12:44:08 pmDo you have a manifold vacuum gauge mounted in your cockpit? That would be my guess, and not oem for a G-30...Stevep.s. might be labelled 'fuel mileage' or similar.At this point, everything suggests it may go to the fuel tank. Been trying to trace but no luck at this time. Goes thru the firewall and then down. I thought it was going to the steering column, but not so. My frustration level is very high right now. AAAAARRRRRRGGGGHHHH!
Re: Vacuum Part Mystery Reply #7 – December 09, 2020, 07:00:42 pm Sometimes there is a vacuum line going to the charcoal cannister. The cannister adsorbs gasoline vapors from the gas tank, so they don't get out into the air, and then vacuum from a running engine sucks those gas vapor back into the engine (slowly which might account for the tiny hose). Hope this helps. RonB 1 Likes
Re: Vacuum Part Mystery Reply #8 – December 09, 2020, 08:34:56 pm Have you tried tracing where the white line goes?It looks like a vacuum supply for the dash HVAC controls and flaps. It may go to a vacuum storage container that supplies the HVAC system.While the rubber line can age and leak, nylons lines usually last the life of the vehicle, unless damaged.Larry
Re: Vacuum Part Mystery Reply #9 – December 10, 2020, 07:54:53 am Quote from: Larry W - December 09, 2020, 08:34:56 pmHave you tried tracing where the white line goes?It looks like a vacuum supply for the dash HVAC controls and flaps. It may go to a vacuum storage container that supplies the HVAC system.While the rubber line can age and leak, nylons lines usually last the life of the vehicle, unless damaged.LarryI will continue attempting to trace today. I thought it might be that but after it passes thru the fire wall it drops down. Going try and trace underneath.
Re: Vacuum Part Mystery Reply #10 – December 10, 2020, 09:31:25 pm Mindispower. We have a couple of pictures (to jog our memory in the future) of our vacuum tubing.Chevy 350 - 89 TK. So I pulled them up.The "thin white wire" you talked about I think is the same one that we had worked on.One end goes to the big "ball" attached to the underside of the hood and the other side goes thru the dash to the air conditioner. That one is more difficult to replace because it goes thru the dash so we got a repair done and everything works great now.See attached pic.I will send you a PM to see about getting the part number for that line.
Re: Vacuum Part Mystery Reply #11 – December 11, 2020, 01:31:01 am Hi Jane. I've heard of engines that have a vacuum switch to shut off the air conditioner, when the engine is laboring and has low vacuum. Like full throttle going up a hill. Do you think that was the purpose of that? Could the ball be a vacuum reservoir? And do you have vacuum boost on the power brakes or 'Hydroboost". Just curious! RonB
Re: Vacuum Part Mystery Reply #12 – December 11, 2020, 09:05:23 am Quote from: Jane and Scott - December 10, 2020, 09:31:25 pmMindispower. We have a couple of pictures (to jog our memory in the future) of our vacuum tubing.Chevy 350 - 89 TK. So I pulled them up.The "thin white wire" you talked about I think is the same one that we had worked on.One end goes to the big "ball" attached to the underside of the hood and the other side goes thru the dash to the air conditioner. Exactly the same as mine. It is so brittle that it snaps at the slightest touch. I am thru the firewall and removed anything in the cab I needed to do to trace it.That one is more difficult to replace because it goes thru the dash so we got a repair done and everything works great now.See attached pic.I will send you a PM to see about getting the part number for that line.
Re: Vacuum Part Mystery Reply #13 – December 11, 2020, 09:09:57 am Quote from: Mindispower - December 11, 2020, 09:05:23 amExactly the same as mine. It is so brittle that it snaps at the slightest touch. I am thru the firewall and removed anything in the cab I needed to do to trace it.
Re: Vacuum Part Mystery Reply #14 – December 13, 2020, 01:12:37 pm Quote from: JonS - December 09, 2020, 01:41:44 pmYours appears to be a Chevrolet, check your vacuum heater controls in the dash. See if they are working.JonThey do not work, so that's my answer.
Re: Vacuum Part Mystery Reply #15 – December 13, 2020, 01:14:32 pm Quote from: Mindispower - December 10, 2020, 07:54:53 amI will continue attempting to trace today. I thought it might be that but after it passes thru the fire wall it drops down. Going try and trace underneath. Success at last! Thanks. HVAC. 1 Likes
Re: Vacuum Part Mystery Reply #16 – December 14, 2020, 06:32:28 pm TY all for your input. Took a while but I got 'er done. 1 Likes
Re: Vacuum Part Mystery Reply #17 – December 14, 2020, 09:38:53 pm Quote from: Mindispower - December 09, 2020, 12:20:49 pm1990 Chevy G30 5.7lThese are vacuum hoses I am replacing. The thin white one is what I cannot identify and local parts store cannot either.Thanks all for your input. Problem solved!
Re: Vacuum Part Mystery Reply #18 – December 20, 2020, 02:17:00 am Quote from: RonB - December 11, 2020, 01:31:01 amHi Jane. I've heard of engines that have a vacuum switch to shut off the air conditioner, when the engine is laboring and has low vacuum. Like full throttle going up a hill. Do you think that was the purpose of that? Could the ball be a vacuum reservoir? And do you have vacuum boost on the power brakes or 'Hydroboost". Just curious! RonBRon, This is the vacuum line that fixes the problem where air blows out only at the dash and not thru the front vents.Ours was not nearly as bad as Mindispower's, we just had a small crack not even an inch long.There were a couple posts about the Ford chassis with this issue, that further explained the issue, but I could not find them with a quick search.Jane 1 Likes
Re: Vacuum Part Mystery Reply #19 – December 20, 2020, 11:29:56 am Mindispower, congrats on the fix! Did you replace the white line with the same material or just standard vacuum hose? I have the same setup and a am wondering in case I need to do this repair at some point. Thanks!
Re: Vacuum Part Mystery Reply #20 – December 20, 2020, 12:40:18 pm Quote from: pierats - December 20, 2020, 11:29:56 amMindispower, congrats on the fix! Did you replace the white line with the same material or just standard vacuum hose? I have the same setup and a am wondering in case I need to do this repair at some point. Thanks!Ran a new 5/32 hose from engine compartment through the firewall to hook up with the good original hose. I have pics but cannot seem to post 'em. 1 Likes
Re: Vacuum Part Mystery Reply #21 – December 20, 2020, 02:33:53 pm Quote from: Mindispower - December 20, 2020, 12:40:18 pmRan a new 5/32 hose from engine compartment through the firewall to hook up with the good original hose. I have pics but cannot seem to post 'em.How to Post Photos
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