Wiper vacuum hose under dash, how to replace?
Thread Starter
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
Wiper vacuum hose under dash, how to replace?
Today did some more troubleshooting on my wiper door not closing. Found the "red" hose from wiper door valley to the override switch is bad. Has anyone replaced this hose and has any input on how to do it?
I though about either attaching a string to the old hose or joining them together to fish them out, provided the hose is not cut. Not sure if the hoses are taped together either.
I though about either attaching a string to the old hose or joining them together to fish them out, provided the hose is not cut. Not sure if the hoses are taped together either.
Former Vendor
Joined: Aug 2006
Posts: 76,656
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From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Which red hose? What year is the car..
In most cases, you can just snip off 1" of the hose and plug it back in.. Cracks form age can hamper the end of the old hoses so you might be better off in the long run just trimming a bit off and plugging it back in.
But to be honest... the most common issue with this part of the system is the valve at the wiper arm... So you can check this valve, I did a video on how to test it on our youtube page and it is the only correct video on how to test it.. (from the middle port, not the lower one)
-Willcox
In most cases, you can just snip off 1" of the hose and plug it back in.. Cracks form age can hamper the end of the old hoses so you might be better off in the long run just trimming a bit off and plugging it back in.
But to be honest... the most common issue with this part of the system is the valve at the wiper arm... So you can check this valve, I did a video on how to test it on our youtube page and it is the only correct video on how to test it.. (from the middle port, not the lower one)
-Willcox
Last edited by Willcox Corvette; Apr 2, 2017 at 10:33 PM.
Thread Starter
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
It's a 1970. The G hose in the above diagram. Disconnected it from the override switch under the dash and the vacuum at the arm, and blew compressed air in. I could feel the air from around the column, but not out of the end going to the override switch.
i was getting vacuum at H. Attempted to put mityvac on G, and finger on other end with nothing, before attempting to blow air in.
i was getting vacuum at H. Attempted to put mityvac on G, and finger on other end with nothing, before attempting to blow air in.
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
I did the same job recently and that's probably the worst one to replace as it goes through a grommet in to the engine compartment and back through another grommet from the engine compartment to under the dash. I cut one end of the hose at a long angle (like a pencil) probably around 60 degrees so you can stuff the tapered end through the grommet. Use some dialectic grease on the outside of the tapered part and it will easily go far enough through the grommet that you can grab it on the other side. If you just leave the hose at a 90 degree angle the edges will bind in the grommet. You can then cut the hose back to a 90 degree angle and join it up to your override switch. I also had the same problem with the white hose from the safety switch to the relay that you are having with the red one. It was shinny and crystallized inside when I cut it open and would not hold vacuum no matter how much you cut off the ends but looked almost new from the outside.
Last edited by CanadaGrant; Apr 3, 2017 at 12:23 AM.
Safety Car
Joined: Sep 2013
Posts: 4,355
Likes: 2,633
From: Draper Utah
FWIW - When i replaced my dash vacuum hoses i broke a golf tee in half and connected the new hose to the old hose. Then I pulled the new hose through using the old hose. Mostly I pushed on the new hose so they would not disconnect. I also sprayed the firewall grommet with silicone to help slide the hoses through.
Team Owner
Joined: Sep 2006
Posts: 31,283
Likes: 4,374
From: Westminster Maryland
Hi D,
My belief is that the hoses are very rarely the cause of vacuum system problems.
Even trimming just a 1/2" off each end as W suggests is all that's typically needed for a good seal.
Have you tested the hose to be sure it's the culprit?
With good access to each end of this hose the test should just take a moment to make sure!
Are you certain?
Regards,
Alan
My belief is that the hoses are very rarely the cause of vacuum system problems.
Even trimming just a 1/2" off each end as W suggests is all that's typically needed for a good seal.
Have you tested the hose to be sure it's the culprit?
With good access to each end of this hose the test should just take a moment to make sure!
Are you certain?
Regards,
Alan
Last edited by Alan 71; Apr 3, 2017 at 07:15 AM.
Thread Starter
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
Alan, I attempted to pull vacuum with finger over the wiper override side (both hoses) and mityvac at the "red" hose at the vacuum switch in wiper valley, and didn't get any vacuum. Then blew air from same point as mityvac was connected in wiper valley, and could feel air by the column, but nothing at the house. It's safe to say the hose itself has issues.
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Thread Starter
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
Not looking forward to the replacement. Will have to see if I can find routing under dash or where it's hole is. If can pull the grommet, and replace/patch hose will do that. Not sure if they are taped together or how run into the car after the grommet.
Thread Starter
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
Wasn't sure if they taped them together at some point. I'm going to likely tie a line to the hose in hopes it is not fully cut, so hopefully can bring back to correct position with minimal pain. Really hate dash work.
Might try blowing more air in to see if can feel te source of hole. I know I should order some of that Flex Seal stuff to fix the hose.
Might try blowing more air in to see if can feel te source of hole. I know I should order some of that Flex Seal stuff to fix the hose.
Thread Starter
Drifting
Joined: Aug 1999
Posts: 1,451
Likes: 84
From: Round Rock TX
Found it was more comfortable to remove the steering wheel rather than the seat. The red hose (G from picture above) had a coupler about 1-2" after the grommet. The hose wasn't connected to the coupler, but is now. The only casualty was the T fitting with 1/4" on either side and maybe 1/8" in the middle. I am attempting to glue it back together and will see how that goes.