Two vacuum hoses keep blowing off !

westfield · October 14, 2009

Okay...How do I fix this...this has happened twice over the past two weeks. At start up...the ex blow two lines off the vacuum tree and it runs crappy till i reattach the vacuum lines...what should I look for to correct the problem..
Thanks!

ps..the car has 150,000 miles on it and it runs great (till the lines blow)

BrooklynBay · October 14, 2009

Check the modulator for leaking transmission fluid.

geoph1986 · October 14, 2009

I would say that you should replace those lines as they are probably old and stretched. I had the exact same problem, and once I replaced the lines, they never blew off again.

mrboyle · October 14, 2009

BrooklynBay said:
Check the modulator for leaking transmission fluid.

X2

The if tranny modulator fails it will allow vacuum to pull fluid up to the intake and soak the other vacuum lines with tranny fluid. Once soaked they expand and fall off. Check modulator (pull line off modulator @ tranny and if fluid runs out its bad), replace if bad, replace vacuum hoses that got soaked and return to service.

westfield · October 14, 2009

Thanks all...i'll check the mod and see if the vac lines are old to

camsdad · October 17, 2009

Transmission modulator. Check your fluid level.
Been there and done that.
Swapped it out and never had the problem again.
Be very glad you are here asking.
When it was happening to our 94 explorer, my wife took it to a transmission shop and they said the transmission was shot.
They quoted $1200.
I spent $12.00 for the modulator.
Had my niece's boyfriend do the job since you could not just reach in there and remove it without removing some of the exhaust to gain access. I think he had to use some metric sockets too.

ExploringNC · October 19, 2009

I'm confussed? How can a vacuum line (negative pressure) blow off? You would have to have a positive pressure in the line to blow it off.

BrooklynBay · October 19, 2009

A flow of transmission fluid being drawn into the hose could cause it to slip off.

Maniak · October 19, 2009

I've had a couple hoses slip off over the years.

Each time, The lines were soft, one from just age, the other had Trans fluid in it.

They never came off "while driving". They both came off while starting.. And both times it was when I started the X, but didn't let it turn over long enough to actually start. I'm guessing that when the motor stopped spinning the motor may have spun backwards a bit and causes positive pressure in the upper intake, blowing off the hose.

Once the hoses were fixed (not soft/squishy) they were fine.

~Mark

clearwtrbeach · October 19, 2009

I just replaced a vacum modulator through the hump inside, there was a small hose maybe 3-4" from the modulator to a metal tube. Is there another hose that I may have missed.

BrooklynBay · October 19, 2009

Check the hoses connected to the vacuum tree.

Itchybruno47 · July 1, 2015

Maniak said:
I've had a couple hoses slip off over the years.

Each time, The lines were soft, one from just age, the other had Trans fluid in it.

They never came off "while driving". They both came off while starting.. And both times it was when I started the X, but didn't let it turn over long enough to actually start. I'm guessing that when the motor stopped spinning the motor may have spun backwards a bit and causes positive pressure in the upper intake, blowing off the hose.

Once the hoses were fixed (not soft/squishy) they were fine.

~Mark

X2. Has happened a few times to me. New hoses and keep key turned when starting till she fires. No more problema!

Two vacuum hoses keep blowing off !

westfield

Well-Known Member

BrooklynBay

Moderator & long time member.

geoph1986

mrboyle

I Drive By Brail

westfield

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camsdad

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ExploringNC

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BrooklynBay

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Maniak

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clearwtrbeach

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BrooklynBay

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Itchybruno47

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