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Oil Leak from Vacuum Pump

Posted: Thu Nov 02, 2017 10:07 pm
by sfd_656
Our 1996 l400 recently sprang a leak from what i think is the vacuum pump (passenger side of the engine compartment on the front of the motor with a line running to the brake booster). It appears that the top piece is broken off? Does anybody have any insight? What is the black plastic part that looks broken? Is the pump rebuild-able with some o rings?
Thanks
vacuum pump
vacuum pump
vac pump com.jpg (12 KiB) Viewed 10376 times
vac pump 2 com.jpg
vac pump 2 com.jpg (12.26 KiB) Viewed 10376 times
vac pump comst.jpg
vac pump comst.jpg (8.04 KiB) Viewed 10375 times

Oil Leak from Vacuum Pump

Posted: Fri Nov 03, 2017 9:57 pm
by poochike
sfd_656 wrote:Our 1996 l400 recently sprang a leak from what i think is the vacuum pump (passenger side of the engine compartment on the front of the motor with a line running to the brake booster). It appears that the top piece is broken off? Does anybody have any insight? What is the black plastic part that looks broken? Is the pump rebuild-able with some o rings?
Thanks
vac pump com.jpg
vac pump 2 com.jpg
vac pump comst.jpg
I'm pretty sure that's your oil pressure sender. Common problem, easy fix. CVI, RJD, Amazing Auto, Rising Sun, Coombs Country Auto will all have the part. About $20 if I remember correctly. I carry a spare with me just in case.

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Oil Leak from Vacuum Pump

Posted: Sat Nov 04, 2017 10:03 pm
by sfd_656
Thank you, does the fix just involve removing the old sender and threading in the new one and reattaching the wire? What causes them to break? I have the new part on the way.

Oil Leak from Vacuum Pump

Posted: Sun Nov 05, 2017 7:13 pm
by poochike
sfd_656 wrote:Thank you, does the fix just involve removing the old sender and threading in the new one and reattaching the wire? What causes them to break? I have the new part on the way.
That's it. Believe it's a 22mm deep socket or a small adjustable wrench to remove the old one. They're just a weak point in the system. Usually the wire connection doesn't bust off, it just leaks from the top. Maybe yours was bumped from some recent work to cause the wire connection to bust off? There's a through bolt underneath that attaches to the banjo. If this comes out with the oil sender be careful not to lose the 2 copper washers.

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Oil Leak from Vacuum Pump

Posted: Mon Nov 06, 2017 12:08 am
by sfd_656
Thanks again.

Oil Leak from Vacuum Pump

Posted: Wed Nov 08, 2017 5:10 pm
by poochike
sfd_656 wrote:Thanks again.
You get things sorted?

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Oil Leak from Vacuum Pump

Posted: Wed Nov 08, 2017 5:27 pm
by sfd_656
Parts just arrived and getting dark outside will have to wait until friday. Old sensor needs a 1 1/8" deep socket (will have to borrow one, new one from mardy fits in a 24mm deep socket

Oil Leak from Vacuum Pump

Posted: Fri Nov 10, 2017 3:20 pm
by sfd_656
All done, leak is cured.

Oil Leak from Vacuum Pump

Posted: Sat Nov 11, 2017 3:17 pm
by poochike
sfd_656 wrote:All done, leak is cured.
Nice one.

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Oil Leak from Vacuum Pump

Posted: Wed Dec 27, 2017 9:46 pm
by P.Gaudreault
I have the same oïl leak with my 1998. Thank for all these good info. Is It possible that this leak make the engin cough at a different speed? Like all the van is shaking.

Oil Leak from Vacuum Pump

Posted: Thu Dec 28, 2017 1:24 pm
by poochike
P.Gaudreault wrote:I have the same oïl leak with my 1998. Thank for all these good info. Is It possible that this leak make the engin cough at a different speed? Like all the van is shaking.
No, it will not cause the van to shudder or have performance issues. That is unless you lose all your oil before noticing!

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Oil Leak from Vacuum Pump

Posted: Fri Dec 29, 2017 5:38 pm
by sfd_656
P.Gaudreault wrote:I have the same oïl leak with my 1998. Thank for all these good info. Is It possible that this leak make the engin cough at a different speed? Like all the van is shaking.
The leak gets worse quickly, order parts and repair asap, check/add oil every time you drive the vehicle until repaired.

Oil Leak from Vacuum Pump

Posted: Thu Jan 04, 2018 5:18 pm
by P.Gaudreault
Ok Thank you for the advice. I will order the part ASAP.

Oil Leak from Vacuum Pump

Posted: Wed Jan 31, 2018 10:40 am
by Delica_Acadie
poochike wrote:
sfd_656 wrote:Our 1996 l400 recently sprang a leak from what i think is the vacuum pump (passenger side of the engine compartment on the front of the motor with a line running to the brake booster). It appears that the top piece is broken off? Does anybody have any insight? What is the black plastic part that looks broken? Is the pump rebuild-able with some o rings?
Thanks vac pump com.jpgvac pump 2 com.jpgvac pump comst.jpg
I'm pretty sure that's your oil pressure sender. Common problem, easy fix. CVI, RJD, Amazing Auto, Rising Sun, Coombs Country Auto will all have the part. About $20 if I remember correctly. I carry a spare with me just in case.

Sent from my SM-G920W8 using Tapatalk


Hi there so is this the part : oil pressure switch : http://www.ccautos.ca/4d56-4m40-oil-pressure-switch/

I am trying to attach a pic of mine on my van. I noticed it cause the part is a wet and black and the top bug is loose...so make me wonder if i need a plug as well that goes on the oil pressure switch.

Oil Leak from Vacuum Pump

Posted: Wed Jan 31, 2018 2:18 pm
by poochike
Delica_Acadie wrote:
poochike wrote:
sfd_656 wrote:Our 1996 l400 recently sprang a leak from what i think is the vacuum pump (passenger side of the engine compartment on the front of the motor with a line running to the brake booster). It appears that the top piece is broken off? Does anybody have any insight? What is the black plastic part that looks broken? Is the pump rebuild-able with some o rings?
Thanks vac pump com.jpgvac pump 2 com.jpgvac pump comst.jpg
I'm pretty sure that's your oil pressure sender. Common problem, easy fix. CVI, RJD, Amazing Auto, Rising Sun, Coombs Country Auto will all have the part. About $20 if I remember correctly. I carry a spare with me just in case.

Sent from my SM-G920W8 using Tapatalk


Hi there so is this the part : oil pressure switch : http://www.ccautos.ca/4d56-4m40-oil-pressure-switch/

I am trying to attach a pic of mine on my van. I noticed it cause the part is a wet and black and the top bug is loose...so make me wonder if i need a plug as well that goes on the oil pressure switch.
The plug on mine also sits loose, but I don't think it's a problem. As long as it's doing it's job. If you don't see the oil light come on when you start the van then perhaps you do need a new connector.

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