Hi folks,
My vacuum pump located under the rear seat bench for soft close, central locking etc, has given up on my 1997 S420. I believe this is due to the motor burning out from running for long periods of time, trying to draw vacuum with leaks present.
I have bought a new vacuum pump suitable for my vehicle but would like to test each line and fix any leaks before installing the new pump.
To test for vacuum pressure and leaks I have bought a kit from good ol' eBay as pictured. :wink
My question is, does anyone know what pressure (using the units on the display gauge) the lines should be able to hold and for how long roughly?
Any advice on testing or replacing leaking items from anyone who has done this job before would be much appreciated! [emoji106]
TIA
Vacuum Tester 1 by
yojayLDN, on Flickr
Vacuum Tester 2 by
yojayLDN, on Flickr
Hi folks,
My vacuum pump located under the rear seat bench for soft close, central locking etc, has given up on my 1997 S420. I believe this is due to the motor burning out from running for long periods of time, trying to draw vacuum with leaks present.
I have bought a new vacuum pump suitable for my vehicle but would like to test each line and fix any leaks before installing the new pump.
To test for vacuum pressure and leaks I have bought a kit from good ol' eBay as pictured. :wink
My question is, does anyone know what pressure (using the units on the display gauge) the lines should be able to hold and for how long roughly?
Any advice on testing or replacing leaking items from anyone who has done this job before would be much appreciated! [emoji106]
TIA
Vacuum Tester 1 by
yojayLDN, on Flickr
Vacuum Tester 2 by
yojayLDN, on Flickr
Hi folks,
My vacuum pump located under the rear seat bench for soft close, central locking etc, has given up on my 1997 S420. I believe this is due to the motor burning out from running for long periods of time, trying to draw vacuum with leaks present.
I have bought a new vacuum pump suitable for my vehicle but would like to test each line and fix any leaks before installing the new pump.
To test for vacuum pressure and leaks I have bought a kit from good ol' eBay as pictured. :wink
My question is, does anyone know what pressure (using the units on the display gauge) the lines should be able to hold and for how long roughly?
Any advice on testing or replacing leaking items from anyone who has done this job before would be much appreciated! [emoji106]
TIA
Vacuum Tester 1 by
yojayLDN, on Flickr
Vacuum Tester 2 by
yojayLDN, on Flickr
I found the specified values once, but don't remember where. Basically, pull whatever vacuum you can, and watch for fast leaks. Most will be quite fast, or you won't be able to pull a vacuum at all. Fix those first. Eventually, you will get to a point where most things will hold a vacuum for a period of time. Those are harder to trace. Use an automotive stethoscope to find them. Or, if you have access to a smoke generator, use that. Once you get to a point where you lose 5 lbs or less in a minute, call it good. I found the factory values unobtainable, whatever they were.
However, you also need pressure. The door lock actuators many times hold vacuum, but leak like a sieve under pressure. There is an easy permanent fix for them, once you get them out, using tiewraps. Do a search here for it. Other items that use pressure are seat bladders, trunk lock, gas flap lock, and probably some others. Some people use a bicycle pump, but I use a hand pump that does both vacuum and pressure. If you can live without the seat bladders, assuming they leak, block the lines off either at the connection at the front of the seat, or at the pump. The controls valves can leak, or people can inadvertently turn them on.
Areas of leakage include the locks, seat bladders, and all of the lines connected to the distribution block in the passenger kick panel. Be sure to also check the vacuum line between the engine and the distribution block, as I found a big leak there. There is a dedicated vacuum only line between the PSE and the distribution block. If you can hold vacuum on that line you are miles ahead.
Once you find and correct leaks ignition off, turn on the ignition, engine off, and see if you can pull a vacuum while the AC vents open and close. I found my HVAC system had a leak at the actuator on the intake air box in the engine compartment.
Be aware that the pump under the back seat has nothing to do with soft close. That pump is in the trunk behind the carpet on the front left side. It's only function is soft close.
Do a search here on PSE, bladder leaks, etc. You will find a lot of info.
