Questions about 73 1280se 4.5 (108)

hi my car has vaccum door locks and i don't know if they work
how do you lock the door? i dont see any lock buttons

secondly there is a brown wire that comes out of the hareness that goes to the alternator.it looks like it goes to someplace near the front of the intake manifold? (you might have to take the air cleaner off to see it)can somebody post a picture of were it goes


thanks

[MikeTangas]

Your locks are vacuum operated. The simple act of locking the driver's door will lock the other doors, as well as the trunk and the fuel door.

As for the wire you ask about. I assume you mean the one pictured below that comes off the alternater harness and crosses the alternater.



That wire makes it's way along the front of the valve cover and up the front of the intake to plug in at the brass temp seansor pictured below. That sensor is the 212*f thermo switch for the aux fan.



Hope this helps.

yep thats it thank you very much!
the top half of my sensor is busted off. yours looks brandnew did it come with the car or where did you order it from?

ok where is a good (cheap) place to shop for interior items like

trim around shifter part#115 267 02 97

left front door uppermost wood piece

left front door wheatherseal (leaks like a sive and is probably the cause of me needing the wood)


oh any idea how to troubleshoot the vaccum locks?

[MikeTangas]

You can get the weather strip and the thermo switch right here through PartsShop or FastLane. The wood pieces and some of the other trim items are going to have to be hunted down at a breaker yard. The 108's are getting a bit harder to shop for now a days. Try doing a serach, there have been a number of parts dealers posted before.

How to troubleshoot vacuum locks. Wow, I'm not sure there is enough bandwidth to cover it all .

First, what do your locks do?

You will need a Mighty-Vac vacuum pump, an additional vacuum gauge is nice to have too. You'll use the vacuum pump to test individual parts of the system.

Get in the car, start the engine have the driver's door closed. With the enigine running lock the driver's door. All doors should lockl, now unlock the door and all should unlock. Leave the engine run for a minute or two, shut the engine off and repeat the above. How many times can you lock/unlock - should be about 6. If nothing happens while engine running then you have a major vacuum leak.

Coming off the intake is a yellow vacuum line, it goes through a blue/black check valve. You can test the check valve with the mighty-vac. From the check valve the yellow line heads up by the brake booster where it splits at a three way splitter. One leg goes into the left fender to the vacuum resevoir the other leg goes into the firewall - it eventually comes out and goes into the driver's door and to the master valve. The master valve splits the vacuum to direct the other doors to lock/unlock.

To check the condition of the door lock actuators you will have to carefully remove the inner door panels. You will then be able to access the actuators, but using the might-vac you can try to isolate the problem side at the master valve. You will probably have to replace/rebuild the actuators as the upper diaphrams probably have deteriorated. You will also want to replace all the connectors from the hard line to the diaphrams.

Tracing out vacuum leaks is a very time consuming process. It takes patience and persistance, but in the end it is nice to have a functioning central lock system. Also, a major vacuum leak, such as one would have if the vacuum line isn't connected to the intake can also affect the engine performance.

Would it ba a bad thing to just plug the vac line at the intake point? My car has a performance problem at high speeds and my locks don't work. I was just wondering if this might be part of the problem.

Thanks
Derrick

ok i got in the car started it closed the door and pushed the lock button down the passenger side tries to lock but doesn't have quite the vaccum to do so the rear doors don't try to lock but i tried locking them manualy and the locks are a little stif so tonite i will
take the trim off and grease the lock and get them working freely
what is the next step of troubleshooting the vaccum locks?

oh and where do i buy a new connector for the brown wire it has a special plug on the end to plug in to the aux fan switch switch
and mine broke off

[MikeTangas]

I don't know if the connector is still available, look through PartsShop and FastLane they might have it. Might also try the dealer.

Now for the locks. The passenger front tries to lock but wont go. Sounds to me like the upper diaphram for that door is shot - probably has a hole worn in it from the passenger window making contact with the actuator. The rear doors probably aren't going to lock, or even try to lock, until the front passenger lock is vacuum tight. There really isn't anything you can grease to free up the rear locks, the only "moving" part to the system besides the actuator is a small, spring loaded link that allows the locks to be operated no matter what position the actuator is in.

If you find the front passneger upper diaphram in the condidtion I described, you will most likely want to replace/repair both of the rears too. When I did mine it was suggested I do al, I only did the two that were bad and 6 months later the locks stopped working. Had to go through the entire troubleshooting sequence to find the one door I didn't do was the problem.

The diaphrams for the actuators, while on the inside of the door, are still external and exposed to the weather and elements. The upper diaphrams tend to wear out first as a result. Even the slightest pin hole leak will bleed off the vacuum quickly. You can tee a vacuum gauge in the line and run the engine to build vacuum, shut down and time how long vacuum remains. If the system is tight it should hold all night without problem. More than likely you'll see vacuum fall off to zero in minutes if not seconds if tested today.

While doing your trouble shooting, be sure to disconnect the leg going to the resevoir and be sure to plug that line. removing the resevoir from the equation will allow even the smallest of leaks to be easily observed.

There are 3 or 4 (can't recall off the top of my head) connectors to the master valve. Be sure to replace all to eleminate them from the situation. Rarely do the master valves go bad, but they can.

For the straight connector, simply use apprpriate size vacuum line from the local Pep Boy's/AutoZone and use about 2 inches per onnection.

ok i will take apart the passenger side door tonite
did you ever think of this

if you spray a little carb cleaner near the suspected leak the engine should rev up a little

ok i ripped the passenger side door apart and started the engine and tried locking and unlocking it when i lock or unlock it i hear a whoosh comming from the drivers side master valve? i think its the rubber that conects the vac hoses to the master valve
were can i get repacment hose for that?

[cth350]

Make a visit to pep boys. Here's your shopping list...

- They'll have a half dozen sizes of vacuum line. All the rubber is replacable. You need two sizes of it. One for the pieces in the door, and one for the rubber to the distributor. About 2 feet of each will last you a lifetime.

- Pick up a hand held vacuum pump if you didn't get one already.

- An assortment pack of vacuum caps. Little rubber caps in a handful of colors & sizes to close off vacuum connections temporarily.

- Get a 5 pack of the blue bullet connectors. It's the right size for that temprature sensor. It's ugly, but for now it works just fine. The correct connectors are still available from anybody that can order benz parts directly.

- A pair of fuel line cut-offs. They are funny little C-clamps that will crimp the fuel line. They come in a handy two-pack.

- A fuel pressure guage that will read 32psi. It needs to be plumbed for 5/16" fuel line.

- If you fuel line rail hose is ugly or leaking, get 2 feet of fuel injection grade hose. It's about 4 times more expensive, but it's important to get the right stuff. Ideally, you want the euro hose with the braid on the outside, but that can wait. A leaky fuel hose under the hood can't.

The other thing you need is the EFI diagnostics info from the the 3.5/4.5 engine manual. THAT you won't get at pep boys, but if you email me directly and can handle a 2mb email attachment, I'll mail you a copy. It's the usual welcome-pack I send all the poor souls with a 4.5.

Your next course of action is to split your problem space in two. Which do you want to tackle first, the doors or the drivability? If you want to tackle the engine, cap off the vacuum line that runs to the body.

The D-jet system is very sensitive to vacuum. Most likely the vacuum line from the manifold to the manifold pressure sensor on the bulk head is shot. Replace it on general principles. It's 5/16". There is post someplace in the archives about reading the vacuum level at this sensor. You'll have to look it up, I don't remember the magic numbers involved.

-CTH

i already have the fuel line cut offs
what are the two sizes of the vaccum line?
my fuel system/rail is fine looks it brand new and dosent leak (previos owner took care of it)
i email you about the manual
plus i think i got drivability (i drove it home after i bought it
and i have install some new subframe bushings fixed the power steering fixed the trans cooler leak changed the oil and spark plugs and all that what else should i do?

oh where can i buy a door check/stop (for less than the $50 fastlane wants)

[MikeTangas]

It might be 17 or 17.5 inches HG, but will probably require adjusting the CO mix at ECU, not adviseable without an exhaust analyzer. Stevebfl quoted the optimal number when I was dealing with my manifold sensor, and yes I used 5/16 fuel hose but you will need a small hose clamp for the manifold end.

Also, that whoosh you hear from the master valve when you operate the locks sounds normal. Mine makes the same sound. Took a while to locate the source at the valve, but it is coming from the forward end of the valve. There is a cotton fiber filter on that end, and if you plug it with your finger, the noise will stop but the system won't work very well.

How did the passenger side upper diaphram look?

I don't think you'll find much cheaper for new parts than FastLane/PartsShop. Used parts are a whole nother story.

where should i go for a used door stop/check?
i did'nt get a good look a the diafram becuase by the time i got all the trim off it was dark i'll look tomorrow morning

what is the othe size of vac line mentioned by ch350

[MikeTangas]

I don't recall the size. I took a connector with me and bought some that was a shade smaller in ID than the connector to compensate for stretch and age. A tight fit on the vacuum hard lines and actuators, but a tight seal.

ok i pick up a vaccum pump for $25 with all the diff. adapter and juck
included i tested the hose from the tee under the hood to the driver side door from there i tried to test the black and white lines from the drivers door to the passenger door (i unpluged the lines off both sides and i pluged the lines and the pass. door but i cant build up any vaccum i think the black and white line must tee off to the rear doors somwhere. can you tell me where and maybe a pic. or two

thanks
scott