ALDA Service -- 85 300SD -- Differant!? - PeachParts Mercedes-Benz Forum

71inka02 · #1 01-20-2009, 05:30 PM

OK -- taking tomorrow off...actually took today off too - but regardless....

Car has been feeling a bit sluggish, so for tomorrow, I'm planning a 'banjo bolt' clean on my 85 SD...along with some other maintenance stuff -- Just pulled car in the garage, and lifted the hood - thought I'd go ahead and get that part out of the way, in an effort to make the best use of my time!

The line from the 'banjo bolt' goes directly to the ALDA instead of a 'switch over valve' that I'm familiar with on my 83 300D --- The device pictured is supposed to be the 'switch over valve'....isn't it? So, can anyone tell what I've got....?

No abusive harrassment on my ignorance, please.

Thanks in advance for help, direction and information...

oldsinner111 · #2 01-20-2009, 05:38 PM

Alot of people bypass if not working.Its a safety device to prevent overfueling.But serveral people have told me to by pass.

Brian Carlton · #3 01-20-2009, 05:43 PM

Quote:

Originally Posted by 71inka02

The line from the 'banjo bolt' goes directly to the ALDA instead of a 'switch over valve' that I'm familiar with on my 83 300D --- The device pictured is supposed to be the 'switch over valve'....isn't it? So, can anyone tell what I've got....?

From the factory, the line from the banjo bolt goes to the port on the underside of the switchover valve. The line for the ALDA goes from the horizontal port at the top of the valve to the inlet at the ALDA.

The PO bypassed it because the valve was clogged with soot and he didn't want to bother to clean it. If you reconnect it, you'll also likely need to replace the sending unit for the valve. That device also becomes clogged over time and, although the plumbing looks correct, the valve won't operate when (if) the pressure reaches the setpoint..........15 psi.

winmutt · #4 01-20-2009, 05:47 PM

85 is a change over year. Any number of things could be making it run slow. Did you do filters first?

71inka02 · #5 01-20-2009, 05:48 PM

Quote:

Originally Posted by oldsinner111

Alot of people bypass if not working.Its a safety device to prevent overfueling.But serveral people have told me to by pass.

OK -- I understand that, and thank you...but the device on my firewall, next to the brake booster isn't the same device that's on my 83 300D - The device pictured, that's on my SD, actually appears to have an 'electrical' connection coming into the bottom....I've seen some under hood pictures of other SD's, and they've had the style switch over valve - like on my 300D.

If I'm not making myself clear - please don't hesitate to let me know...

winmutt · #6 01-20-2009, 05:51 PM

Your 83 has an electrical connection as well.

71inka02 · #7 01-20-2009, 05:55 PM

Quote:

Originally Posted by Brian Carlton

From the factory, the line from the banjo bolt goes to the port on the underside of the switchover valve. The line for the ALDA goes from the horizontal port at the top of the valve to the inlet at the ALDA.

The PO bypassed it because the valve was clogged with soot and he didn't want to bother to clean it. If you reconnect it, you'll also likely need to replace the sending unit for the valve. That device also becomes clogged over time and, although the plumbing looks correct, the valve won't operate when (if) the pressure reaches the setpoint..........15 psi.

Hey BC --- I'm sorry, but I'm way confused...! If you look at the picture I posted in the thread...why is this device so differant from the one on my 83? The underside of this has, what appears to be an electrical connection.

71inka02 · #8 01-20-2009, 05:57 PM

Quote:

Originally Posted by winmutt

Your 83 has an electrical connection as well.

winmutt - you very well may be correct ---- I've just never noticed it, and this device on my 85 looks totally differant -

And also - I have changed my fuel filters within the last 500 miles...thanks for the advice on that.

Brian Carlton · #9 01-20-2009, 06:08 PM

Quote:

Originally Posted by 71inka02

Hey BC --- I'm sorry, but I'm way confused...! If you look at the picture I posted in the thread...why is this device so differant from the one on my 83? The underside of this has, what appears to be an electrical connection.

They all have an electrical connection. Look behind the electrical connection for a nipple that protrudes downward from the main body of the valve.

71inka02 · #10 01-20-2009, 06:14 PM

Quote:

Originally Posted by Brian Carlton

They all have an electrical connection. Look behind the electrical connection for a nipple that protrudes downward from the main body of the valve.

OH -- OK...the old 'nipple behind the connection trick'....I'll do that, and thanks. so this being differant in appearance is maybe just a 'newer' version, I guess.

So - when I do the banjo bolt and tube cleaning tomorrow...should I reconnect things the proper way and see what happens?

You also mentioned I may still need a new valve - What is the 'legal or official' name of the valve - want to make certain I get the right thing.

Thanks again for the help....

winmutt · #11 01-20-2009, 06:52 PM

Overboost vent.

Brian Carlton · #12 01-20-2009, 06:53 PM

Quote:

Originally Posted by winmutt

Overboost vent.

I'm thinking of the switch in the manifold that closes at 15 psi. It can't be "overboost vent".............??