I Can't Get The ALDA Off Of My 1980 W116 300SD With 617 Engine

[Squiggle Dog]

After doing some research on this forum, I have decided to remove my ALDA, boost overload switch, and plug the hole in the intake manifold where the banjo bolt used to be. My banjo bolt broke and so did the vacuum tube. I also had the boost overload switch disconnected anyway, and will need the switch and mounting bracket for it out of the way so there is room to properly mount the manual heater valve.

I have a thin 24mm wrench, which I placed on the nut directly under the ALDA. I put an adjustable wrench on the 27mm nut underneath. The 27mm nut on the injection side turned easily and made the ALDA spin with it. It turned out several threads, but it seems like it will not pull out; it just spins.

I know the nut on the injection pump side isn't supposed to come out anyway, but I have been trying for hours to turn the wrench on the 24mm nut on the ALDA side counterclockwise, while simultaneously turning the 27mm nut on the injection pump side clockwise. They will not move at all in relation to each other.

I jammed the adjustable wrench against the metal stop next to the plastic valve next to it (which I had to move out of the way), and used all my strength to try to turn the 24mm wrench counterclockwise. All that happened is I rounded off the nut on the ALDA side. I even used Caterpillar penetrating oil to see if that would help.

There just seems to be no way to get the ALDA loose from the injection pump coupling. I even tried hitting the ALDA with a hammer, but there is really not enough room because there is always some sort of hose, tube, or pipe in the way. I tried using a large C-clamp to hold the ALDA, but it was awkward and there was not enough room to work.

This is really frustrating. I'm about ready to take a rotary tool and cut off the ALDA so I can get a socket or something over the nut on the ALDA side.

If I ever do get that ALDA off, I want to use a cap of some kind to cover the hole.

[whunter]

ALDA issue threads

ALDA issue threads


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[Squiggle Dog]

Thanks for the links. This is probably more of a rant than anything since the nut on the ALDA is rounded off. I think that at this point I'm going to have to take the top off of the ALDA, and cut the lower half off around the nut so that I can get a socket and breaker bar onto it. Though, I think that first I will try the method in one of the links where a screwdriver was wedged into the ALDA and smacked with a hammer.

I must have damaged the ALDA somehow, because even though everything is put back together correctly, the car now feels sluggish.

[Squiggle Dog]

I tried the screwdriver in the ALDA trick, and all it did was start to bend the screwdriver. I am concerned that my ALDA may never come off without drastic measures and possibly damaging the injection pump, so I decided take apart the ALDA to remove the parts inside.

The screws holding the ALDA halves together were stuck as well. They were super tight. I thought I was going to break the bit and wrench I was using, but three of them finally came loose. One of them did not, and I could tell it would never come loose without ruining the screw head, so I used a rotary tool and cut off the corner of the ALDA top. I was then able to pry off the top.


I removed the disk that is in the ALDA, which should have the same effect as removing the ALDA, only there will be no hole to plug. The rubber seal ring on the ALDA top had shrunken anyway, so it wasn't sealing well.


I was actually able to adhere the corner back onto the ALDA with aluminum epoxy. I coated the sealing face of the ALDA lid with Reinzosil and put the top back on without the internal parts. I made sure to coat the screws with anti-seize paste.

I removed the overload protection switch from the firewall since it is no longer useful, and I need the room for when I properly install the manual heat valve (it's supposed to rest against the firewall, but I have it spaced out a bit for now).


I removed my broken and repaired vacuum line as well.


I wasn't able to find a bolt of the correct thread pitch to plug the hole in the intake manifold, so I made a temporary plug so I could get to the hardware store.

[Squiggle Dog]

At the hardware store I discovered that the correct bolt size is M8 with a 1.0 fine thread pitch. I picked out bolts with lengths closest to the threaded portion of the banjo bolts. I made sure to use aluminum sealing washers.


The ALDA is still on my vehicle, but the internal parts are gone, making it work the same as if it was not there. I don't know if I'll ever be able to get it off without taking drastic measures and possibly damaging the injection pump. At least I don't have to plug the hole that would have been there.


And here is the new bolt in place of the banjo fitting. I am glad to have less parts to worry about, and no vacuum line to get plugged up and make the ALDA restrict the acceleration. My car feels quite lively now. Hardly any throttle is needed to get it rolling.

[dibsen]

How did you separate the 2 halves of the ALDA? What did you use?

I have a ratcheting wrench with a bit adapter and I couldn't fit that in the tight space. I am thinking vise grips with a philips bit or something.

Why did they put the head of the screws on the bottom? Guess they didn't want anyone messing with it

[whunter]

Originally Posted by dibsen

How did you separate the 2 halves of the ALDA? What did you use?

I have a ratcheting wrench with a bit adapter and I couldn't fit that in the tight space. I am thinking vise grips with a philips bit or something.

Why did they put the head of the screws on the bottom? Guess they didn't want anyone messing with it

Remove the ALDA for easy access.

I can't get my alda off! How?!

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[Squiggle Dog]

I used a pair of angled screwdrivers (each one had the tip in a different position relative to the handle), as well as a bit held by a wrench.