Brian, Installed the kit today on 603 engine. Only problem was aligning bolt with nut in clamp as you described. Found ovalizing the proximal hole in clamp with rat tail file made it easy. Thanks again for offering this nice kit to us.

Sorry to revive an old thread, but could you confirm something for me?

I'm having trouble following this. What year/model is this for? (I have an 83 300D-T and 84 300D-T (both Calif.)
Does this mean that both coolant sensor and the piggyback valve are entirely unnecessary without the egr? I wish there was a nice picture like the one posted by Dave M. Has anyone done something this to their 83 or 84 300D-T, and would like to post pictures for the benefit of others?

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J. S. Park

'82 240D Manual 240D (sold)
'83 300D-T 230k (sold)
'84 300D-T 118k (sold)

That is correct. Just be careful that the piggyback valve is only for the EGR. On some engines, there were two valves, and one controlled the EGR and the other was transmission vacuum related. It all depends on which vehicle you have. "Most vehicles" use those piggyback valves simply to regulate EGR.

Just track the hoses and see if they end up at the EGR valve. If so, then the piggyback valve is not required.

The kits instlalled very smoothly, thanks to Brian Carlton's detailed instructions.

However, I went on to remove what I thought were unnecessary vacuum lines, and I have two questions about what is actually necessary and unnecessary:

1. On my 1983 300D-T, I removed all the lines from the egr, all the way upstream to the black plastic box on top of the valve cover (I found no arv vacuum line). so far so good. However, in my zeal, I removed the plastic box "switchover valve" and contents as well. Now I'm realizing that I went too far--that one of the functions of the box is to allow a "bleeding" of vacuum depending on accelerator travel, thus reducing vacuum to the transmission when the accelerator pedal is pressed. So, I should put it back. Can someone please confirm this for me?

2. On my 1984 300D-T California (the system is different on it; see attached diagram), I did something similar: removed all lines from the egr and arv, including the "vacuum converter" (#84) on the passenger side wall of the engine compartment, just back of the headlights, and going all the way to the vacuum junctions at the driver's side of the engine compartment. Because there is no plastic "switchover valve" on top of the valve cover for this year/Cali model, I was assuming that on this car, I did not mess up--that the transmission-related-accelerator-vacuum-reducing function is somewhere else, and not integrated in the parts that I removed. (The trans. certainly feels okay). Is this correct? Or, did I mess up this one also--could it be that the "control unit" (#80), using the data from the "rpm sensor" (#82), actually uses the "vacuum converter" (#84) to do just that, i.e., reduce vacuum to the trans depending on accelerator pressure? Please don't tell me that I just answered my own question!

Any light you can throw on these questions will be much appreciated.

Attached Thumbnails

 

__________________
J. S. Park

'82 240D Manual 240D (sold)
'83 300D-T 230k (sold)
'84 300D-T 118k (sold)

From the pic you posted... it appears I can remove the EGR valve, the vac line to 84 "Vac Converter"

What about this "Air Recirculating Valve" No 71 to "Switchover Valve" No 81?

Basically trying to get the last word on the '85 Fed/'85 Cali's...

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

It looks like maybe the entire vacuum converter (#84) can be removed. On my '85, this thing sits directly in front of the coolant fill tank.

Also, looking at the pdf for the EGR section, it appears that the entire EGR operation to control that single vacuum line to the EGR valve is snaked all over the place! valves here and there...temp switches, rod sensors, etc, etc..... I think if we got down to it, we could remove a LOT of the vacuum lines under the hood and maybe a box full of misc parts.

Chris
'85 300SD

Interesting to say the least! I recall somewhere that our vehicle also uses some of those bits to control the ol' 722 trans, that's why I've yet to install it.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Here's my overall conclusion to the whole question of what to remove to make life simpler under the hood:

1. A lot of vacuum stuff directly related to the egr and arv is all over the place; I've taken them all out and capped up the vacuum system as far upstream as possible.

2. Items eliminated include the black box on top of the valve cover (my '82 300T-D; my Cali '84 300D-T doesn't have this), and everything downstream of it.

3. It seems that on some models, this black box also contains valves connected to the accelerator linkage, and therefore controls transmission smoothing. Even on my '84 Cali which does not have the black box, a careful study of the vacuum diagrams (see posts above) leaves open the possibility that, black box or not, egr-related vacuum is related to transmission modulation.

4. However, as at least one or two others have posted above, getting rid of this junk and capping off the vacuum as upstream as possible lessens the likelihood of leaks in the system overall. The probable result (not 100% sure on my 84 Cali) is that the transmission modulation gets full vacuum, regardless of accelerator position. For me, this has resulted in a noticeable improvement in shifting. I guess the logical downside is that at high engine speed, when not as much vacuum is needed, the modulator gets full vacuum anyway, theoretically leading to unnecessary softness (?). But I have not noticed this problem.

So, this is my practical solution. To recap, I've taken out everything egr/arv related downstream of #c below. I've also capped off the accompanying black vacuum return lines.

a. main trunk (thick line) from vacuum pump to brake booster
b. one of two thinner lines branching off from this main trunk
c. point at which #2 branches off into about three or four different places, including egr, arv, trans mod., etc.

-------------------
p.s. I've also removed cruise control with its accompanying linkages, since I never use cruise control, and it doesn't work.

__________________
J. S. Park

'82 240D Manual 240D (sold)
'83 300D-T 230k (sold)
'84 300D-T 118k (sold)

I'm trying to absorb, and am comparing pics to '84 Fed vs '85 Fed. I barely recall my '84 Fed 300D.

Happen to have any pics of what ya did?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]