Just took about a fifteen mile jaunt with the plain jane vacuum actuator cruise unit such as JC Whitney sells for about $100. Works just like it has on everything else I've ever put one on.
It's not going to pin the needle to a MPH like the stock system does, but the price is right and it's certainly good enough, no surges, no more than 2-3 MPH variance around here. Seemed to have no problem pulling the throttle.


My vacuum setup is a little more robust than normal 300D's, and I need to do some testing and will take some photos tomorrow.

But it DOES work!

I think I'm going to go watch a movie to reward myself..



/edit/ And I'm a little more sure than I was that I can make use of the stock cruise control stalk.. That will be just perfect if so..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Is that the model with the magnets on the driveshaft to monitor speed. I was thinking about putting one on my 409d. I'd like to see the pictures.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

It is that same unit Kerry, purple module, modest little wireing harness, pickup and magnet on the driveshaft. I will have some photos tomorrow, but I'm not done tweaking the actuator position and such yet. I think I'm going to give it a little more mechanical leverage on the throttle lincage, it's travel limited as it is now and cannot reach WOT. Not a huge deal, but. It holds speed pretty well thus far, about what I usually get from them.
Workes better than on the non turbo VW's due to the 300D actually being able to get out of it's own way..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Did you wire it to where it uses the Benz's cruise buttons, or are you useing the switches that came with the unit ?

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"If anyone knows other lessons I need to learn, please tell me. I'm tired of learning them the hard way".
by JerryBro

The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels

I have not gotten to trying to use the Benz cruise switch yet, but I think it can be done.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Wolf, what happened with your cruise amp re-solders? I remember in your other thread you were able to get them working.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

All but one of them are still working, and I'm yet to get anymore to play with. The problem I was finally left with was that I could induce a surge with any amp by swaying the car back and forth, or hitting a bad section of road. I got tired of troubleshooting and needed a functioning system, no questions asked. I kept intending to pull the cluster and lube the speedo head as it almost looks like the needle fluctuates a small bit over rough roads and sways with the inertia of the car and brings on the surge. I'll get back to playing with it eventually, and still plan to solder up some more amps. It's just so finicky and expensive, if I can do it cleanly(stock cruise stalk) I think I'll be staying with the aftermarket setup personaly.

I have not given up on the OEM setup, there fun to play with and work amazingly well when there functioning correctly, if one has the money to toss at it I highly recomend using them, but for the money and time the aftermarket setup is a much more sure thing.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Did your kit have any adapters for a manual transmission? Clutch cut out switch?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

There is usualy a switch you mount on the clutch pedel that uses a small chain you affix somewhere to pull a lever on the switch when you push in the clutch. And the usual brake light switch hookup where you just tap into the hot and cold side of the switch.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

I looked into a Rostra electronic servo unit a while back for about $225. I have also seen the servo units in JCWhitney too. Any experience with them? How easy is the install of the vacuum unit? It is nice to know a simple $100 unit will work. I have a bad knee and can't drive long distances without cruise so I don't take the MB as much as I would like too. RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

I've never seen an aftermarket electric servo unit, I know they exist though, just no experence with them. I'd be curious to see one though.

The vacuum servo was not all that hard to install. I clamped the sheathing of the cable to the old electric servo actually, the little bell crank on the OEM servo pulls at is a good place to attach the cable as it seems to have some mechanical leverage designed into it. I have toyed with the idea of extending the lever a little to give the vac servo a little more leverage as well. I had previously installed a round vacuum sphere from a chevy truck underhood, and I think it's probibly going to be needed using the vac servo. I also have my door locks run off an SDL's electric pump so that's one less thing for my vacuum system to have to support. I have much experimenting to do, and photo takeing, but I got around to none of it today. Tomorrow I hope.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Does your vacuum pump have a problem?
At cruise speeds, the engine should be doing 2-3K revs and the vacuum pump should be able to handle any load you put on it. Remember, that not many items use vacuum continuously, not door locks, brake booster or climate control, not even (I suspect) aftermarket CC servos.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.

I don't believe the pump has a problem, last I checked it pulled 20 inches or so pretty quickly, but I have a slow leak in the ACC for one thing. It was part of my trying to get a decent shift out of the thing. Part of my further experimenting is going to be removing it and seeing what happens. As far as that vac servo for the cruise, I have the feeling it takes a heck of a lot of vacuum to operate it, and if it works as I'm guessing it need a really steady source, as it just vents vacuum when it needs to decelerate. We'll see.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Which cruise unit are you using, the Audiovox one? Keep posting details of what you've done because I'll probably fix my cruise the same way soon and any problems that you encounter along the way could save me some time.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

I want to keep this thread alive a little bit longer!

Anyone have any idea if these things could be plugged into the transducer that the original cruise control used to monitor the speed? For mine it's on the back of the speedometer but I think it's somewhere along the cable coming from the transmission on earlier cars. Seems like that would be easier than fixing a new sensor on the driveshaft plus it's one less part to buy.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k