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  #1  
Old 10-26-2016, 08:17 AM
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W115 300d vacuum help

Hello,

I have a problem in my 1975 W115 300d and I couldn't find any schematics of the vacuum system of my car in the internet.
It was a manual gearbox and I installed the automatic gearbox, and also the Injection pump for the automatic transmission cars.

The problem is my auto gear box is always at 1st gear, and VCV valve on the injection pump is working ok since the pump was all tested on the bench.
I tested everything and there is no leaks.

Any one can help me trying to figure out what could be the problem, if is vacuum related or anything else?

PS: Just wondering how many vacuum the vacuum pump needs to produce?

Thanks

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  #2  
Old 10-26-2016, 11:25 AM
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If the car is stuck in 1st gear, the vacuum pump is the least of your worries, you likely have transmission issues or a misadjusted linkage somewhere.

Vacuum pumps tend to produce somewhere between 20-22mm/HG when working properly.
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  #3  
Old 10-27-2016, 05:56 AM
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Originally Posted by Diseasel300 View Post
If the car is stuck in 1st gear, the vacuum pump is the least of your worries, you likely have transmission issues or a misadjusted linkage somewhere.

Vacuum pumps tend to produce somewhere between 20-22mm/HG when working properly.
Since I'm adapting the auto transmission to a manual car, maybe I'm missing some thing!
You're mentioning linkage, does the W115 auto cars had also the linkages like the w123 auto cars?

thanks
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  #4  
Old 10-27-2016, 09:22 AM
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I'm not familiar enough with the W115 era to know if they have a bowden cable on them or not, but you do have a linkage that comes into the cab for you to select the gear. Make sure it's actually going into "D" and not some other gear.
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  #5  
Old 10-28-2016, 08:18 AM
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Originally Posted by Diseasel300 View Post
I'm not familiar enough with the W115 era to know if they have a bowden cable on them or not, but you do have a linkage that comes into the cab for you to select the gear. Make sure it's actually going into "D" and not some other gear.
Hi,

That is checked and is definitely in "D"

Any instructions on how to check/tune the transmission modulator valve?

Thanks
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  #6  
Old 10-28-2016, 10:15 AM
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I'd go back to the throttle linkage - the manual version is going to be different than the automatic version across the top of the engine - and I think the W115 version is different than the W123 version. Have a look in either the W123 or the W115 FSM to see how they all get linked together.
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

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  #7  
Old 10-28-2016, 10:18 AM
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Actually thinking about it - you're doing something a little bit more advanced than just converting a diesel W115 to have an automatic gearbox. If you're using vacuum then you're upgrading it to a more modern W123 version. If I remember correctly the W115 versions didn't use vacuum for automatic transmission shifting on the diesel models.

You therefore need to combine the two systems => combine W123 with W115
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #8  
Old 10-28-2016, 11:01 AM
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Even with the vacuum completely disconnected, you shouldn't be stuck in 1st gear.
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  #9  
Old 10-28-2016, 12:14 PM
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Quote:
Originally Posted by Diseasel300 View Post
Even with the vacuum completely disconnected, you shouldn't be stuck in 1st gear.
I had a car of this series. It was very slow to shift out of first. This was a gas engine.

In this case it was the vacuum modulator.

And if the transmission you have has a VM they are easy to check for correct function. Just pull the vac line off of it. If there is any transmission fluid dripping from the hose or the nipple then it is bad.

Can you shift the car in manual mode? That is, can you start out in first and manually shift your way up to drive?
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  #10  
Old 10-28-2016, 01:07 PM
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Originally Posted by Idle View Post
I had a car of this series. It was very slow to shift out of first. This was a gas engine.

In this case it was the vacuum modulator.

And if the transmission you have has a VM they are easy to check for correct function. Just pull the vac line off of it. If there is any transmission fluid dripping from the hose or the nipple then it is bad.

Can you shift the car in manual mode? That is, can you start out in first and manually shift your way up to drive?
Actually I can't shift manually!
It don't do anything.

I have to check the modulator on the gear box

The gear box was from a 1977 w123 240d and the injection pump came from a W123 300d and I have to check again if it has the connections for the linkages since I don't have 100% sure (it rested for 1 year trying to get the pump, and got one from the US!)
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  #11  
Old 10-28-2016, 01:35 PM
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Originally Posted by gaiex View Post
...
The gear box was from a 1977 w123 240d ...
I would expect that to be a non vacuum version 722.117

Does it have a linkage at the front of the transmission on the right hand side? If so this is a solid linkage that connects to the accelerator linkage. For these types of transmission the place for the vacuum dashpot is actually a screw to adjust the modulating pressure. So no vacuum needed (if it is the type I think it should be).
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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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  #12  
Old 10-29-2016, 02:57 PM
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Quote:
Originally Posted by Stretch View Post
I would expect that to be a non vacuum version 722.117

Does it have a linkage at the front of the transmission on the right hand side? If so this is a solid linkage that connects to the accelerator linkage. For these types of transmission the place for the vacuum dashpot is actually a screw to adjust the modulating pressure. So no vacuum needed (if it is the type I think it should be).
I will check the car Monday to see if it has any linkage connection that I could have missed, but I remember that it has a modulator, that's why we connected the vacuum hose.

Maybe the transmission wasn't from a 77 but from a newer car!
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  #13  
Old 11-04-2016, 08:20 AM
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Hi guys,

I was doing some tests and looking on the transmission, it looks like it doesn't have any linkages that I can see and while at idle the vacuum is like at the pic bellow, when I accelerate it goes to 0.

I also turned 360 counter clockwise the modulator adjuster on the gear box and no difference, at least with the car on the hoist, I didn't test drove the car yet.
How many turns can we do on the modulator adjuster?






Last edited by gaiex; 11-04-2016 at 04:44 PM.
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  #14  
Old 11-05-2016, 11:52 AM
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Profile

Could you complete your profile, or add a location ?
I always like to see where people are that I am helping.
Having said that, I can get a photo of my 300D automatic linkage.
I have a couple of these cars.

By the way. The w115 never came in a 300d, only 300D
The 300 (d) was built 1957-62
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  #15  
Old 11-05-2016, 12:11 PM
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Yeah well the OM617 was added to the W115 range at the end. It was officially a 240D 3.0...

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!
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