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Discussion Starter #1 (Edited)
I was checking the HVAC system today and it's not pulling any vacuum. Does anyone know where I can get a replacement?
 

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What type of ride? Year and Model, as the Diesel uses a Vacuum pump, and the gassers don't.
You can buy a generic Check Valve at a local parts store, and use it, your old one could be in the wrong position as it could be in circuit backwards.
Check valves will only allow air in one direction.
 

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Discussion Starter #3
It's a 1981 rabbit pickup diesel. Here's a picture of the brake check valve:
44178
 

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Well I will tell you that over 330K of driving a diesel it isn't the check valve that usually goes, as you have a diaphragm vacuum pump it is usually the diaphragm that is the issue, they make re-build kits to repair them. The first indication I usually got for a holed unit was that the vacuum assisted servos on the HVAC stop working. After repairing the thing I would also notice that my brakes functioned better....

 

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Discussion Starter #5 (Edited)
Hopefully, it's not that. I rebuilt the diaphragm vacuum pump a few years ago. Is there any way to check for sure short of uninstalling it and taking it apart? Also does everything else in the picture look correct?
 

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Yes it all appears to be correct, to check for vacuum cut but do not pull off the little hoses, and if there isn't a whole lots of suction going on when the engine is running the pump needs rebuilding. I can tell you that I usually had to rebuild them about every couple of years, as my car was a hardy daily work driven car.... VW later in the production run went with a Vane driven vacuum pump that was more robust...
 

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Discussion Starter #7
Ok I'll try that. maybe I should get the new kind of vacuum pump instead of rebuilding it.
 

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Used is going to be cheaper than new, and rebuilding one only take a few minutes and cost are very cheap.
 

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With the engine running you should be able to pull the hose off that little check valve you pictured and tell if you have a vacuum on it or not.
I would rebuild the pump as a vane pump is a lot more money and something that is hard to find. The pump rebuilds in short order and those parts are still very common. The valves inside the pump sometimes get plugged up with oil and gunk too making the stroke of the pump next to worthless.
 

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Discussion Starter #10
Well, I went ahead and got a vane pump. I didn't like the idea of having to rebuild a pump every couple of years.
However, I noticed that there's a hose coming from crankcase to the pump I currently have, but there's no place to put it on the vane pump. What should I do with it? Tie it into the brake booster hose?
 

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If that is the one that is off the plate to the side of the block? I would just cap it off at the source...DO NOT tie it in to the Brake line........AS that will have oil pressure that will blow oil in to the vacuum booster.... The blanking plate pictures is off a 80 Ish- 90 ish 1.8 EFI or CIS engine as that is where the mechanical fuel pump goes for Carbed Rides.

New:



Old new Side by side....


The hose isn't needed for the Vane type, and the plate on the block You can use a Rubber Cap with a hose clamp, but I would be replacing it soon with the proper plate as the oil pressure in the engine will blow a hole in the cap...

Plate numbers for the new picture.
9 Seal 028127311A
10 End cap 063 103 113
11 Spring Washer B8X15 N01224110
12 Socket head Bolt M8X18 N0147123

ETKA is a good source of info.

The only issues are that early models are usually a lot of blanks,,,but using the Europe or RHD pages and looking at the Caddy (VW Rabbit Pickup, or Golf )
has a lot of the missing pages. Just have to remember that the English is RHD vs LHD and a lot of the VW MK1 parts are used in the Cabriolet up to 93, but the big differences are in the body and interior as the Cabriolet was European Built and not Westy or American... as in 84 the lines merged from Rabbit to Golf.


I suppose that after thunking on it after posting you can carefully remove your plate, and use a piece of tin .020 at least trace the outline of the plate, drill Holes to accommodate the screws to blank out the hole for the hose and make a new seal out of paper seal material and Seal the hole....Better in the long run than a rubber cap... as it may blow off under the pressures in the engine.

Trace the outline of the plate cut two holes for the Screws,,,,,then place one seal on both sides of the Tin...One for the block and one for the cover. Or run to a wrecking yard and take a plate off the Rabbit, Cabriolet, or Golf as I think they are the same as the 1.5 but can't verify that.
 

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Discussion Starter #12
So, after doing some more investigation, the plate (#17 in the second picture) has a T shaped hose fitting. One hose goes to the valve cover and intake manifold. The other hose goes to the pump. Maybe I should just tie the second hose into the first one?
 

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2 things I do know, that the oil deflector was added to the later 1.6 diesels to prevent splash oil into the air filter plenum. On the older pumps I just had one hose to the brake booster, and the loser hose was attached to the bottom half of the pump, and I always thought that it was to help lubricate the bearing.... I don't think I would tie it to the valve cover you you may start burning more oil.... but it has been 20 years since I wrenched on my 81 diesel.......
 

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Nice find there on the old line connection kit. I have done that to my 1.6 after I replaced the diaphragm pump with a vane style.
 
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