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Vacuum Pump repair XD2S, "2nd Model"


LBC28730

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Brakes were really stiff as if booster wasn't functioning.
By the process recommended in the factory service manual, the first step was testing the vacuum pump and it failed, even after being topped off with oil.

Although I am not having much luck finding exactly the proper parts by Peugeot reference, I have come across a diaphragm that looks like it would be perfect. 

This diaphragm is a "Febi 2442" and is typically listed for Mercedes of the same year range. 

Has anyone else had experience with rebuilding this?

I have also found some valves for the upper section (Febi 8491) and for not much money, I think I'll give those a try. 

Thanks for any input. 

295702135_423458576500257_6969476591363231684_n.jpg

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I was just going to suggest replacing with an electric vacuum pump - The mechanical once are really quite noisy and add to the diesel clatter a fair bit. 

I bought a Hella pump that I was going to try with my diesel, mostly as an NVH reduction measure just so the car isn't so loud, but also to hopefully simplify the underhood mess of hoses!

Feel free to document the install - I'd be curious what pump you get, how you wire it in, and where you put it.  :)

Rabin

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Aumtoni 20804130 Power Brake Booster Auxiliary Pump, Vacuum Pump Assembly Compatible with Chevrolet Camaro Volvo V40 Cadillac CTS Replace#31317530 009428081, Electric Vacuum Pump https://a.co/52pX8t7

 

I purchased one of these for not much reason other than it produced the proper amount of vacuum, had good reviews, was reasonably priced and had isolating mounting.

I'm already leaning towards a different direction primarily due to the lack of a good spot to mount this properly. 

The only clean/accessible spot I can see would be on what I assume is the plenum box at the firewall, but I feel that may magnify the vibrations of the pump and possibly produce harsh sounds in the passenger compartment. 

I'm looking at some other "universal" pumps that appear to be much easier to mount, albeit substantially more expensive. 

I also have a CS130 alternator on the way,  which I hope to fit later this week!

Edited by LBC28730
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15 hours ago, SRDT said:

Have you looked at alternators with a vacuum pump on the back?

I have not.  I had no idea such a thing existed!

I think at this point and since I already have parts coming,  I'll go with what's known to have general compatibility.

That's interesting though and I'm curious to look into it. 

From a reliability standpoint, I greatly prefer items with more modularity. I'm my experience things that combine multiple requirements can be a hassle down the road when one aspect fails and the entire unit has to be replaced. 

Still,  interesting subject to look in to,  thanks for the information!

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15 hours ago, SRDT said:

Have you looked at alternators with a vacuum pump on the back?

I have not.  I had no idea such a thing existed!

I think at this point and since I already have parts coming,  I'll go with what's known to have general compatibility.

That's interesting though and I'm curious to look into it. 

From a reliability standpoint, I greatly prefer items with more modularity. In my experience things that combine multiple requirements can be a hassle down the road when one aspect fails and the entire unit has to be replaced. 

Still,  interesting subject to look in to,  thanks for the information!

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15 hours ago, SRDT said:

Have you looked at alternators with a vacuum pump on the back?

Wow,  after just a little searching I've found a lot of information on these. 

Really neat how many vehicles use these ,  including diesel land cruisers. Parts and rebuild ability of the vacuum pump by itself seem to be very accessible. 

Probably not going that route this time around but will certainly keep it in mind for other applications.

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I had no idea such things existed either!  I went with electric to hopefully reduce the noise/clatter a bit, but I like the simplicity of having it integrated into the alternator.  Would assume it’s pretty quiet as well.

 

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15 hours ago, SRDT said:

To drive the electric pump you may need a more powerfull alternator anyway.

That was my thought as well. 

In order to leave plenty of leeway for future additions, I went with 130a.

From what I see of the combination alternators the highest is 70a. That may be sufficient and there may even be stronger examples available, though.

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I was able to pretty easily fabricate some brackets to mount the vacuum pump behind the vacuum accumulator tank. 
I've got my vacuum switch and now it's just a matter of running all the lines and the wiring. 

If this works as I expect, I'll make a DIY post so others can do the same with pretty simple tools. 

20220803_033731.jpg

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  • 2 weeks later...

I could swear I found reference to using this particular pump in auxiliary pump applications but I can't seem to find it. 
Initial set up: Pump would run, pull a vacuum, but then stutter, as in cycling fast, when it appeared to be at full vacuum. 
After smoke testing the system for leaks, it appeared that the pump itself was leaking. 
I got a replacement pump and I am getting the same results. 
The pump itself has no sensor, it's just a pump. So, I think it has to be the vacuum switch that must be the issue. 
I have a new switch coming, if that doesn't work then I am going to just buy one of the complete kits from Summit or somewhere like that. 

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Oh yeah absolutely. I even considered adding to it but I don't think that will be necessary.

Currently everything fits behind the reservoir nice and tidy. 

The pump pulls a vacuum but when it goes to shut off it keeps short cycling.

I smoke and vacuum tested the system so there's definitely no leaks.

If it's not a faulty switch I guess it could be that the pump just isn't compatible with that switch.

Too bad they don't make an adjustable switch. 

I actually drove it like this and it works great but I'm sure the pump would burn out pretty quick.

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Good news!
I was running the vacuum pump with constant power. My thought was I would disconnect it when I reached my destination, for now, until I replaced the switch.
I forgot to disconnect it and a couple hours came back expecting it to still be short cycling and it wasn't. 
Turns out, it goes through a bit of that which seems unfavorable until it stops. 
Now it seems to shut down even faster, as I guess the action of the vacuum switch works better as it gets cycled more. 

I would call this install a complete success. 


Vent (climate control) selection is working whereas it was practically non existent before (vacuum actuation).
I plan on going through and taking photos and putting up part information, so that others can do it as well. 

 

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Awesome!  Does the vacuum switch you’re using have any specs?  One would hope it turns on at a lower vacuum setting than it turns off at so that it doesn’t cycle so much - but it sounds like it’s sorting itself out.  :)

Have you removed the mechanical pump and assorted hoses yet?  I’m curious how much quieter it is without the mechanical pump always running.

 

 

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Unfortunately I don't have very good documentation on either the switch or the pump itself. 
The pump is an OE replacement used by various newer vehicles like Volvos and Cadillacs. 
I DID remove everything but since it never was working, not really sure how much difference there is.
I'll have to take a recording once I get it all sorted out. 

It SEEMED to be sorting itself out but something has failed and it stopped working. I haven't had time to determine with it is yet. Could be anything from the relay to the switch or the pump itself. I'm going to try just switching out the relay today before I go anywhere and see if that makes a difference.
It occurs to me that it could be something as simple as a check valve going bad and allowing the pump to run constantly while I was away, and burn out, as I still had it wired to always hot as opposed to accessory on. 

Furthermore, I'm having lighting issues again. I went through the front grounds and cleaned them up and it made no difference. 
I am pretty sure my flasher relay has burnt up bc it was acting funny during using the hazard lights, I could hear it buzzing and not fully engaging/disengaging.

As I have NO turn signals or hazard lights at the moment, I'll address that asap.

Side note/not electrically related, I DEFINTELY have a sunroof leak after taking the previous silicone off, which I completely expected. 
I can't seem to find a good diagram of the drains in the FSM. 
Are these as typically placed, on the rears of the sunroof frame, running down the C pillars?
I have some ideas for the motor connection, maybe a shark bite type fixture. I also think I have a good aftermarket solution to make a good sunroof seal.
I'll document it, if it works out. 

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  • 1 month later...

I replaced the switch and the pump with the same ones. 
When it works, it works perfectly. 
I am now trying to sort out why it only seems to work intermittently. 
I feel it has to be something in the wiring so I am going to remove everything and reinstall, paying particular attention to splices and wire gauges. 

As I hadn't found a good switched source, I was finding initially that it worked great just wired directly to always hot power. 
When I wasn't driving, it wouldn't take much to create a vacuum and maintain it, as all the check valves seem to be fine. 

Then it seemed to operate intermittently, and and thought that it may be overworking the vacuum pump. 
I found that any time I could identify that it wasn't working, if I put power directly to the pump, it functioned, and the relay functioned as it should, as well. 

I am assuming there is something not completely connected in the wiring I created to make this work so hopefully after rewiring the whole thing, it will function properly and consistently. 

Once I get it sorted out I will post the whole process/diagrams. 
 

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The vacuum system should be a closed system in that it should be able to run, build vacuum, then shut off until something like brake booster or HVAC controls use it.  It’s not going to be completely sealed, but it shouldn’t run continuously, or even cycle very quickly.  
 

I’d put a vacuum gauge into one of the hoses so you can see how much vacuum is being built up, where does it shut off, and how fast it leaks down.

When I was using a vacuum pump I borrowed to test the filter head for leaks, it worked, but what I didn’t realize was that there was no set vacuum and it destroyed my freshly installed primer pump diaphragm during testing!  Expensive lesson learned, but just make sure you know what the details are.

If it’s not holding a vacuum at all, then you’ll need to find the leak - using a smoke machine might be the best way to figure that out…  (There are DIY versions to make smoke machines online)

Rabin

 

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As for the lights - There are grounding trees under the dash, in the rear quarter panels, and on the core support.

Also make sure the car has good chassis to engine block grounds, and battery to chassis, and battery to block grounds.

I take all all electrical connections apart, clean, tighten, and protect every one - Same for the grounding trees.

Rabin

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On 9/22/2022 at 9:40 AM, Bean said:

The vacuum system should be a closed system in that it should be able to run, build vacuum, then shut off until something like brake booster or HVAC controls use it.  It’s not going to be completely sealed, but it shouldn’t run continuously, or even cycle very quickly.  
 

I’d put a vacuum gauge into one of the hoses so you can see how much vacuum is being built up, where does it shut off, and how fast it leaks down.

When I was using a vacuum pump I borrowed to test the filter head for leaks, it worked, but what I didn’t realize was that there was no set vacuum and it destroyed my freshly installed primer pump diaphragm during testing!  Expensive lesson learned, but just make sure you know what the details are.

If it’s not holding a vacuum at all, then you’ll need to find the leak - using a smoke machine might be the best way to figure that out…  (There are DIY versions to make smoke machines online)

Rabin

 

Oh it doesn't run continuously, I may have said that wrong.
Although it is supposed to be connected to accessory power, I have had it running always hot through the vacuum sensor. In theory this shouldn't be a problem as long as the system is holding vacuum, and it has. I replaced all the vacuum lines and check valves just as a matter of course. 
The only issue I am having is the relay, that I have to knock on to make it work when it needs to. 
This may be remedied when it has a solid mount and the vibrations could make it actuate as it should, but I am looking to just use a better relay that functions properly. 

On 9/22/2022 at 9:46 AM, Bean said:

As for the lights - There are grounding trees under the dash, in the rear quarter panels, and on the core support.

Also make sure the car has good chassis to engine block grounds, and battery to chassis, and battery to block grounds.

I take all all electrical connections apart, clean, tighten, and protect every one - Same for the grounding trees.

Rabin

I did replace and upgrade chassis to engine, battery to chassis and battery to block. Under dash grounds will be next and I completely anticipate that remedying my remaining issues. 
I'm not sure, what is it that you refer to as "core support"?

As always, I greatly appreciate your input and insight. 

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15 hours ago, LBC28730 said:

I'm not sure, what is it that you refer to as "core support"?

I believe he is referring to the grounding trees near the headlights in the front. Those grounds up front always get very dirty and corroded. Make sure you clean those thoroughly. I am curious what your final setup is regarding the vacuum pump once you get it figured out. My 85 TD wagon needs a pump, and with the prices of the mechanical pumps, I'm considering an electric one.

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