Eberspacher BN2 Rehab

[supertobs]

Hello,

I would use this thread to pos some questions on the BN2. I have a M060 factory installation on my 1971 1302. It did only produce some smoke and then the 8 A fuse was broken. Now there is no tic-tic by the fuel pump. I guess this is the current issue.

For Strategic spares and to investigate the entire BN2 mechanisms, I puchased an identical BN2 including most of the pipe ducts in good condition.

I have some questions and kindly ask for your help.All my questions are on the spare one I have. I want to get it to work and use it to heat my work area.

Control switch:
- I don't have the identical control switch. I can connect to 2.5 mm2 brown, 2.5 mm2 red and 0.5 mm2 grey.
Would two switches each on red and grey do the work? I would switch grey, then after 3-5 min cool down the red one?
- Anyone with a control switch with green knob for sale?

Air Intake:
- I have difficulties to pull the rubber seal to attach a new flexible pipe. I don't want to destroy it. Cn it be that the unit has to be split in half for it?

Fuel overflow:
- It looks like that I have a very small crew in the fuel line. Maybe someone has closed it? I guess I can simply test by blowing air through it?

Thanks a lot!

Tobias

[notchboy]

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[axeman569]

Glad I found this thread. I am getting ready to start on my Eberspacher.

[notchboy]

Busdaddy is the Shiz. A brother from another mother for sure. He is a Canadian example of information we are just learning and hes actually experienced.

Gasket material and all Russ Wolfe sent me is on its way to you guys!!
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[D/A/N]

I did some digging around and a week or so ago decided to PM busdaddy from the Bay Window forum as he seems to have a fair amount of experience with Eberspacher heaters. I asked him about diaphragms and he said the following (quoted with his permission)

I've separated diaphragms by sitting the rivet over a small diameter socket just big enough for the rivets head and punching it into the socket from the opposite side with a 1/8" dia flat ended punch, most of the time they leave enough meat on the end of the rivet to re use it. Some have also had good results with drilling and replacing it with a tiny bolt and nut, but if its the one that has to poke a valve pin it may throw off the calibration.
Before you try anything soak those diaphragms in something like ATF for a week, they often soften up and become usable as is.

It's very likely that I'll get this heater up and running with the good regulator diaphragms I already have and a rebuilt fuel pressure diaphragm, but I thought I'd put this out there in the event someone else wants to know how to rebuild these annoying diaphragms. .

[notchboy]

That was my attempt 8 years ago before I said screw it. Part of the reason I got into BN4's

Much easier to work on and have very satisfying results.

https://www.thesamba.com/vw/forum/viewtopic.php?p=8390611#8390611
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[raygreenwood]

Notchboy beat me to it ....with pictures.

Its not actually that compicated. Both of your pictures showed what the brass plate is doing. Its performing two functions....
1. Its acting as a simple washer. The brass pin coming through from the other side on a simpler diaphram...is deformed with q punch or press to clamp the washer.

2. Its a machinable surface.....acting as a seat for a valve or orifice.

Purely construction wise....you can clamp the diapgram back together with a simpler rivet and washer set....but that does not produce a sealing seat surface on the other side.

If we think ahout this....and how thick it needs to be.....we can make something that will work.

It,does not have to be a copy of the original. It just has to have the same dimensions and function.

Let me look at the pictures and I will make a suggestion in the am. Ray

[D/A/N]

Shit.....your pics of dead diaphragms don't bode well for us. You got at least one of them pretty cleanly apart. But then again, maybe Ray can see something about how to do this?

I found this guy who rebuilds early Type 1 and 2 fuel pumps and he seems to have found a way to grind off the swaged part and replace part of it with a screw and washer. That's probably easier though on the fuel pumps since on the other side of the nipple is just a big post that a spring centers on and not a thick stepped brass washer with a fiber one beneath. Scroll a bit down this page thought for the general idea about screws:

http://www.vintagewerks.com/Fuel%20Pumps/fp_restoration.html

[notchboy]

This first pic is what Im sending you. And as you can see from my pics of diaphragms past......

The material Im sending you seems thinner than the og stuff, so I doubled up on it when I made mine.

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[D/A/N]

Ok, cut it mostly in half before it flew out of my vise and all the way across the apartment. It turns out that the center pin is the much thicker bit underneath the nipple in the pics on the previous page.

The brass circle beneath the pin is stepped and the bottom rests on a fiber washer. Not sure if all of this complicates or simplifies the possibility of separation

[raygreenwood]

Sorry I forgot to post pics of the fpr diaphragm construction.

Since you have several.....section it wilh a cut off wheel straight across the center to see exactly,ehat is swaged by what. Ray

[D/A/N]

Still waiting on the diaphragm material but I've been thinking about this job enough that I figured I'd try to get at one of those diaphragm assemblies and see if I could separate it. The results are so poor, I'm almost embarrassed to share......at least I have 5 of these left!! Grinding away at one shoulder of the center nipple/pin did nothing so we ground at another shoulder. Nothing to even suggest that the nipple was related to anything at all. Got frustrated and ground at the next layer down and still nothing doing. I know this is shitty work so don't laugh. What ultra-obvious step did I miss?

[D/A/N]

[raygreenwood]

[D/A/N]

Okay, nevermind, a little more wiggling did the trick!!

Hey, Ray, if you're out there, what do you think about getting those diaphragms apart? I can't tell if that small nipple in the middle is the end of the rivet or if the slightly larger circle is also part of it.

[D/A/N]

It's a snow day in NYC, so I figured I'd poke around the heaters a bit and see what I could discover. From the used parts I picked up over the weekend, I at least have a working glow plug, 2 good fans, and the 2 good diaphragms for the regulator I mentioned the other day. I don't have the knowhow yet for testing the rest of the parts, but I feel pretty good that I didn't get hosed on the deal.

As for the heater I started this thread out with, the fan definitely works. Problem is, I can't get the heater halves to separate. It seems to be on account of this rubber boot that is very very firmly attached to the intake inside the heater b/c this is the sticking point when I try to pry the halves apart. It seems strange to me that this would be the hold up as the boot is clearly connected to something on the bottom half of the heater. All screws connecting the halves are out, fuel lines are off, etc. I don't want to pull a gorilla move and just yank this boot off and tear it. The other heaters I got just had a remnant of paper/aluminum hose in this location, not this fancy boot. Any tips?

[neena]

[D/A/N]

[notchboy]

The pump is super easy. Get the diaphragm separated from the body then just pin it out like a nut.

I also have plenty of gasket material Russ Wolfe sent me that I can pass some on to you. As well as copies of the manuals he scanned.



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[raygreenwood]

Show me pictures both sides of the diaphrams. I can tell you how they are put together and how they will come apart.

The rubber material you will need for fuel is either viton or another fluoroelastomer.
Buna-n....which is Nitryl....is not suitable.
Some purpose made diaphragm sheets are using either a nylon or polyester scrim cloth that is impregnated with a heat cured polyester resin. You see this reddish material in items like accelerator pump diaphragms etc.

The assembly method for most diaphragms is similar to what you see in a vacuum advance diaphram. Ray