Eberspacher BN2 Rehab

[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?

[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]

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

[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]

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

[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

[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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[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]

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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[axeman569]

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

[notchboy]

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[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