well as started in another post here in the forum i have a restoration of our fuel level senders going on .

luckily on previous restorations the fuel level resistor - wiper has been in relatively good condition enabling me to just clean the rust off and resurface the resistance winding for a good operational result.

but i did acquire another unit via "frank the rat " from thom Hellbreakers ..(sp?) in holland , who offers  a lot of recycled parts .

this one was well and truly cactus . with just the mechanical parts seeming to be ...erm ...existing?



so on disassembly found the resistive windings actually corroded through in quite a few places .....bugga !!!!




ill step ahead here with the pic , having found a what seems to me a suitable resistance wire to replicate the winding , after a couple of attempts to buy the correct thing .
 it seems that 50 ohms per meter will suffice for the job , with just some simple calculations , available from a local (aussie) supplier ....



here it is , with now a sample of the nichrome wire i found that should be suitable across the windings . notice the frayed windings of the base backing  ...


just using my favorite nylon brush on the drill i was able to clean up the assembly , reasonably well .... with a rotary tool used to polish it up a bit more , but still leaving some traces of corrosion in there .






just arrived today i purchased a litre of "kbs Rust Blast ", which is supposed to cut the rust , etch the base material and leave a coating of zinc phosphate ...ready for electroplating some zinc back onto the surfaces . Well thats the plan going forward , possibly with a little nickle as well . unsure if i need to apply chromate after the zinc plating ...?



here's the result of the rust blaster ...looks as though it has done what it says ...win !!





so now considering the way to wind the coil across the base , keeping in mind the length needed to cover the wiper sweep ... i think ill have to find a .75 or .50 mm pitch bolt to lay down the windings with more or less equal turns


hopefully i have some bees wax on the way , as the windings are retained with something waxy ....and also to cover the electrical connections whilst in the electrolysis bath whilst plating happens ..
the journey continues

what do you think ...so far ?

Bloody Marvellous, :1B:cant wait for next bit.

Nice one Charlie.

Nice work.  Quite the task you've taken on.  As for winding the wire resistor unit, maybe a lathe with an adapter on the carriage that can guide the wire and maintain tension, and power the carriage with the lead screw for the given pitch.  Experiment with disposable wire first (like 30GA wire wrap wire).

Thanks guys

Yes Rob thats the intertion to try with something relativly cheap as the nichrome wire is about $2 per metre  (34ga) i have in mind a small hand winder worth about $50  which looks to have a suitable gearset , ill gave to make a few arms for auto tensioning as the nichrome wants to run away from the bobin pretty quickly

Anyhow not impossible to do  

But i have a trip to plan end of the month so everything will be on hiatus till after then  tyres to buy etc 

Cheers

I have a question for Charlie and Rob. For Bricks not running a fuel gauge would it not be possible to do away with the windings and just have on and off for the low level light. I think that Bruce's K75s has stuffed windings but his low level light still functions due to dual wiper arms.
Regards Martin.

Yes @Martin, that should be possible.  The wire-wound resistor plate is a separate circuit card from the one that detects low fuel level.  There are also two wiper arms - one for the resistor and one for the low fuel.  So, just remove the resistor circuit card and leave the low fuel circuit card in place and you have achieved your goal.  Make sure the upper wiper arm does not interfere with the operation of the sender.

Thanks Rob you have confirmed my thinking. Most of the Bricks in the K Kronie Kluster don't have fuel gauges so repairs would be simplified. Maybe you could set up a organ donor scheme with non gauge owners donating their circuit cards.
Regards Martin.

as Rob says , no real issue 
but i have found many are unreliable 

but that could be because i have only ever been inside tanks that have extraordinarily high kilometers

anyhow this is what came off this sender 

it appears to be just single sided phenolic circuit board , etched for the desired operation , then tinned .

this one seems to have bent with the corrosion forming behind the "board " on the metal , evidence is seen with remains of rusty crap impregnated into the surface.

in any case it must have been fiddled with during its service life , with deep scores of the wiper into the surface , where a light sweep should have been calibrated (or is that just a hamfisted fix for someone that relies on the 4 litre lamp ?)

 



its pretty much just held in place by a plasic rivet of sorts to the body of the mechanism

i guess ill have to cutout, etch and Tin a replacement to suit

Charlie I've never seen one like that. Do you know it's origins as in model and year?
Regards Martin.

martin all the ones i have seen look the same but that  gouge is deep

perhaps never seen it off the backing plate ?

Arrr the light illuminates the dim dark recesses of my mind.
Regards Martin.

Hi guys and girls...it's been a while, but never-the-less, I still sneak a peek to see what's going on.

Charlie, I hope all is well with you. I was looking at a video of a bloke here in Oz bringing back to life a VB Commodore (V8 engine).

He was pulling apart the fuel tank and had a good shot of the original fuel gauge sender.

It looks remarkably like your busted K100 sender unit (the guts of it...not the tank mounting bit).

I could be wrong, I could be right (I should make that into a song!).

Google VB Commodore fuel sender and have a squiz.

good to see you call in occasionally ol mate 

yes have played and sorted a few fuel senders , (with the local sports car club , getting things working again )

ill take a look ,, and thanks for the comments

I would fix the windings with a bit of epoxy adhesive at the sides, anything else may well dissolve in the fuel.

hope it all goes well.

Love this thread... I've just pulled the fuel sender from a k100 I bought on a whim this summer.

well ive abandoned the rewiring of the resistor windings ....having found what seems to be an already manufactured part ...(likely out of china for this particular sample ) 

with the help of  Burkhard Förster...in another place , who had an injured wiper resistor assembly .
he pointed me towards a vw replacement sender .

which looks remarkably similar ... although i predict the differences in metal parts are a concoction of a copy of the original part , the original vw sender likely made in the same factory as the original bmw unit ....  seems likely .

anyhow the costs involved in getting a winder that would hold the board whilst i rewind it  the tensioning device for the really thin but resiliently straight wire and all that stuff , makes it a reasonable trade off to buy the part for under $25.00 (aussie) and mod it to fit .

some pics may help tell the story better ?









 the mod being to file back about 1/2 a millimeter across the board height , so that it fits into the locating jaws of the original assembly .

the resistance of the swept area is about the same as the bmw unit , although being speced at 10 to 90 ohms ...i measure about 107 ohms for this one .
so careful placement should give a good fuel gauge meter sweep of full to empty ..

one thing that is evident is that the sample here is not coated with a waxy compound like the bmw unit , im sure the waxy stuff would likely protect the windings from corrosion .. and hold them in place during operation ...
more research to be done ... 

you might notice that the oxidization of the base metal after  several weeks without carrying forward with electroplating ....yet 
...the rust blast stuff seems to work well .

 the journey continues

charlie99 wrote:he pointed me towards a vw replacement sender .

Assuming the replacement works out, could you point to a source, part number, or similar?

Yes no problem   i have the part identifier

On the computer ....when i can get to it

charlie99 wrote:Yes no problem   i have the part identifier

On the computer ....when i can get to it

 No rush, and much appreciated.

charlie99 wrote:Yes no problem   i have the part identifier

On the computer ....when i can get to it

Any luck with the the part number and/or source?  Has it worked out as a replacement?

Check out VW part number 113919049D, I picked one of these copies of eBay for less than £14 but have not tried it yet.

Yes thats the one mate   they measure about 107 ohms and need a slight file to fit it in 
But looking to find some waxy substance that will hold the windings in place and protect the wire not ised for connection to the wiping arm...

Charlie I'm assuming that the waxy substance has to be fuel resistant. I have a waxy coating product that I'll try today to see if it's fuel resistant. It does take a while for the coating to dry so I might not have an answer today.
Regards Martin.

Yes would be interested to find out Martin

Was thinking of coating something and leaving it in e10 fuel for a couple of weeks
Cheers

Have you considered using a fuel tank liner?  Fuel resistant and can be painted on. 

The stuff I use is RedCote fuel tank coating.

Point-Seven-five wrote:Have you considered using a fuel tank liner?  Fuel resistant and can be painted on. 

The stuff I use is RedCote fuel tank coating.

hmmm interesting concept 

thanks for the idea...

cheers

Sorry Charlie the stuff I tried didn't hold up on the fuel test. It was LPS 3 a waxy thick rust preventative coating that I had used previously. When I tried to remove it the only way I could remove it at the time was with thinners. It  however had been left drying for quite a few years. This time I let it dry for a couple of days and then sat it in a jar of fuel and the coating dissolved. You might want to try a fuel proof 2 pack epoxy.
Regards Martin.

If the replacement part is also intended to be immersed in fuel (perhaps this an incorrect assumption?) why would you have to apply any kind of protective coating beyond what it already has?

CDNRider wrote:If the replacement part is also intended to be immersed in fuel (perhaps this an incorrect assumption?) why would you have to apply any kind of protective coating beyond what it already has?

The VW Beetle has the fuel sender mounted in the top of the tank, so it's not submerged in fuel, only exposed to fumes all the time.

The Chinese knock off is not engineered with durability in mind.

Tranberg wrote:
The Chinese knock off is not engineered with durability in mind.

Mine arrived this week, but with the Canadian winter just around the corner, I'm not likely to test it out before next spring.

would have not thought it possible to restore/salvage that piece. Brilliant.

charlie99 wrote:Yes would be interested to find out Martin

Was thinking of coating something and leaving it in e10 fuel for a couple of weeks
Cheers

Why not the actual uncoated part for a few months or longer?

My fuel sender looks worse than the worst pictured here, so are there any news in the matter?

sorry no news just yet 

have something sitting in fuel as a test

Upon taking my old fuel sender apart, I saw that it was in terrible shape.  About the same time, I got notification that it's back in stock here: https://www.euromotoelectrics.com/product-p/flf-565edl.htm.  My new one should arrive next week.

That looks like a Christmas cheese cracker on an easel.

Not even Charlie would touch that one.

Wow   and yuck ...

That's pretty much what mine looked like.It went straight into the trash but I got lucky and found a good used one on Bay for 30 bucks .

CDNRider wrote:Upon taking my old fuel sender apart, I saw that it was in terrible shape.  About the same time, I got notification that it's back in stock here: https://www.euromotoelectrics.com/product-p/flf-565edl.htm.  My new one should arrive next week.

 
Like a lot of you, I have many projects on the go, but I'm very pleased to be able to report progress with my '86 K100 project. I replaced

• fuel sender, 
  
• fuel pump, 
  
• fuel filter, 
  
• submersible fuel lines, 
  
• exterior fuel lines, 
  
• fuel injectors, 
  
• front brake master cylinder, 
  
• battery, 
  
• and the fluids. 
  
• And gave the gas tank a major cleaning.
  

Started like a charm!  Idles wonderfully! I can't wait to do some road tests, but the tires are from 2002, so I'll change those this week some time.

I find all of the plastic pretty clunky (although most isn't on, and I haven't seen it on) and the rectangular headlight screams 1980s.  I don't want to do a café conversion, but I'd like it to be stripped down somewhat. Any suggestions on minimal fairings (at a reasonable cost), ideally (but not necessarily) available from a North American source? Maybe sourced with a round LED headlight?

CDNRider wrote:Started like a charm!  Idles wonderfully! I can't wait to do some road tests, but the tires are from 2002, so I'll change those this week some time.

I find all of the plastic pretty clunky (although most isn't on, and I haven't seen it on) and the rectangular headlight screams 1980s.  I don't want to do a café conversion, but I'd like it to be stripped down somewhat. Any suggestions on minimal fairings (at a reasonable cost), ideally (but not necessarily) available from a North American source? Maybe sourced with a round LED headlight?

Lots of info on custom bikes with a search in the Forum's 'engine.' 
Perhaps in a new thread of your own that isn't specifically about fuel sender repair.

Charlie99 regarding, "the resistance of the swept area is about the same as the bmw unit , although being speced at 10 to 90 ohms ...i measure about 107 ohms for this one, so careful placement should give a good fuel gauge meter sweep of full to empty .."

I'm interested in modifying a spare sender that I have. I took it apart yesterday and ordered a VW unit. How do you plan do this placement?
The BMW board and the picture of the VW one, really can't be adjusted side to side. With the higher resistance of 107Ω, the gauge will indicate empty too quickly

I've never cared for non-linear way my gauge reads. It will read full fine but the mid-range is inaccurate and then it quickly shows only a 1/4 tank.

Glenn

I'm thinking about using a piece of 26 gauge wire for the "resistor"

https://www.engineeringtoolbox.com/copper-wire-d_1429.html

AWG Gauge   (Ohms/1000 ft)
 26                 41.6

41.6/1000 = .011/X'

X' = .264' or 3.17"/8.05cm

It's been a really long time and my brain isn't what it used to be, but I think the formula for resistors in parallel is:

Rp=(R1xR2)/(R1+R2)

If you use a 560 ohm resistor in parallel you will get a value of 89.835 ohms.

Hope this helps.

Thanks, makes a lot more sense!