Help! Advice needed re: seized bolts on fuel tank and sender unit

retroman

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Hi folks,

Advice needed please.

My 2002 R1150GS is in for a 12k service (at 72k miles).

My tecchie advises that he has attempted to remove the fuel tank sender unit to renew the fuel filter, but the captive studs are corroded badly and seized solid: one has sheared off already, he thinks that he'll have a similar problem with the others so has halted work for now.

We've discussed options over the 'phone, his preferred route would be to source a good second hand tank, but to my mind this seems a bit drastic.

I'm wondering if I collected the tank and took it to an auto engineering company, they could (perhaps?) drill out the remaining studs, and retap the holes at a slightly wider diameter for new studs. Would this work in theory? If so, can anyone recommend a company who could do this? I live in Cardiff but would be willing to travel to deliver the tank to a recommended company.

Thanks in advance, all advice gratefully received, especially from anyone else who has encountered this issue.


PHOTO-2025-02-24-11-27-46.jpg
 
Cut off the nuts, clean up the studs with a die .

The studs are spun welded in place so not a straightforward job to replace.
I wouldn’t worry about losing one stud, I’ve worked on plenty of tanks with a single stud missing. Even had a couple of tanks with 2 studs broken off and no leaks.
Just do not overtighten the nuts on each side of the broken stud to compensate.
And use silicone gasket all around the O ring .
 
Been here myself before. Soak/ scrub them with some sort of penetrating oil for a few days couple of times a day then use a 1/4 inch ratchet once you get a bit of movement opening, back off and close again,soak then open and close trying to go a teeny bit forward each time. Could take 2 minutes could take 20 minutes to do each one all it costs you is a bit of time and patience.
Make a mixture of 50% ATF and 50% acetone or if you can't do that use neat diesel. Which ever you use get a small dish, pour it into it and get an old tooth brush and drip/ scrub the threads and nuts a couple of times a day for a few days before trying to loosen . Try also to get some below the nut
Put down some paper towel around the rest of the base as it can get messy
Good luck and hope you get sorted
 
Why would anyone attempt to remove such a corroded nut without cleaning the corrosion off and heating it with a Mapp torch. It's mechanics 101. And replace the tank ? They are a pain when they're this corroded. But it's not uncommon. You just need to get them hot enough. Glowing red. And take all the rust off with a wire brush or drill attachment.

Does no one have basic skills anymore !

You could possibly get away without one stud. I wouldn't chance it with two. Fuel leaks are nothing to take lightly.

A new stud could be fitted from the inside. Sounds like it's beyond your mans skillset though.

A second hand tank might be the best option if you can find one cheap. It depends what's left after the job.

Or you could just keep riding and leave the filter alone. Yes the fuel filter is a service item, but I've pulled out perfectly good filters from 30 year bikes that flowed just as good as a new one.
 
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Or you could just keep riding and leave the filter alone.

Doesn’t sound like a bad idea looking at the rust on the studs

Maybe possible to get an air line on it and blow back through the filter then rinse the tank ? Just an idea, I have no experience with these bikes
 
Had same issue on mine. Dealer sheared one off and said didn't want to continue, bring it back when I got it sorted.

Eventually went the route outlined by dub 24 in post 3 above.

Took a while but eventually all were free 👍

Still never replaced the filter as it looks a bit of a job. I'll do it someday.

Did a bit of checking on internet and seems some people have put high mileage on without changing filter. My bikes on 65000 miles. I think the filter must have over 35k on it now.
 
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Thanks for the suggestions. My tecchie not happy returning the bike reassembled with a sheared stud in the tank, and I'm reluctant to ride in this state if there's a leak and associated fire risk, despite the above assurances.

So I think I'm going to source a replacement tank with all studs intact, then when fitted I'll get the original tank refurbed through an engineering firm, although it sounds as if it's going to be a struggle.

Old Bike Fun .... :blast
 
Hi folks,

Advice needed please.

My 2002 R1150GS is in for a 12k service (at 72k miles).

My tecchie advises that he has attempted to remove the fuel tank sender unit to renew the fuel filter, but the captive studs are corroded badly and seized solid: one has sheared off already, he thinks that he'll have a similar problem with the others so has halted work for now.

We've discussed options over the 'phone, his preferred route would be to source a good second hand tank, but to my mind this seems a bit drastic.

I'm wondering if I collected the tank and took it to an auto engineering company, they could (perhaps?) drill out the remaining studs, and retap the holes at a slightly wider diameter for new studs. Would this work in theory? If so, can anyone recommend a company who could do this? I live in Cardiff but would be willing to travel to deliver the tank to a recommended company.

Thanks in advance, all advice gratefully received, especially from anyone else who has encountered this issue.


View attachment 388975
I'd change your Techie, Toot Fucking Sweet, Rodney!!

Why the fuck would you even go near those in that condition ??? Gentle rotary wire brushing and soak in penetrant for 15 to 20 mins whilst I would do something else !!

I have seen far worse and have yet to ever break a stud

As far as it goes, I presume you would accept the word of @Steptoe as he has said it a few times over the years It will be okay It can survive without one stud

Especially as the gorilla broke one of the upper studs Its even reduced the pressure more!!!

The studs are welded to the tank originally, I would be happier to ride it as is with a new pump flange gasket with very light smear of rubber grease so it seats in the groove neatly and centred, than if someone was to be messing with the structural integrity of the flange or the main tank

P.S. HE works for you so you Instruct what you want done! AND tell him never ever to put a spanner to studs on a tank that look like that EVER EVER again without cleaning and lubricating !
 
Above input noted with thanks, especially from Steptoe who I know is a legend with all things oilhead.

I will call in at the workshop next week to examine/discuss. Apparently at least two other studs are in a similar condition, they are currently undergoing a soak in oil.
 
I'd change your Techie, Toot Fucking Sweet, Rodney!!

P.S. HE works for you so you Instruct what you want done! AND tell him never ever to put a spanner to studs on a tank that look like that EVER EVER again without cleaning and lubricating !
That's not happening, these guys have looked after my bike exceptionally well since it went out of warranty, including a gearbox rebuild. Welly had the same issue with a Dealer in post 6 above, so I'm not alone in this.

Good indy BMW tecchies are not exactly thick on the ground here in Wales, either. Shit happens, and it's happened to me.

The other issue being, can I be arsed? I'm 59 this year, the bike is 23, perhaps it's time for a newer bike without age related corrsion :blast ... but I persevere for now.

My RE Himalayan is keeping me on the road for now.
 
When you’re sorted with a tank cover the filter flange with waxoyl/dinitrol. I have covered the hole bottom of the tank with the stuff since I got the bike in 2004. Never any bother with corrosion or removing the filter. Some on here said the bike would go on fire mind. :D
 
I've made some progress in that I've sourced a replacement tank, in black, with all studs intact, and in good condition. It's now en route from the breaker.

Only problem being, I'm told I also need a replacement 'fuel pump flange assembly', as mine is FUBAR's due to corrosion :blast . Breaker currently sifting through boxes of bits, update awaited, hopefully the one from the tank donor bike will also become available.
 
Only problem being, I'm told I also need a replacement 'fuel pump flange assembly', as mine is FUBAR's due to corrosion :blast . Breaker currently sifting through boxes of bits, update awaited, hopefully the one from the tank donor bike will also become available.
Ehm I am pretty sure that @Steptoe @mikeyboy Would Laugh out Very Loud at that bit in Blue !!

I certainly am I have seen Much Much Much worse condition Pump Flanges than that (And I got the studs off without snapping, Because I am not a careless Cnut!) If it were me (and I know it is not I would give it a hit of wire brush a lick of Kurust and a light coat of waxoyl or Owatrol

I would definitely change the hoses though and at this time go the extra mile and fit quick release couplings and get a new Fuel pump flange O ring for the cap ( 04 O-ring 73X5,3 1 07119900019 ) and for the flange ( O-ring 1 16141341008 ) They swell and with the luck your guy is having??? Bound to happen and always carry a couple of Little O rings for the QR couplings in your tool kit
 
The broken stud can be sorted by a decent engineer,
Tank needs to be drained and flushed,
Drill out broken stud and silver solder a replacement in.
I've already been in touch with Steptoe, his guy who could do this has ceased trading and he dosen't know anyone else who could do it:nenau so that is of concern, if Steptoe doesn't know of someone then who would?

So I'll keep my original tank, have it repaired in slow time by that elusive decent engineer, then keep it as a spare or sell it on. Or, it will slowly moulder away to nothing in my garage with all my other bits accrued over the years (more likely TBH).

As for comments by Dr Farkoff, I trust my tecchie who has worked on my bikes for over 20 yearts, if he says the flange needs replacement then I'm in no position to argue (I'm no mechanic) and it WILL be replaced. That aside, all other comments and especially part numbers noted with thanks.
 
As for comments by Dr Farkoff, I trust my tecchie who has worked on my bikes for over 20 yearts, if he says the flange needs replacement then I'm in no position to argue (I'm no mechanic) and it WILL be replaced. That aside, all other comments and especially part numbers noted with thanks.

No problem at all You are most Welcome

I have been working on BMs for the last 22 Years its only since I got my ass handed to me by "The Virus That shall not be Mentioned" that I backed off mainly due to health reasons and decided to concentrate on my own stuff

I have noticed an Upsurge in the Questions re the Oilheads and it is nice to see, and nice that I can give someone a pointer and help them out and posted that thread "Is the Oilhead the New Airhead?"

Your Flange Oooo Err Matron is not pristine from your photo but I would dare to consider it quite serviceable (If the photo is a good representation??)

AS for Options Basically ANY GS will have that Pump / Gauge set up "but" NOT the GS Adventure

I think I have a decent one hanging up if your man can change the 4 way Connector on the cable??
 
No problem at all You are most Welcome

I have been working on BMs for the last 22 Years its only since I got my ass handed to me by "The Virus That shall not be Mentioned" that I backed off mainly due to health reasons and decided to concentrate on my own stuff

I have noticed an Upsurge in the Questions re the Oilheads and it is nice to see, and nice that I can give someone a pointer and help them out and posted that thread "Is the Oilhead the New Airhead?"

Your Flange Oooo Err Matron is not pristine from your photo but I would dare to consider it quite serviceable (If the photo is a good representation??)

AS for Options Basically ANY GS will have that Pump / Gauge set up "but" NOT the GS Adventure

I think I have a decent one hanging up if your man can change the 4 way Connector on the cable??
Many thanks indeed (y)

My breaker (James Sherlock) is currently looking for the flange that came off the donor bike, update awaited. But if no joy I will drop you a PM.

Thanks again DrF :beerjug:
 
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I have seen snapped ones ground flat , drilled out and then replaced with closed head rivnuts , worked fine and did not leak .

I did a repair on an Adventure tank that I had for my first 1150.

It had three or four snapped studs and as the tank was being resprayed I made sure it was properly flushed of any fuel and vapour and welded on new studs made from Cap heads that had the head ground down to a flat about 1.5mm .
Again it worked fine
closed head rivnuts.webp
 
I have seen snapped ones ground flat , drilled out and then replaced with closed head rivnuts , worked fine and did not leak .

I did a repair on an Adventure tank that I had for my first 1150.

It had three or four snapped studs and as the tank was being resprayed I made sure it was properly flushed of any fuel and vapour and welded on new studs made from Cap heads that had the head ground down to a flat about 1.5mm .
Again it worked fine
View attachment 389980
Blimey Neil. Seems you could set yourself up with a profitable side industry here, replacing these damn studs (y)
 
Blimey Neil. Seems you could set yourself up with a profitable side industry here, replacing these damn studs (y)
Stress full enough to do it on my own bike , but I do find Rivnuts very usefull. I reckon new studs could be easily fitted by someone with a bodywork stud welder .
 


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