# Water tank leak 7090+



## rayc

My first problem with my Rapido. There is a leak from the water tank that appears to be near the outside wall end. The only things at that end are the overflow which can be discounted, the water inlet which is for some unknown reason at floor level and impossible to get to. There is also the dreaded foot which has been known to puncture the tank. Carol had the foot problem when hers was new leading to a replacement tank I believe.
The amount of work required to remove the tank is unbelievable. It looks like the gas locker furniture will have to be taken apart and the dinette false floor lifted up. Unless I can think of a way to do it the whole false floor will need raising which means dismantling the side seat which also houses the batteries.
If I was looking for a way to make the tank removal as expensive and complicated as possible then I could not better the Rapido way. I have no idea how much the labour would be if I took it to a dealer. Anyway it has got to come out as it is the only way that the source of the leak can be 100% identified. Any idea how much a new tank would cost from Rapido and what the lead time is likely to be?. It is complicated being a bespoke one that is formed to fit round the seat belt anchor metalwork.


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## WildThingsKev

Have you tried putting a small camera down the back of the tank in order to identify the source of the leak? You could also hold it inside the tank to double check it's not a crack like Carols.


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## rayc

WildThingsKev said:



> Have you tried putting a small camera down the back of the tank in order to identify the source of the leak? You could also hold it inside the tank to double check it's not a crack like Carols.


Many thank. I can see inside the tank as it has an inspection hatch each side of the seat belt stanchion. I cannot see a crack around the foot fixing [ what do you call a bit that is built into the tank to allow a support to be inserted?].
The camera idea of looking at the rear /underside of the tank is a good one bit it will have to be small one on the end of a flexible arm.

I have managed to get a 10mm spanner on the fresh water input and there was no slack in it.

This morning I filled the tank through one of the inspection hatches in 10% steps with 20 minutes between steps. 10% to 40% steps were ok and that makes me think the fresh water input is ok as it was completely submerged. Of course water moves up the filler tube as the tank fills as it is at the bottom of the tank. At 50% full the leak returned.


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## rayc

I bit the bullet and after dismantling the gas locker, dinette settee base and false floor the tank was removed. It took the best bit of 4 hours or so.
The fault is I am disappointed to say a manufacturing one. The foot is a bit of hollow tube fitted with a yellow cap at the floor end. The end that goes in the tank is rough and not chamfered. This has over time cause a leak from the tank insert. It was obvious as the pipe had water in it and that can only get there from above.
What to do now is the question. I have made enquiries from a Rapido dealership for the lead time for a spare so will have to wait and see the way forward.


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## josieb

A point to bear in mind. If you need to order a new tank (I hope not) if it is in stock it will take 2-3 weeks. Then you have to factor in they close for August.


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## rayc

Another couple of photos. I can not see that this can be repaired so I shall have to throw myself at the mercy of Wokingham motorhomes and Rapido to get a new one. A little galling when it is obviously poor design by Rapido but what else can I do?


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## WildThingsKev

So has the tight fit actually caused a stress crack up inside the moulding?


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## Techno100

Would have been a better job with a piece of 4x2 across the floor :lol:
Unless it's a warranty replacement I'd be looking at having it welded and plate over that socket completely and support the tank on a timber frame.


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## rayc

Techno100 said:


> Would have been a better job with a piece of 4x2 across the floor :lol:
> Unless it's a warranty replacement I'd be looking at having it welded and plate over that socket completely and support the tank on a timber frame.


Warranty a long time ago I'm afraid. How is the welding done on the plastic? The 4 x 2 method is the one I shall use when it is replaced.


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## rayc

WildThingsKev said:


> So has the tight fit actually caused a stress crack up inside the moulding?


Not visible to the naked eye but it is definitely weeping - as i am with the cost and amount of work to replace it. It is clear that the leak is from that moulding as the tube with yellow foot fills with water which then escapes past the yellow cover.


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## Techno100

rayc said:


> Techno100 said:
> 
> 
> 
> Would have been a better job with a piece of 4x2 across the floor :lol:
> Unless it's a warranty replacement I'd be looking at having it welded and plate over that socket completely and support the tank on a timber frame.
> 
> 
> 
> Warranty a long time ago I'm afraid. How is the welding done on the plastic? The 4 x 2 method is the one I shall use when it is replaced.
Click to expand...






https://www.google.co.uk/search?q=p...rome.3.57j0l3.7850j0&sourceid=chrome&ie=UTF-8

It is most likely Poly Ethylene so google for a repairer


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## Techno100




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## WildThingsKev

Same as the kayaks I rotomould. It is quite an easy job to do so long as it is accessible with both hands, which it probably isn't. Apart from kayaks I have welded up some yacht water tanks in the past.

Kev


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## rayc

An update. I received a very prompt response from Wokingham regarding getting a new tank. £400 inc VAT and delivery to them within 2 - 3 weeks.

I could not see a break or split in the tank insert and suspect it was small and possibly closes up when the foot is removed and no weight of water in tank. I know I caught it on the first day it dripped so no damage to the fabric of the MH. I have done some repairs to seal any leak from the top of the insert where I know the dribble originated. I'll keep it to myself for now until I am sure it is fixed. I have done away with both feet completely and replaced them with two wooden plinths, one either side of the seat belt stanchion.

I am now familiar with the process for removing the gas locker surround, dinette false floor and dinette seat and surround. That is the order it should be done in as there are some hidden fittings only accessible in that order. I think that the tank can be replaced by one person in a 8 - 10 hour day, so a new tank and labour will cost circa £1000 at a dealers.

The floor beneath the faulty leg has been slightly indented so it is clear that the tank as been rocking slightly and pressure being applied over the 5 years since manufacture. There is no indent or problem with the mid van leg. The tank is not strapped in so there is the possibility of slight movement within the dinette seat base.

It is obvious from Carol's topic referenced below that this is a generic Rapido problem and I strongly suggest that anyone with the tank in the dinette seat checks if the tank can be rocked, especially when about half full.

http://www.motorhomefacts.com/ftopt...r-tank-split-has-anyone-else-had-a-probl.html


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## WildThingsKev

Thanks for the tips, I'll keep an eye on mine. When Carol first posted I checked and found there was a very slight rock when empty but when full it flexed a little and settled on both feet. I put a thin spacer under the foot to prevent it but will check again.


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## Techno100

I may endeavor to do a preventative job on mine as I wont be selling for at least 7 yrs. A shame that its a pi** poor design


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## Techno100

More pictures of your wood butchering skills would be appreciated


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## rayc

Techno100 said:


> More pictures of your wood butchering skills would be appreciated


If that was meant for me then I did not take any photos of the furnishing strip out but could list what I did in what order and where the fixings were etc.

I have had a very quick reply from Anthony Pfaff of Rapido in response to my question of whether Rapido would be willing to meet or share the cost of a replacement tank.

He said: "Where a vehicle is outside warranty any help from Rapido is considered on a set basis. We rely on our dealers to analyse and repair any problems and it is only where the work is carried out by a Rapido concession that any consideration for help can be made. As a manufacturer we need to ensure where we are participating that the work is carried out to our standards and because of this I cannot supply parts for owners to fit themselves. I am willing to consider supplying the reservoir if the work is done by a Rapido concession."

Fair enough I suppose. I would still have had to presumably pick up the labour cost plus the diesel etc to take/return to the dealer. This could be protracted as presumably the dealer would have to remove the tank to investigate and then wait 2-3 weeks for the replacement to be delivered. 
Ray


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## josieb

Did Rapido give you any indication as to the set time allowed for replacing a tank as 10 hours seems rather extreme.


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## rayc

josieb said:


> Did Rapido give you any indication as to the set time allowed for replacing a tank as 10 hours seems rather extreme.


No but my reasonable estimate of a capable DIY owner considering the work involved and having done it once. I would be quicker next time and I realise that a 'professional' who has done it before may be even quicker and a small electric screw driver will be useful.

The jobs involves dismantling the gas locker completely, removing the table, lifting the false floor and removing the seat base completely.
Things to get out of the way such as the air duct that runs under the tank that prevents the tank being pulled forward with it in situ.
Undoing the couplings to the water pump which is situated on the tank plus the power and water level leads. Disconnecting the water outlet hose from the tank. The water filler has got to be removed on the outside wall as the tank filler is at the lower rear of the tank so the hose has got to come out with the tank.
The whole process has to be reversed and when the gas locker is put back together it has the be resealed with mastic. I would also not consider using the feet again and would make a couple of small plinths to spread the load. Refill with water and reconnect gas supply and recommission water and gas systems.

I do not know if Rapido have a 'book' time for replacing parts in the same way as car manufacturers do but I would be interested in their estimate if they have one.

If the tank is £400 how much labour could I expect for £600 from a Rapido concession to give my estimate of circa £1000 for the whole job?


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## Techno100

Yes I meant you Ray :lol: I meant can we have pictures of the plinths you have constructed


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## rayc

Techno100 said:


> Yes I meant you Ray :lol: I meant can we have pictures of the plinths you have constructed


Sorry but I never took any photos of the two plinths.
Each were built out of two bits of wood 20mm deep, about 90mm width and 200mm long, with two bits of spacing blocks in between, such that one bit of wood sat on the floor and the other bit was what the tank rested on. I think the overall height was 90mm which is the same as the amount of the original post that sat outside the tank.
The one on the outside wall was a bit shorter than the inside one as the seat belt stanchion is already bolted to the floor. They were held in place on the floor by the L type of brackets that can be bought at B&Q.
They only took me 1/2 an hour or so to knock up so nothing complicated. I lined the piece that the tank sits on with some rubber 'mat' to cushion it a bit.

Ray


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## Techno100

Sounds good to me matey :thumbup:
I'll wait until I'm not busy as bee and do it for sure 8)


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## rayc

WildThingsKev said:


> So has the tight fit actually caused a stress crack up inside the moulding?


On closer inspection I don't think it cracked but the rocking over the years has caused the leg to rub on one part and presumably weakened it allowing water to seep through when under load. I may be wrong though and although the leg has remained firmly in the socket it has stressed the socket in the area of the patch or something completely different.
It can be seen as the dark patch on the photo below.


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## Techno100

Completely rubbish support idea from Rapido. It's not rocket science to spread the load.


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## Ian_n_Suzy

Hi Ray, 

Thanks for the heads up re this issue, as my Van has the same type of tank (albeit, the layout is different so would not require anything like as much work to get out).

Hope you and Lesley are both well (did Lesleys shoulder heal OK?)


CHEERS


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## WildThingsKev

rayc said:


> WildThingsKev said:
> 
> 
> 
> So has the tight fit actually caused a stress crack up inside the moulding?
> 
> 
> 
> On closer inspection I don't think it cracked but the rocking over the years has caused the leg to rub on one part and presumably weakened it allowing water to seep through when under load. I may be wrong though and although the leg has remained firmly in the socket it has stressed the socket in the area of the patch or something completely different.
> It can be seen as the dark patch on the photo below.
Click to expand...

I must admit I'm slightly at a loss to explain why it has leaked. Rotomoulding is a "stressless" process and the interior of my tank looks well moulded and at least 4mm thick up inside this piece. I can't see that yours has come anywhere near rubbing through. You could hit one of these tanks with an axe and not get through - I've tried it with scrap kayaks! Rotomoulded products can cope with quite a lot of loaded deformation for years, you should have seen my fathers old oil tank.

When you removed the leg did it seem as though there was a slight taper up inside the moulding? You showed that the top end of the leg was cut roughly and maybe had a jagged piece. As you suggested, repeated pressure just stressed the tank enough to eventually open up a small fracture.

I've attached the photo of the inside of my tank in this area from the previous thread, it is a good moulding.

Did you say that your tank rocked when half full? (But not when empty?)

Kev

ps Does your tank have a date on it?


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## rayc

WildThingsKev said:


> rayc said:
> 
> 
> 
> 
> 
> WildThingsKev said:
> 
> 
> 
> So has the tight fit actually caused a stress crack up inside the moulding?
> 
> 
> 
> On closer inspection I don't think it cracked but the rocking over the years has caused the leg to rub on one part and presumably weakened it allowing water to seep through when under load. I may be wrong though and although the leg has remained firmly in the socket it has stressed the socket in the area of the patch or something completely different.
> It can be seen as the dark patch on the photo below.
> 
> Click to expand...
> 
> I must admit I'm slightly at a loss to explain why it has leaked. Rotomoulding is a "stressless" process and the interior of my tank looks well moulded and at least 4mm thick up inside this piece. I can't see that yours has come anywhere near rubbing through. You could hit one of these tanks with an axe and not get through - I've tried it with scrap kayaks! Rotomoulded products can cope with quite a lot of loaded deformation for years, you should have seen my fathers old oil tank.
> 
> When you removed the leg did it seem as though there was a slight taper up inside the moulding? You showed that the top end of the leg was cut roughly and maybe had a jagged piece. As you suggested, repeated pressure just stressed the tank enough to eventually open up a small fracture.
> 
> I've attached the photo of the inside of my tank in this area from the previous thread, it is a good moulding.
> 
> Did you say that your tank rocked when half full? (But not when empty?)
> 
> Kev
> 
> ps Does your tank have a date on it?
Click to expand...

The date was May 2008. The tank could rock when empty and half full. I never tried it full as it began to leak at about half full as far as I could tell in a couple of fillings. It is interesting that there was a slight indent in the floor made by the foot whilst the good foot had not made one.
I did not notice a taper and the foot could be pulled out easily so hadn't jammed up there. Anyway leak it did and from up the top somewhere as the tube has water inside it. I am fairly confidant that I caught the leak on the first day it happened as it had been parked up for 5 days with about 40% water with no leak and then within a short time after filling it to 90% the leak was there. In addition when the tank was removed there was no indication on the floor or any fixings, such as the blow air hose that runs under the tank, of any water staining etc.

It has been back in now for 36 hours at 90% full with no apparent leaks. I will be away for 5 days now doing about 250 miles so hope it stays that way.


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## carol

Didn't get to end but want to go to sleep 

When Wokingham did ours we stopped overnight at the. TWO Poplars. Pub and they did it next morning and we were away in time to get the tunnel crossing at about 1630. So not long 

Carol


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## WildThingsKev

Well hopefully that's that. As you suggested earlier, I'm sure the tank must be the same on all 709*s and yet all 3 leaks posted about are on 7090s and all with a different tank date of manufacture. It seems it could be more to do with how accurately and neatly the leg has been cut than the quality of the tank itself?


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## mentaliss

rayc said:


> I bit the bullet and after dismantling the gas locker, dinette settee base and false floor the tank was removed. It took the best bit of 4 hours or so.
> The fault is I am disappointed to say a manufacturing one. The foot is a bit of hollow tube fitted with a yellow cap at the floor end. The end that goes in the tank is rough and not chamfered. This has over time cause a leak from the tank insert. It was obvious as the pipe had water in it and that can only get there from above.
> What to do now is the question. I have made enquiries from a Rapido dealership for the lead time for a spare so will have to wait and see the way forward.


 Im not sure if I understand, is the pipe joint suppose to be fixed or is it fitted into the tank after the tank is fitted into its position....


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## rayc

mentaliss said:


> rayc said:
> 
> 
> 
> I bit the bullet and after dismantling the gas locker, dinette settee base and false floor the tank was removed. It took the best bit of 4 hours or so.
> The fault is I am disappointed to say a manufacturing one. The foot is a bit of hollow tube fitted with a yellow cap at the floor end. The end that goes in the tank is rough and not chamfered. This has over time cause a leak from the tank insert. It was obvious as the pipe had water in it and that can only get there from above.
> What to do now is the question. I have made enquiries from a Rapido dealership for the lead time for a spare so will have to wait and see the way forward.
> 
> 
> 
> Im not sure if I understand, is the pipe joint suppose to be fixed or is it fitted into the tank after the tank is fitted into its position....
Click to expand...

The piece of pipe is just being used as a short leg and is a push fit into the tank insert. The legs need to be fitted into the tank prior to it being fitted into position because there is no way to access to fit them once the it is in position, especially the one nearest the side wall. Not that it worries me now as my modification included doing away with them and having a small plinth where each leg was.


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## Techno100

I've completely removed those seat belts too Ray, a few KG in the bin


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## carol

I only caught this Ray as I got an emIl just now re my original post.

I can tell you we took ours in first thing 0830 i. The morning, went into Wokingham (dropped in by them) and they picked us up just after lunch as we were catching the tunnel at 1600. So not long

Essanjay had made a great attempt at fixing it when it first happened in July the Friday as they broke up for their holidays in France. it was John Who contacted them (Rapido) first, phoned me, and said he had told Antony Pfaff that I would be calling after. TBH I was lucky, by then due to holidays we were just out of warranty, but they rushed it through and got Wokingham to do the job (don't forget we had purchased it in Germany!). They wouldn't admit it was a design fault, but with many others having the same problem it must be. He had to take a tank off the production line for us. We cannot fault Rapido they were great, and Rapido Wokingham were excellent. 

Carol


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## rayc

carol said:


> I only caught this Ray as I got an emIl just now re my original post.
> 
> I can tell you we took ours in first thing 0830 i. The morning, went into Wokingham (dropped in by them) and they picked us up just after lunch as we were catching the tunnel at 1600. So not long
> 
> Essanjay had made a great attempt at fixing it when it first happened in July the Friday as they broke up for their holidays in France. it was John Who contacted them (Rapido) first, phoned me, and said he had told Antony Pfaff that I would be calling after. TBH I was lucky, by then due to holidays we were just out of warranty, but they rushed it through and got Wokingham to do the job (don't forget we had purchased it in Germany!). They wouldn't admit it was a design fault, but with many others having the same problem it must be. He had to take a tank off the production line for us. We cannot fault Rapido they were great, and Rapido Wokingham were excellent.
> 
> Carol


Thanks Carol. I am happy that after my modifications and repair that the tank will no longer leak. It proves the worth of MHF and its members that I was aware of the chances of it leaking before it did, thanks to your original topic. Ray


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## WildThingsKev

MY TURN!

Two pages ago I said I'd keeep a check on our tank and on the last page I smugly posted that our tank looked like a perfect moulding. Walked back to the van at Sarlat le Caneda today and noticed some water underneath which I assumed had come from a neighbouring van. One hour later I came back to the van from the supermarket and noticed a damp patch under the gas locker; I immediately knew what it was.

We have driven a lot of bumpy roads over the last 41000 miles so in a way I'm surprised it has lasted this long, luckily I also caught it promptly.

I drained the tank, removed the seat top and have had a root around at the 3 potential trouble spots; feet, filler connection, angle bar at front. It is wet under the outside foot although I can't sèe any cracks inside (by taking photos) but from what Ray has said that's not surprising. 

Not a job to tackle on the road but we come back next Sunday so will muddle through, there was a Jardi next to the supermarket so popped in and bought a 10li container with a tap and I always carry a flexible 10li bag anyway. Plenty of Evian in the garage to flush the loo.

I've been meaning to add an extra hot air outlet at the front because its cold up there when skiing, now I can split the man hours.

Kev

ps. Ray, standby for a pm week after next!


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## macd

This is rayc on malcs I pad. As a temporary fix you may be able to cut a small water bottle half way down and fit it over the boss inside the tank. Stick it on with plumb solvent glue. I will look out for a pm but may not have access before thursday


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## WildThingsKev

Thank s Ray. I've re-read Carols original thread and Monkeyman posted a tip of fitting a short length of hose to the pump inlet and dropping the other end into a water container. That will make things a bit easier for the next wèek.

Kev


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## WildThingsKev

Update; searching for something on this thread I just realised that I had never posted photos on my fix. Since this will undoubtedly happen to others here is how I went about it.

After all the dismantling already described by Ray we get to the actual repair on the tank itself.

The hairline crack on mine was at the bottom of the moulded in boss which takes the legs, so it was easily accessible to weld. I was expecting it to be in the top of the boss where the (very unevenly cut) top end off the leg finished. The tank now sits on some custom cut foam blocks; stress-free! 

I rotomould kayaks with the same materials and repair quite a few so I'm familiar with the work. 

What had happened is that 
1) The boss moulding is too close to the outside wall (there should be a separation of 5x plastic thickness whereas it is only about 3x) leading to poor powder distribution in moulding and an inherent weakness. 
2) the bottom of the leg (also poorly cut) embedded itself into the vinyl floor so when cornering/braking the tank had to flex at the weak point because the rest of the tank is free to move a bit. 

In preparation for applying an adhesive up inside the boss (where a weld is impossible) I "flamed" the inside of the boss to oxidise the polyethylene surface for better bonding; this glosses the plastic and makes it more transparent. Only then did I see that the stress fracture was actually at the bottom of the boss and was seeping water when the leg was loaded. (when I filled the tank on a bench with the legs removed it didn't leak). You can see the crack in one of the photos.

The tank is a standard tank grade of polyethylene and easy to weld. Since the crack was only hairline and would not be stressed again (resting on the new foam base) I used some ski repair strips for welding. I use a gas pen with catalytic tip for welding, the hot gas exhaust doesn't contain much oxygen. 

The adhesive was not required but for reference I would have used "Lexel" which bonds well to polyethylene even when wet. "Soudal Fixall" from Screwfix is an alternative.

Kev


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