Fireproofing your Kombi... a must read for all Kombi owners.

Discussion in ''How To' & 'Handy Hints'' started by Schmoburger, Jul 22, 2006.

  1. Schmoburger

    Schmoburger Active Member

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    Nowra/Jervis Bay area, NSW.
    A nasty stigma that has been attached to aircooled VW's since the beginning of time is that they are a firebomb which are capable of combusting at the drop of a hat... and the common uneducated view is that "Oh, yeh... VW's catch fire because they are aircooled so they overheat!" :?

    Puuuh-leazze!... A tiny bit of common sense and a basic understanding of the principles behind combustion should be enought to prove that this is codswallop... if the engine got hot enough to ignite even a magnesium crankcase on a type 1-2 engine, then.... well... you wouldnt expect the rear of the bus to still exist!

    In reaality, I'd guess that 99% of vintage Volkswagen fires can be attributed to a compromised or poorly maintained fuel system.... for instance degraded or incorrect fuel hose, leaking carburetters, a leaking fuel pump, or "popped" hoses. The other 1% are electrical in nature or caused by oil contacting hot surfaces, and are unlikely to occur.

    In this article, you will learn all the tricks to prevent you ever being in the situation that a Melbourne kombi-pilot was in in mid-2005... standing on the footpath watching helplessly as your kombi burns furiously on the road... :?

    Read on....

    Firstly, you should replace all of your fuel lines anually... as the high temperatures generated by an aircooled engine, combined with constant contact with petrol can cause the rubber hose to degrade fairly rapidly... it begins to split, crack, and eventually burst over time. you may easily get over a year from a set of fuel lines... up to a few years if you are lucky... however it is not a risk worth taking. The job is simple, as all fuel lines are flexible rubber hose, and on a Kombi, the fuel tank is behind the firewall, so the distance the hose has to travel is minimal.

    When replacing fuel lines, always buy the highest quality German cotton-sheathed rubber fuel hose, in the correct thickness and diameter for your bus. Some American sizes can be made to fit, however this is dangerous water, so avoid it. Correct diameter is important, as using to narrow a diameter will put excessive strain onto the hose ends, leading to splitting... too wide a diameter will slip off. As an imprecise measure, the fuel hose should fit firmly on the brass fitting, and require some effort to push, but not require shoving or pliers to push all the way home. it also should not stretch more than about 1mm in diameter when on the fitting.

    Also avoid using cheap and nasty hoses that happen to be the right diameter.... they may fit, but many arent designed to stand up to high pressures, temperatures, and exposure to fuel, and will hence break down very quickly indeed.

    Observing these precautions is doubly important on fuel-injected buses... as much higher pressures exist in such systems.

    When cutting lengths of fuel line, ensure that you have a clean, square cut, and make sure you cut enough hose off to allow for some slack... tight or stretched hoses can cause problems.

    After replacing fuel lines, EVERY end should be clamped to it's fitting, preferably with screw-type clamps, to reduce the chances of the hose working loose and slipping off the fitting. Saying that though, it is important that you do not overtighten the clamps, as this puts excess stress on the rubber... simply tighten until it bites and holds.

    Once your fuel lines have been clamped... get lockwire or similar and wind it around the hose tightly then follw through and wind tightly around the clamp, then wind tightly around the fuel pump or carburetter body. This ensures that the hoses can never come completely off under any circumstance, however there is also a far more importnt reason for this extra precaution... the brass fittings themselves in the carbies and fuel pumps of aircooled VW's have a nasty nasty habit of coming unstuck from inside the unit and falling out, causing fuel to be sprayed over the hot engine. In fact this is one of the most common causes of fuel related kombi fires. By securing the hoses with wire, you relieve some of the strain from the fitting itself, making it slightly less likely to come loose... however in the event that it does come unstuck, it will remain in place, and at worst only dribble a little fuel, rather than falling right out and turning the entire engine bay into a bomb. In the case ot the T-section in between the carbies on a type 4 engine, wire it in the same manner as the carbs, but follow through in a triangle pattern onto the next hose, then the next one then back to the one you started with... this will keep everything together in that area if done tightly.

    Another idea which I believe to be helpful is to insulate the T-section with good quality heat resistant electrical tape. The idea of this is to ensure that if the T cracks, as many of them are plastic, the fuel will be more or less contained if the tape is applied tightly and without gaps. I actually use this to secure the T rather than using clamps, as it seems just as effective.... however it will count for nothing if you use cheap tape.

    With regards to fuel filters, ensure that you have it installed in the line between the fuel tank and the pump, not between the pump and carbs... the pressure from the fuel pump can easily blow the filter off or even crack or explode some cheap plastic ones if they are on the pressurised side of the pump, resulting in a fireball... so dont do it, even if it seems easier...on that note, a filter after the pump serves no purpose, the pump has its own strainer, meaning contaminants dont enter the engine anyway... if you have a filter, it is to prolong the life of the pump by removing gunge before it enters it. If your bus already has a filter after the pump... remove it before you drive the bus any further, or you are endangering it's life!

    Another common cause of fuel plumbing failure is due to abrasion or laceration. Every VW with an aircooled engine has a hole in the rear engine tinware through which the fuel inlet hose from the tank passes into the engin bay to feed the carburetter/s. This tinware is only a few millimeters thinck and has sharpish edges, so a rubber grommet is installed from the factory in the fuel hose hole to prevent chaffing or cutting of the hose. EXCELLENT!... however there is a problem... like rubber fuel hose, this rubber grommet deteriorates with age and heat and can evntually fall out or disintegrate... leaving the delicate fuel hose resting and rubbing on the sharp tinware. If left unchecked, the tinware will cut or rub through the fuel hose, and eventually it will rupture and potentially cause a fire. For this reason it is a good idea to change this grommet anually with the fuel lines.

    Another abbrasion hazard is found in late bays... in the form of a small metal tab at the top of the rear tinware. This tab is a guide for the fuel line into the left hand carburetter... i am not entirely sure of how many peole actually use it as such, however if you do, it is advisable to wrap heat resistant 'leccy tape around the section of fuel hose that sits in this guide, this should prevent any abbrasive action against the actual hose.

    The final fire risk is from leaking hardware such as pumps carbies and inlet manifolds. Inlet manifolds can occasionally crack, however this is not terribly common, so I am just mentioning it for posterity.

    Carbies can be prone to leaking or weeping from seals that are old.... slight weeping is usually not cause for concern... however profuse leakage should be rectified ASAP.

    Same deal with fuel pumps, over time they can develop leaks around the gasket. on a type 4 engined kombi, this is not too much of an issue unless it is profusely dripping fuel, as the fuel pump is located under the engine away from most hot bits. On a kombi with a type 2 engine though, any fuel pump leakage should be rectified, as the pump is in the engine bay.

    By now, your fuel system should be fireproof, however you should inspect all hoses and fittings for condition and fit at least fortnightly to ensure they stay that way... I check mine at least weekly. When inspecting the fuel system, you should inspect hoses for cracks, splits, bulges, or other damage that will inevitably lead to failure and fire if left unchecked. Press each fuel hose between a finger and thunmb along it's length... it should be firm but supple. If any hose is hard, it has degraded and requires immediate replacement with the correct replacement hose as described earlier in this article. The same applies if any splits are found along the length of the hose, or if cracks are found at either end, or if bulges or blisters are found in any hose... replace the offending hose/s right away. Check fittings by ently but firmly wiggling them ever so slightly... when you are satisfied the fittings are in correctly, give the hose ends a gental push home. After the plumbing has been taken care of, check the fuel pump gasket and carburetter gaskets and seals for leakage, and rectify if needed... be your own judge... as mentioned before, a thin coating of residue around the gasket or pump body of carby seals is ok... but if there is a consistent dampness or worse... its a good idea to rectify it.

    Now that you are aware of all the VW fire-safety precautions, there should never be any reason for your bus to ignite... however, just to be safe... ALWAYS, ALWAYS, carry a charged extinguisher on board... it's even better if you have two or three. If you have the room to put it, I would recommend a CO2 (black) extinguisher of around 7kg, and a smaller dry powder type of aroung 1kg.

    Now that you have an insight into what causes fires in VWs, you can go and take preventative meausures, plan an inspection and maintenance regime for your fuel system, and drive your bus with confidence and peace-of-mind!:cool:

    Cheers!
    Kieran

    Article Copyright 2006 Kieran Boundy/BWM
     
    Derek Engel and combiclaire like this.
  2. ttmck

    ttmck Super Moderator Staff Member

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    When you have nothing to do bored out of your brain do this simple little safety trick to your fuel lines esp the Right hand carby its a common fault the brass tube comes out , if it does turn it round and knock it back in with some wood
    this wiring up the lines might just help


    Rh carb [​IMG]

    Fuel pump [​IMG]
     
  3. Schmoburger

    Schmoburger Active Member

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    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    Cheers Tom! :cool:

    Yep... mine is done slightly differently, but yeh, same result in the long run... keeps the ferule more or less in place. Depending upon how tightly you wire it, it may still be able to come "unstuck", however it will not fall out past a certain point... so it will just dribble out and hopefully be able to be smelled (this is where checking the lines REGULARLY comes in :) ), so it can be rectified, rather than it falling out without warning and spraying semi-pressurised fuel over the hot bits. :shock:

    wired in nice and tight like Tom's however, most of the tension will be taken off the ferule, so it is less likely to work loose anyway. :cool:

    I was gonna take pics of mine, but I am too lazy to move the mattresses/table/spare wheel off the top of the engine cover! :lol:

    Cheers!
     
  4. ttmck

    ttmck Super Moderator Staff Member

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    lazy bones !!!! :lol:

    na good post mate i came across the pics so thought it might be a good sunday morning project
     
  5. KahunaKombi

    KahunaKombi Super Moderator Staff Member

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    Godd posts guys :wink:
     
  6. R Mac

    R Mac New Member

    Messages:
    3
    Location:
    Adelaide, SA
    Was working on the fuel system last night on my olds mans Bay ('76 2lt.) The original pump is by-passed and a replacement unit has been placed inside the engine bay on the back left wheel well (if looking from the rear of the van forward.) Is this sort of arrangement alright? The current pump works fine although I?m concerned that the internals may have hardened as the van has been sitting for a while?

    Schmoberger, cheers for guide (I need all the help I can get!) and for the heads up re the second fuel filter after the pump as this is what was on our Bay. And ttmck ta for the photos, most appreciated.
     
  7. Schmoburger

    Schmoburger Active Member

    Messages:
    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    Personally, I would be wee bit concerned about the safety of a pump in the engine bay, however so long as it is secured properly and all hoses are clamped well, i cant see it posing a terribly significant problem. I would be more concerned with the effect that the heat in the engine bay would have on the components in the pump (presuming it is an electric unit). Being on the left, it is slightly less likely tcatch fire if omething goes wrong, as at least it is not within a hop and skip of the alternator.

    Ideally, I would get a new pump (of the same type if possible considering it seems to work well), and still consider moving it outside of the engine bay... this way there is little risk of a catastrophic fire in the relatively unlikely event that the pump goes pear-shaped, but more to the point, the pump internals will not be compromised by heat so quickly.

    ANyway.. I think it should be fine in the meantime so long as everything is secure and the pump is in good working order. :cool:

    Considering the van has been sitting for some time, I would strongly suggest replacing the fuel lines anyway however, so it may be best to buy a new pump and relocate it whilst all the plumbing is out. ;)

    Kieran
     
  8. R Mac

    R Mac New Member

    Messages:
    3
    Location:
    Adelaide, SA
    Yep its an electric pump and we discovered that there is a gremlin in the wiring between the coil and the pump, so its getting no charge when the ignition is on. Luckily dads got a bit of experience with car wiring so it should take too much to sort it out.

    On the fuel lines, I want to get the van on the road first so we can pick up any other issues we have and the existing 4.8mm rubber line will do short term. Will replace with the correct 5mm cotton line prior to regular driving and long runs. As for relocating the pump, I?ll definitely keep that in mind for down the track. Thanks for the advice.
     
  9. Schmoburger

    Schmoburger Active Member

    Messages:
    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    Here are some more piccies to supplement teh text... freshly taken yesterday. :cool:

    Finally got off me lazy ass! :lol:

    Here is the right hand carburetter fitting clamped and wired up... the clamps and wiring job arent as good as Tom's but they still do their job very well...
    [​IMG]

    Here is the left hand carb...
    [​IMG]
    [​IMG]

    This is where your fuel filter should be fitted... right below the fuel tank, BEFORE the pump... it should be the first item in the fuel system after the tank itself.
    [​IMG]

    The fuel line I am holding aside in this picture is the one which plugs into the t-section between the carbies, or feeds the single carburetter on a 1600 powered Kombi. If you follow it up to where it seems to almost dissapear.. that is whgere the grommet is...you can only just make it out.
    This picture is taken from under the Kombi, between the RH back wheel and the transmission looking backwards. the item to the right is the starter motor.
    [​IMG]

    Here is the stock fuel pump, with the inlet and outlet hoses secured with clamps and wire... again, the wiring looks dodgy, but is quite secure. the left hose is the outlet hose to the engine, the one on the right is the inlet from the fuel tank via the inline fuel filter. This is a single piece of wire wound around the pump body a few times, with each end wrapped around one of the hoses and clamps.
    [​IMG]

    Here is the retaining tab that holds the left fuel line against the firewall and out of the way. it is rather sharp, so if your bus still has it attached, it is a good idea to do as I have done and wrap that section of hose in heat resistant tape. This item is located between the T and the LHS carb on the firewall.
    [​IMG]

    Here are examples of GOOD and BAD fuel lines...

    This one was fittewd between the RHS carb and the T on my bus when I bought it... it is too narrow a diameter, and as a result, as it has hardened it has split and cracked around the ends from being overstretched. This line was also stretched far too tightly between the carb and T, and hence had started to slide off the fitting. It was removed and replaced promptly... remember tho that this cracking also occurs on hoses that are the correct diameter as they begin to degrade.
    [​IMG]

    This fuel hose is the correct diameter, however it has hardened and deteriorated with age, exposure to heat and fuel. I am pressing quite hard on this hose, however you will notice it does not squash at the end... this means the hose is past it and is not what i consider servicable.
    [​IMG]

    This is a brand new unused length of hose, of the correct diameter. You can see it is free of cracks, and squeezes out of shape when pressed between a finger and thumb with firm pressure. This means the hose is servicable.
    [​IMG]

    here are two lengths of fuel hose... the one on the right is the correct diameter for a Kombi, the one on the left is too small and should not be used.
    [​IMG]

    Cheers! :cool:
     
  10. Schmoburger

    Schmoburger Active Member

    Messages:
    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    No wukka's mate... every person that reads this and takes heed is another person who wont contribut to the death of a Kombi. :cool: :D

    On the subject of the fuel lines again... I really do insist upon taking out each one and checking them thoroughly for defects if nothing else... In the long run it is really not worth not checking... and I strongly advise replacing them anyway. :)

    The unfortunate fact is that many people who have bought buses (or bugs or type 3's), figure that the fuel lines can wait... this is sometimes a bad mistake... I consider installing new and correct fuel lines to be as important to the safety of both the car and driver as having the wheel nuts tightened. driving on old or incorrect fuel lines is like driving with the front wheelnuts done up finger tight. :shock: :lol:

    I dont want to seem pushy, but I cant stress enuff the importance of impeccably maintained fuel plumbing... a perfectly restored bus can blow up in seconds due to something so seemingly small as substandard fuel plumbing. This one did about a month ago...

    Before...
    [​IMG]

    After...
    [​IMG]

    All fuel lines that break and burn are "just fine" until they break... It seriously isnt worth the risk putting off maintenance until "tomorrow" or "next week" or "when the bus is back on the road"... a lot of Kombi's burn up in their own driveway! :shock:

    Cheers mate... sorry if I seem to be using a harsh tone... just trying to beat the importance of good fuel lines into everybody's head until it hurts.... cos they are THE single most important thing to get right. :cool: :lol:

    Kieran
     
  11. Racer X

    Racer X New Member

    Messages:
    83
    Location:
    Adelaide
    so bad fuel lines caused the fuel smell i had in my old bay thought it was the proximity of the engine to the cabin could be fortunite that my bus got hit by a truck before it burnt down. could be a common thing for new owners of kombis i myself only owning 2 now thought it could have been common and normal to have a fuel smell thanks for the info
     
  12. Schmoburger

    Schmoburger Active Member

    Messages:
    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    yep.. could have been bad fuel lines. Also, a petrol smell can be caused by a perished rubber elbow in the fuel filler tube.;)

    A slight petrol smell can come through the heaters (when turned on) occasionally on a lot of buses, and is often harmless... however any petrol odour should be checked out and have it's source positively identified, especially if it is always present. :)

    A leaking fuel filler neck will often cause a strong petrol smell most noticable when turning left, and should be repaired.
     
  13. Racer X

    Racer X New Member

    Messages:
    83
    Location:
    Adelaide
    never had a problem filing up no leaks there just a constant smelll matters not now ive lost the van if anyone finds a 75 bus in the wreckers left hand back pulled away from the van the gearbox is good and starter ok too
     
  14. Schmoburger

    Schmoburger Active Member

    Messages:
    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    With the recent spate of Kombi burnings on the left coast, I thought it worth bumping this post to the top again... perhaps Brookie you could sticky it. :)

    Cheers!
     
  15. brookie

    brookie Guest

    Done-don't know why it hasn't been "stickied" already:)
     
  16. kombikid76

    kombikid76 New Member

    Messages:
    652
    Location:
    sunny sydney
    Nice thread schmo. Bus i got atm had 2 fuel filters after the pump insider the engine bay and none before.... makes you wonder doesnt it?

    The heat of the crankcase probably wont be enough to ignite fuel, the main concern is sparks in the dizzy igniting the fuel if you do spring a leak ; - )
     
  17. Benniee

    Benniee New Member

    Messages:
    28
    Location:
    Newcastle
    Just thought I would post a question on this one....

    Why not use braided fuel line? Would it increase the time between changes?

    I remember having a modified car years ago and when getting my engineers check I had to replace a lot of fuel + hydraulic lines with braided lines.

    Benniee
     
  18. syncro

    syncro Well-Known Member

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    8,875
    Location:
    Southern Highlands
    One of the most dangerous things is having an electric pump connected to the ignition. Engine stops, pump keeps pumping.
     
  19. Schmoburger

    Schmoburger Active Member

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    4,381
    Location:
    Nowra/Jervis Bay area, NSW.
    steel braided or cotton?

    Cotton braided ones from Germany are considered the most long-lasting and safest of the standard fuellines, and some will last a fair while before they start to break down and perish.. hence i referenced them before. :)

    I wont touch any fuel hoses from repco, autopro, supercheap etc... regardless of how good they are supposed to be.

    As for steel braided, it stands to reason these are even better still... but cost a motza in comparison to the OEM rubber/cotton ones which do the job just as well. :cool:

    It's basically horses for courses... by all means use steal braided lines if it makes you feel more secure as they will not do any harm... make sure however that the actual rubber hose inside is rated for use with petrol. :)

    ANd definitely be careful with electric pumps as Phil said... they can at best fill your cylinders and crankcase with petrol in the event of a mmishap and make life very difficult... at worst they can create a fireball which will make life even MORE difficult. :eek:
     
  20. syncro

    syncro Well-Known Member

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    8,875
    Location:
    Southern Highlands
    Also with an electric pump it is better to have the metal fuel filter on the pressure side as per the manufacturers. Electric pumps are cooled and lubricated by the fuel flowing through them. They get very hot very quickly if the filter becomes blocked and they run dry.
     

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