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Leaking 1.5 bmc fuel filter


Pamber1106

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Just changed fuel filter on 1.5 bmc engine. Diesel seems to be gathering around the bottom of of the filter housing have fitted new seals as per workshop manual. Any ideas help much appreciated. Thanks in advance for help 

 

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Have you fitted all 4 new seals?  No twists in either of the big ones? You worked out that they are different sizes?

 

The tiny o ring goes under the steel washer on top.

 

Check with tissue, preferably blue, to establish were it is leaking from.

Did you undo any unions?

Edited by Tracy D'arth
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It can be very easy to get the element slightly cocked in the housings. The top and bottom seals are slightly different so make sure you have them in the correct place and then when you tighten the centre bolt only tighten it until the element just about touches that seal but while you can still twist the element. then gradually tighten the bolt while twisting the element. If you hear or feel metal to metal scraping rather than resistance  as you tighten up onto the seal the     element is cocked.

 

  • Greenie 1
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Hello thanks for help. Had two large seals in packaging and one small o ring. Have fitted o ring under washer and one seal top and bottom. Could this be problem. Trouble is last person who owned her was a bit off a texas ranger when came to looking after her. So only put it back way it came out so it could be wrong. 

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The top seal is a bugger to get in square. I had a similar issue the first time I changed my fuel filter, learnt lots of lessons about checking it was seated correctly but still struggled with leaks the next few times too. The only difference was knowing where the problem was likely to be.

I found it wasn't enough to feed the seal in by hand, instead, get a thin electrical screwdriver, or something similar AND PREFERABLY BLUNTER to make sure the seal is pushed fully up into the housing.

 

Rob

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25 minutes ago, Pamber1106 said:

Hello thanks for help. Had two large seals in packaging and one small o ring. Have fitted o ring under washer and one seal top and bottom. Could this be problem. Trouble is last person who owned her was a bit off a texas ranger when came to looking after her. So only put it back way it came out so it could be wrong. 

 

Have you checked you have the two large seals in the correct place. Easy to get wrong. The "small" O ring should be two and two different sizes. The larger one goes around the neck that hangs down under the filter head. I doubt it will hurt if you leave the old one of these in place for one filter charge. The smaller one goes around the bolt on the outside BUT:

 

It has been known for pattern filter suppliers to supply an undersized O ring that will leak.

 

Early versions did not have a O ring around the bolt but did have a soft washer. If the top of the bolt hole has a taper then it needs the correct O ring. If its just a machined flat then its a soft washer. I would try to get a Dowty washer from choice

 

Neither the above will cause a leak around the base but incorrect fitting and using the wrong large o ring can.

7 minutes ago, p6rob said:

The top seal is a bugger to get in square. I had a similar issue the first time I changed my fuel filter, learnt lots of lessons about checking it was seated correctly but still struggled with leaks the next few times too. The only difference was knowing where the problem was likely to be.

I found it wasn't enough to feed the seal in by hand, instead, get a thin electrical screwdriver, or something similar AND PREFERABLY BLUNTER to make sure the seal is pushed fully up into the housing.

 

Rob

 

^^^^^^^^

 

This plus twisting the canister when refitting as I explained earlier but if the leak is not running down the outside of the filter it can't be this seal.

 

Dry the whole assembly off and dust with talcum powder and run the engine. The talc should go dark where the leak is. Alternatively wrap some tissue around the filter so you can see if its leaking from above or below the tissue.

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If there were only 3 seals in the kit, its a poor pattern part.  Buy better not cheaper.

Look at the diagram. 

From the bottom you have the smaller of the two square section o rings, the filter, the larger of the two square section o rings, the o ring about 20mm in diameter in the groove on the stem of the filter head, and then the tiny o ring on top of the filter head under a steel washer on the through bolt.

.

Ensure that there is not an old ring in the filter head preventing the new one seating.

 

Its very easy to get a twist in the o rings.

 

If you still cannot get it to seal as I said before,  establish from where it is leaking and come back to us.

 

I will ask again, did you undo any unions?

 

Some pictures may help.

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1 hour ago, Pamber1106 said:

OK. Thanks. All unions good and tight it's just seeping from bottom. The filter is a good old fram one. I will pull it apart weekend and see what I got. Like said many thanks for help and reply l

 

1.5s don't usually have a drain screw in the bottom of the bowl but its a standard CAV item so someone might have fitted a bowl with a screw to yours. If so is the soft washer/O ring on the screw leaking.

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4 minutes ago, Pamber1106 said:

No drain hole in this one. Many thanks for the thought. Gonna strip it out and try again. But still puzzled why so many seals perhaps because it may be different ones for other applications 

 

The same head plus an inverted cone fitted can be used with a different bowl for a sedimentor (water trap). In its day it was and still is a very common design of filter and was found on a wide range of vehicles. It can also be used with a longer filter and the same basic design was cast in pairs so one double head supported two elements.

 

It is relatively recently that spin on filters became popular. I suspect as a result of many in the motor trade being less skilled.

 

I susepect that you will find you have the thin "top" O ring in the bottom.

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4 minutes ago, OptedOut said:

 During our time in a private boat share we never changed any seals, same when we owned a Land Rover. Must have been lucky!

 

Within reason  don't think you were lucky. On the courses and based on my experience with "Saturday" turn round "engineers" I advised leaving them alone for the first couple of changes until the students were more confident.

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50 minutes ago, Pamber1106 said:

No drain hole in this one. Many thanks for the thought. Gonna strip it out and try again. But still puzzled why so many seals perhaps because it may be different ones for other applications 

No, all the seals are for one application, no spares, in fact, if you had only 3 you are 1 short.  You need all the seals !

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32 minutes ago, Tracy D'arth said:

No, all the seals are for one application, no spares, in fact, if you had only 3 you are 1 short.  You need all the seals !

 

Ah, I thought he was complaining that those filters have far more seals than modern spin ons.

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18 minutes ago, Pamber1106 said:

Ah so two   big ones  on top and two on bottom. Plus one little one for bolt. Could explain why leaking only had one one each when took it apart. 

 

Do you mean that you never removed the old seals? It will never work like that.

The filter top one goes in a groove in the filter head and the bottom one fits inside the bottom cup and the recessed part at the end of the filter.

 

So you are OK now?

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28 minutes ago, Pamber1106 said:

Ah so two   big ones  on top and two on bottom. Plus one little one for bolt. Could explain why leaking only had one one each when took it apart. 

 

 

Two large seals roughly the same diameter, one wide in cross-section and one thin. The wide one site in the recess to the bottom  filter bowl. The thin one fits into the groove in the filter top. If you have not removed the top one when you took the old filter out then that is the problem as Tracy says. If this is the case I would advise that you leave the old one in place and reuse it. If it did come out take great care in fitting the new seal because its all too easy to twist it. Then (as advised by someone else) use something like a blunt thin screwdriver to make sure its fully pushed up into its groove.

 

You should have two much smaller ones (I know you only have one). The smallest goes around the bolt as long as the top of the bolt hole in the head has a taper. The larger one goes around the nose hanging down from the middle of the filter head but if you do not have this one just use the old one. This one can't create a leak.

 

Unless you do as I suggested and identify exactly where the leak was coming from we can't really answer your question. You have had much detailed advice but provided little feedback re exactly where the leak was, which seal you put where and so on. You were even given an exploded view showing what went  where.

 

There is supposed to be only one seal (the correct one) in each position, so only having one seal in each position that has been correctly fitted should not cause a leak. Incorrect assembly will. The usual problems are not fitting the top seal correctly or fitting the filter slightly cock-eyed so part of the top sits against the metal filter head rather than the rubber seal. The diesel then runs down the filter and pools on top of the joint between filter and bowl. That makes novices think the leak is from the bottom.

 

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45 minutes ago, Pamber1106 said:

Many thanks for your help. Yes you are correct as it does pool around the bottom of the filter housing. Much appreciate your time and knowledge 

 

So on balance its the large top seal that is the problem. As repeated above: twisted, two where there should be only one, not in its groove all the way round or the filter cocked in the top housing.

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