Fuel pump leak - changing out the seals

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MyBongoiscalledDave
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Fuel pump leak - changing out the seals

Post by MyBongoiscalledDave » Sun Jan 19, 2020 9:52 pm

Hey bongonauts,

I have recently seen a substantial fuel leak from the fuel pump. I've found the fact sheet on how to change the seals but I'm struggling with a couple of bits.

Firstly, my shovelhands don't fit in the hole to reach the two bolts at the back of the unit. I can reach them from underneath, but that doesn't seem useful. Also, my socket set doesn't have a socket shallow enough to sit over the bolts. Any ideas? Welding a 10mm socket to a piece of flat bar or something?

Also, how many seals are there and where can I source them from? And why do you have to have to take the bell housing off if the seal is at the back? Or is there one inside the bell housing too?

Thanks in advance.

Regards,

Adam
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Re: Fuel pump leak - changing out the seals

Post by Ian » Mon Jan 20, 2020 9:57 am

Adam, can't help with the fat fingers problem I'm afraid. But we do have a set of seals and shims in stock, see https://bongoland.co.uk/product/diesel-pump-repair-kit/
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Re: Fuel pump leak - changing out the seals

Post by g8dhe » Mon Jan 20, 2020 11:33 am

A while ago now but dandywarhol put up a handy post https://www.igmaynard.co.uk/bongo/forum ... =3&t=15644
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MyBongoiscalledDave
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Re: Fuel pump leak - changing out the seals

Post by MyBongoiscalledDave » Wed Jan 22, 2020 4:06 pm

Thanks for the replies guys. And for the link.

I am wondering if there is anyone who sells just the seals for the job, rather than buying the the entire lot for the whole pump.

I had a little Google, but didn't come up with anything.

Any ideas?
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Re: Fuel pump leak - changing out the seals

Post by teenmal » Wed Jan 22, 2020 11:13 pm

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Re: Fuel pump leak - changing out the seals

Post by JulesMartin » Thu Jan 30, 2020 6:51 pm

Hi Teenmol, I've just done this job on mine this afternoon and can't see how anybody can get their hands down between the pump and engine so hats off to those who can. I took all the injector pipes off and the little motor thingy on the top of the pump that's held on with two of the four 10mm bolts with crossheads on them. Be really careful if you go down this route as the tiny drive shaft underneath this has to line up with the slot underneath it and there is a spacer under the top bolt. Follow the factsheet and you won't go wrong. You'll need a mirror to see what you are doing. halfords do an excellent mirror that has lights on it as well. If you can't get your hand down the back then you'll need to pick the seal out by reaching up from underneath. with the injector pipes removed you can get your left hand in from the back of the pump and right hand up from under the pump, all by standing in the doorway you don't have to lay underneath. I used a mirror and a bent safety pin to pick out the seals. It is a nasty job it has to be said but worth doing. my old seals were rock hard and once done it's quite an achievement.
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Re: Fuel pump leak - changing out the seals

Post by Bob » Thu Jan 30, 2020 7:29 pm

Jolly well done. =D>
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Re: Fuel pump leak - changing out the seals

Post by MyBongoiscalledDave » Fri Jan 31, 2020 8:21 am

Well done! I'm off to but the parts for this afternoon.

I'm going to buy the Bosch fuel pump repair kit because I can't find the newer green seals for sale on their own anywhere but they seem to be in the kit from mazdabongo.com which is pretty close by to me.

I'm guessing there is one seal behind the bell housing and one behind the piston plate, correct? So two seals replaced completes the job.

Sorry to be anal about this, I'm just a little confused and want to have as good an understanding of the job before I tackle it.

And I've enlisted the help of a small handed welder to do the tricky but behind the pump!
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Re: Fuel pump leak - changing out the seals

Post by JulesMartin » Fri Jan 31, 2020 11:23 am

Yep correct two seals one behind the bell housing visible on the side of the pump nearest to you and the other on the inside of the pump. I ordered my two seals from here and they are genuine Bosch parts and fit really nicely and easily once you can get your fingers in the right place. if you are going out shopping see if you can pick up a 10mm ratchet spanner this really helps round the back of the pump as there is not really enough room for sockets
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Re: Fuel pump leak - changing out the seals

Post by Northern Bongolow » Fri Jan 31, 2020 12:54 pm

I'm the same as you and will have a go at most things with confidence.
I bought a second hand pump off eBay for £30, pulled it apart on the bench to see what sort of job it was to do a full rebuild. 3 years later it's still in a bucket in a million parts. Another on of life's lessons learnt.🤔
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Re: Fuel pump leak - changing out the seals

Post by JulesMartin » Fri Jan 31, 2020 2:58 pm

I think it's all about making a decision about what you can/maybe do and what you can't. What needs to be done and what you'd like to do (if it ain't broke don't fix it) and preventative maintenance and finding a happy balance between them all. Good quality tools is also a help. this posts job is simply not possible without mirrors and torches.
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Re: Fuel pump leak - changing out the seals

Post by Northern Bongolow » Fri Jan 31, 2020 3:44 pm

Don't forget the hands of a ladies doctor and the fingers of a harp player.,😁
MyBongoiscalledDave
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Re: Fuel pump leak - changing out the seals

Post by MyBongoiscalledDave » Wed Feb 19, 2020 2:24 pm

So how do you stop the springs from falling out, it feels like they're not gonna simply stay put when I take the housing off ...

Any ideas?
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Re: Fuel pump leak - changing out the seals

Post by MyBongoiscalledDave » Sun Feb 23, 2020 1:24 pm

Well I've replaced the two seals! I used the priming pump on top of the fuel filter to prime the pump and it started reasonably easily. On a test run it seemed okay, until I reached 4000rpm where I'm getting a flat spot where it won't rev any further, both when in drive and and park on the drive. Is this likely to be because of putting the font housing back together wrong? I followed the factsheet. The two shims sat back in the housing and I replaced the seal without taking the springs out but I feel like I'm missing something. In the photo on the factsheet there was the housing, the shins and another part that I didn't see when I took it off. Does this sit in the housing and I just didn't take it out or have I lost it without realising when I took it off?

It does drive okay, but seems to underpowered and obviously won't rev over 4000rpm.
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Re: Fuel pump leak - changing out the seals

Post by Northern Bongolow » Mon Feb 24, 2020 1:13 am

The bit behind the seals that goes all the way through side to side is I think called the advance piston, this enables more fuel to be delivered before it is needed inside the pump, failure to put it back together correctly could give your symptoms.
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