Replacing Fuel pump seals (with pics) *DONT DELETE*

Technical questions and answers about the Mazda Bongo

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dandywarhol
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Replacing Fuel pump seals (with pics) *DONT DELETE*

Post by dandywarhol » Fri Oct 19, 2007 4:56 pm

I replaced the pump seals today and took a few pics along the way.

Here's where the leak can be found.

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Running your hand under here will show up the leak.

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Tools needed for the job:

10mm combination spanner
10mm socket/extension/ratchet in 3/8 size
Smallish hands
Patience
Ability to visualise what can't be seen. :?

1. Check you can get your hand/fist in this space. If you can't, get someone with a smaller hand or a friendly Scout!

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2. Remove the power steering reservoir and air inlet pipe to help access the job.

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3. This is where the fuel leaks from. It's a domed cover which houses the adjusting spring and shims for the advance piston. Directly opposite it, at the engine block side, is a blanking plate which the advance piston stops against. This is where most pumps leak.

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Carefully remove the domed cover, there is spring pressure as you unscrew the bolts.
TAKE GREAT CARE THAT THE ADJUSTER PLUNGER AND IT'S SLEEVE DON'T FALL OUT!
There's a double spring assembly and shim set under them - easly lost if dropped! You will lose some diesel when you remove the domed cap.

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Then remove the plate diagonally opposite. This is the tricky bit as you are working blind, you'll have to visualise it. Hopefully the pic will help you feel where it is. The first pic is the plate with the score marks on it from the advance plunger bashing it for 12 years! I only had 180 grit emery paper but it did the job after finishing off with a rub with Tee Cut.

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These are the seals, the black ones are the originals. The green seals have a different section and ridges, presumably to seal better.

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Before removing the seal from the blanking plate side it is best to fit a new seal into the recess in the pump body (with some fresh diesel) and refit the domed cover and adjuster assembly on about six threads. Then there will be space behind the plunger to use a fingernail to prise out the original seal from the hidden blanking plate side.
"Feel" the new seal into it's recess behind the blanking plate and refit the cover. Remember this operation is blind, although a small mirror MAY help.

I don't have a torque setting for the 6mm bolts but be careful as you are bolting into an alloy housing. you'll get a feel for the torque when you remove the bolts initially. Then finally tighten the domed cover bolts evenly against the spring. Then refit the air filter hose and PS reservior.

You should now have a right wrist looking like this :lol:

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The pump will self bleed as you crank the engine over on full throttle and eventually start. This is an ideal time to test the condition of your battery :lol:

The complete job should realistically take about 1.5 hours, it's a bit of a faf but I instantly noticed the absence of raw diesel smell on it's first run :D

Someone please feel free to use this as a fact sheet - no responsibility etc. etc.
Last edited by dandywarhol on Sat Oct 20, 2007 2:35 pm, edited 2 times in total.
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Post by haydn callow » Fri Oct 19, 2007 6:44 pm

What a SUPER post. Very many thanks. Well done.
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Post by brorabongo » Sat Oct 20, 2007 12:21 am

Nice work!!

:idea: Do you think you would get a better view of the flat blanking plate from underneath the vehicle, or even reach it at all?

I have not had any leaks yet, and may never will. I will however, take a mental note of this thread just incase, but with my memory being as it is, I'll forget about it by next week ](*,) :lol:

Do I see a posiflow? I have a magnet on my fuel line, but I wonder if it does any good when using veg oil :-k
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Post by dandywarhol » Sat Oct 20, 2007 12:37 am

Hah, well spotted Donald :lol: My Yamaha came with the magnet blocks on it when I bought it second hand and I tried it on the Bongo. Actually forgot it was on til I had to move it to do the job today. :?

You can't see the blanking plate at all - you can only feel it and the bolt heads from below the pump. Once you've seen what it looks like you can then "feel" it - nothing falls out of there when you remove it.
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Post by brorabongo » Sat Oct 20, 2007 12:49 am

dandywarhol wrote:You can't see the blanking plate at all - you can only feel it and the bolt heads from below the pump. Once you've seen what it looks like you can then "feel" it - nothing falls out of there when you remove it.
Thanks, that will save me in the future, if ever I need too do that job.( [-o< not!!) as I'm sure I would of spent time taking the engine tray off, just find it's a no-go #-o :lol:
Cheers.
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Post by tridentlee » Sat Oct 20, 2007 9:51 am

fantastic write up & pics, i had mine done by my mechanic at work whilst he was doing a service on the bongo & he said it was quite easy to get to from underneath , but he does have access to lifting ramps, so ididnt get the sore arms , great item for anyone looking to do the seals on their pump, lee
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Post by rwill19050 » Sat Oct 20, 2007 7:34 pm

dandywarhol, 10 out of 10 and a Gold Star for the post, (and some soothing cream for the wrist :D )
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Post by mikeonb4c » Sun Oct 21, 2007 12:09 pm

This may sound sad, but this is most exciting thing I've read on BF recently. An invaluable piece of work. I have to face this job on mine and wasnt feeling confident to try it myself. Now I do. If I can't follow those instructions and pics then there's no hope for me! So thanks++++ Dandy for a superbly written up piece on one of the Bongos 'type fault' problems. It should be invaluable to many members.

When I'm next up in Scotland (which I hope wont be too long) I must drop by in Edinburgh and buy you a pint (or two)

Mike

PS - and I wondered if the pump might prime itself on the starter/key. One simple problem (hopefully) vanished

PPS - The O rings I bought locally look like the old ones from your Bongo. I'd have thought they'd be OK to fit but what your view - do you still feel strongly that the new ones you've put on are a 'must' - if so I'll order some
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Post by dandywarhol » Sun Oct 21, 2007 1:45 pm

Thanks for all the replies folks (also in PMs).
For the sake of less than £4 I'd fit the later type modified seals Mike. Even the originals are NOT round cross section, but there again they aren't quite square either.

Here's where I got mine: http://www.lawsondiesel.co.uk/
£1.65 each inc. VAT

PS.........pints greatly received :lol:
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Post by mikeonb4c » Sun Oct 21, 2007 2:30 pm

Thanks Dandy - I'll order some

Mike 8)
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Post by smartmonkey » Mon Oct 22, 2007 1:49 pm

Mike, dont worry when it won't start after you have finished the job. You sometimes have to crank them over for ages before it fires up. Just keep the throttle fully down and will go eventually. If your battery is a little down it migh need a jump or a re-charge before it fires. Sometimes the glow plugs have got cold before the diesel gets through so let them heat up a few times whilst you are cranking.

Don't forget to say hello on you way up the A1.

Cheers
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Post by mikeonb4c » Mon Oct 22, 2007 4:47 pm

smartmonkey wrote:Don't forget to say hello on you way up the A1
Cheers
Will do SM. It occurs to me that a nice trip might take me up past Lindisfarne and Berwick on Tweed, thence to Edinburgh and on. Now thats a trip I'd love from start to finish Beers etc along the way. I'll start formulating a plan 8)

Mike

PS - ordered O rings from Lawsons today. Nice people - I told them to expect the Bongo tribe in dribs and drabs (or is that Dabs :lol: )
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Post by dandywarhol » Tue Oct 23, 2007 12:11 am

They are nice people - Michael Lawson even took time out at his lunch break to show me a damaged pump etc.

Also transpired I took a fancy to his sister 20 odd years ago :oops: .......small world.......... :lol:
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Post by mikeonb4c » Sun Oct 28, 2007 12:22 pm

Well, I reckon a man's got to know his limitations
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And I think Dandy should be beatified. To say you need patience (of a saint) for this job is an understatement. You need stamina too.

Just spent longer than I care to admit to trying to under the bolts on the hidden backplate. I can get my hands in there and I can get the spanner on the nut, but I just can't get the force needed to undo them. For me at least, I found there's no space to get any force behind the spanner. I had a bit of luck getting one of them to move a smidgeon by using a long screwdriver to lever the spanner against the engine block, but then realised that was tightening it and not loosening it (something to watch out for on the visualisation front by the way - you have to think about it and when you are distracted by the other problems, its easy to forget). I was concerned anyway that trying to lever the spanner might result in damage to other delicate parts sited near the injector, should I slip while doing it.

Another worry was that the ring spanner didnt feet really snug on the bolt head - is it slightly worn? Might I risk burring it with my attempts. You can't see it to ascertain its condition.

So I paused and took stock of things. This is a job that separates the merely willing from the capable. Its not a job for a 50+ occasional DIY mechanic whose back doesn't like bending over for long periods and who has to have glasses perched on the end of his nose (these are the things that undermine your patience - I noticed my skill deteriorating over time). The leak itself has been present for a while and is relatively minor. A professional mechanic experienced with Bongos and working with a good set of tools etc. would probably have this job knocked off without too much hassle (Dandy suggests 1.5hrs) so - for me - the balance of risk against return makes it not worth persevering myself, much as I hate being defeated by the job. At least I've got the correct O rings and some instructions to give the mechanic who does the job.

I'm going to have a cup of tea and have a look at fitting a simple cruise control that BF member wrster kindly let me have. If I have better luck with that I'll report back later.

I thought I'd write the above promptly so others contemplating this job are able to consider the pros and cons.

Bye for now :roll:
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Post by smartmonkey » Mon Oct 29, 2007 2:52 pm

Well done for stopping Mike. Some peeps keep going without thinking and just bust stuff. You had a go and for sensible reasons made a strategic withdrawal - result one fully functional Bongo.

Due to my bad neck and appalling lack of talent I had to stop playing the guitar before I accoustically wounded someone. I think my withdrawal was a bit less sesible than yours though.