Bosch Diesel Injection Pump Disassembly

Unread post by **KennyW** » 30 Oct 2009, 20:53

Did they change the VP20 pump from all mechanical to semi electronic late Mk1 or at new body etc Mk2.

This is my pump no 0 460 494 455 which is not much different from yours Mike.

Kenny

Unread post by **CitroJim** » 30 Oct 2009, 20:54

It changed to the AS3 (armoured, semi-electronic) in '95-96 Kenny, at the same time as the keypad appeared....

Unread post by **KennyW** » 30 Oct 2009, 21:07

Thanks Jim, I was thinking not to put the armour back on the pump but after reading the post about insurance companies and my knowledge of how they work I WILL put back the armour

Kenny

MikeT · Unread post by **MikeT** » 30 Oct 2009, 22:17

Now we have the distributor head and governor levers out the way we can begin removing the heart of the pump. Looking in through the end, we see the camplate. This just lifts out....

Like so...

and then a spring..

There are four rollers...

and a part who's name escapes me right now

MikeT · Unread post by **MikeT** » 30 Oct 2009, 23:17

The rest is held in place owing to a small clip that covers a dowel pin which can be picked out with a slim bladed screwdriver. Be careful, it's very highly tensioned and will gladly fire up into your eye

With that out of the way, the timing pin can now be moved up and out of the timing piston.

Lift out the roller ring, squarely

and the timing pin still held inside it

With the timing pin out, remove the timing piston covers either side of the pump (your pump may differ slightly but be basically the same)

The timing piston is now free to slide out of it's housing leaving the pin holder to just fall out.

MikeT · Unread post by **MikeT** » 31 Oct 2009, 21:48

KennyW wrote:This is my pump no 0 460 494 455 which is not much different from yours Mike.

I suspect yours is identical to the one on my Xantia Kenny though they are all similar looking as that's the VE series for you!

Both our Xantia's pump numbers comes back as VE4/9F2250R610-5 whereas the one I just pulled off a P-reg MK1 Xantia is VE4/9F2250R610-2

They are VE's for 4 cylinders using a 9mm plunger with a max rpm of 2250. I believe the "R" depicts the rotation R (Right) for clockwise. And that's all I know so far until I get hold of some Bosch data.

Needless to say I now have an armoured pump to tackle, once I've finished this Pug one.

MikeT · Unread post by **MikeT** » 01 Nov 2009, 17:34

With the main shaft free, just push/pull out through the pump, bearing in mind the small woodruff key will also be loose and easy to lose.

And finally we get to the vane pump - the heart of the pump IMO. Looking inside we see a pair of Torx T20 bolts clamping the eccentric vane pump in it's housing. Simply undo and lift out the cover plate and then the vane pump wheel and it's vanes.

These vanes are designed to slide up and down their slots against the pump body as the eccentric wheel rotates, causing the paddling/pumping of the fuel.

However, these were very resistant to moving and two may have possibly been seized in position which would had a major effect on the pump's efficiency IMO.

MikeT · Unread post by **MikeT** » 01 Nov 2009, 18:25

Although I was hoping to show a complete strip down, some of you may have noticed a few omissions but apart from the main shaft bush, they are unlikely to leak anyway. What I will single out is the vane pump pressure valve which I purposely left until last as it's very useful to understand how this valve works.
A 12mm deep socket can be used to remove it.

In the post above, I said IMO the vane pump is the heart of the design and this valve, together with the restriction in the outlet and the viscosity of the fuel is what determines the pump's internal low-pressure circuit (assuming a perfectly working pump) and like many parts of this incredible design it is also adjustable. 8)

MikeT · Unread post by **MikeT** » 02 Nov 2009, 11:57

That's about it and in the words of the BoL, re-assembly is a reversal blah blah blah. Any questions?

What I would like to add is this pump was in a pretty poor state - the LDA full of engine oil, one seal weeping, lots of rust and/or varnish deposits and a possibly failing vane pump. And I also believe the timing device had restricted movement if not completely seized. Having said that, I'm willing to bet it would still have started and ran the engine.

Next up will be a MK1 Xantia pump taken from a running car that was fuelled on diesel AFAIK. I won't blog the complete job, just the differences which from appearances means the armour, immobiliser and timing actuator.

Unread post by **CitroJim** » 02 Nov 2009, 22:30

The contamination/varnish you have found in your pump is pretty typical of the ones I've pulled apart Mike. Do you know what fuel the car was running last time it was in use.

Yes, the pump would likely start and run the car but a bit roughly.

I've found the LP relief valve seized a few times too, which would result in high transfer pressure and lots of leaks.

Before you wax too lyrically about the incredible design of a Bosch, go do the same on a Lucas DPC. It makes the Bosch look a bit basic and crude. Do you fancy a donation of a scrapper to play with? I have one that was very heavily contaminated with bio and is beyond repair but perfect for a guide on how to strip them...

MikeT · Unread post by **MikeT** » 02 Nov 2009, 23:51

Look back in the thread Jim and see the bottle of fluid I drained. I think it was WVO though I'm only guessing not having seen/smelt the stuff before. It had a strong smell of white spirits but an oily texture. Whatever the orange contamination is, it was worse around the driveshaft coupling end and in between parts from the vane pump to roller ring. The governor appears to have been immune as does the plunger area though rust/varnish is again mildly evident near the distributor head o-ring.

I'm not up on the pressure valve mechanism yet, can you move it easily to test for operation? And talking of which, I haven't matched up the new seals either, are the valve pair included, it seems a fairly basic kit?

I'm surprised biodiesel has caused any pump problems as I've read nothing but advantages of using it - so much that I'll be trialling it myself. Unlike WVO which I have no confidence in.

I'd like to take you up on the offer of a lucas but I've taken on too many projects as it is and there's two more VE's to go yet. Is it possible you can keep it available for an extended period for me, Jim?

Unread post by **CitroJim** » 03 Nov 2009, 13:19

Mike, it's here whenever you want it. It's not eating anything (except perhaps itself from the inside out) and not taking up space...

Yes, the pressure relief valve can be checked by depressing its middle against its spring.

MikeT · Unread post by **MikeT** » 03 Nov 2009, 14:41

CitroJim wrote:Yes, the pressure relief valve can be checked by depressing its middle against its spring.

Just needed to be sure before I inadvertantly reset the pressure setting. I think it resisted initially but it's now free so all fine on that score, thanks.

I've begun the rebuild but won't bother blogging it as A) It's a reversal of the disassembly procedure and B) It's already been done on that VW site.

Any thoughts on the "fuel" I drained from the pump?

MikeT · Unread post by **MikeT** » 04 Nov 2009, 12:43

I'm now convinced that all the orange contamination seen was gum/varnish and not rust (except the external distributor head).

It seemed to have mostly concentrated around the camplate (heat related?) with the main shaft-to-plunger coupler suffering the worst. The camplate was a close second and at least two of the three rollers were seized because of it. Also cleaned out a lot of it in the spring recesses on the distributor head (where grease was also found from previous assembly).

The timing relies on a pressure differential to push the camplate against a fixed spring. Assuming the vane-pump pressure was accurate (which is already suspect due to the stuck vanes found), I would think the additional resistance caused by the gum on the rollers would have restricted ignition advance quite noticeably.

I have said before I have no confidence in WVO and these findings only re-inforce my opinion whereas I'm still happy to use SVO at this point in time.

Unread post by **KennyW** » 04 Nov 2009, 21:17

Hi Mike and Jim,

Just a wee update re the removal of the pump.

All your tips etc were correct but I had a minor faux pa

I got a ratch moon shape spanner from a friend who has own garage. Located problem nut under pumpo and slipped the spanner on and off i went and then realised i had ratched set the wrong way

Threads are now shreaded

But another friend suggested I lock a 2nd nut on thight and unscrew the stud instead.

In order to do this i had to stripe the HP pump, Alternator and braket to give more room.

I must admit it did not take long and the room and view is better.

Once the nut is off and the bolt is remove the pump will be off.

But my wife's car is blowing from the back box so guess what i have to do first

Kenny