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  #11  
Old 23-09-14, 12:18
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brm1286 brm1286 is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

Any update on this?

I imagine if you catch it early enough, then you won't cause too much wear to the pushrod/ mechanism. If it's rattling for a long time then something has to be wearing/ deforming so the longer it rattles, the more damage will be done.

Time to give mine a go it seems!
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  #12  
Old 23-09-14, 12:28
theboywonder theboywonder is offline
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Join Date: Nov 2012
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T4 Post Icon Re: 2.5 Vacuum Pump stripdown and fix.

Hi, I'm a new chap to posting but having trawled the site looking for solutions to the rattling vacuum pump I decided the best option was to buy new. As budget is tight (as always) I opted for eurocarparts Dansk unit about 140 all in. Made by Mechanex which could be "made in China" for all I can tell. The casting looked OK and the fit was near perfect so hoping for the best. However, push rod/tappet bar was bought from VW main dealer at 40. It was whilst I was speaking to the parts guru he mentioned that it was unlikely that this rod would wear considerably and to that end they rarely change it but do change the pump. I still bought it just in case and after fitting the rattle has gone. I guess its up to you guys to decide whether buying a new rod is a waste of money or not. Back to the other issues with the good old VW.
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  #13  
Old 30-09-14, 23:24
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Abyss Abyss is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

agreed, the rods aren't the problem, VW are. They mounted them on the heads incorrectly (wrong angle).
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  #14  
Old 01-10-14, 09:54
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welshjas welshjas is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

ebay 59 vw crafter vacuam pump fits and does the job mine was perfect
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  #15  
Old 06-10-14, 21:06
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Fatboy35 Fatboy35 is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

Further to the excellent First post, a few pictures.

NOTE. I have not fitted or proved the strip / rebuild yet, but a bench test showed a Vacuum IS being drawn

****Pump now fitted, all good, no 'tapping'***


Cleaned ready for strip down.



Cover removed (T25 Torx x6)



Close up of uncleaned seal (stuck in place) and NRV's



Seal removed



Seal and NRV's removed with piston removed



Piston, pushrod and spring assembly removed but in order



Cleaned and reassembled (note: I did not clean the NRV assemblies, I don't know how fragile they are)



Block side (seal requires replacing)



How I 'THINK' it works.


Spring pressure draws piston back 'Drawing Vacuum'



Cam acting on on pushrod moves piston out preparing for 'Vacuum draw'


I think the cam and push rod are supposed to be in contact at all times using spring pressure to maintain contact. When it fails, oil gets trapped behind the piston and stops the spring short of full extension, creating a 'break' in contact between pushrod and cam, the 'Tap' is the contact forming again on the next cycle (I 'think' )


Hope the pictures compliment the excellent initial post.


Chris

***Pump now fitted, all good and no 'tapping' since fitting***

'There's a lot to be said for understatement'

Last edited by Fatboy35; 12-01-16 at 19:27. Reason: Post fitting update
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  #16  
Old 06-10-14, 22:13
aladins78 aladins78 is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

Quote:
Originally Posted by Fatboy35 View Post
Further to the excellent First post, a few pictures.

NOTE. I have not fitted or proved the strip / rebuild yet, but a bench test showed a Vacuum IS being drawn


Cleaned ready for strip down.



Cover removed (T25 Torx x6)



Close up of uncleaned seal (stuck in place) and NRV's



Seal removed



Seal and NRV's removed with piston removed



Piston, pushrod and spring assembly removed but in order



Cleaned and reassembled (note: I did not clean the NRV assemblies, I don't know how fragile they are)



Block side (seal requires replacing)



How I 'THINK' it works.


Spring pressure draws piston back 'Drawing Vacuum'



Cam acting on on pushrod moves piston out preparing for 'Vacuum draw'


I think the cam and push rod are supposed to be in contact at all times using spring pressure to maintain contact. When it fails, oil gets trapped behind the piston and stops the spring short of full extension, creating a 'break' in contact between pushrod and cam, the 'Tap' is the contact forming again on the next cycle (I 'think' )


Hope the pictures compliment the excellent initial post.


Chris
Great post. That's also how I think it works.

I can confirm that cleaning does stop the tapping however I've done it twice and both times it's come back after 5-7k
My vans done 245k and I've no record of it ever being changed or for how long it was tapping before I got the van.
I suspect my pumps to worn for cleaning to work as a permanent fix. But if your van has less miles or you do less than my 12-20k a year it's well work the time and effort to try cleaning it first.

Gavin
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  #17  
Old 07-10-14, 07:10
JonCa JonCa is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

Just a question / thought

All the inlet/exhaust valve stems have an oil seal on them. Is there a similar seal on the vacum pump push rod that needs replacing as well as a clean/de-oiling of the pump itself
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  #18  
Old 07-10-14, 10:46
cumbriankeith cumbriankeith is offline
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Location: Grange over Sands
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Default Re: 2.5 Vacuum Pump stripdown and fix.

What an excellent how to, now with pics - always makes it so much easier for us to see what's going on and whether we like the look of doing it.

I had mine off a while ago due to a bit of an oil leak from the "seal" onto the block, which had failed. As already said it's a daft design/application for the pump, being mounted with oil collecting down into/onto it.

I wonder whether I should get it off again for a strip/cleanup... ? Does leaving it getting oily inside actually cause the problem to occur/get worse? I don't think mine is actually noisy, yet - done 155k.
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  #19  
Old 09-10-14, 07:31
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welshjas welshjas is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

oh well that's my next job after last camp nov 7th lol awesome pics I think ill be giving it a go
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  #20  
Old 09-10-14, 19:15
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Abyss Abyss is offline
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Default Re: 2.5 Vacuum Pump stripdown and fix.

glad to see one of my spare pumps being put to good use, didnt know you were stripping it down for this Chris

Still got some more if anyone wants
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