VW T4 Forum - VW T5 Forum banner

21 - 40 of 56 Posts

·
Literally, white van man
Joined
·
4,068 Posts
glad to see one of my spare pumps being put to good use, didnt know you were stripping it down for this Chris T:

Still got some more if anyone wants :ILU:
Well, It wasn't the plan to strip it because you said it was working, but so is the one I have on at the moment, however it 'taps' sometimes, I've just got a new set of Conti's for the steels and am a bit skint so I thought I'd strip it down, see how it works and have it ready for when I next do my oil change, swap it over and see how I go,

....and I had my phone whilst I was doing it so I thought pictures might help put it back together, one thing led to another and here we are LOL:

Just out of intrest, do you have to drain the oil to change it do you know?

Chris
 

·
Registered
Joined
·
779 Posts
My pump has been tapping for over 2 years (8000 miles) if the bus is parked up for a week it stops for a while so I'd hazzard a guess the oil drains back a little.
Is there a risk that leaving the pump to tap could also damage the camshaft?
 

·
Registered
Joined
·
3,259 Posts
Just out of intrest, do you have to drain the oil to change it do you know?

Chris
nope. All your oil sits in the sump, though expect some trapped in the vac pump.

I find my vac pump rattles more when im running low on engine oil. Top my engine oil up, and bingo it shuts up..kinda handy tbh lol When I say low, i dont mean massively low either, all within a litre (which is the difference between max and min marks on the dip stick)
 

·
Registered
Joined
·
75 Posts
emptied mine over the weekend. it was tapping really bad. it was full to the brim, emptied it out and pumped it a few times and lots more came out. refitted and its now quiet with no tapping noise. mine is a 1995 reg so probably taken 20 years to fill up!!!

A:A:

drew
 

·
Registered
Joined
·
779 Posts
nope. All your oil sits in the sump, though expect some trapped in the vac pump.

I find my vac pump rattles more when im running low on engine oil. Top my engine oil up, and bingo it shuts up..kinda handy tbh lol When I say low, i dont mean massively low either, all within a litre (which is the difference between max and min marks on the dip stick)

I thought I'd give this a try! I keep the oil half way on the level mark 3/4" bend in the dipstick, but reading this I've topped it to near the top limit of the acceptable level mark & the pump has shut up even though it was tapping loudly before hand, done a couple hundred miles & still quiet?

Why would this make any difference?

Maybe its worth making everybody aware.
 

·
Registered
Joined
·
3,259 Posts
I thought I'd give this a try! I keep the oil half way on the level mark 3/4" bend in the dipstick, but reading this I've topped it to near the top limit of the acceptable level mark & the pump has shut up even though it was tapping loudly before hand, done a couple hundred miles & still quiet?

Why would this make any difference?

Maybe its worth making everybody aware.
Go on then, tell everyone! :D
 

·
Registered
Joined
·
835 Posts
This thread helped me at the weekend so here's the pics of mine. I had the rad off to change so seemed a sensible time to do this. Will know if it's quieter when I refit rad tomorrow night. Push rod looked ok so didnt do anything with that.

Two halves of pump. Piston still in.


Piston removed showing oil behind it.
 

·
Registered
Joined
·
835 Posts
Wow, sounds like a different engine now that's been cleaned out. Really surprised how much difference it made!
 

·
Registered
Joined
·
2,163 Posts
Just a quick note about rattly pumps. Mine had been knocking for ages and I'd been on this forum looking at various ways of sorting it.I'd just about decided to get a genuine VW one after all the horror stories about the cheap ones on fleabay and then got some info about the angle they're fitted isn't the way Pierburg (the manufacturers of the pump) designed them to be fitted. Evidently because of the angle they're fitted oil gets behind the piston over a period of time and stops the piston returning fully so more clearance for the pump pushrod.........and we know what that means................nasty rattle!! Anyway decided to do it yesterday so pump off and to the bench.Took the 6 Torx bolts out and took the plate off, it's not under load or anything but there's some seals and valves there so either take a note of what goes where or take some photos.When you've got that lot out of the way put a 15mm socket in the vice,put the end of the piston rod in it and undo the nut on the other end(11mm spanner) Leave a few threads to go then just take the tension off by clamping it up in the vice. Now you can remove the nut,open the vice and remove the piston rod and spring. The only thing now holding the piston is friction so either clout it on a wooden surface or poke it out from behind. The piston has a stepped nylon seal so take care of it.Now the interesting bit, mine had less than a teaspoon of oil behind the piston so I wasn't convinced that oil was the problem but I carried on and cleaned the oil up.Putting it back together is just a reversal of the way it came apart,making sure you get all the valves in correctly(I think they'll only go in the right way). I realised that something had changed when I started to fit it back on.............because the piston was now returning fully the overall length of the piston rod and the separate pushrod was now longer making it just a little more awkward to fit!! Got it all back together and fired it up and............rattle's gone!!!!! Acess is a pig so it's not the easiest job to do but so far so good. Maybe it'll get oil behind again but I reckon it's worth a try for the money I've saved!!
Just completed this job after reading this thread and mines quiet now, thanks for the info.

T: 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 :D


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' LOL: )


Hope the pictures compliment the excellent initial post.


Chris

As above thanks for this, your pics were a godsend

A:A:A:A:A:A:A:A:A:
 

·
Literally, white van man
Joined
·
4,068 Posts
It Just seemed from the photos all where using new ?
I'll be using a new 'block' to pump seal but the original pump 'cap' seal is fine if you are careful when seperating for cleaning (and mine was gopping and stuck, but it's still good after a careful clean)

Chris
 

·
Registered
Joined
·
435 Posts
I'm planning to do this (time permitting!) and remember seeing another thread (on here, I think, though the internet can take you off on a tangent quite easily!) where it was recommended to replace the seal the rod runs through. Size is (IIRC) 18x10x5.5mm
 

·
Premium Member
Joined
·
2,415 Posts
I went and bought a new Perburg pump thinking the ticking came from there but it turned out that the pump is ok. There is no oil coming out when I pull out the tube. Now I am stuck with a new Pierburg pump that I dont need.
 

·
Registered
Joined
·
2 Posts
Just thought I'd add to this, I've done 4500 miles since I stripped and cleaned the vac pump with not even a hint of a noise.
Until I did a service yesterday, now it's rattling again! I'm in 2 mind about if it's worth cleaning again or to get a new one? It's a bit of a bugger if I'm going to have to clean it every time I do a service.
Hi there I serviced my t4 2.5tdi 102 hp yesterday and it has developed a rattle at idle and it goes away around 1500rpm, after a while it completely goes away even at idle I am for pointing my finger at the vacuum pump as its on the pulley side of the engine all the noise is coming from. Is that similar to what others experience with pump faults?
 
21 - 40 of 56 Posts
Top