pump seal replacement while still on car?

Technical questions and answers concerning all models of VW diesel vehicles.

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stringwalla
Glow Plug
Posts: 2
Joined: Wed Oct 10, 2018 10:16 am

pump seal replacement while still on car?

Post by stringwalla »

Hey everyone, I've owned many Mk1 diesels off and on for over 20yrs and new to this forum. My current is an '84 Rabbit with 87K original miles. I have an age related pump leak that just started. Seems to be coming from the top plate cover of the pump (the rectangular seal on the rebuild kits). I'd love to avoid going to a shop to have the pump removed, and purchasing a rebuilt, or paying for a rebuild just yet.

Question is, if I undo the 4 bolts holding that hold the top on, can I theoretically lift the top off cleanly, and replace that seal while still on the car? Or will some highly complicated mechanism come flying out in pieces?

Just trying to buy some time and save $$ before a total rebuild is eminant. I only drive the car about 4K miles p/yr. And will be putting it away for winter in a few weeks. Thanks for any experienced input
sgnimj96
Turbo Charger
Posts: 259
Joined: Thu Feb 20, 2014 2:08 pm

Re: pump seal replacement while still on car?

Post by sgnimj96 »

The cam/roller assembly inside the pump will fall apart if you loosen the pumps head bolts!
http://pics2.tdiclub.com/members/drivbi ... 20head.jpg
There are rollers (bearings) under the camplate that easily fall out if spring tension is removed. Big problem
https://youtu.be/3_iGFz0vS1k?t=221 See how everything is assembled vertical.

If you run the pump after that, the pump will be destroyed at least. If the timing belt gets messed up while destroying the pump, engine damage will happen.



It is possible to do on the car(plenty of threads), but I don't recommend it. The pump should be vertical when loosening the head bolts.
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: pump seal replacement while still on car?

Post by Fatmobile »

If you are just pulling the top off there isn't much bad that can happen.
The '84 pump is pretty simple.
The accelerator links to the lever inside and can be weird to release. Just shove the shaft down through the top as you pull up.
Or as you get it high enough you can see how to release it from the lever inside.

Plan to change the o-ring around the accel lever shaft.
Also plan to swap the o-ring around the max fuel screw because you will need to screw that out a ways to put the top back on.
The form fit seal for the lid has little nubs on it, shave those off with a razor so it will fit down into the groove in the lid.
DGK-126 seal set has more than what you need.

The hard part is the springs on the accel lever. I have a special tool for that.
A piece of wire to hold the first spring/lever in place:
Imageipumpsprings3 by vwfatmobile, on Flickr

And at this point I would hope you marked things as you took them apart.

You can also put a small hose through the out bolt hole and syphen some fuel out first.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
stringwalla
Glow Plug
Posts: 2
Joined: Wed Oct 10, 2018 10:16 am

Re: pump seal replacement while still on car?

Post by stringwalla »

Fatmobile, thanks so much. As your response eases my concern about the task, I also realize it's maybe too involved for a novice. So I will definitely seek a rebuilt unit or rebuild mine at this point. I'll have a shop do the labor and have the peace of mind of a warranty. Any other components to consider as well at this point? Like timing belt, etc? Any recommendations on a reputable rebuilder? Just want it to be like new. with only 87K it should be fine mechanically fine, just old seals.

Sgnimj96 scared me even further.

Heard about the Giles rebuilds, but expensive. And always wondered if the extra performance sacrifices durability? Thanks fellas-
Fatmobile
Global Moderator
Posts: 7564
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: pump seal replacement while still on car?

Post by Fatmobile »

Our forum sponsor Jack at vwdieselparts.com offers a fair-price injection pump rebuild.
Check his store.
No your engine can handle a giles pump without wearing out early.
I've been turboing Rabbit for awhile and they handle it.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
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