How to test your VE pump for excessive input bushing wear

[fspGTD]

To test your VE pump for excessive input shaft bushing wear, rig a dial indicator and magnetic base up to the flat-machined anvil on the back of a vice.  Then clamp the pump securely in the vice and set up the dial indicator so it measures the play of the pump's input shaft, like this:


Move the pump input shaft back and forth by hand, and read the movement of the dial indicator needle to accurately measure it's play in that direction.  It is recommend to check the play in several different directions.  I found the play to be worst on my 1.6lTD pump in the 10 o'clock to 4 o'clock direction.  I think most of the wear on belt-driven pumps is caused by the belt tension.

It might be possible to measure the input shaft play while leaving the pump installed on the motor but with the head removed, by setting the magnetic base up on the surface of the block deck.

The wear limit is .2mm (or about .008") according to Bosch.  If the wear is excessive, it is recommend to be fixed which entails a complete pump disassembly/rebuild.  Excessive side play not only makes it harder for the input shaft seal to work to stop leaks, it supposedly can cause side loading of the plunger, which can result in a catastrophic plunger seizing failure.

Unfortunately, replacement bushings are not available from Bosch to my knowledge; they are only available as new replacement parts integrally with a new pump housing.

[Asymtave]

Just tried my hand at re-building my one and only injection pump due to a fuel leak at the drive shaft ultimately caused by worn bushings.  When new bushings are installed they must be reamed to 17mm along the centerline of the pump.   This involves a dedicated jig, not simply a 17mm reamer in a drill press.

So - I took the pump body to Superior Fuel Injection in Toledo who installed and reamed new bushings for me.  I didn't ask where they got them but it was obviously run of the mill for them.  When the guys asked what I was doing their reply was "Uhhhh - Nice reliable pump but not exactly one you want to learn on!"  

I never measured side play but it was probably .010" or .012" before and is probably .002" now.

Eric

[fatmobile]

The bushings are readily available at a bosch service center and they aren't even $5 each. I picked a couple up but haven't torn down the pump and put them in yet.
 It takes 2 of them.
 We did a pump tear down post on the vwdieselparts.com forum and a bosch certified injection pump guy from Zips Diesel in MPLS came on and helped us through it.
 He gave us part numbers for the bushings, told us how they have to be removed so we don't ruin the bore and gave us some torque specs for putting it back together.
http://www.vwdieselparts.com/forum/viewtopic.php?t=4172

[fspGTD]

Great info - thanks for the additions, guys!

[Asymtave]

Oops.  Just wanted to correct an earlier post of mine.  I had said that "Superior Fuel" in Toledo had installed bushings for me when it was in fact "International Fuel Systems."  I've read Superior Fuel here so many times.... Call me Pavlov's Dog.

Yes - the thread that Fatmobile mentions is the one that got me going on this.  Also, there is a thread up in the French section on this site that has some awesome photos of the disassembly anyway.  (High Bandwidth.)  From what I have seen from the level of knowledge on this forum most should be able to handle the rebuild.  Just take pictures as you go along and keep it clean.

Eric

[fspGTD]

Thanks again for the info, great stuff!

My local diesel injection specialist can do the rebushing work, but farms it out to a specialist who in addition to being able to install the bushings correctly, is also able to somehow restore the surface of the input shaft as well (probably polishing it up, but I also heard they can weld it and and turn it to restore them where needed.)  The service is reasonably priced, it seems that most of the cost is in the labor needed to get the pump disassembled down that point.

The VE pump disassembly threads are great, but one mistake I see being made in each of them is not keeping the camplate rollers in their original positions.  According to the Bosch VE pump service manual, the rollers do not necessarily have identical diameters, and so in order to maintain an even pressure on all the lobes of the camplate, they are supposed to be kept in their original factory-matched positions on the timing adjustment rack when the pump is being rebuilt.

[Asymtave]

Keep the rollers in their respective places?!?!?   That's new to me but it makes perfect sense.   I'll let everyone know if something fails down the road!

For having 150,000 (I assume) miles on it my pump had surprisingly little wear - almost none.  What an awesomely engineered and built machine.  The drive shaft had a little wear where the seal rides, but I didn't judge it bad enough to do anything about.  No leaks so I guess it's OK.  Actually - one of the axles that the cam bearings ride on actually had galling (a word used in my trade to describe abnormal metal on metal wear) where it sits in the bearing holder.   I assume that the axles are meant to float and slide around lubricated by fuel but this one must have stayed put and just got pounded into the bearing holder by the spring pressure.  I would have replaced it if I had a spare but I just threw it back in.  It really wasn't that bad.

Another thing to watch out for that was brought up by a tech from ZIPS Diesel:  You need to make sure the dowel pin on the cam plate lines up with the woodruff key slot on the drive shaft.  The cross coupler between drive shaft and cam plate allows two assembly options.  One of these will time the pump 180 degrees out internally.    Also, if you plan to take your governor shaft out be sure to measure it accurately (depth mic, calipers, etc.) so that you can put it back in place.   This might be part of the tuning that a trained pro would do on a bench test, but us rookies are better off putting it back where we found it.

Eric

[Wayland]

Could somebody please repost the pic at the beginning of this thread? All I'm seeing is a red x.

[fatmobile]

Here's a link to a topic I started on vwdieselparts.com:
http://www.vwdieselparts.com/forum/viewtopic.php?t=7993&highlight=pump+bushing

[gldgti]

can we have this thread stickied here or in the FAQ? would be great!

[Wayland]

I was hoping for a pic of how to set up the dial gauge, as it's not to clear in the text.