Play in Bosch injection pump

[smutts]

I have some play in the timing belt shaft of the pump, but no leaks. How much play before I need to worry?

[rallydiesel]

There is a thread in here about checking the amount of play. Just because there is no leaks doesn't mean the roller carrier is not machining itself into the pump housing. I would tear that pump apart and check the housing and press some new bushings in there asap.

Here's the thread:

http://www.vwdiesel.net/forum/index.php?topic=3238.0

[rallydiesel]

This is what happens when you keep running a pump with worn bushings:

[rallydiesel]

Ummm, because the bushings were worn on that particular pump. The wear was only on one side of the housing. If the belt is overtightened, it will lever the shaft and eventually the roller cage will contact the pump housing. Yes, the wear is actually caused by the dynamic timing movement, but the cage should not wear into the housing like that. Other pumps I have rebuilt did not have the wear shown above. I don't know about you, but I would not want metal flakes from the housing plugging up my injector nozzles. Also, I have talked to Bosch techs that have mentioned that heavily worn bushings can cause damage to the pump housing.

[rallydiesel]

I will have to check, I do still have the old parts. Yeah, that pic doesn't really show the depth of the wear. The pump actually ran well before I opened it up. Funny thing was, it didn't leak from the main seal until the belt tension was relieved, at which point it dripped like an old faucet. Tighten the timing belt and the leaking stopped. 

[rabbitman]

Both of my pumps look like that inside except for the dark discoloring.

Seems to me like for how slow the roller ring rotates it shouldn't wear like that but I guess the diesel's not actually forced to lube that, it just soaks in there.

Funny thing was, it didn't leak from the main seal until the belt tension was relieved, at which point it dripped like an old faucet. Tighten the timing belt and the leaking stopped. 

Mustuv been old and stiff

[SolarSteve]

Both of my pumps look like that inside except for the dark discoloring.

Seems to me like for how slow the roller ring rotates it shouldn't wear like that but I guess the diesel's not actually forced to lube that, it just soaks in there.

Funny thing was, it didn't leak from the main seal until the belt tension was relieved, at which point it dripped like an old faucet. Tighten the timing belt and the leaking stopped. 

Mustuv been old and stiff

Not trying hi-jackthe thread, but my power steering pump does the same thing???  When the belt is tensioned it is fine, but as soon as I loosen the belt it leaks like hell.  What's up with that??!!

[Rabbit TD]

I know this sounds like just trying to be cheap, but has anybody ever just pressed out the bushings and rotated them 180 degrees to put the elongated wear on the oposite side of the pump so when the belt is tightened the shaft can't be pulled off center and used a new seal.  I just got finished rebushing one of these a while back but I did think about trying that but didn't.

[rabbitman]

I know this sounds like just trying to be cheap, but has anybody ever just pressed out the bushings and rotated them 180 degrees to put the elongated wear on the oposite side of the pump so when the belt is tightened the shaft can't be pulled off center and used a new seal.  I just got finished rebushing one of these a while back but I did think about trying that but didn't.

I thought about that when I did mine too, I liked the thought of having new bushings better.

[burn_your_money]

You'll likely damage the bushings during the removal and install and either way they would need to be reamed afterwards.

[smutts]

Cheers for the feedback, Well, not to worry, I have a pair of spare pumps.
If I get time I will get the dial guage on it to measure the wobble and let you know.