Leaky Bosch pump on Volvo L90C

[James Sorochan]

Bosch 0 401 846 994

Slow drip making a mess. Do I just change the top gasket or should I also change the o-rings?……. Or is there more to do? Thanks

 

[thepumpguysc]

Depends on where it was/is leaking from..
If it was leaking from the pump housing and the barrel, it’s either the orings or the housing is eroded..
If it was leaking at the dv holder, u have to have a special socket to get it loose.. it takes an oring and dv gasket..
If u can get a close up of the housing where the oring rides, I might be able to tell if it’s eroded..??

 

[James Sorochan]

Here are some pics of the housing.

 

[James Sorochan]

The first picture didn’t look promising but I cleaned it up and it looks not so bad to me. But I’m just the flunky here.

 

[James Sorochan]

The gaskets not so good

 

[thepumpguysc]

Probably just the orings then..

 

[James Sorochan]

OK, thanks for this thepumpguy. I'll call the rebuild shop that worked on my P-7100 and see if they have some.

 

[James Sorochan]

Parts are ordered. Will find out tomorrow how far away they are. Don’t forget to pay attention as to the orientation of the shims when you take things apart. I guess they control the fuel delivery. I just found out after I pulled things apart and cleaned up a bit. I’ll try to position the same as the other ones that have not been touched yet.

 

[thepumpguysc]

As long as they have the same number on the shim, your ok.
& put the # up to where you can read them.
If u noticed, the barrel has elongated hold down holes.. that’s for setting the equal delivery between cylinders.!!
U could remove ONE of the nuts from another cyl on the pump to get an idea of where it’s supposed to be..
Be sure to tighten the nuts up before starting the engine..
Pull the stop back and forth to make sure the control rack is free.. BEFORE starting the engine.. u don’t wanna find out the rack is stuck AFTER it’s started..

 

[James Sorochan]

Yes Sir, thank you again.

 

[James Sorochan]

Changed out the o-rings on two of the units and put back together and torqued the flange nuts to 35 ft/lb…. Still leaking. Do I need to take one of them apart? Quite a few little parts. The machine has 14000 hours on it… maybe it’s time to pull the pump and let the rebuild shop fix it?

 

[thepumpguysc]

It looks like the hsg is eroded in 1 of the pics.??
It’s REAL EASY to bust the housing if u don’t know what ur doing..
I suggest u take it off and do it once..

 

[James Sorochan]

Sorry. That was the pic before I cleaned it up. This is what it looks like.

 

[thepumpguysc]

Order new orings and the metal spacer.. & give it 1 more try..

 

[James Sorochan]

When I installed o-ring ( part 15 ) I rolled it on and it ended up being inside out. It’s not a round gasket but is flattish with raise edges. I thought that may have caused it so I pulled unit out again and flipped it over and reinstalled. When I put it back on housing I put a little dab of grease on the shim to hold it in position before tightening the flange nuts. Hooked up injector line, primed feed pump and started her up and no leak. Nice. Second unit was still leaking though. When I pulled out second unit I found part 15 damaged. I had one extra set of o-rings thankfully and installed new one then reinstalling the same as first making sure the top shim didn’t slide down into bore cutting into the o-ring as you tighten unit down. Ran machine for 5 minutes with no leak.
Thanks thepumpguy for your advice and telling me to give it another go. One thing I would recommend to anyone working on equipment is to take lots of pics with your phone as you take things apart. Keep everything meticulously clean if possible and don’t be in a hurry.