300TDI vacuum pump woes

[fossil]

Over the last few days the the Disco had developed a clicking noise from the engine I couldn't locate. Went out this morning and noticed a small puddle of oil underneath her. On checking I found that one of the welch plugs from the top plate on the Vaccum pump was missing. I remembered reading in one of the threads here that someone had simply replaced the welch plug and all was good again.

Anyway I took the vaccum pump off to see what could be done and when I did so the plunger and the sleeve it rides in at the rear of the pump both fell straight out. When I had a look the sleeve is help in by two grub screws in the rear of the pump body. One of these screws was backed right out and the other was gone completely. Looking down the pump body there is a small lip that the plunger sleeve rests on. For about a quarter of its circumference this lip had been pounded away I assume by the plunger sleeve moving on it.

I'm now wondering where the missing grub screw is, I assume it has fallen into the block at some point in time. I'll drop the sump off when I get a gasket and hopefully find it in there. There is also the alloy from the pump body floating around somewhere. So if you here your vaccum pump start to make a loud clicking sound I'd be getting to it straight away.

The missing welch plug.
http://i557.photobucket.com/albums/ss11/ausfossil/vaccum%20pump/001.jpg

Grub Screw
http://i557.photobucket.com/albums/ss11/ausfossil/vaccum%20pump/004.jpg

No Grub Screw
http://i557.photobucket.com/albums/ss11/ausfossil/vaccum%20pump/003.jpg

Damaged lip inside the pump
http://i557.photobucket.com/albums/ss11/ausfossil/vaccum%20pump/007.jpg

http://i557.photobucket.com/albums/ss11/ausfossil/vaccum%20pump/006.jpg

Cheers
Iain

[roverrescue]

At least its a pretty direct fall to the sump from that location. Hopefully not too much carnage on its way down.

BTW no sump gasket on a 300tdi just sealant.

And depending on kays, if I had to remove the sump for any purpose, I would pull a conrod big end cap and check for wear and need very little motivation to replace the 4 conrod big ends?

Steve

[fossil]

At least its a pretty direct fall to the sump from that location. Hopefully not too much carnage on its way down.

BTW no sump gasket on a 300tdi just sealant.

And depending on kays, if I had to remove the sump for any purpose, I would pull a conrod big end cap and check for wear and need very little motivation to replace the 4 conrod big ends?

Steve

Thanks for the tip on the sump gasket. 230k on it at the moment, would it be worth checking the end cap wear?

Iain

[MacFamily]

BTW no sump gasket on a 300tdi just sealant.



You can purchase a sump gasket for a 300tdi through KARCRAFT part number KC301 I bought one 2yrs ago.

Karcraft Australia Pty Ltd (http://www.karcraft.com.au)

[roverrescue]

IMHO at 230k with the sump off youd be crazy not to undo 8 nuts??

S

[Roachey]

Yeah, I know the problem well. They would have to be the most badly engineered piece of work I've come across on a German engine! I've had 2 welsh plugs fall out of the same pump, so when you put another plug in, cut some small 'V's on the perimeter of the plug so you can centre pop the edges of the pump body in on the plug. It shouldn't come out again.

Stuart

[roverrescue]

Iain,
Just looking at your pictures, I see 6 hex bolts about the perimeter.
Im I right in guessing that this failed pump actually failed (leaked) in its past and someone has repaired by bolting and sealing?

One experienced Landy mechanic I know is of the opinion that although they pumps are "fixable" say using bolts to replace the rivs when they leak, for peace of mind you should just replace the unit...

Steve

[fossil]

Iain,
Just looking at your pictures, I see 6 hex bolts about the perimeter.
Im I right in guessing that this failed pump actually failed (leaked) in its past and someone has repaired by bolting and sealing?

One experienced Landy mechanic I know is of the opinion that although they pumps are "fixable" say using bolts to replace the rivs when they leak, for peace of mind you should just replace the unit...

Steve

Steve
The genuine Wabco units have the rivets in them. This is an aftermarket pump. The only branding is RM on the cover plate. It came with torx screws where the wabcos have rivets. I took them out and replaced them with the bolts a while back as the torx loosened a bit and normal bolts were easier to tighten. Apart from when the torx loosened a bit I never had any leaking from it till the Welch plug parted company.

Picked up a new pump today $350 + GST. The parts guy at FWD motors was saying he thinks the pumps go if the diaphragm in the brake booster gets a pin hole in it and the vaccum pump has to work overtime. As far as I can tell my booster is OK so don't whether that is right or wrong.

Cheers
Iain

[Roachey]

Iain,
Good chance that if the system vacuum has a leak anywhere the pump will not disconnect and will work itself to death. I've also heard it from reliable sources that this is the case. The body will overheat, expanding the aluminium and presto you've covered your engine bay and the road in the life blood of your wheels.

Stuart

[roverrescue]

Ummm "vacuum has a leak anywhere the pump will not disconnect "

The vacuum pump on a 300tdi is a simple two pot plunger and diaphragm driven by a cam lobe. No "disconnection" that I can establish. If the cam is turning and the plunger is plunging the vacuum pump will be making vacuum as a function of cam RPM.

It cant work hardy or easier apart from the minimal effect that the diaphragm will be under MORE stress not less to a fully sealed brake booster. The stroke limit of the plunger is going to be well less than the flexibility of the diaphragm such that in a zero load setting (holed booster or vacuum line) the diaphragm will just keep pumping?

Steve