Vacuum Pump?

[J Lovett]

New to the board and just trying to keep my truck running on an island with very few diesel mechanics. been through the standard stuff. Now I have a very loud rattle coming from the alt. / vac pump side of the engine. Increases / decreases with rmp. It's not the main pulley. I did that last month.
Do the vac pumps go bad? How do you change one? Local parts stores here don't stock them and the Chevy dealers on the island are absolutely no help.

Great site, it's getting me inspired to do some upgrades.

Any tips and advise would be greatly appreciated.

Aloha,
Jesse

[Bnave95]

Welcome :cool:

Vac. pump do go bad and can still give you vaccum. I had a bearing go bad once. They can also lock up. Taking belt off,things to check.
Tenchen pully,Alt,AC clutch,water pump,power steering,and vac pump.
Not knowing how many miles you have on the truck but the most common noise is Alt. and vac. pump.

[moondoggie]

Good Day!

Sometimes you can use a REALLY long screwdriver as a stethoscope to isolate where a noise is coming from.

Blessings!

[jspringator]

Thats the way my vacuum pump sounded before it died.

[J Lovett]

Thanks guys!
The truck has 140K. I changed the alt. at about 100K. I'll try the long screwdriver trick. If I take the belt off and spin the vac pump it feels... like a pump. Easy then resistance, but there is noise as I rotate it. The alt just squeaks a little.
What's the best manual for this truck? Got the Chilton 28624 and the Haynes 10330. They don't say much about vac pumps. How do you get it off and what do you change? The whole deal w/ the pulley or just the guts of the pump?

Thanks again.

[Bnave95]

You will get the pump and the pully will have to be pressed off and pressed back on.

[BobND]

You can also just buy the "pod", the actual crimped can unit with the diaphragm inside. It bolts to the drive part of the pump with either 2 or 4 little bolts, depending upon when it was built.

That saves a little $$$, and the need for a special puller to remove the drive pulley, and reinstall it on the new pump.

And, yes, those things can make the damnest noises when they fail. When mine went, last fall, my first thought was a failed rocker arm!

[16gaSxS]

surprised no body have suggest this:

If it is your pump consider dumping the pump and getting a TurboMaster and replacing the wastegate control with it, it's the only thing the vacuum runs and then you can remove the pump and put a 1993 belt on. No move maintaince for the vacuum system.

[Scooby]

I no longer use the vac pump on my 96, and was thinking of removing it. I have seen several suggestions as to which belt size to use. Is the one for the 93 a good number ???

[Kennedy]

Just wanted to mention that I offer the pump with a new pulley installed. If you have noise it's possible that the whole shaft assy is going bad. Also, most of those who complain about multiple replacements went with cheap aftermarket reman/pods. The OEM stuff is pretty darn solid, in fact, yours may be original. I prefer to keep the ECM in charge of boost whenever practical as it is actually a smarter system in many ways. Far from perfect, but does well.

[16gaSxS]

I no longer use the vac pump on my 96, and was thinking of removing it. I have seen several suggestions as to which belt size to use. Is the one for the 93 a good number ???

Hey Scooby;

Thats what I put on my '95 and no problems, one less system to maintain and fail.