Explain the vacuum system to me.

[hex0rz]

Okay, since diesel engines do not create vacuum unlike the gasoline engine, I need to gain a full understanding of how this works.I believe my system needs a lookin' at. I got a leak going on at the vacuum pump, PS area. It looks like one of the pieces on the unit uses crankcase oil to lubricate as well?Does the powersteering fluid get used in the hydroboost?....does not compute. I need to know what seal or rebuild kits to get fix this mumbo jumbo.

[Mopar1973Man]

Vacuum pump is the little unit the bolts in between the gear case and the power steering pump. Yes the vacuum pump uses engine oil to lubricate the vacuum pump.

Yes... Power steering fluid is pumped into the hydro booster.

[hex0rz]

Well, thats interesting. You would think that they would have used the vacuum pump with a brake booster instead of power steering fluid with a hydroboost.Okay, so I believe I got a leak somewhere on this unit. Does a "rebuild" just entail new seals or is there other parts with it?How do I diagnose if its functioning properly? I read a little that if my brake pedal is spongy and/or takes more foot pressure to stop than usual, the unit can be going bad.I just need to know what is entailed in a seal kit compared to a rebuild and/or if I need to by a new unit?...i know, asking alot of questions!Okay, two more questions!1. Is it easy to remove from the bay without having to remove much or do I really have to open it up to get it out?2. Would I be better off going through cummins for a seal kit than through an o'reilly's or napa? Just wondering if there tolerances are not on par like they ought to be.

[Mopar1973Man]

Here is the hydrobooster rebuild article... http://articles.mopar1973man.com/general-cummins/33-brake-system/79-brake-hydrobooster-rebuild As for vacuum direct brake booster were on the 1st Gens and then upgraded to the hydrobooster later in the 2nd gens.

[War Eagle]

"How do I diagnose if its functioning properly? I read a little that if my brake pedal is spongy and/or takes more foot pressure to stop than usual, the unit can be going bad."If your brake pedal is spongy then you may have a master cylinder problem.I had to replace my master cylinder to cure my brake pedal issue.A master cylinder problem wouldn't necessarily have anything to do with an oil leak at the PS/Vac pump but could show up as an brake oil leak around the connection between the master cylinder and the hydro booster.

[hex0rz]

I will be sure to take pictures of the area when I start working on the truck, for more feedback. I did check the rear brakes and the rear slave cylinders need replaced or rebuilt. One side was leaking. I know that can contribute to a spongy pedal.On the other hand, I noticed that when cold and when I apply the brakes the first time driving of the day, the brake can be reeeal touchy. Barely have to apply any pressure and she will wanna stop in a hurry.

[IW378]

I rebuilt mine a couple months ago. You can get a rebuild kit from geno's garage that will replace the seal that is leaking and everything else you need to do the job. plus a dvd to show you how to do it:thumbup2:. took me about 3 hours. have a helper cause you have to take the ps pump and vacuume as a unit.

Luke

--- Update to the previous post...

FYI on Genos site you will be looking for a gould vacume pump reseal kit. 59 bucks

Luke

[hex0rz]

Thanks for the heads up, bro! I heard of them before on other threads but did not realize there really is not anyone else out there.I called O'reilly's and they do not even carry a reseal kit. Just teh pump, at $400!!!!! :ahhh:I ordered one, hopefully, I will see it this week and not next week, considering its a holiday.

[hex0rz]

Alright, so what and how many bolts are holding this nightmare on the engine?

[IW378]

2 bolts on the front of the vacume pump to the back of the timing cover and probably another bolt through a bracket on the side of the block that hangs below the vp44. If you look at the posted diagram you can see the 2 bolt holes on the front. The bracket , not shown will be coming off the lower stud on the power steering pump.Luke

[hex0rz]

2 bolts on the front of the vacume pump to the back of the timing cover and probably another bolt through a bracket on the side of the block that hangs below the vp44. If you look at the posted diagram you can see the 2 bolt holes on the front. The bracket , not shown will be coming off the lower stud on the power steering pump. Luke

So only three? Nice, I'm glad, cause I'm getting tired turning the wrench...