90firstgen

Hey all, I was driving home the other day and I heard this sound that sounded like I hit a big rock.. ya know it hits the underneath side of your pickup a few times before it exits out the back. I was following this car who was going way too slow so I stomped on it and got around her. I look down and see that I'm going somewhere in the vicinity of 90mph so i hit the brakes to slow down a little, only to notice I dont really have much for brakes. I get pulled over on a side street, pop the hood and look down at my vacuum pump and one of the diaphrams is sitting about a half inch from the fan and radiator. Long story shorter... the 3 bolts that hold the bottom diaphram onto the pump were apparently loose because it broke all 3 bolts off! My question now is how do I take the vacuum pump off? Do I have to get into the gear case to do it? I got all the broken bolts out etc. and was going to put 3 new ones in and bolt her back together but there just isn't enough room to get the bolts started because of the way the diaphram is designed. Thanks for the help in advance.
Dan

wannadiesel

The vacuum pump is held on by a couple bolts, just pull it off. No need to get into the timing case. Get a new gasket from Cummins.

90firstgen

Thanks for the speedy reply! Sounds simple enough. Anybody have the part number for this gasket by chance?
Thanks
Dan

BearKiller

Did the whole pump brake off, or just a diaphragm??

I had to eliminate the bottom diaphragm, on the Ford, due to clearance issues.

When I removed the diaphragm, there was no operating rod in the bore; that diaphragm was just going along for the ride, doing absolutely nothing.

If I hadn't had clearance issues, and left it on, I don't know if I ever would have known it was inoperable.

90firstgen

Just the diaphram fell off. Everything else is intact. Sorry I haven't been able to get on in awhile
Dan

BearKiller

If my memory serves, the diaphragm seals with an O-ring, instead of a gasket.

I had to remove the whole vacuum-pump/power-steering assembly on mine and just shot a bead of black RTV around the old gasket and reassembled; it hasn't leaked a drop since.

90firstgen

Well I finally got a gasket and did the repair to the pump. Cleaned off the o-rings real good on the diaphram and stuck her back together. Problem is.. I still dont have hardly any vacuum. It's just a tad better than before w/o any vacuum. All of the hoses are on correctly and all of the hose clamps are on correctly. Any ideas? I have a feeling I need to get a seal kit from cummins and pull the pump back off and redo everything. I'm guessing the o-ring on the diaphram is leaking. I checked all of the obvious stuff like bad hoses etc... Thanks for the help
Dan

BearKiller

Did the operating rod drop out when the diaphragm fell off??

With no rod, it can't pump.

90firstgen

I thought about that. I'm not sure how these things are put together on the inside. There was a rod on the diaphram itself that I could push and it would spring back up. Is there something inside the pump that fell out? Even so, One diaphram should be ok still right? It hasn't ever been touched and one working diaphram should be enough, even if its a little slow to get the pressure negative. I'm stumped. The only thing I can think of right now is needing to replace the o-rings. Thanks
Dan

dpuckett

There is a lobe (similar to a cam lobe) on the shaft inside the housing that drives a pushrod that pumps each diaphragm.

There is also a bearing in there somewhere. Need to make sure all your ball bearing ***** are in there. I had the bearing poop out on me and I ended up replacing the whole shebang with an intercooled unit. Dodge wanted like $500 for the housing with all internals, plus the diaphragms are about $100 apiece, if memory serves me correctly.

Daniel

sdstriper

Diaphrams are about $115 each, for remanufactured ones at Advanced Auto, Checkers etc. You'll fill your shorts if you get prices from Cummins or Dodge...

90firstgen

Ok time to revive this, went to cummins today and told them I wanted the kit with all the o-rings. He said that he didn't see a kit available for this but I could buy the individual o-rings. So I decided to go that way...... he's trying to order one of the rings when it says its been discontinued or something of the sort. SO does anybody have the part number to the seal kit for the non-i/c vacuum pump? It would save me a LOT of trouble! Thanks!
Dan

Underpsi

A little bit off topic but still the same style pump, are they more reliable then the newer style pumps? it seems nobody makes the rebuilt kits for them like they do the newer ones?

tboling

The newer one's make your brakes way better. The old setups are more costly to work on, thats the reason I changed mine over. Seal's are the only real problem with the newer pumps. Got my hole pump for $100.00 used.

90firstgen

Alright guys cummins called me back and said there was still a kit available. It'll be here in the morning. I'll post the part number for anyone else that needs it