Hey everyone,

Since I have an 01 I don't get over here much, but my grandad has an 90 2500 CTD 2wd and we are working on the brakes. I put a new booster in, and changed what I thought was the only vaccuum pump, attached to the side of the PS pump. Afterwards we started it and the pedal was still rock hard. I put my vac gauge into the line and it was jumping all over the place. I traced the hose to a tee that goes down to what looks like an identical pump on the bottom of the PS pump as well, and up to the booster. After disconnecting the tee, I checked vac on from both pumps, the new one pulled 24 in. and the one on the bottom was verry erratic, so I temporarily plugged the other outlet of the tee and left the lower pump disconnected. My question is are there two vac pumps run in series to pull vac for the brakes.

Thanks for any help

Cole

 

The 91.0( non-intercooled) had a system with 2 identical vacuum pumps. It was switched to a newer style in 91.5. I'm guessing the 90 has the same setup. So it looks like the other pump is in need of replacement...or maybe try swapping in the pump you took off.


Den

 

Den,

Thanks for the quick reply. Setup sounds like what we have. I ordered a replacement pump for the lower as well. I would just swap in the one I took off, but that lower one doesn't look too fun to get to, much less twice if the upper pump was bad.

Thanks again,

Cole

 

Often times its the Oring that goes bad on the pump. Its about 2.00 for a new oring, be sure you dont clean the oil out of the rotor assy, its supposed to be there.

 

I just replaced the lower diaphram pump on my 91...same as the 89 and 90 system.
I pulled the power steering pump off and changed the diaphram pump on the bench...much easier that way.
BTW, it may have been JUST the o ring.....I changed because I started leaking oil big time.
I do feel better with the new pump though....sometime with brakes new is ok.
I think the NAPA rebuild was about $130.
Jay

 

Jay

Just finished the lower pump about 30 min ago. The PS pump must come off to get to those bolts. I just pulled it up and left the hoses intact and did it from there. Now he has a new master, new booster and both new pumps, although I don't think the upper one was bad. Had I seen the other pump, I would have checked vac on each one seperately but no book. Oh well new parts on brake jobs are a good idea.

BTW, he didn't have any oil leaks, so the o ring was proabably OK, but I think the diaphragm had ruptured in one of them.

Cole