kc8ksg

Well I think I need a vacuum pump, because it takes a while for my vents to change setting after I press one of the buttons, and it also changes quicker with more throttle, I pulled the big line off that goes to the brake booster and it doesn't seem to have a whole lot of vacuum like it should. My question is how hard is it to rebuild one cause I have seen rebuild kits, or is is easier just to replace it? And where would be a good place to get the pump or rebuild kit at for a good price.

**EDIT** Well here is what I found searching, I can get the rebuild kit myself for $59.99, but I have no Idea how hard it is to do, or if anyone around here knows how to do it, and I can get one from a junkyard (car-parts.com) for around $250, or get a rebuilt sealed one (http://www.fixinrams.com/) for about $300. Do I have any other options that I have overlooked, or has anyone rebuilt theres before??

Chris

searcher

Sorry to hear about your pump. Your truck actualy has 2 vac pumps. One of mine went out and even though one was still working no vac assist would work right. When I put a vac gauge on and the reading fluctuated rapidly (thought it was gonna break the gauge). I checked at the pumps and found which one was broken; blocked it off; and ran on the good pump. Probably not a smart thing to do but I had already ditermined that if either pump goes out then the brakes go with it. Everything on my truck will run from one pump.

Autozone had the pump for about $140. Advance auto parts had it for I think $180 with a life time guarantee. I haven't tried on this part yet, but Advance is really good at price matching without question. I have price matched radiators with them from Autozone. Hopefully you only have a diaphram shot. Cummins has the seals and bearings at a reasonable price for the steering pump.

I don't know how to post a PDF file to this board but if you will PM me with your email account I will send you the data to tear down and repair the pump. Good luck.

JD730

Thats too bad. searcher has an 89 so he has the older dual diaphram style pump. Yours being a 91.5 w/an intercooler should have the newer/more expensive to get new/rebuilt vacum pump.

I don't know how hard they are too do, but I'm going to rebuild it when the time comes. I would stay away from used ones because you don't know how good the seals are and how many miles are on the unit.

searcher

I'm sorry for the mistake there. I looked up a '91 and it was the same as mine. I just failed to see that you had the '91.5. I do like the '89 3 speed. Seems like everything is so much simpler and cheaper.

kc8ksg

Well of course I have the more expensive one!!! LOL So I guess that the rebuilt pump for $300 is about the best deal other than doing it myself, but I would hate to sepnd $59 then just screw it up and have to spend the $300 anyway, but I guess I'll see, so far it still works and the brakes are okay, the pedal moves a little depending on engine speed and the HVAC is a little slow but I can deal with that for a little while, and I still haven't checked for leaks, but I have the feeling I won't be that lucky!!


Chris

JD730

How is your brake booster? I had a problem with my booster 2 weeks ago. Was leaking pretty bad part way down.

Like I said before I've never rebuilt one yet, but checking for leaks is deffenitately a good idea, why didn't I suggest that before.

kc8ksg

Yea, I am going to take the main line off at the pump and check how much vacuum it has there, then go from there, but I'm probably not lucky enough for it to just be a leak.
BTW: I called Advanced Auto today and another pump (with my friends employee discount) runs about $300, so if I have to get one that's probably the route I'll end up going.


Chris

kenirwin

If you have good supply pressure (vacuum), its probably not the pump. If you have low vacuum you should get the anti-lock light on the message center. Put a temporary guage on the truck and check to see what happens when you operate your heater/AC controls. Also check closely for a mouse chewed line/rubber boot under the hood or under the dash. Another posibility is the dash mounted push button switch or its associated connectors. They are ususally the weak link. The pump does not have alot of extra capacity but you should see >15" when the engine is running. Another good way to check for a leak is to shut off the engine and see how fast vacuum drops off. Should stay steady for a while and slowly decrease. Hope this helps. Ken Irwin

kc8ksg

The vacuum does bleed off quick after the truck is shut off, usually if you push on of the heater controls you will hear the vents switch, but it doesn't do that now or you could press the brakes a couple of times till you used up all the vacuum but now as soon as the truck is off the vacuum is gone. Also my brake pedal moves with engine speed, I don't know why that is but I assume it has to do with the vacuum problem, but you can watch it move if you go from an idle up to the governor. My ABS light doesn't work but my brake light is stuck on, that is what got to noticing that I had low vacuum in the first place, but I tried unplugging the vacuum sensor but they light stayed on.


Chris