Did you get the
vacuum pump renewal kit? It's pretty straight forward to fix your problem. Did your o-ring kit come with instructions? The kit I bought from Cummins has instructions which are pretty clear and easy to follow. The only thing I have been told, and this is by Peter Gould (
GOULD GEAR AND ELECTRIC INC.) is to
not put oil on the shaft seal when replacing it because it may push itself back out after assembly and re-installaton. It makes it difficult to install when dry but care is needed to push it in and seat it properly. Also, it's
very important, take a close look at the old shaft seal in the vacuum pump, note how it is installed and make sure that the new seal is in the same orientation as the old one. It is very easy to place it in upside down and if that happens, you are back to square one and buying a new seal kit and doing the job over again. No special tools needed but large sockets, 1" and 1 1/4" sockets will help you drive out the seals and components. Some guys use short sections of PVC pipe in the proper diameter.
In a nutshell:
1) Disconnect both batteries
2) Drain the fluid from the pump
3) Disconnect high pressure supply hose and the 2 return hoses from the PS
pump
4) Disconnect the vacuum hose from the vacuum pump
5) Disconnect the flexible oil supply from the VP
6) Remove the steering pump and VP together as
one assembly
7) Separate the PS pump and VP pump
8) Take the VP housing and VP bearing housing apart and remove cross coupling plate (the disk with the cross)
9) Place bearing housing seal-surface-side-up on workbench. Drive the seal retainer
out of the VP housing (with socket) , as you will see, it is aluminum and needs
something under it to level and brace it before hitting with hammer. Don't put this
in a vice, it will hurt it. This is a good time to note the position of the seal.
10) Remove old o-ring from the shaft seal sleeve
11) Press the seal out with appropriate socket
12) Clean all parts
Basically now we reverse the dis-assembly process to put it all back together:
13) Install the new shaft seal (remember how it came out?) by pressing it in and
carefully seating it fully
14) Lubricate and Install new o-ring on the sleeve
15) Reinstall cross coupling plate
16) Reinstall the sleeve - did you remember to note how it came apart?
IMPORTANT - make sure the o-ring is not pinched or distorted while
seating the sleeve
17) Replace the larger o-ring in the groove in the VP housing
18) Put the two halves of the VP back together making sure the dowel pin
seats into the dowel hole and the SP shaft end seats into the cross
coupling slot in the VP (rotate shaft if necessary). Secure the capscrews to 22
ft-lb
19) Assuming there is nothing wrong with the PS pump, carefully attach the
two pumps back together aligning the drive dog on the PS pump with
the slots in the VP cross plate. Torque to 18 ft-lbs. Don't forget to
put the pump support bracket in the correct orientation (because you
took photos and drew pictures and took notes when you disassembled
this unit, right?) You must replace the support bracket in the correct
location.
I bet you can figure the rest of this out, put the whole unit back on the truck with the new gasket, and reinstall all of the lines and hoses. When bolting the unit back on, do
so carefully and evenly by snugging the bolts down in a circular pattern and not all at
once. Remember, this is aluminum and it needs gentle handling. Connect the batteries.
Next we bleed the system.
Raise the front of the truck up (if you haven't done so already) and turn the steering wheel to the left full lock.
Do not start the truck yet. Fill the PS pump with fluid to the 'full cold' level on the dipstick, and leave the cap off at this time. Turn steering wheel from lock to lock at least 20 times in both directions. Did you eat you Wheaties? Trapped air may cause fluid to overflow but have an assistant check and maintain fluid to the 'full cold' level as the level may drop as the air is relieved and you don't want to suck air in while you are trying to get air out or you will never get it bled. Start the engine (here is where you know if the truck was properly jacked) - turn the steering wheel at least another 20 times in both directions stop to stop. Let me add here that you must
never hold the wheels to the stops for more than a second or two, especially when applying the brakes at the same time, whether on the road or during a repair. Ask me how I know and I will tell you that you will break the PS shaft because that's what happened to me. If I have left out anything, I'm sure someone will correct me. If you have questions, ask away!
Late entry: After re-installation, make sure that hoses are not touching anything, even each other because they naturally vibrate and will send harmless but earth-shattering sounds which can make you cry if you don't know why it is doing this.
But if your PS pump has a problem, don't bother trying to rebuild it, even Pete Gould said it's not worth the trouble and even he has had major difficulties trying so he doesn't do them himself anymore. It's a bear to take apart and much easier to replace the whole unit.
