I had to move my truck last night across the driveway. When I was leaving for work this morning I noticed a huge puddle of PS fluid under the truck.

This afternoon I moved the truck again and after shutting down I could hear air leaking from somewhere. Upon closer inspection it is air pushing out the PS fluid from the reservoir cap. Also, power steering was basically gone this afternoon.

A little History:
My truck will leak small amounts of PS fluid from time to time, but nothing like this. Usually when it's cold the PS pump groans pretty bad. I keep an eye on the fluid level.

Question:
Is this simply my PS pump giving up the ghost? I kind of hope so because I've had the vacuum pump seal kit for a good while and have been too lazy to fix it. Is there anything else I should check before removing the vacuum and PS pump assembly?

Thanks
Brad

 

anytime the fluid is pushed out of the reservoir the hydroboost is dumping fluid back, the pump is not at fault, most all folks have good results by replacing the fluid with a synthetic oil.

bottom line it usually only happens when the truck is left outside in cold temps, and the syn PS fluid helps keep the hydroboost from puking its oil out. do a search on the Cummins forum you will see lots of posts on this

 

Let's say I replaced all the fluid with synthetic and it still puked, what would my options be at that point.

I'm trying to get all my ducks in a row.

Thanks for the help.

Brad

 

Hydro boost would be faulty.
A powersteering pump when not running has NO means of storing pressure. so therefore it is impossible for it to be the cause of fluid being dumped out of the reservoir. but folks always blame the PS as the culprit.

that being said you could have other issues with the pump ( but if the pump is making enough pressure to run both the brakes and steering and not groaning and moaning it should be fine).
The powersteering fluid I think is the most neglected thing and virtually no one ever changes it, some vehicles I'm sure 10-15yrs later still have the factory fill in them.

 

Well like I said the PS pump has been known to moan and groan pretty bad with sub-freezing temps. But the last time I moved the truck the PS was basically gone...I could hardly steer.

I'll definitely try changing out the fluid as that will be much easier than replacing the pump.

On another note. For those who have removed the vacuum and ps pump assembly, how difficult is it to get that thing out of there? To me it appears there is not much clearance to get it out from either the top or bottom.

Thanks for the replies,
Brad

 

Once the steering fluid is areated, the steering and brake boost will perform poorly and the pump may spew oil once shut off. You need to purge all the air out of the system before you start the engine.

Jack up the front end enough the tires have no weight on them.
Fill the power steering pump and turn the steering wheel (engine off) from lock to lock several times. Keep an eye on the fluid level and add as needed. This will push all the air out of the system and not make foam out of the oil.

 

Thanks for all the tips. I'll give this a try and update the thread.

Brad

 

Update:

I first tried purging the air out of the system as described above. Cranked it up for a few minutes and it puked out a lot of aerated fluid. It looked like red-orange foam. I left the ps pump cap off for this.

So I sucked out all the old fluid with a syringe and added synthetic ps fluid (Royal Purple). I fired up the truck and there was absolutely no moaning, but I now have no power steering and no power brakes.

It was getting late so I stopped there. A few things of note:
After replacing the power steering fluid I did not do the air purge again.
I also noticed that the brake fluid is low (just above the "fill" mark).

So, does this mean that my hydro boost is bad? I guess tomorrow I'll try to purge the air and top of the brake fluid and see what happens.

How bad of a job is replacing the hydro boost? How much $$$?

Thanks
Brad

 

You need to do the air purge after the truck has been off for a long period of time. Once the fluid is areated (foamed), you will not be able to purge the air and fill the system. It will take lots of steering wheel turns to fill the system. Also, it is important not to let the steering fluid tank run empty just like bleeding brakes. Once there is air in the system it is difficult to remove.

It sounds like someone has put dextron in the power steering system. This is a no-no on these trucks. I'd get it all out and refill with synthetic power steering fluid (brand of your choice). I personally like the redline synthetic or vavoline syn.

 

Well, like I said after the "foaming" I removed all the fluid I could and replaced with synthetic. I did suck the reservoir pretty much empty, so maybe I let a lot more air in the system.

Is there a "trick" to purging the air like disconnecting the line to the brake booster? Or will it just take lots of turning of the steering wheel?

Thanks a lot for the help
Brad

 

Actually if the fluid becomes areated,(frothy) letting it sit over time it will leave on its own.
recheck your fluid level and with the wheels off the ground turn the wheel back and forth lock to lock. lifting the front wheels off the ground helps reduce the likelyhood of cavitating the pump again before it forces the air out.
I guess you could "loosen" The feed line to the hydroboost, if you remove it, it will pump the reservoir dry before you can shut the truck off, not sure if it would help, I guess it can't hurt (I've never had to do that)

 

Alright,

I just got finished purging the air per the service manual (turn lock-to-lock 20 times). Then it said to start truck and let idle and maintain fluid level.

When I started the truck the fluid level immediately dropped a lot and then, within a few seconds, here comes the frothy aerated fluid puking out of the reservoir. Is this the booster sucking the ps fluid up when the truck is cranked? Does this indicate that the booster is the problem and not the ps pump?

The brake booster cost more than a ps pump, so I want to make sure that this is the problem before I start throwing money at it. Man, this is confusing

 

Anyone have any opinions on this?

Brad

 

Did you have front wheels off ground while turning? NICK gave good advice, but needs adjustment in procedure. Wheels off ground, resivor full, start engine and run 5 seconds while turning wheel. let set 15 mins for aeriation to go. repeat 5 seconds and apply brakes this time. Keep res full and repeat all steps till oil is clear.
You may have a hydroboost failure. A restricted hose could explain, also. Pump will be under high pressure. JMO of course.

 

Thanks for all the help. I do think it's a hydro boost problem. I started another thread on my difficulties swapping the old rod and spring onto the new unit. Any help on that would be great.

I went ahead and took out the vacuum pump and ps pump to do the vac pump seal and I decided to go ahead and replace the ps pump while I have everything out.

I'll update the thread when I get it all back together.

Brad