Hey all, my power steering pump camp keeps coming off. Almost like it's got too much pressure. I'm stumped as to why but it makes a mess whenever it comes off. Any ideas?

 

One of the plastic clips may be slightly "stretched", cracked, or broken. I had one which did that a couple of times and finally bought a new cap... no more trouble.

Pressure should not be building up inside, because IIRC, the cap has a tiny vent hole in it which is why you cover the cap with a plastic bag when washing down the engine bay to keep water out of the PS system.

 

Check the cap to make sure the pin hole vent isn't obstructed.

 

Will the pinhole being obstructed cause pressure to build when turning the wheels?

 

Thanks for the tip about the plastic bag when washing the engine compartment.

 

The temperature and volume inside the reservoir changes constantly while the system is working. That is why the pin hole vent is there, to prevent pressure buildup.

 

Just out of curiosity, did you add fluid to your reservoir prior to your having problems? I just experienced this same problem and the culprit was adding transmission fluid to the reservoir instead of power steering fluid. The transmission fluid is higher viscosity and the pump built enough additional pressure to blow the cap off. The simple fix was to loosen a hose on the rack and drain out all the fluid and then refill with power steering fluid. Work the wheel from lock to lock several times to purge out all the air.

 

It is my understanding that we are to use ATF in the power steering pump: Ford Super Duty Power Steering Flush | Superdutypsd.com

 

This was just a thought. I actually experienced this on a Dodge truck, but what I was getting at was to make sure you had the proper fluid in the reservoir.

 

If the reverse was true, adding power steering to a system designed for transmission fluid might cause foaming.

 

Were you using the vrakes or turning the steering wheel with the engine off? This will push the cap off

 

When you turn the wheel to full lock and you hear the PS pump working hard it's pumping more fluid which comes back through the return line from the master brake cylinder through the rubber line that comes directly back to the reservoir.

 

The cap shouldn't blow off if the vent is unobstructed. Fluid will burp out the hole.

 

At this point, it would be good for all of us if the OP would simply respond with an update so we can know if he is still having the issue.

 

The cap blows off sometime while driving. I checked the vent hole and it's super small. I was able to push a paperclip through the vent hole but there was some resistance. Hopefully that's the issue. The pump has been whining more lately and the truck has a tad over 200,000 miles on it so I'm wondering if the pump may be on it's way out. Sorry for the delay in response. Water pump went out on the girlfriends car so had to replace that.