PS pump 'cap' keeps blowing off...

[Axekicker]

I'm headed down to the parts house to pick 'anther' 6-pack of power steering pump caps. They keep blowing off. I've never heard of this happening to anyone else. (Yes... . I'm sure they are the right ones; bought one at the dealer for comparison... . and it matched up perfectly... and promptly blew off also) Truck is stock under the hood, except for an aftermarket air-filter set-up. Am I the 'Lone Ranger' on this one? Your thoughts!

 

[07 ThunderRoad]

Did this problem start after a repair to the ps system? When the cap blows off, is fluid spraying out with the cap?

 

[RDHamill]

Does the ps system have a vent?

 

[steved]

The cap is the vent... someone else had this issue a few years back, and I want to remember they took a cap apart and modified it slightly to release pressure better.

 

[dpotter]

Check with your local Dodge dealer as there is a recall on p/s caps. I am not sure of the years, but if you supply your VIN, they can tell you if any recalls are open on your truck.

 

[cerberusiam]

I think there is a problem with your PS system allowing pressure to back feed the reservior. Have never had a problem with the caps unless the pump had issues.

 

[rbattelle]

The cap is the vent... someone else had this issue a few years back, and I want to remember they took a cap apart and modified it slightly to release pressure better.

Here's a good thread on the subject. Notice the hydroboost unit could be partially to blame.



Mine definitely holds pressure, but hasn't blown off yet. Been holding pressure since mile 1.



-Ryan

 

[Elite1]

I am having the same problem... just put my 4th cap on! A mechanic friend told me, I may be over filling the fluid, which could build up too much pressure...

 

[steved]

When I overfilled one time, it simply barfed the excess fluid out on the ground... it did not blow the cap off.

 

[NIsaacs]

Maybe the fill spout is bad and not the fault of the lid?



Nick

 

[steved]

You may have something there... the cap is two pieces, the inner seal it and the outer clamps it down. If that locking deal was slightly larger than normal, it would cause the cap to not release pressure.



If this was my truck, I would have drilled a 1/16th inch hole in the gray part of the cap (looking at it from the bottom) to make sure it could vent.

 

[ScottLewis]

The stock cap (at least on my '06) had a pressure release feature, something like a radiator cap. Mine was keeping enough pressure in to cause leaks. The dealer went so far as to replace hoses, under warrranty, but that didn't resolve the leaking. I did the cap mod referred to before and have had no problems since.

 

[Axekicker]

Solution

I took my new cap and cross-drilled the lower shaft just under the lid, then drilled a small hole through the center of the cap to vent excess pressure. So far it's worked. To answer a previous question... . No. When my cap used to blow off it did not spew fluid out of the reservoir... it just blew the cap off. Now that I've drilled some pressure-relief holes through the top, it's staying in-place. The fluid is not 'foamy' so it's not 'sucking' in air and after checking all the components in the system, I can find no leaks. So... . after these past several months since I've posted the original question... the answer, in my case, appears to be drilling a few holes in the lid to relieve any internal pressure that may build up. Now the cap stays in place... and I have five extra caps... just in case! Thanks for all the comments & help guys. TDR-Rocks!