I am down to my 3rd PS reservoir cap. I keep loosing them, I don't know what's the scoop ? I looked at tank and everything looks fine, new cap locks correctly and it takes some effort to "un-screw" it. But they keep coming off.

I don't do any offroad, just interstate/highway driving.

Anybody have same issue ?

 

my o6 drw six spped did the same thing and they said something about to much presure building up and its blowing them didn't keep it much longer after that to get anymore our of the dealer sorry im no help

 

When was the last time that you flushed the PS system?

 

The only thing I can think of is that the system is getting hot and causing the pressure to rise real high and popping the cap off. Have you checked your cooler to make sure that its clean? If so maybe its time to flush and add new fluid. Let us know what you find out.

 

Other's have experience the same issue. Pressure build up is blowing the caps off. Simple solution is to drill a small vent hole in the cap.

MikeyB

 

Take cap off and wash it with soap and water.
Put stem in mouth, seal top part of the stem with lips and pressurize. Air should pass through the cap. Pull a vacuum on it, air should NOT pass.

If abnormal, use a flat screwdriver, gently pry the cap from the stem at the slots to take it apart. see link for pic. Use soap and water to clean everything again.

Use a Dremel to grind down the center part of the cap that puts pressure on the seal. Take just a little off at a time and snap it back together to get the correct amount of pressure on the seal to make it pass pressure. The final result is about 1/16" of material left in the bore and air passing as described above.

https://www.dieseltruckresource.com/...3&d=1209321914

 

If you dont fix the cap, you'll start burning through ps pumps in short order.

 

As per Blackpuff's post, I took my power steering cap apart to have a look see.


I must be misunderstanding Blackpuff. The cap has the brown rubber sealing cap that is really a one way valve.

Unless I'm really missing something, the brown rubber sealing cap is designed to allow air INTO the p/s pump via the cap but NO air or pressure out.

Blackpuff's modification will allow air to pass in both directions. Now this might be fine or it may let fluid leak out.

Blackpuff, is that the intent of your modification? Let air pass in and out thru the p/s cap?

Anyone else had a look see at the p/s cap?

...Joe

 

The way DC shipped the cap, the seal is actually pinched in between the two parts of the cap. If you take some of the materiel away from the area directly above the seal, it floats between the two pieces. The forces of nature take care of the rest. Mine doesn't leak or hold pressure so I'm happy. Hope this helps.

 

Blackpuff, thanks for your reply.

I must be overthinking this.

I wish I had taken a picture of the other end (the pointy end) of the brown sealing cap.
Perhaps our brown sealing caps are different??? But our trucks are the same year...

On my brown sealing cap, there is a hole that goes right thru the middle of it. The pointy end of the cap has the hole closed off by a very small "flap" arrangement. Air can pass in thru the top of it it but not out of it.

With my cap (no mods) it would allow air (a very small amount) in but not out. By grinding down the ctr part of the cap, it will allow air out by releasing the top pressure on the sealing cap but the original function of the sealing cap letting air in would remain the same.

Sorry, I'm not trying to be difficult or argumentative.. Just trying to understand...

Thanks, Joe..

 

I think the difference might be that I bought a new cap about two years ago. DC may have changed the design. The brown seal does not have hole all the way through it. Did you look at the picture I posted? If you zoom in you can compare the caps. You can't see all of the seal, but maybe it will answer your question.

The bottom line is, if your cap is holding pressure in the reservoir when the engine is off, your cap is messed up. Can hear it release when you take the cap off?

If not, there is no problem.

Some folks just drill a hole, but I'd rather not because it lets contaminants in the system.

Edit: You raised my curiosity, so I took my cap apart to check the seal. It is a solid piece with no passages at all.

Best Regards.

 

Both my current and last truck would release pressure when you opened the cap.

DC has a procedure to apply vacuum to the reservoir in order to get air purged out of the system, which got me to wondering if that could be your problem...

http://dodgeram.info/tsb/2005/19-008-05.htm

 

I go and silicone my caps to the reservoir. Every 25-30k miles I go and drain most of the system by pulling the hoses off the cooler , refill with Amsoil ATf, resilicone the cap and its good to go!

 

While doing some maintenance to my truck today I noticed a small amount of PS fluid leaking near the pump reservoir area. I decided to inspect my cap as per this post. It was a little tough prying apart the cap but finally got it apart without too much damage. The deign is pretty simple...if it was done right. The dipstick part has a vent in it near the top which vents to the top of the cap under the black part. The vent has a one way valve (pinkinsh couloured rubber oring type thing) that is supposed to only allow air in one direction. The way it is installed it is supposed to allow pressure out of the reservoir and not allow anything back into the cap. There is also a vent channel in the top of the grey cap portion that is the passage to allow pressure to vent after it goes through the one way valve. As per this post I cleaned the cap and tried blowing on it and there was no air passage. After taking it apart I ground away some of the center section of the black cap and put it back together, it will now allow air to blow past but not allow it to got he reverse way...the way it was originally designed to but didn't work. The black center section was putting enough pressure on the one way valve to just keep it closed all the time...causing pressure build up and possible cap blow off or oil leakage or other issues.

Thanks for the pics and suggestion as this is a definite problem on our trucks....the fix is easy and it will likely prevent damage in the future.

 

The secret to getting it apart is to squeeze the sides 90* from the notches, and pry at (inside) the notches. I used a small flat screwdriver.

Glad it worked out for you.

Puffer