Power steering reservoir cap keepe coming off

[Ghosterbear]

Power steering reservoir cap keeps falling off or blowing off? I have lost 5 in last 3 years. i double check them to make sure they are on tight.
Installed a Borgeson steering box and steering shaft from Geno's about the time this started happening.
Have double triple checked that all air is out of system and have over 37K miles on since the install.
Is there a chance that the Borgeson builds up to much back pressure?
I'm stumped! Anyone out there had this problem?? Any ides would be appreciated.
Ghosterbear

 

[bigceltic]

Power steering reservoir cap keeps falling off or blowing off? I have lost 5 in last 3 years. i double check them to make sure they are on tight.
Installed a Borgeson steering box and steering shaft from Geno's about the time this started happening.
Have double triple checked that all air is out of system and have over 37K miles on since the install.
Is there a chance that the Borgeson builds up to much back pressure?
I'm stumped! Anyone out there had this problem?? Any ides would be appreciated.
Ghosterbear

I had a problem with PS pressure causing my brakes to come on and it was due to the PS cap not venting correctly. I had to drill out the vent hole a bit and that fixed it. Let me look for the thread.

https://www.turbodieselregister.com/threads/2006-brake-lights-staying-on.256143/#post-2482478

I bought the new cap but still modified it.

Here is another thread on the subject https://www.turbodieselregister.com/threads/p-s-pump-blowing-cap-off.151564/

 

[seafish]

You are experiencing a known problem. The factory PS res caps have a vent that is too small and/or easily blocked.
The solution is to find the factory vent hole underneath the cap gasket and enlarge it or simply make your own hole underneath the cap gasket but in a way that allows the pressure to escape.

 

[EDankievitch]

There actually is a rubber check valve built into the cap that only allow air in when it cools off but will not allow the extra pressure to vent off when it , the steering fluid warms up. It would cause me brake lights to stay on after driving a while. I ended up cutting the rubber flapper out. No more issues.

 

[seafish]

There actually is a rubber check valve built into the cap that only allow air in when it cools off but will not allow the extra pressure to vent off when it , the steering fluid warms up. It would cause me brake lights to stay on after driving a while. I ended up cutting the rubber flapper out. No more issues.

I'm sure your mod works fine, but instead of removing the entire rubber gasket, drilling a hole through it on the opposite side of the cap from the vent hole is the way most people do it. Doing it this way allows for vent gases to pass both ways during heating and cooling but also allows for the rubber to prevent dirt from entering directly into the PS res. NOT that ALOT of dirt would get into the system, but I believe that is what the "flapper" is for.

 

[Hoefler]

There was a TSB out for this, contact your dealer for a updated cap.

 

[bigceltic]

There was a TSB out for this, contact your dealer for a updated cap.

I actually tried the updated cap but it did not work for me (other's may have diff experiences). Slightly drilling out the hole (enlarging it) fixed the problem. However, as pointed out by another member, I may have received old stock even using the new part number.

 

[Crunch]

A few months ago I noticed my power steering reservoir cap was missing, and wondered how it could have happened. Now I know. I replaced mine with a $15 cap from AutoZone. So far no problem, but I may look at drilling it out a bit more to be on the safe side.

 

[bigceltic]

I have been looking for the orig thread pics but am unable to find them in the various forums. Maybe too old? Regardless, if I recall correctly, the fix is just to grind down the "nubs" that are indicated by the arrow so that the brown rubber stopper can come up enough to release pressure.

Update:
Post #10 here: https://www.cumminsforum.com/forum/...6051-pressurized-power-steering-cap-part.html

I think the image prob is due to my company blocking them, so you may be able to see the pics.

 

[Ghosterbear]

Thanks for all the info guys! I think I will go with the small hole drilled in the cap as I have seen that fix before. I have purchased 5 different caps from 2 dealers and they all look and "lock" on the same way. There is no final stop, if you tighten it all the way it will just lift off. you have to stop about 85 to 90 % of the way to the final stop to keep the cap from being able to be pulled up and off. I'm thinking that pressure builds up in reservoir and with road vibration the cap loosens and falls off.
If you have a dealer or other mechanic do an inspection always check your cap as they will "tighten" it all the way and it will fall off from road vibration plus it will blow out fluid all over.
Thanks again for all the help!
Ghosterbear

 

[jhenderson]

I have been looking for the orig thread pics but am unable to find them in the various forums. Maybe too old? Regardless, if I recall correctly, the fix is just to grind down the "nubs" that are indicated by the arrow so that the brown rubber stopper can come up enough to release pressure.

View attachment 117532

Update:
Post #10 here: https://www.cumminsforum.com/forum/...6051-pressurized-power-steering-cap-part.html

I think the image prob is due to my company blocking them, so you may be able to see the pics.

Actually, you buff the flap to thin it. If you grind the nubs it puts seal directly in contact with the cap and prevents it from venting at all.
My cap always locked. Perhaps the OPs reservoir has a broken tab.

 

[Wiredawg]

I lost one on my 09 4500, the 2nd one I drilled it, installed aircraft safety wire through the cap, and wired it to the power steering fluid neck. never came off again and never dropped the cap when checking.

Cheers, Ron

 

[Ozymandias]

Why is there so much air in it that needs to be vented is the question I think about it.

There should be just a little from the heat expansion of the fluid itself.