Hey guys I have a quick question for the knowledgable. I have an early 80's saginaw style power steering pump. I run hydro assist and this past weekend after enlarging my filler neck (homegrown resorvoir) with rad hose and hose clamps my pump blows a seal (main pulley shaft seal on the front).

My thoughts are the cap should not be air tight (which i made it cause the stock one looked like it sealed) or old power steering pump just pooped on me because I added another 3/4 of a quart to the top of my resorvoir causing greater pressure from gravity at the lower portion of the pump?

any thoughts?
I dont want to blow a new one tonight!

It might be me, probably crazy for thinking this way, but I believe there was a reason that the factory put a "Hot Full" line on the dipstick.

The OEM cap is not airtight. If you look at it, it should have a rubber seal to keep oil in, and contaminates out. Air tight? No.

Remembering that oil expands as it gets hot (like most everything else) and thats why there is supposed to be a empty spot in the top of the reservoir.

I have seen overfilled reservoirs before, and when the steering system heats up, it overflows. Yes, even with the cap screwed down tight.

So, I would guess that given the situation you have created, its not at all surprising that your seal blew.:p

Thank you. You don't think the resorvoir on top is part of the problem though right just the now air tight cap on top?
Thanks

just take the air tight cap off, replace the seal and call it a day.

It powersteering fluid needs room to expand as the oil gets hot. Creating a pressurized zone above the fluid with no way to relieve the pressure is where your problem is. Get rid of the air tight thing as mentioned, you should be fine.

thanks everyone i took the cap off modified it a bit to allow breathing room then for shits and giggles put it back on ran the truck for a bit no leaks with the old pump. (it was running out the other day). Ever wonder how in the hell chevys tend to fix themselves.:smokin:

Never seen that. My GMC always waits for me to fix it. Lazy truck....