PS leak
 

I got my truck on the road last fall and all was well but all of a sudden I notice a puddle of ps fluid under it. Hard to tell for sure but it seems to be coming from the big nut on back of the pump. I think it's behind the nut leaking not where the fitting goes into it. The big nut I robbed off a square body pump (pre 81 sae) to use on the LS pump. Is it supposed to have a washer/seal/o'ring of some sort? It's going to be a *#^* to work on it. Pretty tight in there.

Re: PS leak
 

Found a picture of one. Looks Like it has an o ring.

Re: PS leak
 

Anyone know the spec on that o ring?

Re: PS leak
 

I went thru this recently....I ordered Gates 351160 seal kit. This kit is listed for Saginaw pumps back to '68 and also newer LS pumps from 2000's.

It has all the seals in it, for a rebuild. I only used the o-ring for the large fitting out of the kit, leak stopped. the kit is under $7 from Rockauto.
The o-ring is critical for sealing, and if it's old and shrunk up it won't seal. It should be somewhat tight and you should feel it compressing when you screw it in the pump housing.

Re: PS leak
 

The item listed as A in the attached pic is the Main valve (where the pressure hose attaches)....

You can see the O ring on the "big nut"....

Note....one of the more common issues is the metal casing leaking from its perimeter seal O ring due to someone using a lever against the metal case to tension the drive belt.

If the case is dimpled in as above, replace the case and new O ring....

:chevy::chevy::chevy:

Re: PS leak
 

Thanks guys. Probably easier to buy that kit than to run around town trying to match the old o-ring.

Re: PS leak
 

So I finally got some time to pull this apart. I went to my local industrial supply and they had two orings, one smaller and one a bit bigger in diameter. The bigger one didn't work. Couldn't get it to slip into the pump. So I go to my local GM dealer. Parts guy says "Last 5 digits of your serial number?". He didn't appreciate when I jokingly said Don't be silly. So I go through explaining 65 truck, 08 motor, 79 fitting. He couldn't (or wouldn't) pull out any 79 parts books. He did look on the computer for a seal kit for the 08 pump and printed it off for me. It shows the o'ring i.d. as 14.5mm. The original oring measures about 9/16"i.d. which is about 14.5mm. No other dimensions in the picture. So I went to my local Piston Ring parts store and they've ordered a 79 seal kit for me.