P/S pump leaking from backside - The 1947 - Present Chevrolet & GMC Truck Message Board Network

treetop_73 · 04-23-2010, 03:27 PM

I traced the leak somewhere to the back of the unit around where the pressurized line comes in or the return line. Took some time to clean the whole unit, then drive around until it started to leak, crawl under, trace the leak back. But it is not coming from the front where I heard it could be. There is no fluid running down the lines but just down the back and dripping from the bottom. Anyone run into this? I don't want to replace the unit if it is just the line leaking or connection. I don't get much time to work on the truck with the warden and my baby so I want to try to know what to do before I find time so I can get right to it.

Thanks in advance.

ray_mcavoy · 04-23-2010, 04:52 PM

Hi treetop_73,

There are two bolts (or stud-bolts) on the back of the pump. They secure the pump into the reservoir. And sometimes serve as mounting points for the pump depending on the bracketry.

There are O-rings in between the pump & reservoir around those bolts. If those bolts are loose or missing, fluid can leak past those O-rings and onto the backside of the reservoir.

I once put a rebuilt pump assembly on a Dodge (similar pump as GM) and forgot to transfer those two little bolts over from the old pump. It had a slow leak out around the plastic plugs that the rebuilder had stuck in those holes.

treetop_73 · 04-23-2010, 07:30 PM

Thanks. I'll try to see the backside and see if they are there.

Does anyone have a photo of a complete pump from the back side to see where they are located?

ray_mcavoy · 04-23-2010, 08:41 PM

Hi treetop_73,

You're welcome. Here's a pic I snagged off an auto parts website. I drew a couple arrows pointing to those bolt locations.

treetop_73 · 04-23-2010, 09:15 PM

Thanks ray_mcavoy. I'll check those on Monday. The wife said I can spend the day outside that day as she will be home to watch the baby

CLASSIC87' · 04-23-2010, 11:32 PM

EXACTLY the same problem I've been noticing on my Blazer... and its been leaking alot. I will be looking at those studs asap...

ppbr2001 · 04-24-2010, 01:19 AM

I have to fill the reservoir every time I fill the gas tank!! I better look at that myself!

04-23-2010, 03:27 PM	#1
treetop_73 Registered User Join Date: Feb 2010 Location: Victorville, CA Posts: 98	P/S pump leaking from backside I traced the leak somewhere to the back of the unit around where the pressurized line comes in or the return line. Took some time to clean the whole unit, then drive around until it started to leak, crawl under, trace the leak back. But it is not coming from the front where I heard it could be. There is no fluid running down the lines but just down the back and dripping from the bottom. Anyone run into this? I don't want to replace the unit if it is just the line leaking or connection. I don't get much time to work on the truck with the warden and my baby so I want to try to know what to do before I find time so I can get right to it. Thanks in advance. Attached Images __________________ '85 GMC High Sierra 2500

04-23-2010, 04:52 PM	#2
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,366	Re: P/S pump leaking from backside Hi treetop_73, There are two bolts (or stud-bolts) on the back of the pump. They secure the pump into the reservoir. And sometimes serve as mounting points for the pump depending on the bracketry. There are O-rings in between the pump & reservoir around those bolts. If those bolts are loose or missing, fluid can leak past those O-rings and onto the backside of the reservoir. I once put a rebuilt pump assembly on a Dodge (similar pump as GM) and forgot to transfer those two little bolts over from the old pump. It had a slow leak out around the plastic plugs that the rebuilder had stuck in those holes.

04-23-2010, 07:30 PM	#3
treetop_73 Registered User Join Date: Feb 2010 Location: Victorville, CA Posts: 98	Re: P/S pump leaking from backside Thanks. I'll try to see the backside and see if they are there. Does anyone have a photo of a complete pump from the back side to see where they are located? __________________ '85 GMC High Sierra 2500

04-23-2010, 08:41 PM	#4
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,366	Re: P/S pump leaking from backside Hi treetop_73, You're welcome. Here's a pic I snagged off an auto parts website. I drew a couple arrows pointing to those bolt locations.

04-23-2010, 09:15 PM	#5
treetop_73 Registered User Join Date: Feb 2010 Location: Victorville, CA Posts: 98	Re: P/S pump leaking from backside Thanks ray_mcavoy. I'll check those on Monday. The wife said I can spend the day outside that day as she will be home to watch the baby __________________ '85 GMC High Sierra 2500

04-23-2010, 11:32 PM	#6
CLASSIC87' OL BLUU Join Date: Mar 2004 Location: WICHITA, KS. Posts: 1,065	Re: P/S pump leaking from backside EXACTLY the same problem I've been noticing on my Blazer... and its been leaking alot. I will be looking at those studs asap... __________________ More Drop and pics... whatch'a think?: http://67-72chevytrucks.com/vboard/s...d.php?t=249927 My recent 2wd Blazer progress thread: http://67-72chevytrucks.com/vboard/s...d.php?t=393427 http://67-72chevytrucks.com/vboard/s...d.php?t=394870

04-24-2010, 01:19 AM	#7
ppbr2001 Registered User Join Date: Mar 2010 Location: Hydro, OK Posts: 89	Re: P/S pump leaking from backside I have to fill the reservoir every time I fill the gas tank!! I better look at that myself!



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