Power Steering Pump

[les & des]

We have an iteresting one for you guys.

Our motorhome has been parked since October besides the last of
January when we had a couple of tires replaced. The last time it
was started was February 11th when we did an oil change. (yes,
Mobile 1 15w50. We have been synthetic for several years.)
Anyway back to the situation. About two weeks ago we noticed a
puddle of what looked like transmission fluid. It seemed to grow,
so when we had decent weather, we got under the motorhome to
try to locate the source of the leak. It seemed to be coming from
the area of the power steering pump, so we decided to check the
ps fluid. It was overfull and when we took the cap off, more spilled
out. That seemed to be the source of the leak. Since then,
nothing else has been noted. Some other factors: The GMC is
parked on a slight incline with the nose a little lower than the tail
(the airbags are fully deflated, but the back end is on blocks.
We've had a few bouts of single-digit weather followed by
temperatures in the 40's or 50's.

Any ideas? Anything we should worry about?

Thanks for your help and input.


Les and Des
73 Painted Desert
Rocky Mount, NC

mailto:lpraisee
vist us at: http://www.livingpraise.org

 

[william myers]

Has anyone found a power steering pump available from local autoparts
stores? I have checked several (autozone, napa, etc) and no cross to
the GM PN. A-1 is a major rebuilder and I may send the orig off to be
rebuilt. Perhaps someone has been down this trail allready. If
necessary I can always get one from the GMC suppliers or try to
rebuild myself. Mostly a leak problem out the back.

BTW I crossed the Goodyear upper radiator hose PN someone posted to an
Autozone one (shaped hose not flexible), I'll report on the fit after
installing.

Thanks,
Bill
'74 Glacier

_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com

 

[jim bounds1]

Bill,
No problem, the PS pump is available locally. You have to answer a
question though. There are to pumps used, one has a shaft for the pulley
to fit on and the other uses a bolt. One is an "innie" and the other is an
"outie". You have to replace yous with the right one to allow the pulley to
fit.

Give me a call at work tomorrow and I'll give you the #'s, my parts data
base is at the shop and I am at the house right now.

Hope this helps,

Jim Bounds
- -------------------------

>Has anyone found a power steering pump available from local autoparts
>stores? I have checked several (autozone, napa, etc) and no cross to
>the GM PN. A-1 is a major rebuilder and I may send the orig off to be
>rebuilt. Perhaps someone has been down this trail allready. If
>necessary I can always get one from the GMC suppliers or try to
>rebuild myself. Mostly a leak problem out the back.
>
>BTW I crossed the Goodyear upper radiator hose PN someone posted to an
>Autozone one (shaped hose not flexible), I'll report on the fit after
>installing.
>
>Thanks,
>Bill
>'74 Glacier
>
>
>
>
>_________________________________________________________
>DO YOU YAHOO!?
>Get your free @yahoo.com address at http://mail.yahoo.com
>
>
>
Jim Bounds / Co-op Motor Works Orlando www.gmccoop.com

 

[travis martin]

Another thing that you might consider is that the pump itself is generic to
GM; only the sheet metal can differs with application. Well, actually, the
regulator is specific too, come to think of it. And the pulley might be
different as well.

But the pump is extremely easy to find. Get one off of a Chevy pickup or
whatever, then move your can from your defective pump to the replacement. If
the pulleys are different, use your old one. The outlet fitting contains the
regulator, so use your old one.

The only other caveat is that some of the later pumps had metric
fasteners...If you run into this, you'll want to keep the fasteners with the
right pump.

This is no different from using the CV joints off of an Eldo or Toro...the
shafts are different, but the joint itself is the same.

Travis, lurker

- -----Original Message-----
From: EMERYSTORA
To: gmcmotorhome
Date: Sunday, March 21, 1999 9:02 AM
Subject: Re: GMC: Power Steering Pump

>

>
>stores? I have checked several (autozone, napa, etc) and no cross to
>the GM PN. >>
>
>Whenever I can't find a match to the GM part numbers I tell them to look up
a
>1976 Olds Tornado with a 455 V-8 and most of the time its a direct fit. I
>haven't done this with the power steering pump but would be interested in
what
>you find by doing this.
>
>Emery Stora
>77 Kingsley
>Santa Fe, NM
>

 

[clark searle]

Just a word of caution about a "generic" steering pump. Although pumps look
alike, they can have big differences in the top pressure they'll produce.
There's an internal relief valve that determines the maximum pressure. I don't
know this for a fact, but I suspect that the higher load on the front tires of a
GMC leads to a higher pressure requirement than a pick-up. If the pump pressure
setting is too low, it's liable to burn out quickly if the relief valve pops off
during normal turning.

Clark Searle
78 Kingsley
Mt. Pleasant, MI

> Another thing that you might consider is that the pump itself is generic to
> GM; only the sheet metal can differs with application. Well, actually, the
> regulator is specific too, come to think of it. And the pulley might be
> different as well.
>
> But the pump is extremely easy to find. Get one off of a Chevy pickup or
> whatever, then move your can from your defective pump to the replacement. If
> the pulleys are different, use your old one. The outlet fitting contains the
> regulator, so use your old one.
>
> The only other caveat is that some of the later pumps had metric
> fasteners...If you run into this, you'll want to keep the fasteners with the
> right pump.
>
> This is no different from using the CV joints off of an Eldo or Toro...the
> shafts are different, but the joint itself is the same.
>
> Travis, lurker
>
> -----Original Message-----
> From: EMERYSTORA
> To: gmcmotorhome
> Date: Sunday, March 21, 1999 9:02 AM
> Subject: Re: GMC: Power Steering Pump
>
> >

> >
> > >stores? I have checked several (autozone, napa, etc) and no cross to
> >the GM PN. >>
> >
> >Whenever I can't find a match to the GM part numbers I tell them to look up
> a
> >1976 Olds Tornado with a 455 V-8 and most of the time its a direct fit. I
> >haven't done this with the power steering pump but would be interested in
> what
> >you find by doing this.
> >
> >Emery Stora
> >77 Kingsley
> >Santa Fe, NM
> >

 

[travis martin]

True, but the relief valve is in the outlet fitting...thus I recommend that
you keep your original outlet fitting when you change pumps.

Travis

- -----Original Message-----
From: Clark Searle
To: gmcmotorhome
Date: Thursday, March 25, 1999 9:19 PM
Subject: Re: GMC: Power Steering Pump

>Just a word of caution about a "generic" steering pump. Although pumps
look
>alike, they can have big differences in the top pressure they'll produce.
>There's an internal relief valve that determines the maximum pressure. I
don't
>know this for a fact, but I suspect that the higher load on the front tires
of a
>GMC leads to a higher pressure requirement than a pick-up. If the pump
pressure
>setting is too low, it's liable to burn out quickly if the relief valve
pops off
>during normal turning.
>
>Clark Searle
>78 Kingsley
>Mt. Pleasant, MI
>

>
>> Another thing that you might consider is that the pump itself is generic
to
>> GM; only the sheet metal can differs with application. Well, actually,
the
>> regulator is specific too, come to think of it. And the pulley might be
>> different as well.
>>
>> But the pump is extremely easy to find. Get one off of a Chevy pickup or
>> whatever, then move your can from your defective pump to the replacement.
If
>> the pulleys are different, use your old one. The outlet fitting contains
the
>> regulator, so use your old one.
>>
>> The only other caveat is that some of the later pumps had metric
>> fasteners...If you run into this, you'll want to keep the fasteners with
the
>> right pump.
>>
>> This is no different from using the CV joints off of an Eldo or
Toro...the
>> shafts are different, but the joint itself is the same.
>>
>> Travis, lurker
>>
>> -----Original Message-----
>> From: EMERYSTORA
>> To: gmcmotorhome
>> Date: Sunday, March 21, 1999 9:02 AM
>> Subject: Re: GMC: Power Steering Pump
>>
>> >

>> >
>> >> >stores? I have checked several (autozone, napa, etc) and no cross to
>> >the GM PN. >>
>> >
>> >Whenever I can't find a match to the GM part numbers I tell them to look
up
>> a
>> >1976 Olds Tornado with a 455 V-8 and most of the time its a direct fit.
I
>> >haven't done this with the power steering pump but would be interested
in
>> what
>> >you find by doing this.
>> >
>> >Emery Stora
>> >77 Kingsley
>> >Santa Fe, NM
>> >
>

 

[clark searle]

I kinda doubt that, but I'd at least suggest verifying that the relief valve is
in the outlet fitting. A relief valve operates by bypassing the oil within the
pump from the high pressure side to the intake side. The main purpose is to
protect the pump as well as the system from over pressure. An in-line valve
would need a passage to bypass the oil back to the inlet side of the pump. That
certainly is possible, but I'd recommend verifying this situation before
switching pumps.

Clark Searle
78 Kingsley
Mt. Pleasant, MI

>
>> True, but the relief valve is in the outlet fitting...thus I recommend that
>> you keep your original outlet fitting when you change pumps.
>>
>> Travis
>>
>> -----Original Message-----
>> From: Clark Searle
>> To: gmcmotorhome
>> Date: Thursday, March 25, 1999 9:19 PM
>> Subject: Re: GMC: Power Steering Pump
>>
>> >Just a word of caution about a "generic" steering pump. Although pumps
>> look
>> >alike, they can have big differences in the top pressure they'll produce.
>> >There's an internal relief valve that determines the maximum pressure. I
>> don't
>> >know this for a fact, but I suspect that the higher load on the front tires
>>
>> of a
>> >GMC leads to a higher pressure requirement than a pick-up. If the pump
>> pressure
>> >setting is too low, it's liable to burn out quickly if the relief valve
>> pops off
>> >during normal turning.
>> >
>> >Clark Searle
>> >78 Kingsley
>> >Mt. Pleasant, MI
>> >

>> >
>> >> Another thing that you might consider is that the pump itself is generic
>> to
>> >> GM; only the sheet metal can differs with application. Well, actually,
>> the
>> >> regulator is specific too, come to think of it. And the pulley might be
>> >> different as well.
>> >>
>> >> But the pump is extremely easy to find. Get one off of a Chevy pickup or
>> >> whatever, then move your can from your defective pump to the replacement.
>>
>> If
>> >> the pulleys are different, use your old one. The outlet fitting contains
>> the
>> >> regulator, so use your old one.
>> >>
>> >> The only other caveat is that some of the later pumps had metric
>> >> fasteners...If you run into this, you'll want to keep the fasteners with
>> the
>> >> right pump.
>> >>
>> >> This is no different from using the CV joints off of an Eldo or
>> Toro...the
>> >> shafts are different, but the joint itself is the same.
>> >>
>> >> Travis, lurker
>> >>
>

 

[travis martin]

Trust me, Clark, I've done more than a couple. The relief valve is part of
the outlet fitting. It screws into the pump body about an inch and a half;
has a spool valve and spring to bypass over pressure.

Back when I used to autocross Corvettes, we used to change the relief
valve/outlet fitting assembly for one from a 3/4 ton Chev pickup because the
stock Corvette relief valve had a smaller discharge orifice and would
sometimes "back up" if you were turning back and forth rapidly (as in a
slalom).

Is there not an exploded view in a manual?

My point is that GM, like any successful mass producer, standardized as many
parts as possible across its lines for best economy of scale. Thus the
steering pump is pretty much universal to any GM product from the era, with
the variations being accommodated by the bolt on parts--primarily the
reservoir (can), in some cases the pulley, the relief valve/outlet fitting
assembly, and, of course, the mounting brackets.

If you will simply pick one up and look at it I think you will see what I
mean.

Travis

- -----Original Message-----
From: Clark Searle
To: gmcmotorhome
Date: Saturday, March 27, 1999 11:13 AM
Subject: Re: GMC: Power Steering Pump

>I kinda doubt that, but I'd at least suggest verifying that the relief
valve is
>in the outlet fitting. A relief valve operates by bypassing the oil within
the
>pump from the high pressure side to the intake side. The main purpose is
to
>protect the pump as well as the system from over pressure. An in-line
valve
>would need a passage to bypass the oil back to the inlet side of the pump.
That
>certainly is possible, but I'd recommend verifying this situation before
>switching pumps.
>
>Clark Searle
>78 Kingsley
>Mt. Pleasant, MI
>

>>
>>> True, but the relief valve is in the outlet fitting...thus I recommend
that
>>> you keep your original outlet fitting when you change pumps.
>>>
>>> Travis
>>>
>>> -----Original Message-----
>>> From: Clark Searle
>>> To: gmcmotorhome
>>> Date: Thursday, March 25, 1999 9:19 PM
>>> Subject: Re: GMC: Power Steering Pump
>>>
>>> >Just a word of caution about a "generic" steering pump. Although pumps
>>> look
>>> >alike, they can have big differences in the top pressure they'll
produce.
>>> >There's an internal relief valve that determines the maximum pressure.
I
>>> don't
>>> >know this for a fact, but I suspect that the higher load on the front
tires
>>>
>>> of a
>>> >GMC leads to a higher pressure requirement than a pick-up. If the pump
>>> pressure
>>> >setting is too low, it's liable to burn out quickly if the relief valve
>>> pops off
>>> >during normal turning.
>>> >
>>> >Clark Searle
>>> >78 Kingsley
>>> >Mt. Pleasant, MI
>>> >

>>> >
>>> >> Another thing that you might consider is that the pump itself is
generic
>>> to
>>> >> GM; only the sheet metal can differs with application. Well,
actually,
>>> the
>>> >> regulator is specific too, come to think of it. And the pulley might
be
>>> >> different as well.
>>> >>
>>> >> But the pump is extremely easy to find. Get one off of a Chevy pickup
or
>>> >> whatever, then move your can from your defective pump to the
replacement.
>>>
>>> If
>>> >> the pulleys are different, use your old one. The outlet fitting
contains
>>> the
>>> >> regulator, so use your old one.
>>> >>
>>> >> The only other caveat is that some of the later pumps had metric
>>> >> fasteners...If you run into this, you'll want to keep the fasteners
with
>>> the
>>> >> right pump.
>>> >>
>>> >> This is no different from using the CV joints off of an Eldo or
>>> Toro...the
>>> >> shafts are different, but the joint itself is the same.
>>> >>
>>> >> Travis, lurker
>>> >>
>>
>
>

 

[clark searle]

Actually, the outlet fitting only has the flow control orifice in it. The
relief valve is a spool valve that slides in the bore that is in line with the
outlet fitting. They are two separate parts. I verified this by looking at the
GMC Service Manual. Nevertheless, if you switched the spring, spool valve and
outlet fitting, you would maintain the original flow and pressure setting. I
believe the pulley is another concern. Ours is a double shieve pulley pressed
onto the shaft. You would need to retain the dual belt drive and same pulley
diameter.

And trust me, I've got a couple patents on power steering pump design.

Clark Searle
78 Kingsley
Mt. Pleasant, MI

> Trust me, Clark, I've done more than a couple. The relief valve is part of
> the outlet fitting. It screws into the pump body about an inch and a half;
> has a spool valve and spring to bypass over pressure.
>
> Back when I used to autocross Corvettes, we used to change the relief
> valve/outlet fitting assembly for one from a 3/4 ton Chev pickup because the
> stock Corvette relief valve had a smaller discharge orifice and would
> sometimes "back up" if you were turning back and forth rapidly (as in a
> slalom).
>
> Is there not an exploded view in a manual?
>
> My point is that GM, like any successful mass producer, standardized as many
> parts as possible across its lines for best economy of scale. Thus the
> steering pump is pretty much universal to any GM product from the era, with
> the variations being accommodated by the bolt on parts--primarily the
> reservoir (can), in some cases the pulley, the relief valve/outlet fitting
> assembly, and, of course, the mounting brackets.
>
> If you will simply pick one up and look at it I think you will see what I
> mean.
>
> Travis
>
> -----Original Message-----
> From: Clark Searle
> To: gmcmotorhome
> Date: Saturday, March 27, 1999 11:13 AM
> Subject: Re: GMC: Power Steering Pump
>
> >I kinda doubt that, but I'd at least suggest verifying that the relief
> valve is
> >in the outlet fitting. A relief valve operates by bypassing the oil within
> the
> >pump from the high pressure side to the intake side. The main purpose is
> to
> >protect the pump as well as the system from over pressure. An in-line
> valve
> >would need a passage to bypass the oil back to the inlet side of the pump.
> That
> >certainly is possible, but I'd recommend verifying this situation before
> >switching pumps.
> >
> >Clark Searle
> >78 Kingsley
> >Mt. Pleasant, MI
> >

> >>
> >>> True, but the relief valve is in the outlet fitting...thus I recommend
> that
> >>> you keep your original outlet fitting when you change pumps.
> >>>
> >>> Travis
> >>>
> >>> -----Original Message-----
> >>> From: Clark Searle
> >>> To: gmcmotorhome
> >>> Date: Thursday, March 25, 1999 9:19 PM
> >>> Subject: Re: GMC: Power Steering Pump
> >>>
> >>> >Just a word of caution about a "generic" steering pump. Although pumps
> >>> look
> >>> >alike, they can have big differences in the top pressure they'll
> produce.
> >>> >There's an internal relief valve that determines the maximum pressure.
> I
> >>> don't
> >>> >know this for a fact, but I suspect that the higher load on the front
> tires
> >>>
> >>> of a
> >>> >GMC leads to a higher pressure requirement than a pick-up. If the pump
> >>> pressure
> >>> >setting is too low, it's liable to burn out quickly if the relief valve
> >>> pops off
> >>> >during normal turning.
> >>> >
> >>> >Clark Searle
> >>> >78 Kingsley
> >>> >Mt. Pleasant, MI
> >>> >

> >>> >
> >>> >> Another thing that you might consider is that the pump itself is
> generic
> >>> to
> >>> >> GM; only the sheet metal can differs with application. Well,
> actually,
> >>> the
> >>> >> regulator is specific too, come to think of it. And the pulley might
> be
> >>> >> different as well.
> >>> >>
> >>> >> But the pump is extremely easy to find. Get one off of a Chevy pickup
> or
> >>> >> whatever, then move your can from your defective pump to the
> replacement.
> >>>
> >>> If
> >>> >> the pulleys are different, use your old one. The outlet fitting
> contains
> >>> the
> >>> >> regulator, so use your old one.
> >>> >>
> >>> >> The only other caveat is that some of the later pumps had metric
> >>> >> fasteners...If you run into this, you'll want to keep the fasteners
> with
> >>> the
> >>> >> right pump.
> >>> >>
> >>> >> This is no different from using the CV joints off of an Eldo or
> >>> Toro...the
> >>> >> shafts are different, but the joint itself is the same.
> >>> >>
> >>> >> Travis, lurker
> >>> >>
> >>
> >
> >