Power Steering Pump Differences

Hi...

On my 1990 Cherokee Laredo inline 6 jeep, I bought a new power steering pump, but my plastic reservoir wont fit. It is actually a rebuilt one.

The pumps are near identical, even same casting number in the body. However the pump inlet bore differs slightly. The old pump is .765 inch inlet bore, the new pump is .750 inch inlet bore. The reservoirs nipple that accepts the oring and is put in this bore is too big diameter to fit my new pump!

The nipple is tight fit on the old pump, but the roughly .015 inch smaller bore on the replacement is too small for it to work, hence I cant assemble the reservoir to pump.

What do we know about differences in pumps and reservoirs? Was a change made in reservoir to pump joint over the years? If so what? Could this be a pump for a different application?

What reservoir will fit the smaller bore inlet? Is my resercoir correct for a 1990 Laredo?

I got two possible options, return the pump, or get a matching reservoir, although my reservoir is in nice condition.

That is a tough one, usually the O-Rings won't seal!

Did you try lubricating the O-Ring with PS fluid before assembly?

You might be better off to return it and buy one that comes with the reservoir.
I don't think they cost much more.

Its not an issue of the oring, even with no oring, the reservoir nipple cant be inserted, there is over .010 inch interference!

The nipple has a step about half way down, the oring seats on that step, the larger diameter of that step needs to be inserted into the bore, replacement pump bore is .750, nipple is .765 give or take. original pump bore is .765, nipple slides in easy all the way.


Vender and maker have been emailed on a Saturday, expect to hear Monday. Both are reputable firms, they will take care of it I am sure.

I still would like to know which should be correct for a 1990 jeep, and which vehicle does the incorrect one fit.


Seeing as it is rebuilt, it is hard to see it as missmachined, presumably it was installed on someones car before. It is smaller bore, its not as if the rebuilder added metal here.

So this is a learning experience, owned the jeep three weeks this Tuesday, first jeep, big learning curve from my other rides. This is also my newest vehicle.

Plan to camp a lot in it off road., explore offroad. thats why I got a jeep, four months after my buddy got a 2000 cherokee, which he raised, beefed up, limited slip rear, etc...

Thanks for the replies!


Keep jeepin!