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Wednesday, April 1, 2015

Power steering pump tear down

This pump was, as you can read on the the erlier posts in the pump subject, sold as a refurbished pump.......well I guess I just got fooled or I have a twisted definition of the word refurbished. The seller seems to think that refurbished is the same thing as a wirebrush and some rattlecan paint.
Well i saw the signs early and as I wait for some other parts i took the opportunity to take it appart to see what condition it´s in.
I had made some research on the Eaton power steering pump on the www and found out that it most probably would be a rotor roller design  (the most common), The information about these pumps are quite scarce, but I found some link

Strangers Site . com
Steering rebuilders and Truck parts inc

So from the first link I found out some of the weak spots for these pump to look out for during the teardown.

These where the only markings I could find on the whole pump. But I haven been able to dechiper the code despite the second link I found.

As you can see from this picture, this pump has a single inlet (the left one) and a combined pressure relief valve cover and pressure outlet. This pump cant be found on this site Eaton id page.

The second surprice I got was when I took the pump appart and found a lobe pump design instead of the rotor/roller design. This is the only reference I have found for this pump, a picture 

This was what I thaught was the relief pressure valve but it later turned out that it was located  further in in the same hole behind a locking ring.

Made some marking on the gears so that they would go in the same way they came out. Som scoring or pitting was found between the gears but nothing that bad that it will work for many years to come.

Front ball bearing came out easy, but needed a puller to get it of the shaft. The ball bearing was in bad shape, not any play but it rotated rough.

The old seal was marked with ER-90850 CR. New one is ordered, together with new ball bearing and a complete set of appropriate O-rings. 

The shaft under the seal had gotten some corrosion pittings. This is one of the weak spots of these pumps, but after 60+ years, probably sitting in a wrecking yard for the last 30-40 years I can feal that some pittings is no the whole world. However it´s a problem that needs to be solved, otherwise the new radial seal will wear down in a few hours or minutes at worst.  The axle tolerances for this type of  radial seal is 19.0 H11 (that is +0, -130 mym) (18.870 - 19.0). This axle is 19.03, so I will try and have it grinded down as little as possible to get a clean surface for the seal to work against. If that doesn´work out inside the tolerances I will haveto check my sleave for some more cards???

Some cleaning in the kitchen sink.......

Done! everything is taken appart and now the examination and rebuild of each individual part starts.

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