Z3 Air pump rebuild and mounting bushings

[jmai]

Air pump rebuild info and parts interchange

Recently I had to work on the air pump on my 96 Volvo 850. It seems BMW, Volvo and VW all use units made by Pierburg. Major differences appear to be in the connecting wires and mounting plugs, which can be adapted. Common problem is water gets into unit from faulty air control valve, which allows condensation from exhaust to rust the bearing and eventually it will not spin. Common CEL is P0410, secondary air injection system failure. Most common problem is a bad air control valve, which is not repairable, cost about $100 to $125. New pumps are $325 to $400. This article shows how to rebuild the unit. My 98 Z3 2.8 is similar.

http://www.bimmerfest.com/forums/sho...d.php?t=402816

Also the pump is supported by three rubber bushings, also called mountings. These can split and are difficult to remove once the nuts have rusted to the stud. They are easy to replace but totally ridiculous in price, especially if you use BMW factory parts. Volvo and BMW bushings appear to be URO brand and the price vary from $1.76 to $17.25. You need three plus three nuts so it pays to shop around. Prices vary from Volvo to BMW, but they appear to be all the same parts.

Air pump rubber mountings-URO brand (OEM) price comparison

eEuroparts BMW air pump rubber mounting $7.99
http://www.eeuroparts.com/Main/PartD...id=11727559515

Volvo air pump rubber mounting $1.76
http://www.eeuroparts.com/Main/PartD...spx?id=1275534

Foreign Car Parts (FCP) $3.49 Volvo
http://www.fcpgroton.com/product-exe...category_id/14

RMEuropean $2.63 BMW includes 6mm nut
http://www.rmeuropean.com/bmw-parts.aspx#Category

Swedish Auto parts $2.29 Volvo
http://www.swedishautoparts.com/850/...+PUMP+BUSHINGS

Pelican Parts $2.25 Volvo
http://www.pelicanparts.com/cgi-bin/...39%36%29%20%20

Pelican Parts $3.25 BMW includes 6mm mounting nuts
http://www.pelicanparts.com/cgi-bin/...32%2E%38%20%20

Pelican Parts $17.25 BMW Factory part
http://www.pelicanparts.com/cgi-bin/...Z3%202.8%20%20

[cngizbleevng]

Thanks for that info. I replaced the air pump on my wife's Z3 from a salvage yard for $50. Works like a charm. No more codes. I never thought about rebuilding it, but since I kept the old pump, I have an extra one to fiddle with now.

[petr4271]

Here is how to rebuild auxiliary pump and check the relay, might help.

https://www.youtube.com/watch?v=tQ7Q09f5qAs&frags=pl%2Cwn