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Bleeding steering gearbox... ?

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Chicagotrader92
Posts: 157
Joined: May 11, 2023 11:35 PM
Location: Chicago

Bleeding steering gearbox... ?

Post by Chicagotrader92 »

Not sure if this is a dumb question, but I will be swapping my leaking steering gearbox for a used (hopefully not leaking) steering gearbox in a couple of weeks. It seems pretty self-explanatory, especially since I'm replacing the tie rods, center link, idler arm, control arms, and end-links at the same time... AND installing coilovers. (It's going to be a long weekend.) 

My only question is: Is there anything special I need to know about bleeding the new gearbox? Or will it essentially do it on its own as I reinstall the lines and refill the fluid? 
kojo96
Posts: 923
Joined: Mar 31, 2019 7:39 PM
Location: Pleasanton CA

Re: Bleeding steering gearbox... ?

Post by kojo96 »

I'd at the least turn the pulley to prime the pump after getting fluid in it, before starting the car.
Mike W.
Posts: 27513
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Bleeding steering gearbox... ?

Post by Mike W. »

I think there's language in the manuals about turning lock to lock a few times. I'd do it at least a couple of times. But I've replaced a couple of steering boxes and don't recall any issues.
gadget73
Posts: 1308
Joined: Nov 22, 2017 10:30 PM
Location: New Jersey

Re: Bleeding steering gearbox... ?

Post by gadget73 »

I usually spin the pump by hand and keep adding fluid until it stops sucking it down, then start the engine.  Run it lock to lock a few times, top up as needed. 

You can just start the engine but usually the reservoir level drops significantly and it might suck enough air to turn the fluid into a foamy mess. Takes a while for all that to fizz out. 

any time I have a PS system open I use it as an excuse to drain as much fluid out as I can so it ends up all nice and clean. Takes a bit of pump turning to burp all that air out. 
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