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"Remanufactured" M5 steering gearboxs...

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Chicagotrader92
Posts: 163
Joined: May 11, 2023 11:35 PM
Location: Chicago

"Remanufactured" M5 steering gearboxs...

Post by Chicagotrader92 »

Hey gang, 
So my 88' 535i steering gearbox is leaking decently bad. Rather than sending it out for a reseal, I am looking into a straight replacement for various reasons. Mostly because I can't leave my car in a non-movable state for long (crazed garage landlord)

So I thought this could be a good time to upgrade to a quick-ratio gearbox... depending on price and availability. I can see there is one on eBay for $1,250... It's not happening (twice as much as I want to spend.) But I also see several websites advertising remanufactured units for cheap...

https://www.buyautoparts.com/buynow/198 ... NMEALw_wcB

The photos show the ZF-branding, claim a 3-year warranty, and "Fits left-hand-drive 1984-1988 M5"... Do you think these are,

1) "quick ratio" as found in the M5... 
2) Junk or a viable replacement option (if it isn't "quick ratio") 

Thanks, 
vinceg101
Posts: 5005
Joined: Jun 20, 2007 2:40 AM
Location: Los Angeles, CA

Re: "Remanufactured" M5 steering gearboxs...

Post by vinceg101 »

This looks eerily familiar to the unit I bought under the same (mis)understanding it was an actual M5/6 quick-ratio steering box. It looks identical and I'm pretty sure it was probably the same seller (BAP). Same paint color, lack of identification, etc. You can see it here, halfway down on page 1: viewtopic.php?t=139465

It is not an actual M5/6 box, especially at this price.  Unfortunately it is missing its metal ID tag which would identify this (likely done on purpose so they can make the M5/6 claim), so who knows?  I will tell you that while it was fine for about the first year, then it started developing a leak. At first I thought it was the crush washer on the pressure hose banjo bolt or the hose & clamp on top, but after numerous replacements and treatments, it's clear it's leaking out of the joint, not just the bolt & hose.  It's a pretty decent leak now and I have to keep an eye on the PS fluid levels constantly. 

Not sure what I'm going to do other than replace the unit with either 1) Another one of these (look where that got me), 2) A known good used standard E28 unit, or 3) A known good used M5/6 unit (you've seen the costs of those).
 
Chicagotrader92
Posts: 163
Joined: May 11, 2023 11:35 PM
Location: Chicago

Re: "Remanufactured" M5 steering gearboxs...

Post by Chicagotrader92 »

vinceg101 wrote: Jan 21, 2025 4:43 PM This looks eerily familiar to the unit I bought under the same (mis)understanding it was an actual M5/6 quick-ratio steering box. It looks identical and I'm pretty sure it was probably the same seller (BAP). Same paint color, lack of identification, etc. You can see it here, halfway down on page 1: viewtopic.php?t=139465

It is not an actual M5/6 box, especially at this price.  Unfortunately it is missing its metal ID tag which would identify this (likely done on purpose so they can make the M5/6 claim), so who knows?  I will tell you that while it was fine for about the first year, then it started developing a leak. At first I thought it was the crush washer on the pressure hose banjo bolt or the hose & clamp on top, but after numerous replacements and treatments, it's clear it's leaking out of the joint, not just the bolt & hose.  It's a pretty decent leak now and I have to keep an eye on the PS fluid levels constantly. 

Not sure what I'm going to do other than replace the unit with either 1) Another one of these (look where that got me), 2) A known good used standard E28 unit, or 3) A known good used M5/6 unit (you've seen the costs of those).

 
I'm sure you are aware of this guy: https://www.jaysbmwparts.com/work/power ... o-gear-box

I've seen plenty of standard (not quick ratio) gearboxes for pretty cheap on eBay, about ~$100... Was considering just buying one of those and having it shipped to the guy linked above. All in, it would probably be about $500... (Core + rebuild + shipping).
vinceg101
Posts: 5005
Joined: Jun 20, 2007 2:40 AM
Location: Los Angeles, CA

Re: "Remanufactured" M5 steering gearboxs...

Post by vinceg101 »

Chicagotrader92 wrote: Jan 22, 2025 10:26 PM
I'm sure you are aware of this guy: https://www.jaysbmwparts.com/work/power ... o-gear-box

I've seen plenty of standard (not quick ratio) gearboxes for pretty cheap on eBay, about ~$100... Was considering just buying one of those and having it shipped to the guy linked above. All in, it would probably be about $500... (Core + rebuild + shipping).
In theory you are correct, but experience and quality with Jay's services has been spotty, do your research.
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