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740 '91 740 Steering Rack Leaking..

dorvin

idunno
Joined
Sep 13, 2016
Location
Minnesota
Hi there,

Recently picked up a '91 740 to drive in the winter. Shortly after getting it home and giving it a once over, I returned to the garage to find a pool of fluid under the car. It appears the steel hard lines of the ZF steering rack sprang a leak, and dumped the majority of it's fluid. Given the state of the rack, I'd like to be able to just replace the hoses that need repair, but they all look pretty rough, and will likely disintegrate as soon as I try to loosen them.

I've included a link to a gallery of images below. Would you recommend I even try to replace the lines, or should I just plan on a complete steering rack replacement? If a rack replacement is recommended, on a scale of 1 to 10, how difficult would you rank the procedure? How much damage can I expect to inflict if I drive this sparingly in it's current condition? Also, if this doesn't appear to be a ZF rack, please let me know, I identified it based on the VIN plate under the hood, and the shape of the boots.

https://imgur.com/a/wDqFVbS

Oddly enough, the rest of the car is surprisingly clean, hardly a spot of rust on the body, it seems like whatever steel was used for this rack was extra susceptible to corrosion.

Any advice or amusement at the fact that a 740 is having issues is greatly appreciated.

Inb4crush
 
The hard lines that run just above the rack aren't too bad to replace. Not great, but not terrible. Mine turned to dust and I just replaced them with standard brake hardline with bubble flares. Bonus, got to reroute them somewhere easier to access.
 
Add ATF and keep going.

You need a little oil spray under there in Chicago anyway.

Honestly, the thought of coating the underside of the car does sound appealing for rust prevention.. At the moment however, I'm parking this in a garage spot, and I'm sure the owners of the garage wouldn't be too appreciative of a consistent leak.


The hard lines that run just above the rack aren't too bad to replace. Not great, but not terrible. Mine turned to dust and I just replaced them with standard brake hardline with bubble flares. Bonus, got to reroute them somewhere easier to access.

Now that's an interesting idea. I'm a little apprehensive to try to loosen these, as the look like that might just crumble when I try. Was the rack you used brake lines on a ZF rack? Any chance you'd know the size of the fittings or diameter of the line used?


If I can resurrect the existing rack, I'd definitely want to install a magnefine filter to catch anything that might be circulating..
 
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Was the rack you used brake lines on a ZF rack?

I think so? :e-shrug:

Here is the thread I started when I thought I'd have to replace the whole rack. As far as I could tell it's a ZF: http://forums.turbobricks.com/showthread.php?t=339568

It was a while ago, but IIRC it was standard 3/16 line <span style="text-decoration: line-through;">with either bubble or inverted flares, probably M10/1.0 since that's very common and this was a NAPA in rural NH</span>. Just a pre-flared short piece with fittings already on that they had on the shelf.

I would just take them off, it won't be fun but I'd be really surprised if you can't extract enough to at least check the size of the fitting.

EDIT: found my old post, 12mm bubble flares: http://forums.turbobricks.com/showpost.php?p=5748894&postcount=87
 
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I vote for second hand rack. Don't even try to mess with that. To remove & replace is very straight forward. The only issue I see would be the mounting bolts that run through the engine cross member. They could be difficult to remove if they are super rusty.
 
I vote for second hand rack. Don't even try to mess with that. To remove & replace is very straight forward. The only issue I see would be the mounting bolts that run through the engine cross member. They could be difficult to remove if they are super rusty.

:nod:

They get a lot of practice with the torch wrench in Chicago though.
 
I vote for second hand rack. Don't even try to mess with that.

On a nice car, I would totally agree. However, this is TB, and we're talking about a winter beater 740 that immediately ralphed its PS fluid.

My facepalm hack job costs $10 and has worked so far; it's up to you (OP) to figure out how much a secondhand rack needs to cost to be worth being the better solution.

FWIW, literally every time I drive my car I'm sawing violently at the wheel, and it hasn't leaked yet.

Admittedly, mine was only very rusty in the center part of the line above the rack, and the fittings were not nearly as bad as yours. It was a pain for me mostly because of positioning more than anything else, that rust will make it harder still.
 
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Since I'm at the car, a picture to visualize:

vYZeWk_EvKZIChTO28qb1UCGH3N1VslL2sUHAMZ8_9pCiPaznnnkQfhjcjQKXt6yxzRXHU2sFe1Et-Jqf3SY_wGZJC81hH09WtYcpzKf_6IDMLT8dDpJUxc7JQyuki9eGr0IVB3N1w=w800


Restore it to stock crowd can catch feelings, this **** works.
 
I'd replace both lines but keep the rack if it's working. Did the same on my brothers car last summer, found a nice set of 940 lines in better shape that were bolt-on. As long as the bolts are in decent shape it doesn't matter if the lines disintegrate during the swap.
 
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