Steering Box rebuild

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Using a tool like the one in the workshop manual bored to correct ID and tapered on the OD works fine.

Warming the teflon seals up and slipping them on the mandrel works fine. Then while still warm slip the mandrel onto the valve and slip the rings into place one at a time. Just letting them cool contracted into place. No need to press or force them. Just take it slow putting the valve back in the housing so they aren't damaged.

That's a good idea , using the housing to size them . You say this is in the workshop manual ? When I go back to work I'm going to check that out . I don't ever remember seeing that stuff . Was it called the overhaul manual by any chance ? That's a whole different book . You should look around for the old Operation Pride book of TSB's . I think you would like that . It's really the best thing (maybe only good thing) BMW did while they owned Rover. It was about as thick as a smaller phone book , loaded with fixes for a lot of common shittery.
 
That's a good idea , using the housing to size them . You say this is in the workshop manual ? ...QUOTE]

Yes. Section 57 Steering / Overhaul.

All the steps are listed. The LRT-57-019 (RR3923M) mandrel is pictured. They call it an expander. Its OD is for expanding the rings. The ID is for sizing. After installing the rings it is slipped over them and allowed to cool.
 
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Back for a long(er) term update. About 8000 miles on it now.

Steering is still a little weak but that is the pump. Pressures are down. The box is otherwise working well and has only trace amounts of fluid on the output shaft dust seal. That could have come from anywhere. Wiped it clean and it hasn't come back.
 

Leadvagas

Well-known member
Jun 10, 2010
232
2
Leadville CO
Sounds great on the steering box. I understand your reluctance to rebuild a box for some one else. Would you consider making me a the tools needed to do an overhaul? I don't have access to a lathe these days.
 
A further report:

After multiple long trips (southeast AZ to SE UT, yeah, near Moab) and daily driving the box has started leaking (just dripping a little) at nearly 44k miles. The drip only occurs when the vehicle is parked and there is no pressure on the seals. When running it does not drip. Not bad but not great.

I may take one more pass at replacing seals but I believe this time I will acquire some actual hydraulic seals from a reputable supplier (Kaman or legit hydraulic supplier). I believe these "rebuild kit" seals are just low quality and wear quickly under pressure.
 
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Sounds great on the steering box. I understand your reluctance to rebuild a box for some one else. Would you consider making me a the tools needed to do an overhaul? I don't have access to a lathe these days.

Wow, I completely missed this reply/request.

I might entertain making some tools. It would make sense to do a small batch of them. Anyone else interested? If so I could work up a cost/per.
 

robertf

Well-known member
Jan 22, 2006
4,778
354
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Does the mandrel need to be real durable, or could a printed plastic version work?
 
Does the mandrel need to be real durable, or could a printed plastic version work?

The rings are teflon. Softening point and melt point of teflon (as you know from the Bowden tube feed on most printers) is higher than most materials available in filament. If I recall correctly the melt point is above the decomposition point for teflon. The warming and sizing steps seem they would be problematic.

The sizing step uses the ID of a ring compressor LRT-57-020 to form the teflon rings. I put a taper in the bore of the mandrel to do this. The mandrel is warmed and slipped over the rings then allowed to cool. This sets the interference fit of the valve rings to the valve bore. On my first attempt I cheated a little and used .002 steel shim stock to fit the valve into the box while the teflon was warm to allow the bore to set the OD of the rings. Not ideal so I went with v2.0 and put a taper in the mandrel bore to do the job.

So maybe a mandrel for fitting the teflon rings could be printed but the sizing step requires a bore and finish that I think would be beyond most printed parts (assuming a .4 or .3 nozzle). It may be worth an attempt.
 

Leadvagas

Well-known member
Jun 10, 2010
232
2
Leadville CO
Wow, I completely missed this reply/request.

I might entertain making some tools. It would make sense to do a small batch of them. Anyone else interested? If so I could work up a cost/per.

I would definitely be interested if you want to do that I realize that time is money. And that my insistence on running antique junk requires a certain financial commitment to the Junkulus, god of old cars.
 
Time for the perfunctory update. The truck is now at 272k miles. The rebuilt steering box was done about 51k miles ago. I have found that on very hot days the seals seep a little after shutdown but running at pressure it does not leak.


I have to say I am astounded that the rebuild has held up this long.