Steering Rack Disassembly and Refurb

[wheee!]

10 hours ago, Zed Head said:

I didn't really grasp what the pictures showed.  Just to summarize, it sounds like we/us/the Z world is saying that the two metal parts are assembled, maybe fixtured, a pin is driven in to lock them together, then a molten plastic is injected in to the two grooves (which are apparently aligned).  

I could see the plastic as a longitudinal lock, and the pin as a radial/rotational/locational lock.  Without the pin the tube can spin.  One probably came before the other.  A proper design might have the two functions combined.  "Dang it, this tube keeps spinning"...translated from Japanese.

I am beginning to doubt there is a pin at all. I am thinking that @Zkars drilled out the plastic and into the inner rack a small amount and then deformed the inner metal with the punch. I might be wrong (usually am) but a pin plus plastic locking collar seems redundant. The shape of the housing bushing is such that it will clamp any rotational forces down, and the plastic collar will subvert any lateral movement.... my two cents.

[zKars]

You guys are likely right. All those metal shavings that showed up while I drilled through the "plastic" were likely just my imagination.

[wheee!]

You are probably right Jim. I was wondering if it was just the interior metal that was causing the shavings though... That "pin" in the photos looked suspiciously like a deformity caused by the punch.

 

Edit: So my master vehicle tech at work is convinced the pin is inserted first for mechanical grip, then the plastic is thermo injected to further lock the collar and waterproof the the pin and groove. As usual, I am wrong,

Edited January 23, 2018 by wheee!

[Captain Obvious]

57 minutes ago, zKars said:

You guys are likely right. All those metal shavings that showed up while I drilled through the "plastic" were likely just my imagination.

zKars, I honestly can't tell if you had sarcasm font on here or not.

Are you saying that there really truly may not have been metal shavings? Or are you saying "You weren't here when I drilled the durn thing. I know what I saw, and you can kiss my old hairy arse if you don't believe me!"  

[wheee!]

25 minutes ago, Captain Obvious said:

zKars, I honestly can't tell if you had sarcasm font on here or not.

Are you saying that there really truly may not have been metal shavings? Or are you saying "You weren't here when I drilled the durn thing. I know what I saw, and you can kiss my old hairy arse if you don't believe me!"  

If I know Jim, he's bending over at the moment...

[Zed Head]

We need another sacrifice.  Melt the plastic out and see what's left.

[munters]

Did someone ever try to find new Bronce Bushings? (48127-78500)

I need them, but there is nothing avail.

something like this or with a google search

https://www.google.ch/search?q=SWPB+bimetal+bushings&dcr=0&tbm=isch&imgil=kaop3PnikSXRsM%3A%3B36UlV0baVmHrSM%3Bhttps%253A%252F%252Fwww.alibaba.com%252Fproduct-detail%252FBi-Metal-Bush-with-flange-SAE1010_60365193932.html&source=iu&pf=m&fir=kaop3PnikSXRsM%3A%2C36UlV0baVmHrSM%2C_&usg=__fnAzUoPEM731mqNNI_-EOLgaTmY%3D&biw=1568&bih=802&ved=0ahUKEwi6wvyMg7PWAhWCIVAKHcb7BZwQyjcIMw&ei=nfvBWfr_OoLDwALG95fgCQ#imgrc=kaop3PnikSXRsM:

 

Thanks for your thoughts

Marcel

[Mike W]

I searched high and low for these and even conferred with @Captain Obviousand they were no where to be found.  The ID and OD dimensions are extremely odd and I could not find anything off the shelf that would work. I could get the right OD but the ID was incorrect and vice versa. Adding the grease groove inside made it even more challenging.

I ended up buying an uncut piece of bronze bushing material and had them machined at a local machine shop.  Even with that the new ones do not have the grease groove inside but they do provide a very nice tight fit now.  If you decided to have these machined locally I would be happy to give you the dimensions. 

Also to note, one of the bearings is slightly longer on one side than the other.  Not sure why Nissan did that but that's the way they are.

Mike.

[74_5.0L_Z]

Would you mind posting those dimensions.  I would like to search for possible substitutes.

[240260280]

Luv this thread!

[Mike W]

OK.  I promised to post the dimensions of the end bushings and so here you go.  Before I do, some general info about the bushings first:

1. The bushings are different lengths.  The shorter one goes into the end closest to the pinion.

2. The dimensions are extremely strange.  There seems to be a strange mix of both SAE and metric.  The machinist that made the ones I had machined locally did not believe the measurements that I provided and would only do the job if he could measure both the rack as well as the housing.  In the end my measurements were correct.

3. These are kind of a PITA to remove from the housing.  I tried using a modified blind puller and was successful in getting the shorter ones out on a couple of different racks.  However, I had to cut the other ends out to remove them.  Not difficult, just tedious.

4. My local machinist cut the ID of the bushings so they were very slightly undersized (from the diameter of the rack itself).  This way I was able to hone out the ID to try and match the diameter of the rack and make up for any weaR.

Now to dimensions:

ID - 24.98mm (diameter of rack overall is 25mm)

OD - 1.125 " ( 1 1/8") or 28.55mm

Shorter length - 20mm

Longer length - 28mm

Finally, I will tell you that I looked high and low for these and to no avail.  If you feel compelled to try and find them do not even waste your time at McMaster, ASB (American Sleeve Bearing) or any of the other online sources.  I spent over $100 trying to find these off the shelf and it was a waste.  I did have ASB provide me a quote for a custom one (with the inner grease channel) but it was prohibitively expensive at almost $100 each. 

If there was enough interest I'm sure I could have my local machinist fabricate a a bunch of these at a more reasonable cost, assuming there was enough volume demand.

I've included some pictures of the new bushings.

Let me know if you need anything else.

Mike.

[wheee!]

Very nice! Looks very good.