SC Steering Rack DIY Bearing Replace - Page 4

casor · 07-25-2009, 03:38 PM

"Does anyone know if the puck is supposed to be flat on the bottom? Mine is badly worn and needs replacement/ repair."

Rob-

Replacement parts for these are very hard to get as I noted above. If the puck is the only thing worn, you have two options: Weld material onto the worn area and have it machined to spec (close is probably good enough since it is sprung) or have a new part made. It does not seem to be a difficult part to duplicate. And, in any case, I would replace both bearings since these are cheap and relatively easy to replace assuming you have the rack out of the car.
Rob Caso

casor · 07-25-2009, 03:39 PM

As I remember, the puck is flat on the bottom with a slight rounding on its edge.
Rob

avt007 · avt007's Garage

I have fiends that could make a replacement, I think, but what is the material? Mild steel? Too soft, and it'll wear right out again, and too hard, it'll wear the rack instead.

casor · 07-25-2009, 04:01 PM

I'd be guessing if I told you what the material is or may be. If it were up to me, I would use mild steel and let it wear out again which would take quite awhile if it is greased properly. You don't want it wearing the rack. There are so many grades of steel it is very hard to guess.
Rob

avt007 · avt007's Garage

I assume it would be flat across the face, level with what's left of the stepped area.

casor · 07-25-2009, 05:39 PM

Yes - it is flat across the entire face. I had prev listed contact info for ZF in my prev post - you may want to at least call them and try to get a new part but again you could weld or machine another.
Rob

casor · 07-25-2009, 05:50 PM

I would say definitively that the piece in question is clearly not a hardened steel part for it to wear like that. The rack is hardened which makes sense for the application. After thinking about all this, if you weld, you may distort the part and since it is such a simple piece, machining one I think makes more sense. Just use a good carbon steel like 1215 and grease it well. See the link to steel properties in Mcmaster's site.

http://www.mcmaster.com/#alloy-steel/=2wmgrk

avt007 · avt007's Garage

It makes more sense to make a new one. All it takes is a small piece to break off a welded unit, and you've got a jammed steering rack. Scary stuff.

casor · 07-25-2009, 06:37 PM

Rob - absolutely get a new part if you can find one. ZF was a PITA to deal with and as I noted prev they are phasing out the orig racks in our SC's and would be more than happy to sell you the replacement rack for $800. Making one is "Plan B" - get a new one if you can.
Rob

Scott Douglas · Scott Douglas's Garage

I'd like to offer a suggestion here. That looks like an oilite material to me, not a mild steel. It's spring loaded to ride against the rack right? Thus it has a wear pattern on it that is conforming to the rack surface. I think I'd just knock off some of the edges where the material has thinned out from being deformed, grease it up good and maybe put a washer behind the spring that could make up the difference in height that this part has worn, thus maintaining the original pressure on the rack. It won't wear as quickly since it already has a matching surface which looks like it's greater in area than if it were just a flat surface.

avt007 · avt007's Garage

Thanks Scott, but unfortunately it sits in a bore that has a ridge at the bottom that limits the travel of the puck. Mine has bottomed out, so it's useless. And it is steel, and sticks to a magetn quite well.
Rob, I can't see spending $800 (over a thousand Canadian by the time it lands) for a rack that I can fix for next to nothing.
Thanks for the advice guys, keep it coming...............

casor · 07-25-2009, 08:55 PM

Rob - God no!!! I meant try to get a new PUCK from ZF, not the whole banana! Forget that! They prob have the part you need, you just have to wrangle it from them. I also think it's a good idea to the worn puck it to someone who can tell what the material is as was alluded to by the prev post - if you cannot get a new piece.
Rob

avt007 · avt007's Garage

I told my wife that having two 911s was a good idea, and here's proof- I robbed the puck from my 76. It is in far better shape. Now I will have this together in time for Monterey, and breathing room to come up with a solution.

casor · 07-27-2009, 08:29 PM

Perfect! - I have to remember that one......
Rob

avt007 · avt007's Garage

Compare-

casor · 07-27-2009, 10:19 PM

Take notes and measure the good one with a diagram and then get someone to dup it.

RWebb · RWebb's Garage

Quote:

Originally Posted by avt007

It makes more sense to make a new one. All it takes is a small piece to break off a welded unit, and you've got a jammed steering rack. Scary stuff.

BINGO!

We have a winner!

Maybe it is very unlikely that a piece of the weld would break, but...

KTL · 07-29-2009, 07:39 AM

Both of those pucks are good proof that regreasing the rack every........ jeez, I don't know ......... ten years? ........... is beneficial. It's not a hard job to pull out the rack and one could easily coordinate the rack regrease/rebuild with an alignment job.

I did my rack ~6-7 years ago with EP wheel bearing grease. I've got a spare rack on my shelf i've been planning to recondition. This topic got me interested in getting that done and it should give me an opportunity to see how the grease I chose is holding up.

avt007 · avt007's Garage

Getting the puck out is dead easy. Pull the skid plate off, and the access plate for the puck is right there. No need to pull the rack if all you wnt to do is inspect the puck. You could grease the contact points the rack by going full left to full right while stuffing grease down the hole. Not the best way, perhaps, but a lot less work than pulling the rack.

ghnat · ghnat's Garage

A friend has a CNC machine and maybe a metal lathe. If I knew what metal to buy I could mic the old to make a new puck.