SC Steering Rack DIY Bearing Replace

[KTL]

My recent rack I refreshed had 26 needles in 1712 also.

I'd not worry about caged vs. not caged. As long as the bearing meets the required dimensions of inside & outside diameter, you're fine. This bearing is not a super high precision bearing, nor is it subjected to high speeds. As long as the bearing fits properly, you're good to go.

[irl]

Do these look right,

Deep Groove Ball Bearings - Radial Ball Bearings | MSCDirect.com

Shell Needle Roller Bearings - Radial Ball Bearings | MSCDirect.com

[KTL]

Yes. 6202 and 1712 are indeed the bearing trade numbers for these steering rack bearings.

My only suggestion would be, see if MSC has a 6202 bearing that is sealed on both sides. I think a fully sealed bearing, instead of the "open" sided bearing will help the grease in the bearing survive longer. But that's for the next guy to worry about 25 yrs. from now, right?

[frankc]

Eddie,
Those are the same two I just ordered last week (free upgrade to overnight shipping). I will be installing them on Saturday.

KTL,
MSC does offer several sealed options for 6202 and I was debating if that would be better than the open style originally used (the price difference is negligible). I went with the open part thinking (perhaps falsely) that since the 6202 bearing is at the bottom of the rack, that the grease would have a tendency to stay there. Plus, the original bearing still seemed to be well lubricated after 36 years so I didn't see a compelling reason to change anything.

However, I agree it would have been a different story if water or dirt somehow entered the rack.

[KTL]

Yep the sealed bearing is debatable for this application. I suppose it all depends on the grease you use. If it is a long lasting grease that doesn't dry up, it'll get in there. But i've seen a number of racks that end up having a lot of oil in the tie rod accordion boots. So those are the ones that probably have a grease issue that could have benefitted from a sealed bearing. Given that the tie rod boots are sometimes of questionable quality these days (what isn't anymore...... ) the opportunity for dirt intrusion is probably a little higher in the future? Pure speculation on my part!

Incidentally as an aside, the upper steering column uses a similar bearing on the bottom side. Same concept, open on one side, just a different size (6003). I definitely think that location is better off with a double sealed bearing. Each column i've disassembled, that open side of the bearing (open on the inside of the column) is a sticky mess of grease & dirt.

[frankc]

btw, for those interested, the O-Ring for my rack was 17mm ID x 3mm Cross Section. I'm placing an order tonight and will let you know if there are any issues when I go to install.

[Nickshu]

Originally Posted by frankc

btw, for those interested, the O-Ring for my rack was 17mm ID x 3mm Cross Section. I'm placing an order tonight and will let you know if there are any issues when I go to install.

I found the oring in that size at Ace Hardware for 10 cents.

[frankc]

My bearings, o-ring and tire rub prevention kit arrived, so I'm ready to re-assemble the rack.

Question - how much grease should be used? I've read "two tablespoons" at one point, but is the objective to fill all voids in the rack, or simply coat all moving parts?

And it seems a good (Mobile 1) synthetic wheel bearing grease is suitable for this application?

Thanks

[frankc]

Searching the threads here a little more, I have seen two types of grease recommended that are available locally:

Mobil 1 Synthetic Grease
Mobil 1 Synthetic Grease(16OZ) | Product Details | Pep Boys

Valvoline SynPower Synthetic Grease
Valvoline SynPower Synthetic Grease(16OZ) | Product Details | Pep Boys

The Valvoline lists moly as one of the additives, I did not see that for the Mobil 1. I've also read some complaints about the Mobil 1 separating more than others over time.

Note that I will be re-packing my front wheel bearings soon, it would be great if I could use the same grease for both.

If I am better off ordering something online (e.g.; Redline), then I can do that instead.

[KTL]

That Valvoline Synpower will be good. It's a bit thicker than Mobil 1 and I think a better choice for the rack. Either will work just fine. I just like the Synpower better.


Well the old Clymer manual I have, which provided a detailed step by step process for breakdown and reassembly says 0.8 oz (25cc) of grease. That's slightly less than 2 tablespoons (what a stupid english unit of measure.....) so you're just fine using two spoonfuls.

You'll find that there's not a whole lot of room in there to pack it with grease. You simply wipe the rack with grease along the teeth and the underside. Underside is important because that's where the pressure puck rides. Then pack the bearings with grease if not already packed.

Whatever excess grease you have can be placed in the central area where the pinion shaft goes. There's really no need to pack the long areas of the housing with too much grease because it's just going to stick there and not necessarily contact the rack itself. You could pack some in the ends of the housing at the inner part of the support bushings. The bushings swipe the grease off the rack as the rack goes thru. So a little extra at that location seems like it would do some good, keeping a blob at a point where its constantly being wiped off?

[frankc]

Thanks Kevin.

I stopped in the local autoparts store and the two cans of SynPower they had on the shelf were already dripping out the bottom. I will make sure I use some type of sealant on the rack when re-assembling to minimize the mess.

[javadog]

Just out of curiosity, how many of you guys have a rubber boot on the top of the rack, covering where the steering shaft enters it?

JR

[911 tweaks]

the SC's I have done had a hard plastic slide over cover...when was a rubber boot used...??

[javadog]

Maybe it is plastic, not rubber. I'm working on a 77 Carrera 3.0 that had nothing there, yet a "sealing bellows" shows up in the parts diagram. I assumed it was rubber...

JR

[KTL]

Frank,

Not surprising to hear the grease leakage on the shelf. Grease does have a shelf life and you can see some separation if it doesn't get used. Not a big deal, as you can mix it up again. That said, certainly nothing wrong with using the Mobil 1, which i've found has a great shelf life. I've got a small container of it that i've dipped into for maybe 8 years and it still looks good.

The newer racks i've seen don't have gaskets on the cover plates, so it's certainly wise to put some sealant on there. The usual engine sealants for the Porsche would work fine - Curil T, Loctite 574, Permatex Aviation Gasket Sealant, Threebond 1104/94/whatever the current number is..... Even some basic RTV will work fine. As you saw with the SynPower grease, you will see some oil separation from grease that just sits for a long time. So the sealant is wise to do on the cover plates.

Yep i've only seen the plastic "trumpet" over the upper shaft on the rack. Even though it doesn't do a real good job of sealing up around the pinion area, i'd still recommend using it. That area is exposed to the weather under the car. The only thing that separates the trunk from the road down there is the steel belly pan under the car and the pan is not tight seal from the weather since it has to allow the tie rods to connect with the strut knuckles.

[casor]

On my 78 SC, it is a hard plastic not rubber. I doesn't seal a thing as it was before I rebuilt the rack and the rack itself has a perfectly shaped funnel to let water into the needle bearing and the rack itself once it easily gets past the boot. When I rebuilt the rack, I used a heavy clear sealant - like plumber's goop - to essentially glue the plastic boot to the rack. Now the water would have to go way up to the top of the boot, into the car and then down the small opening. If this happens, I have alot bigger issues than the steering rack.

[zevenbergena]

Anyone know any of the tricks of the trade on getting these bracket bolts loose just below the lower U-joint? I'm in the middle of this and can't get those guys to budge! Trying not to round out the head...

[frankc]

A fastener shipment arrived today and included the parts I needed to re-assemble my steering rack. So I reviewed the 914 Clymer instructions posted by KTL (link below) and realized that I forgot to mark the orientation of the rack before removing it from the steering housing . I proceeded to install the rack both ways (with pinion pressed in, but no puck), and the rack movement felt the same to me either way. The old grease in the housing was still in good shape when I disassembled everything, and I did not see any significant wear on the rack, pinion or puck.

So I figure I have a 50/50 chance of having the rack flipped from it original orientation. What are the consequences of having it wrong?

And one more question - The Clymer instructions don't mention using a new 10mm self-locking nut for the Coupling Flange when re-assembling. The OEM flange nut was crushed at the top to lock it - I assume this is not re-usable? Is a Nyloc nut acceptable for this application, or only an all metal type?

I doubt I'll be able for find a 10mm self-locking flange nut locally, so that means another few days wait for a delivery (sigh). If a standard nyloc nut is deemed suitable, could I use that with a flat washer instead of a flange nut?

Steering Rack "Rebuild" Procedure

[KTL]

I recently built a rack and forgot to mark which end came out of which side of the housing. As you noticed, the gear cut is such that it doesn't appear to matter.

You won't have any dire consequences. It's not like the rack is going to seize up. If anything, you might eventually find a little bit of slop on-center if gear wear is high. But I really doubt it.

Actually the squished/deformed thread top-lock nuts ARE reusable. It's the nylock type that are typically said to be not reusable. Too many tighten/loosen cycles with the nylon ring loses it's bite on the threads and the locking factor goes way down to almost nothing. The deformed thread nuts are much more reliable because the deformed threads continue to bite the male bolt threads until the threads wear way down (many many cycles of removal & reinstallation) and that's assuming dry fitment. Deformed thread bolting is dependent on lubricant to avoid thread damage

RE lubricant, i've used jet nut style top lock nuts on brake rotor hats and if they're installed w/out lubricant they scrape off the plating and gouge the bolt. Put some antiseize or moly paste on the threads and no harm done. Just have to adjust your torque applied to avoid over-torquing. Thread lubrication makes a HUGE difference in applied torque.

[frankc]

Kevin,

Thank you for the response. I have been researching the various types of self-locking nuts since my last post. Of course there are many opinions out there, but the consensus on re-usability based on what I have read so far seems to be:

• Deformed (all-metal) nut may be re-usable a few of times, but many sites stated that they should only be used once. And like you said, they damage the bolt threads with every use.
• Nylock nut can generally be re-used a few times, but obviously not for high-heat applications
• Flex-lock (all-metal) nut should be used only once

So armed with this information, I went out at lunch today and picked up some 10mm x 1.5 nyloc nuts, but the fastener store did not have them in the flange style. So now I have four options:

1. Use a new nyloc nut with a flat washer (since it is not a flange nut)
2. Re-use the original deformed flange nut
3. Re-use the original deformed flange nut with blue Loc-Tite
4. Purchase a new deformed flange nut online (and wait)

I have plenty of other projects on the car to keep me busy, so waiting for a new deformed flange nut (or nyloc flange nut) to arrive is not an issue, I just want to do what is safest here since it is a steering component. Since I now already have the new nyloc nut in hand, would you consider that an as-safe or safer option than re-using the old deformed nut?

And I from what little research I have done, it appears using a non-flange nut with washer in place of a flange nut is not an issue (and may even be better in terms of distributing the load more evenly).

Thanks for any insight. It would be great to finish this up and bolt the rack in tonight if possible.

And do the tightening torques listed for the 914 steering rack apply to the 911 rack as well (e.g.; housing covers, coupling flange, etc.)?