SC Steering Rack DIY Bearing Replace

[reddogmotrsprts]

Getting the bushings back in adds 50-100% time to the rebuild process. I would avoid removing them if possible.

Every so often, someone takes one for the team and buys the rare German retainer rings -- the minimum quantity is 500 pieces, IIRC -- and then offers the extra 498 units to the forum. Keep your eyes peeled. Failing that, just ask. I'm sure we're not alone in sitting on a stash of retainers.

We take the bushings out because we machine new grooves in the rack ends for beefy reusable snap-rings that stand a better chance of holding the bushings in place during spirited driving:

[chrismorse]

Hey Red dog,
A few questions - sounds like you have dealt with a few nice racks :-)

Do you make or resell pucks?

How hard do you have to be pushing the car to see rack bushings wear out or get "pushed" out?? Are we talking just racing or occasional track days??

Do you favor synthetic grease for the rack rebuild, or not? What grease do you like, particularly for guys like me that may never open up the rack again?? (I'm almost 70).

What is your recommendation for shimming up the puck
Thanks,
Chris

[KTL]

Is that a purple/plum powder coated rack in the blurry background? NOICE!!!!

I don't want to speak for Red Dog but I can say synthetic EP (extreme pressure) grease is the way to go in my opinion because it's less likely to separate into oil and goop. Many conventional greases tend to separate and dry over time. I have a small can of Mobil 1 red synthetic that i've had on the shelf for at least ten years and the stuff has no sign of separation. It's got a lightly sealed plastic lid on it so it's not been tightly preserved.

Not saying i'd use it in something critical at this point. I just use it for general purpose stuff around the house and minor car stuff. But honestly you can use any brand name high end grease, synthetic or not, and it'll be fine. Don't be cheap on grease. Spend a few extra bucks and the grease will last a long time.

[reddogmotrsprts]

We do make pucks out of a PTFE-impregnated acetal resin which won't mar the rack or chassis; PM if you want one. The pucks from Fenn Lane (chris_seven) are another good option.

I can't speak to the circumstances of bushing ejection, unfortunately. Just one of those things that I don't think is worth risking on a couple $1 single-use parts that I can't even eyeball easily. I definitely wouldn't want to chance it on the track, but that begs the question -- isn't spirited driving on the street less safe?

We experimented with shims first; you can find our contribution to that effort here, somewhere, maybe even in this thread. Delrin is a cheaper (and easier to source) material that should work almost as well.

As far as the grease goes, KTL hit the nail on the head. Good grease is fine. Great grease is a little better. I'd like to see more translucent grease in use because it makes it easier to detect contamination and wear. We use the Mobil 1 synthetic, which is a sort of translucent red color.

Here's a photo of our Red Rack, with a version in "Porsche Silver" powder coat. It has taken a surprising amount of work, but I am pretty happy with the quality of these. It's one of those things that you are motivated to improve after handling so many gnarly old parts and seeing how they fail.

[harvardma]

Has anyone seen wear on the puck and housing like this before?

[sunlion]

Looking for puck with splines also

[Harpo]

My bushings disintegrated possibly due to the heat involved with the powder coating. I will either buy some Slippery Delrin® Acetal Resin Rods which contains 13% PTFE or buy some from reddogmotrspts.

David

[47silver]

does anyone have a part number for the seal?
i have it as 17x23x3 but not sure what type to use.
found this on metricseals but not sure if this is correct..
S 17 X 23 X 3 DS

[rbuswell]

My first stop is always the PET. After that, you may look on Pelican or one of the other Porsche parts retailers. It shouldn't be an overly expensive part so you should at least draw the line at OEM and Genuine is better most the time.

[47silver]

thanks, I was hoping to purchase the seals/etc before i took the rack apart, i could not find any porsche parts for it nor any numbers just the size 23x17x3 (mm)
as there are various types of seals i was hoping that someone had a model number.
i will post when i finally get one that matches.

[rbuswell]

At the risk of offending you, if you don't use the PET for your car, you are missing out on one of the really handy tools for working on any Porsche. The PET is a Porsche company publication that you can get for free. Each model and a range of years has a PET which is a set of very detailed blown-up parts drawings for most every system in the car. It has a parts list in the following page or two after the drawing so you can get the Porsche part number. Many parts houses use that number or they cross reference to it.

It is also an excellent guide to help you take things apart or put them back together. It's usually as good as most service manuals.

If you search for PET followed by your year and model, a link to the PDF for that PET will usually show up on your search engine or instantly download the PDF to your PC depending on your browser setting. You don't list your car or year or I'd try to find it for you. Good luck.

[47silver]

I believe i have the correct pet catalog for 74-77 but it does not show an exploded view of the steering rack. There is an exploded view posted here but it does not give any part numbers.
what I believe are the correct part numbers are:
SKF USA INC HK 1712 NEEDLE BRGS 0.033 LB part number#15
SKF USA INC 6202 SINGLE ROW BALL BRGS 0.102 LB part number#20
17X3 ORING EP70 part number#14
DS 17 X 23 X 3 IKO Seal part number#10

I bought the bearings at ebatmus.com
and the oring and seal at metricseals.com

[rbuswell]

This is more of a conceptual idea but I've found over the years that a car brand dealer has a better parts retrieval system and inventory than is available to the general public. They need to have the right part on hand to fix cars in for repair and they need to do it quickly.

I'm assuming you are asking this question in the first place because you're not 100% confident you have the right part. A trip to a Porsche dealer may be worthwhile. Having that seal fail at the wrong time could be a lot more expensive (and dangerous) than a few bucks more in cost. This is more general DIY wisdom than anything.

[47silver]

My interaction with dealers had been negative. Every part needs ordered snd takes weeks to get.
If i can help it i never buy from a dealler. If you know a friendly dealer who is happy to search his data base for a 10 dollar seal let me know..
For a test call them and ask for the seal, bearings and o-ring part numbers, delivery and cost. I would be amazed that they will not tell you to get a new rack and it needs ordered from germany and pre-paid.

[rbuswell]

Pelican is a Genuine part outlet. Have you tried talking to them?

There are brick and mortar dealers who are very active in online Genuine parts. I've had pretty good luck with Sherman Saelio at Porsche Marin. Very nice guy. You have to be firm with him since he tends to gravitate to Porsche conventional parts wisdom at times, at least with more unusual cars. I've also worked with Travis Bernhardt at Porsche Atlanta Perimeter. If there's a part, they want to sell it to you. They get you on shipping a little but for the right part, it's worth it most of the time.

You should be able to do a search. Pelican blocked my attempt to provide links. They may also be able to do a Zoom or something so you can see the part on their screen. I don't know because I've always been able to do it via the PET.

[47silver]

thanks
I took apart the steering rack last night.
the only seal in the rack on the pinion side is an o-ring. There is not any seal as shown in the parts blow up item#10.
I used an all thread with a socket on the bearing and washers to remove the needle bearing.
the pinion bearing came out easily.
The hockey puck has a .39mm groove in it so probably need to get a new one.

i believe i have all of the pet catalogs. the parts I need are not shown.
I have owned a 75 911 since 2002 and purchased most of my parts for this car from Pelican.
I helped my son rebuild a 72T and we purchased thousands of dollars worth from pelican as i appreciate this BBS.

[75 911s]

Right the rack is never listed part by part in the PET. It's a fully replaced item. There are a few good threads here on rebuilding it. The 75 rack doesn't have part #10.

FWIW I've taken apart 6 racks now and they were all different in some minor way. I would also check the actual rack for straightness. The rack from my 77 coupe was bent. I sourced two new racks for parts and both were different. (Different length rack, but same ratio)

There are two people making replacement bushing kits. Efren (Aircooled Exclusive on Instagram) makes them and so does 914 rubber (Matt @914rubber on IG)

The puck can be reused with showing minor wear imho. Just orient it back the same way. The bearings are found via third party, I think AASE sells them as well.

[KTL]

Sorry for the late reply. I haven’t worked on a rack old enough to confirm seal size that is shown as #10 in the Clymer manual image.

I can confirm the 17x23x3 seal fits in the rubber-isolated bearing sleeve for the coupling shaft above the rack. It replaces the felt seals, which over time have not done a good job of retaining needle bearing lubrication. I have seen the needle bearing seize on a number of these upper rack shafts. I have actually bought a handful of these seals from metricseals.com to “re-engineer” the needle bearing installation in the rubber isolator. Just never got around to installing them on the stillborn racecar project or my ‘86 Carrera project. But I will soon...

As this thread has shown, the bearings are nothing special. You can get them for a reasonable cost from pretty much anywhere bearings are sold. I’ve gotten them from McMaster Carr no problem.

My thought on the puck wear is to measure the original height on the non-worn portion. Then resurface it on a piece of wet sanding paper and measure the resulting thickness after you’ve made it smooth and even again. The difference between the two measurements is your additional shim thickness you add to the stack of shims. I don’t recall off the top of my head the dimensions of the shims. But they can be easily measured and sourced from someplace like McMaster Carr or Grainger

Be sure to use a high quality grease when you reassemble the rack. The reason for the puck wear is grease degradation over time. Also be sure to “polish” the resurfaced puck to a really smooth finish, to allow it to slide even better on the rack. It’s surprising how bright of a finish you can get with even a gritty polish like typical car paint rubbing compound

[47silver]

i forgot to measure the depth that the top bearing was pressed too... there was a video that i cannot find now that i think said .3 mm.
the oring is .3mm so would that make sense that the bearing is .3mm deep?

[Flojo]

side question… what made you guys think of a need of overhaul?
any noticeable issues?
or just the pure fact it's been not maintained in 40+ years?