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One of the functions of the puck is to provide friction. Without friction, the slightest imbalance would set up steering wheel wobble at certain speeds. The friction generated by the puck helps keep it in check. So it's doing exactly what it's supposed to do.
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'88 Coupe Lagoon Green "D'ouh!" "Marge - it takes two to lie. One to lie, and one to listen" "We must not allow a Mineshaft Gap!" |
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Max Sluiter
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Quote:
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1971 911S, 2.7RS spec MFI engine, suspension mods, lightened Suspension by Rebel Racing, Serviced by TLG Auto, Brakes by PMB Performance |
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Quote:
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Registered
Join Date: Mar 2007
Location: Boyertown, Pa
Posts: 251
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These are what you want
1712 is a needle bearing 17x23x12 mm
6202 is a radial ball unsealed 15x35x11 mm 17x23x12,HK1712,Metric, Needle Bearings Search for 6202-INA | E.B. Atmus Co., Inc. Mt receipts d/n have any skf info on them and I don't think that skf even makes the needle bearing. The other option is to take out the bearings you have and look at the nomenclature on them. That's what I did.
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Failure is not an option 78 SC, 06 Cayman S, 74 Targa, 1971 BMW R75, 1975 BMW R90S, 1983 BMW R100S, 2004 BMW R1200GS, 1974 Ducati 750 GT, 1974 Ducati 750 Sport, 1986 Ducati MHR Mille, 1995 Ducati 916, 1994 Bimota DB2, 2001 Tri 955 RS, 1970 Norton 750, 1975 Hon 400 F, 1971 Hon 750, 1967 Duc 250, 2016 Tri Thruxton |
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Thanks!!
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
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VXB is a good online source too
VXB Bearing online: Search Results VXB Bearing online: Search Results
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Kevin L '86 Carrera "Larry" |
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So in the process of removing the rack. One of the pan head Allen holding the rack in place in the smugglers box stripped and the head ended up breaking of with the extractor.
![]() ![]() I wasn't able to get a drill bit in due to the extractor so the approach I used is to well a nut to the screw and it worked amazingly!! Sent from my iPhone using Tapatalk |
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Good one, ZL! I remember trying to turn those screws and gave up fearing the heads would strip. I guess I was right. I got the rack out by loosening the collar instead as I remember.
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Failure is not an option 78 SC, 06 Cayman S, 74 Targa, 1971 BMW R75, 1975 BMW R90S, 1983 BMW R100S, 2004 BMW R1200GS, 1974 Ducati 750 GT, 1974 Ducati 750 Sport, 1986 Ducati MHR Mille, 1995 Ducati 916, 1994 Bimota DB2, 2001 Tri 955 RS, 1970 Norton 750, 1975 Hon 400 F, 1971 Hon 750, 1967 Duc 250, 2016 Tri Thruxton |
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how bad was your steering after removing and reinstalling your rack? I replaced my tie rod ends in the mean time and have major steering play. Alignment i'm guessing is up next
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The alignment in my SC was way off when I finally got it on the road but, according to the mechanic, most of the issue was in the rear as I suspected it would be since I had redone the entire RE of the car also. Nut, bolts, everything. I do remember making sure that the rack was centered when I removed it and reassembled it. I also marked its shaft near to where it goes into the coupler to the steering wheel so it would go back in the same way it came out.
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Failure is not an option 78 SC, 06 Cayman S, 74 Targa, 1971 BMW R75, 1975 BMW R90S, 1983 BMW R100S, 2004 BMW R1200GS, 1974 Ducati 750 GT, 1974 Ducati 750 Sport, 1986 Ducati MHR Mille, 1995 Ducati 916, 1994 Bimota DB2, 2001 Tri 955 RS, 1970 Norton 750, 1975 Hon 400 F, 1971 Hon 750, 1967 Duc 250, 2016 Tri Thruxton |
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
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Major steering play after the rack refurb & new tie rods is the exact opposite of what you should be experiencing. The new rack bearings and fresh grease on the rack will smooth-out the steering feel and new tie rods will tighten everything up.
Alignment that is way out of whack can make the steering feel really light. Maybe that's what you're experiencing?
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Kevin L '86 Carrera "Larry" |
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Book marked for future work
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Enthusiasm > Expertise
Join Date: Mar 2011
Location: Outside Philly
Posts: 606
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puck refurbishment
We're rebuilding a few mid-year racks and find that the condition of the pucks can be a bit, shall we say, disturbing...
![]() This put me in mind of the fact that the 914 and early 911 racks don't tend to have this problem, what with their plastic puck faces: ![]() So why not add a replaceable plastic wear surface to the pucks? First, I scuffed the surface to give the epoxy something to bite into. ![]() Then I cut up some plastic, scuffed it for the epoxy as well, and glued it on. The hole is an artifact of laziness (I used a hole saw with a pilot bit), but I figure it may collect and help distribute grease. The wear surface is scuffed to aid in that endeavor as well, though this is already a PTFE-enhanced acetal resin. I figure it won't take long for the surface to bed-in against the rack. ![]() The puck is currently taller than stock, but if the drag proves to be out of spec, it's easy to either change the spring, add some shims, resurface the puck, or all three. The way I see it, this sacrificial puck face can be easily and cheaply replaced before the puck ever gets to cuddle with the rack, sans lube. And speaking of lube-free fraternization, the plastic face may still perform better than bare metal. Any guesses as to how well this frankenpuck is going to perform in a car?
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Red Dog Motorsports |
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It will be interesting to see if this works but we will probably waiting some time until the rack comes apart again. I don't see any real downsides here as the plastic - I presume a form of nylon - has self lubricating properties. Only thing I can see is that it may wear quicker than lubed up steel. But once the lube is gone from steel, the game is over. Another possibility is the plastic puck parting company with its carrier, but it really has no place to go.
Certainly, the factory had to make these things to a price point, which would obviate the use of a composite puck as we have here. My bet is that it works.
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Failure is not an option 78 SC, 06 Cayman S, 74 Targa, 1971 BMW R75, 1975 BMW R90S, 1983 BMW R100S, 2004 BMW R1200GS, 1974 Ducati 750 GT, 1974 Ducati 750 Sport, 1986 Ducati MHR Mille, 1995 Ducati 916, 1994 Bimota DB2, 2001 Tri 955 RS, 1970 Norton 750, 1975 Hon 400 F, 1971 Hon 750, 1967 Duc 250, 2016 Tri Thruxton |
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
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The picture of that worn puck is unfortunate proof that these old car need a rack regrease after about 20 years! Modern high quality synthetic grease should last a lot longer than the original stuff.
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Kevin L '86 Carrera "Larry" |
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Quote:
This stuff is hard to bond, though, so as you pointed out, delamination seems like the most likely failure. Is there really nowhere for it to go? The case has an "O" bored into it for the rack and not a "D". Both grease and plastic disc should be able to glide along the flat back of the rack at a minimum. One way or another, I'm going to solve this problem more elegantly than the factory. Using a sacrificial material to save the rack makes the most sense to me, and plastic seems like it will offer the best failure mode. If that means machining new pucks entirely out of POM to avoid any chance of delamination, that's what I'll do. Anyone else want to install some plastic and serve as a guinea pig? ![]()
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Red Dog Motorsports |
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
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I'll take a plastic disc for testing. I have a spare rack sitting on my parts shelf that needs refreshing.
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Kevin L '86 Carrera "Larry" |
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Quote:
![]() Got a home for the rack? Send me a PM with your shipping address...
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Red Dog Motorsports |
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Schleprock
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Well i've got an '86 Carrera coming my way that will need a rack refresh. So I can install the spare rack with the guinea pig puck in the '86 and shelve the original rack from the '86.
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Kevin L '86 Carrera "Larry" |
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I still think the puck is metal for a reason - probably to provide some friction (damping) to reduce sensitivity to wheel imbalance during freeway driving.
For the plastic cover, why not turn a ledge in the puck, leaving a high area in the center, and bore a corresponding depression (or hole, depending on diameter) in the plastic? Should not take very long, and then the plastic is trapped against the rack and can't go anywhere even if the adhesive fails. If you don't have a lathe, you could drill a hole into the puck and press / loctite in a pin to hold the plastic, assuming it's thick enough to leave space for everything.
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'88 Coupe Lagoon Green "D'ouh!" "Marge - it takes two to lie. One to lie, and one to listen" "We must not allow a Mineshaft Gap!" |
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