Author Topic: Need stub axel kingpin bushings for early Cobra  (Read 3147 times)

rhbeede

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Need stub axel kingpin bushings for early Cobra
« on: April 24, 2017, 08:21:01 »
Anyone have access to new kingpin bushings and thrust washers for an early worm and sector Cobra? There was an old thread on the forum about a New Zealander who modified the bushings on his 11/16" kingpin axels for improved grease distribution. I have searched for it, but cannot find it again. I would appreciate a member sharing the link, if they know of it, because I wanted to find out the results of the modification.
   The bushings in the early Cobra's are about 22mm OD and 19mm ID. There are no holes or grooves in them. I do not know if they are sintered bronze with steel backs.
   Any help would be most appreciated!
   
   Bob

B.P.Bird

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Need stub axel kingpin bushings for early Cobra
« Reply #1 on: April 24, 2017, 18:27:08 »
Bob,
   Making the assumption that you are referring to Cobras with the cam and peg steering box, the earliest cars used the same stub axle as the later Ace 2.6. At some point in Ace 2.6 production a 3/4" king pin was introduced. David Sanderson tells me his old 2.6, RS 5031, still had the 11/16" pins whilst RS 5035 had 3/4"pins. In any event these 3/4" pins were used in the Cobra. Later the Cobra stub axles were further strengthened by increasing the size of the inner bearing. When we rebuilt CSX 2033 a spare set of stub axles came with the remains and these were thicker than the original ones on '33.The spindles being larger cross section at the root for the larger bearing. The hubs to fit the strengthened stub axles were also stronger having a different housing diameter to fit the larger inner bearing and a much increased wall thickness, especially beneath the threaded wheel hub cap area. I suspect that this last production iteration was the one you refer to as being marketed by Shelby American as a racing part. If you have the early production specification then to upgrade to the final version you will need hubs as well as stub axles. For what it's  worth, driving '33 on the road, there was no difference to be felt between the early and later versions, although the later version does give one more confidence. I think there is a chance that Brian Eacott (see ACtion for contact details) may help with spare bushes etc. for the 3/4" set up.
   So far as grease is concerned the grease nipple is in the pin and not the bearing housing. I find that, greased regularly, the king pin bushes remain well lubricated. If you are lazy though the grease will dry out and the lower bearing will become clogged.
   Turning to boots for the track rod ball joints they are the same part bought in for MGB. As Dan said you may have to trawl through batches to find Lockheed markings. The last Lockheed ball joints I found were marketed for Morgans - maybe worth asking them ?

rhbeede

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Need stub axel kingpin bushings for early Cobra
« Reply #2 on: April 25, 2017, 07:49:23 »
Dear B.P. Bird,
   
   Thank you for the very informative communication! Back in 1967, when I purchased my car (CSX 2073), I upgraded to the "thicker root" spindles, and changed the inner bearing and race to allow for the larger spindle ID. I was interested in your comments about having to change the hubs to accommodate the spindle modification. I had no problem using the hubs that came with my car, so perhaps SAI/ AC had upgraded to the beefier hub by the time they got around to building my car. I do not know when 2073 departed AC, but it left SAI in May of 1963, and received a 289 engine, not a 260. Although it is repeatedly stated that about 75 cars were produced with 260 engines, Shelby did not assemble the cars in sequence, due to multiple issues which affected an individual car's assembly rate. An example of this is CSX 2044, first purchased by Stanford Physics Professor  Dr. Horn, which is documented from the factory as having a 289 at the date of delivery.  This car had black foot boxes, characteristic of really early Cobras. Mine are that off-white color.
   
   Regardless, I was able to source a Kingpin set made in England, so I am good on that issue. I am surprised about the bushing wear, though, since my car suspension gets over lubed. The slop in the pins is very slight, but they are not as tight as when I rebuilt them. All my driving time is now on the track, so even though I have conservative tire size ( 7" tread width on 7" kidney bean wheels, this must stress the stub axel design more than I think!
   
   Thank you for the suggestion to check the MG parts for Lockheed boots for the tie rods.  As I am sure you know the worm and sector ( cam and peg) steering system has no actual ball joints.  Those came with the re-design to rack and pinion, and a spindle that bolted to the upright. The last time I searched for the boots in both the MG and Morgan spares, they sent me boots which were much different than the original ones on my car, and Bristols that I have been allowed to crawl under to inspect.
   
   Please keep me in mind if you hear of anyone with NOS tie rods for the later Ace's, Bristols, or early Cobras.
   
   Thank you, again!!
   Bob

B.P.Bird

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Need stub axel kingpin bushings for early Cobra
« Reply #3 on: April 25, 2017, 14:39:07 »
Bob,
   I think something is lost in translation (two nations separated by a common language.) All the Thames Ditton cars with the Bishop cam and peg steering box had six ball joints. Often called 'track rod ends'and maybe 'tie rod ends' your side of the pond ? Anyway they are the three joints on the steering idler, one joint on the steering link or drag link and one joint on each of the front uprights/caliper carriers.
   Racing '73 sounds like a brave undertaking, could we see some photographs please ? These early Cobras used Greyhound 15" wheels which were 5" rim width so going up to 7" and some modern rubber will multiply the load on the king pin bushings. As you say perhaps more than we think.....
   For what it is worth I find more wear on the thrust washers than the bushes moreover the stub axle and upright thrust surfaces also wear over the years. As '73 likely left Thames Ditton in January '63 that's 54 years. This being the case the thrust surfaces could be cleaned up a little and some slightly thicker thrust washers could be made to fit.
   With apologies - Grandmother sucking eggs and all that

rhbeede

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Need stub axel kingpin bushings for early Cobra
« Reply #4 on: April 26, 2017, 07:13:47 »
Dan, LOL! Yes, I guess us Americans forsook the British language when we refused to pay the tea tax! What we call "ball joints" are the suspension fittings at the bottom of the rack and pinion 289 Cobra uprights. The units tying all those links together in the cam and peg steering with Bishop steering box are called TIE ROD ENDS in the USA! I guess this goes with "hood versus bonnet", "trunk versus boot", and wrench versus spanner"! Thank you for the illlumination! Maybe that is why I never got any response to my forum inquiries 10 years ago!
   
   Other than "racing" with the 42 other Cobras at the 2012 Monterey Historics to celebrate the 50th anniversary of the Cobra, my track time is mainly Cobra Club Track days at Willow Springs in the Mohave Desert. It's a really fast track, where I get to 125mph in two places with  6000 rpm rev limit. We would love to have you guys come join us! As far as pictures, Google Robert Beede CSX 2073, 2012 Monterey Historics. There are some of me in my little red car. Jim Click and others blew my doors off when they passed me towards the end of the race; 500 HP versus my 340! All of them had a lot more rubber than me too! Cheers! (I.e. Bye for now!)

B.P.Bird

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Need stub axel kingpin bushings for early Cobra
« Reply #5 on: April 26, 2017, 21:56:02 »
Had a look: What a lovely picture and what a great colour.