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Big 7 Track Rod ends
#1
       
.jpg   SAM_2615 (2).JPG (Size: 179.79 KB / Downloads: 413)     Rebuilding a spare front axle. I am asking if anyone knows what thread the cross tube and rod ends have. They look like a pipe thread. I have a new set I bought in the 70s at Beaulieu for a fiver just in case.  The tube is not handed but one of the ends only screws in about 1/2" I think its been slightly crushed and want to open it out. Any thoughts.

PS. Forgot to say the tube is 3/4". Pete
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#2
I haven't worked on one for a long time, but I seem to recall that the thread is 3/4 x 16 TPI WF. If you don't have a thread guage You can check yours against a 3/8" Whitworth bolt which is also 16 TPI -it should fit snugly into the threads you have.

If you do need to buy a tap or die, 3/4" x 16 WF is identical to the obsolete imperial conduit standard thread. These turn up on eBay quite regularly and are usually a reasonable price.
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#3
Thank you Stuart. Just what I need. After wire brushing the tubes on the bench grinder I can screw the offender onto 5 ends of the 3 tubes. But as you would expect that's the tube i want to use as its the right length (1/2" difference over the three) and not kinked or pitted. I will search on with your Info. Thanks again Pete
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#4
a tiny bit of cold bending on the existing bends of a better track rod can make an enormous difference in the length.
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#5
True but the shortest is the only straight one. On the longest with the kink and the ends screwed right in. The toe out is visible with just the bare stub axles. It maybe the new ends are longer in the threaded length. An after Christmas Job Pete
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#6
Are they really original BIG 7 track rod ends?  I have a Big 7 spares catalogue and in it the ends look as if they are the pin type like the baby 7.  I used Morris Minor arms with tapers turned down and keyway cut to fit the big 7 stub axle ends.  Morris ball track rod ends.  The arms had to be bent down so track rod cleared under radius arms.....done by local Devon garage many moons ago (they also mended early farm machinery and televisions).  The track rod was an old water pipe which I threaded at each end, but unfortunatly only had a RH thread die so have to take one ball joint out of arm to adjust tracking.  Keep promising myself I will find a LH threaded die one day.....would make life easier.

Peter....easy enough to lengthen/shorten tube by cutting and joining ends together with a tube with same ID as track rod OD pushed over and ends welded round rod.  Can be finished with a chamfered welded part so looks tidy and professional.

Dennis
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#7
(26-12-2020, 07:07 PM)Dennis Nicholas Wrote: Are they really original BIG 7 track rod ends?  I have a Big 7 spares catalogue and in it the ends look as if they are the pin type like the baby 7.  

I can confirm that these are the type of track rod end fitted to my Big 7 and to the several spare track rods that I had in my spares stock. They are also the same as some new ones I had in a packet marked "Austin Big 7 1937-39".
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#8
    The original track rod end on the car with a pinch bolt. The new old stock ones came in the tin labeled Austin Big 7 1937-39. The three spare track rods had a mixture of ends. All right hand threads as are the originals. Not sure I could trust my welding to cut and welded the tube. Probably over time generic ends have settled on one length which might be a tad too long. Pete
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