Author Topic: Cropmaster 3 point linkage issue  (Read 1345 times)

wee-allis

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Re: Cropmaster 3 point linkage issue
« Reply #15 on: 15 March, 2019, 08:18:33 am »

Cobba, if you can't match the thread, have you thought of cutting 10mm of each end so it doesn't bottom in the socket?
If it's old, treat it like gold.
C1300 Inter, 38 Allis B,47 VAK1A David Brown,48 TEA Fergie, 53 Morris Six,  Moruya, Sth coast NSW.

cobbadog

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Re: Cropmaster 3 point linkage issue
« Reply #16 on: 17 March, 2019, 02:38:16 pm »
I agree about the size and I do have that size die but a quick attempt to run it on by hamd appeared to be too small to screw on.
As there is no issues with the threads I was just curious and I don't have 60' pitch gauges, yet.
Cheers, John & Dee. Coopernook. NSW.

franco

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Re: Cropmaster 3 point linkage issue
« Reply #17 on: 18 March, 2019, 12:08:57 pm »
cobba,

The 11/16x18 tpi thread seems to be a common size for tie rod ends. 11/16x18 tpi taps in 60 degree thread angle seem to be common, e.g.
https://www.ebay.com.au/itm/11-16-18-HSS-Right-Hand-Thread-Tap-/280954221551

They don't seem to be available in 55 degree thread angle. However, I would not be surprised if your tie rod in fact has 60 degree threads. At the time the Cropmasters were being manufactured the British motor industry was in the middle of changing over from BSW/BSF threads to UNC/UNF threads, and mixtures of the two thread systems in a vehicle were not uncommon. I had a 1952  MG TD which had a metric engine, Whitworth/BSF gearbox and body, UNF rear axle assembly, BA electrics and BSP plumbing!

So - if you want to cut the threads deeper in the tie rods it appears the tap is available at a reasonable price, but wee-allis's suggestion would seem to be the easier way to go.

Frank.
Cairns, Queensland

Bugly

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Re: Cropmaster 3 point linkage issue
« Reply #18 on: 18 March, 2019, 01:51:22 pm »
Does a 5/8" UNF x 18 tpi x 60 degree pitch tap go into the socket end? If so, then running the die down the thread to re-cut to 5/8" UNF x 18 tpi x 60 degree pitch will sort it.
A 1948 Fordson E83W and a 1950 Ferguson TEA20 ... what a combo!!

cobbadog

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Re: Cropmaster 3 point linkage issue
« Reply #19 on: 18 March, 2019, 04:11:46 pm »
Yes Steve that is also an option. DB spares in the UK suggested moving the steering arm on the spline at the top of the stub xle. When I look closely at this and compare one side to the other the drivers side arm is beneath the rim but the passengers side is not. So by moving the arm around on the spline which is a simple thing to do and make it sit in the same position, under the rim this should solve the problem. Then all I need to ensure is that the steering rod from the pitman arm to the axle has enough adjustment to cope with the change. I did think of cutting the threads equally at each end but then I thought that if the parts supplied were correct I should not have to cut the drag link. The supplier nor the david brown tractor club forum in the UK can answer why the new ball joints are 20mm wider when screwed onto the the drag link.
Hi Bugly, 5/8" is too small in diameter to fit this thread as it measures 11/16" OD. I have been sent a message with a list of tie rod ends supplied by BareCo that suit many different tractors.  The only 11/16" threads listed are for MF and Ford tractors but with different tapers for the ball joint into the steering arm but most oddly a 10mm each difference in the width f the joint. Going by that list I have Ford parts supplied to me and does then resolve the 20mm extra width with the new joints.
I will try and download the chart and post it here later.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: Cropmaster 3 point linkage issue
« Reply #20 on: 18 March, 2019, 04:14:47 pm »
Hi Frank,
thanks for the link to that tap which going by the charts does not exist. I think that by moving the linkage around on the spline will resolve the issue for me but not the strange extra width from old to new ball joints.
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: Cropmaster 3 point linkage issue
« Reply #21 on: 18 March, 2019, 04:44:00 pm »
Have a look at the chart. It lists both MF and Ford with the 11/16" thread size and different offsets. Oddly enough the only David Brown on the list shows a totally different thread size and must be for a later model only.


http://www.bareco.com.au/files-tierod-un1
Cheers, John & Dee. Coopernook. NSW.

cobbadog

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Re: Cropmaster 3 point linkage issue
« Reply #22 on: 20 March, 2019, 04:09:46 pm »
Shifted the steering arm around on the spline at the top of the stub axle/king pin and now have proper toe-in adjustment. If I took it one more spline the inside mounting bracket welded to the rim would touch the nut of the ball joint so back one spline and all is good. Tomorrow I will adjust the steering arm from the pitman arm to the front axle linkage and all will be good. I also have to centre the steering box before adjustment is made.

Still amazes me you buy new parts and have issues like this, but that is part of the fun (?).
Cheers, John & Dee. Coopernook. NSW.

wee-allis

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Re: Cropmaster 3 point linkage issue
« Reply #23 on: 20 March, 2019, 07:09:40 pm »

John, it's just because you cannot always rely on "After market" suppliers being as accurate in their manufacture as we would sometimes like. Anyway, you got it sorted and it managed to fill in a couple of hours.
If it's old, treat it like gold.
C1300 Inter, 38 Allis B,47 VAK1A David Brown,48 TEA Fergie, 53 Morris Six,  Moruya, Sth coast NSW.

cobbadog

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Re: Cropmaster 3 point linkage issue
« Reply #24 on: 21 March, 2019, 04:03:59 pm »
Kept the ball rolling today and got the drop arm linkage to fit, then removed the steering box to have a look inside and clean it up but it wasn't too bad so I greased it up and put some never seize on the 4 thread screw so it went through the steering nut a bit better. Then not to be out done I attacked the 3 point linkage issue and got a result so it was a very fruitful day for me and David.
Thanks to all advise and replies to everyone.
Cheers, John & Dee. Coopernook. NSW.