Handbrake adjustment

[Evos3960]

Hello,
I have a super np and the handbrake won't hold the tractor on a slope. I have had a good look to see if I can see how to adjust it but there is nothing to adjust the handbrake that I can see, could somebody out there tell me how to carry out this adjustment. Many Thanks.

[mathias1]

is it the handbrake (T handle) or a gearbox handbrake?
the (T handle) works on by locking one of the brake pedals.
Picture?

[shepp]

The handbrake is a transmission handbrake with 5 rotating discs and 7 stationary discs that works on the reverse idler gear in the primary gearbox. The set up consists of the disc pack with the rotating discs splined onto the reverse idler gear with intermittent stationary discs that are free to slide but not rotate, a sliding retaining plate, a conical spring, and an adjusting nut with a locking split pin. The whole assembly is mounted on a shaft with a bolt through the centre of the shaft that is free to slide in the shaft and the front casing of the primary gearbox.The handbrake cross shaft has a cam on the internal end that works on the end of the adjusting nut. In action when the handbrake is applied the cam pushes progressively on the adjusting nut which together with it's sliding bolt moves and increases pressure on the conical spring, this moves the sliding retaining plate to compress the clutch pack and thus prevent the reverse idler gear from rotating which locks the transmission. The whole assembly is meant to be adjusted and set up when the primary gearbox is on the bench out of the tractor. There is only one adjustment, which is to set the length from the primary gearbox front plate to the edge of the adjusting nut, presumably with new plates and spring and nut installed.

In practice over the years the stationary and revolving plates wear, also possibly the cam on the handbrake cross shaft and the face of the adjusting nut, so that the action of putting pressure on the conical spring is much reduced and the handbrake will not hold. Some people claim to be able to access the brake unit via the belt pulley plate or the plate with the gearbox oil level and filler plug in, but they must have double jointed fingers on double jointed hands and arms! Even then, the only action that I can possibly see is to remove the split pin and nut and insert a packing washer(s) to take up wear before replacing the nut and split pin. However I would not recommend trying it as if you drop the nut in the gearbox housing............!

To do the job properly the only option is to split the tractor, remove the primary gearbox and have a look at the transmission brake on the bench. However as new plates are not available that restricts the options anyway, unless you are able to get them refaced.

Or does anyone have any alternative ideas?

[mathias1]

aren't these the discs?
http://www.ebay.co.uk/itm/Fordson-Super ... xyrx5TkBDW

[AdrianNPMajor]

Interesting and informative thread.
Re wear, theoretically there would be none between the plates, if, a big 'if', the operators had released the brake prior to setting off. I doubt the wear between cam and nut dome would have been a factor, especially as this assembly is bathed in oil, and the incremental wear is taken up by the load on the spring.
It's still not clear which handbrake we are talking about.
Best, Adrian.

[url=https://postimg.org/image/v8ordk46 ... .jpg[/img][/url]

[shepp]

Firstly, that's a good picture from Adrian, have you got one taken end on which would be even better?
Yes, the components are well oil splashed, but people forget about the handbrake and move off without releasing it and because it is not that brilliant in the first place they do not realise it is still on! So plates could be badly worn, the spring could be weak or broken. Internal oil bathed transmission handbrakes are generally a problem, look at the one's fitted to 1980's and early 1990's International and John Deere tractors! The external dry one on the early 2/3/4/5000 tractors is easier to overhaul, but as far as being effective they are of little use!

The link for the plates from mathias1 is to Silver Fox Tractor Spares, and yes, they are the correct plates, and they do the conical spring as well!! I was not aware that anyone was doing these items, Silver Fox seem to be particularly good on these obscure Major parts.

So my recommendation is still to split the tractor, remove the primary gearbox, fit new plates and spring on the bench, refit the end nut and adjust the nut so that the distance from the inner face of the primary gearbox housing flange to the head of the brake nut is 352.30mm to 352.94mm.

Or does anyone claim to be able to replace the discs and spring working through the side plate on the gearbox??

[mathias1]

Adrian,

getting the transmission coming out is one of the jobs on my shedule for the coming weeks. Wonder If I can first take of the back transmission and then the gearhouse. I don't have much room in my garage. I've got the rear wheels already off.

thanks!

[AdrianNPMajor]

Replying to Shepp and Mathias in chronological order.
Shepp, found no sign of wear on PJE 243.
Mathias, sorry, but you will have to split tractor between engine and gearbox. The cassette comes out through the front. Image again from PJE 243.
Both images got rotated though 90 degrees in the upload. Apologies for giving anyone a crick in the neck!
Best, Adrian.

[url=https://postimg.org/image/gtbfs5vv ... .jpg[/img][/url]

[url=https://postimg.org/image/5gyuadfg ... .jpg[/img][/url]

[AdrianNPMajor]

Mathias, I may have misunderstood.
Is this the stage you are at?
Best, Adrian.

[url=https://postimg.org/image/4rg1y7wz ... .jpg[/img][/url]

[Brian]

As Shepp has said you cannot service the handbrake through the pulley plate, you can however adjust it through the gear selector plate, it is a fiddle but I have done it. I understand that you can remove the plates through the top with the High/Low selector removed but I have never done it, it was always far easier to go in through the front and take the whole primary gearbox out.

I have never seen the plates wear although all things are possible, the result of leaving the handbrake "just on" has, in my experience, resulted in a seized solid gearbox and possible breakage of the primary gearbox housing. Even if you get away with leaving the handbrake on for a short while it usually blues and warps the plates so total replacement is not far away.

I have mentioned many times what we did at pre-delivery on Majors and Super Majors which was to remove the handbrake ratchet and grind off the first four teeth. This means that the brake will either be on or off and cannot be left "just" on. It certainly reduced the number of incidents of handbrake failure/locked gearboxes in our dealership.

[paudie]

Hi evo3960 , if you look through my previous posts under "super major handbrake " and "handbrake adjustment " I got great advice on the same topic, With tips on the removal and refitting of the the gearbox and handbrake.I think you should split the tractor and pull out the primary gearbox out as it would be quicker and less stressful.best of luck mate,
Paudie

[shepp]

The tip from Brian about accessing the handbrake via the selector cover is a good one and one I had not thought of, but everyone seems to agree that it is still better to split the tractor and remove the primary gearbox to work on the handbrake.

What puzzles me with the design of the handbrake is what possible adjustment can be made, other than the original set up instructions from Ford to adjust the nut so that the distance from the tip of the dome on the nut to the inner face of the primary gearbox housing flange is 352.30mm to 352.94mm???
These are very specific measurements, and presumably Ford had done a calculation based on the dimensions of a new reverse idler, the thickness of new stationary and revolving plates and the retaining plate that the spring sits on, the free length of a new spring, and the length of the domed nut. This measurement as above presumably would ensure on initial set up that there was the minimum of "play" in the package of gear, plates, retainer, spring and nut, but that the spring was not exerting pressure on the plate pack that would force the plates together. Presumably also this would ensure the dome of the nut would be as close as possible to the cam on the handbrake cross shaft with the handbrake off, so that when the handbrake was applied the cam would almost instantly start to apply pressure to the domed nut and spring and thus the plates.

If the plates wear slightly in use or the spring tires so that it's free length is slightly reduced, then there is a slight extra movement in the pack before pressure starts to be applied to the plates. But how can you adjust for this??
If you tighten the domed nut up to remove any play in the pack, then you move it that bit further away from the cam anway and this clearance has to be taken up by the cam before any pressure is applied to the spring, so the net result is that there is no difference to the maximum braking effect on the plate pack!!
If you slacken the nut slightly to move it supposedly towards the cam, then there is more play in the pack that has to be taken up as the handbrake is applied before any braking effect takes place, and again there is no difference to the maximum braking effect on the plate pack!!

So it appears to me that there is no adjustment that can be made other than the original set up instructions with new plates and a new spring installed!! Either that or placing shims between the domed nut and the existing spring and plate pack to achieve the original set up dimension whilst removing free play due to wear in the pack without putting pressure on the plates.

Another point is that if the plates do not wear as some contributors have said, then why and how does the braking effect of the handbrake diminish, other than the spring becoming tired and it's free length reducing??

Any one got an alternative theory or theories??!

[paudie]

Shep , in response to your post . When I had my primary gearbox out and discovered that the handbrake was totally wrecked,as someone had attempted to fix The handbrake previously ,obviously with out a clue or manual or this forum, but I reassembled the plates and had to get a few extra ones from a donor primary gearbox which I happened to have lying around as u do ! ,so when I had it all back with the correct sequence of plates etc . I checked the measurements as per this forum and manual. But I felt the plates had too much play ,possibly I thought maybe the second hand plates were worn ?, so I tightened up the castle nut about 1.5 revolutions.A week later I was back in action but I can tell you now that my handbrake now engages after the very first 3 clicks of the ratchet,which makes me think that because I tightened the nut a bit extra on reassembly that it definitely had effected how soon the handbrake now engages.This is just my experience for what it's worth.
Regards paudie

[shepp]

Hi Paudie

You obviously had a satisfactory outcome to your strip down and re-build, but if you had set the handbrake as per the manual it still might have functioned after the first 3 clicks when the free play in the pack had been taken up - as you had set it, the 3 clicks of movement might have been needed to take the cam onto the domed nut, and with very little play in the pack the brake would start to bite immediately. If you had set it per the book, the cam might have been on the dome with the brake fully off, and the 3 clicks would take up the play in the pack and the brake would start to bite at the same point. It is impossible to tell without setting it with both settings and comparing the result - obviously not very practicable! Replacing damaged plates obviously had an impact on the end result, however your brake works and that's all that matters!

As I previously said some experienced contributors say that they have found the plates do not wear if they are not abused, so other than spring fatigue why does the handbrake performance tail off?? I am wondering if these (supposedly wet) disc handbrakes suffer the same issues as the dry disc footbrakes on the Super Major, where because the brakes are not ventilated then dust particles of worn off material can "ball" together and form an invisible barrier between the friction plates so that the braking effect of the footbrake is much reduced? The handbrake discs are only oil splashed, they are not subject to oil under pressure like the IPTO packs of more modern tractors, so there is no flushing of the plates taking place. In addition, gearbox oil contamination on these old dears is also an issue, if not with current owners then with previous owners.

Could it be that the simple act of stripping the handbrake down, cleaning up the parts and re-assembling them if they are not damaged or worn is what causes the handbrake to function properly again?

[oehrick]

Just a thought Paudie, as the gearbox / transmission seal deteriorates and the level drops there will be less lubricant showering the brake plates ??

At 50 yrs 9 months my Major still has plenty of handbrake bite on the original plates despite my periodically having to transfer oil from the back end back into the gearbox using a hose from the trailer pipe, I've cooked it up from time to time but thankfully no permanent effect.

[AdrianNPMajor]

Shepp, when you ask why the handbrake performance tails off, we haven't established that the transmission brake is the subject of this thread. I'm not convinced that it is.
Re the transmission brake, the static and rotating plates are not just splashed with oil, they are bathed in oil - try removing the gearbox filler plug with the engine running and you'll find yourself replacing it pretty smartish to prevent the oil from overflowing.
The interleaved plates of the transmission brake only ever touch each other when all motion has stopped - the handbrake is designed to be applied when the the tractor is stationary. There is therefore no scope for frictional wear, apart from operator misuse as discussed above. The rear wheel brakes, on the other hand, are designed to operate when the tractor is in motion, and the resultant wear is allowed for by using wearable pads pressing up against the rotating discs.
The transmission brake spring is pretty chunky, and in any case spends most of its life not being compressed (compare and contrast the engine valve springs), so it is highly unlikely that it has become weakened over time.
I think the questioner has an issue with the pull-up toggle handbrake that operates the rear wheels brakes, though I may be wrong.
Best, Adrian.

[shepp]

Hello Adrian

Yes, Evos 3960 has not responded yet as to whether he is referring to the actual transmission handbrake or the ratchet operated by the "T" handle that locks the dry disc footbrakes on.
However, I suspect he must be referring to the transmission handbrake, as the adjustable stop on the disc brake housings and the adjustable pull rod nuts are clearly visible and it should be obvious to anyone of even limited mechanical knowledge that they are clearly a means of adjustment of the dry disc brakes. The dry disc brakes do have issues, and always have had issues from being new. They were a step backwards in my opinion. That applies to all the tractors that used them - International Bradford built models, MF 65, later Nuffields and the Super Major.

As far as the handbrake performance tailing off, I don't have any problems with my current Majors, and I cannot remember any particular handbrake issues with the many Majors we bought and sold in the dim and distant past, but clearly some people have had and are having those issues, there are a number of postings about handbrake issues over the years.

I understand what you are saying about the plates lubrication and how the handbrake is SUPPOSED to be used, the spring will have spent at least half it's life compressed(and probably a good deal longer) whilst the tractor is parked up with the handbrake on.

But if people are having issues with handbrakes that they believe have not been abused, then throwing a few suggestions about the causes into the mix might help and clearly gets the debate going!

The original question was about adjustment, and clearly the only adjustment of the transmission handbrake is the initial set up adjustment specified in the manual.

Kind regards

[Evos3960]

I want to say hello and thank the following boys for their help
Mathias I
Shepp
Adriannpmajor
Btian
and Paudie
Hello Boys I am sorry I have not replied before now but I have been out of action untill now , anyway thank you all very much for the help you have given me.
And so to my problem which is not with the T clip which holds the foot brakes rather it is with the lever operated brake with the press button in the top. It seems to me that there is something amiss inside the trumpet housing and I am willing to bet that you are all correct in diagnosing my problem. Many thanks to you all once again, it looks as if I am in for an interesting time. Sorry for the delay in my reply.