Fordson and Dexta clutch pilot bearing causing shaft damage

[1962 model]

Hi,
I would like to bring to the attention of others that the ball bearings fitted to a great many Fordsons and Dextas have been damaging the front gearbox input shafts for over 60 years.
The reason for the damage to the spigot of the front gearbox shaft/ clutch shaft is that Ford must have had a special roller bearing fitted to the insides of the Major and Dexta flywheels, their "special" bearing was obviously of a smaller outside diameter ( for their own reasons )

Now if one gets a bearing from the local bearing shop ( which could be the same number as the one removed ) then chances are that it is the wrong bearing.
If an incorrect bearing shop bearing is hit hard enough it will fit into the inside of the Major and Dexta flywheels, however what happens is that the bearing then does not have the correct operating clearances and will seize in most cases.

In use this new-crushed bearing cannot turn and starts to wear the end of the gearbox front shaft/ clutch shaft and over the years the shaft is rendered defective and not in a usable condition on sucessive clutch replacements.

THE FIX TO PREVENT THIS DAMAGE TO THE GEARBOX FRONT SHAFT/ CLUTCH SHAFT WEAR DAMAGE IS TO INSIST THAT YOUR BEARING SHOP SUPPLY YOU WITH a bearing having A "C4" CLEARANCE in this instance it will be unlikely to seize and cause undue wear to the spigot of the shaft.

Either that or find someone who can supply a "genuine" Ford pilot bearing, but even then chances are that some enterprising spare parts stocker has subsituted a bearing with the wrong C3 clearance which will almost certainly seize upon a very short time of use.
EACH new BEARING SHOULD BE CAREFULLY CHECKED FOR THE CORRECT RUNNING CLEARANCES.

There may well be great disapointment from manufacturers that I have raised this matter as it could have an effect on sales of replacement shafts, but fair go they have had it too good for over 60 years now replacing shafts worn from incorrect pilot bearing fitments!
Many mechanics will not have realized why so many pilot bearings are found seized.

Mike.

[Billy26F5]

Thanks for bringing this up Mike, I think the aftermarket companies have taken this in to mind as I don't remember Super Billy's bearing (from Agriline) being a bad fit. I might be quite wrong about that but we'll only see when he runs again. Billy and Davie are fine with their original bearings.
Sandy

[Redtruck]

Good day fellows,
I appreciate this post as it hits home for me. I’m working on a 1954 unit with the single stage clutch. The pilot bearing spun on the transmission input shaft. I have a remanufactured input shaft and purchased a pilot and throw out bearing from the same supplier. The problem I’m seeing is the input shaft is .05mm larger in diameter than the ID of the bearing. Measuring the old input shaft on an undamaged spot - it has the same OD as the new shaft. Does the pilot bearing press fit onto the transmission input shaft? Do you know what the difference in clearance is between the C3 and C4?

Thank you much for any help or direction here,

Paul

[Billy26F5]

It shouldn't be too tight a fit, as the input shaft has to slide in and out when the engine is fitted or removed. According to what Mike says you want the bearing to be a bit free, as opposed to having a preload. I had always understood C4 to have a slight preload while C2 has a bit of play (as an example, although I've seen several different opinions), but the only way to be sure is to compare these bearings and feel how they work.
According to a contemporary SKF list the pilot bearing (E1ADKN-7600A) is a 6205Z. This was used till March 61 when E1ADDN-7600 was fitted instead.
Sandy

[shepp]

The usual bearing clearance grades are C1, C2, C3, C4 and C5. A C3 grade is taken as the standard normal clearance, C1 and C2 have less clearance and C4 and C5 have more clearance. Is the commentator in this article sure that the issue here is not more to do with the supply of the nearest metric equivalent bearing size instead of a genuine Imperial size bearing?

[Redtruck]

Thank you for your replies,

The bearing I have is stamped 6205Z. The New Holland site lists bearing 28043200 which replaces E1ADDN7600 and E1ADKN7600A. In the description it states 6205Z with dimensions 25x52x15mm. From the Messick’s site it lists the same 28043200 number but also states special internal clearance bearing # 6205-Z. I’ll reach out to the original seller and follow up with what I learn.

Thanks again,

[Billy26F5]

The Z is not a clearance, it means the bearing has a metal shroud covering the balls. I have often also seen CN being between C2 and C3, but that might not be a real clearance. There is a chance that the metric confusion could have occurred, but the 1950's SKF list for Fordson tractors would likely not have such mistakes (I saw it on ebay and managed to keep the pic saved for reference) and it clearly says that E1ADKN-7600A is a 6205Z. E1ADDN-7600 is a later bearing that has appeared before on the forum (see this: viewtopic.php?p=35584#p35584). In any case always compare old and new just in case, but watch out for previous mistakes.
Sandy

[mathias1]

I got 62052RSSKF bearing as pilot. it says it is normal clearance. Should I worry?
when I need bearings I always try to order skf or any other good quality brand.

[Billy26F5]

See how it fits, if it feels very tight swap it for a higher clearance bearing, you've got a sealed bearing, which is an unusual choice for a pilot bearing, they're normally of the shrouded type. Good bearings are always worth using.
Sandy

[Redtruck]

I called Messick’s today (New Holland dealer). They mic’d one of their pilot bearings on hand. The OD was less than 52mm and the ID was slightly less than 25mm. I have seen some Fordson Major pilot bearings listed as 24.99 ID and some 51.8 OD. I’m assuming this bearing was at those measurements. It doesn’t help with my 25.05 OD input shaft. Working with a local bearing supplier today. He found a 6205 with a 25.4 ID. Hoping to find one with the 51.8 OD. I read that a pilot bearing should be press fit in the flywheel .001-.002” per inch of OD. I’ll try to get the flywheel mic’d tomorrow to see how that looks. If this comes up as a dead end - after looking through some posts here and doing a bit more research, I’ll probably go with a non magnetic sintered bronze bearing honed to fit.

Thanks for the discussion here,

Paul

[Redtruck]

I got 62052RSSKF bearing as pilot. it says it is normal clearance. Should I worry?
when I need bearings I always try to order skf or any other good quality brand.

Do you know what your transmission input shaft OD is?

[Redtruck]

Thinking about this more. I wonder if New Holland is supplying a bearing with the idea that the input shaft has some damage. Maybe a 24.99x51.8x15mm bearing works correctly for the preload and the buggered up input shaft needs to be turned down to fit. I’ll mic my old input shaft for curiosity.

[shepp]

The original bearing for this application would be a standard 2 inch by 1 inch by five eights or half inch Imperial sealed ball bearing. These Imperial bearings are still available from specialist bearing and oil seal factors such as The Bearing Company, Henderson Bearings etc, look online. One inch is 25.4mm so obviously a bearing with an I/d of 25.05 is going to be way too tight on the spigot shaft. As I previously commented, I bet this chaps problems stem from the supply of a metric equivalent bearing, a trick too many classic parts suppliers do! As a matter of interest, New Holland Gold Value parts supplied under a NH part number are, in fact, ALL Sparex parts - good quality but you will get metric equivalent sizes in some cases.

[Billy26F5]

I've had a look around and the closest I can find is a 1/2" thick bearing. I'm still a bit unsure about this, I wouldn't expect a 1950's part list to have the sort of mistakes we get now, but the only way to be sure is to measure several flywheels, input shafts and original pilot bearings to see what we get, unfortunately I can't measure Super Billy anymore, but we got the Agriline one in 2011 and it fitted just fine, not too tight on either the flywheel or input shaft. The half Super Major input shaft might be measureable but I seem to remember it's quite worn, we've never had the bearing or flywheel. Probably best to measure before ordering to be on the safe side.
Sandy

[Redtruck]

Hello and thank you much Fellows,

I mic’d the worn input shaft I have, but the OD is less than the 24.99mm ID of the New Holland Dealership bearing. I tried to mic the pilot bearing ID on my flywheel, but my caliper doesn’t have a long enough reach. No new information on possible metric bearings. After reading Shep’s note, I too started to research imperial bearings further. There is a 1641 bearing that is 1x2x9/16. I couldn’t find anything with a 5/8” depth. My local bearing supplier has a fully sealed 1641 on the shelf I hope to have tomorrow. He suggested I remove one of the seals. This will help it to run cooler. I’ll follow up once I have a chance to fit it up.
Thank you again,
Paul

[Billy26F5]

I would see if you can get a shrouded bearing, they're much better for this job. Probably is worth measuring the flywheel, but it all points to the metric mearing at the moment.
Sandy

[Redtruck]

Happy Saturday Fellows,

Following up on that 1x2” bearing. It is loose on the input shaft and falls right through the flywheel. I did confirm the measurements and it is 1x2. Back to the drawing board.

Have a good week,

Paul

[Billy26F5]

This points to the metric bearing even more. Try it and see how it feels.
Sandy

[shepp]

That is very strange. There is no way that Ford would have used anything other than standard generally available Imperial sizes for its bearings and components, especially clutch spigot bearings. If you specify a non standard size for something as simple as a clutch spigot bearing you are running into extra costs from the bearing manufacturer if they have to make a special one off size for you. I'll research the standard Imperial sizes available in the 1950's when I get a spare moment. There is no way that Ford would be using metric bearings in the 1950's!

[Redtruck]

Good day fellows,
I had a chance to bring this over to the machinist who ground the flywheel. He measured the pilot hole in the flywheel to be 2.046 inches. This is .001 inches less than the 52mm bearing I have. He recommends using a bit of emery cloth to polish the transmission input shaft and fit up with the 25x52 bearing. I had hoped to assemble without removing material from the shaft or flywheel, but having a custom bearing/bushing made doesn’t seem like the answer. You fellows please enjoy your week,

Paul