Info needed; Explorer disc brake swap to 9" Ford?

[Beck]

Does anyone have experience on installing Explorer disc brakes to the 9" Ford rear axle?

I am having an axle retention problem in one of my little pulling tractors. Currently I have 8.8 axle ends on my axle. The axle itself is a concoction that I have made. The jest of it is; it is chain drive which goes through a 4T65E final planetary and differential. My axles are currently retained by the small clip on the 4T65E axle spline. The clip isn't strong enough and the axles intermittently pop out while driving in the pits.

I use the mechanical portion of the Explorer parking brake for brakes. I have removed the rotors. My wheels are only 12" so the rotors wouldn't clear. I want to keep these mechanical brakes.

I have purchased 9" ends and retaining rings, along with a spacer that is used for the Explorer disc brake conversion.

Here is my problem; I have seen different "required" measurements for the brake backspacing on the axle shafts.  I called Dutchman Axle (I'm currently using their custom splined 8.8 axles) and Quick Performance (I bought their 9" ends) today. They both said I need 2.5" backspace. Currie says it needs to be 2.229".

One more question, I have Explorer sized axles which have larger bearings. The Explorer axle is 1.619" at the bearing. 9" bearings have 1.562" bores. Could the Explorer sized axles be turned to use the 9" bearings? Dutchman Axle says, "No", but I don't understand why. I think there would be enough shoulder, .028", on them to stop the bearing.

[enjenjo]

I see no reason the axle can't be turned down, unless it's just too damned hard. And even then it can be ground to size. I would call Moser and see if they can do it, they have done this type of work in the past for me when the local guys couldn't get it done. And their shop rate is fair.

I would just duplicate the axle stick out you have now since you will be using the same brakes. Measure from the outside face of the axle to the housing mounting flange, and ignore any part of the bearing housing that sticks out past the flange.

[Beck]

I would just duplicate the axle stick out you have now since you will be using the same brakes. Measure from the outside face of the axle to the housing mounting flange, and ignore any part of the bearing housing that sticks out past the flange.

That makes sense. I was trying to calculate the 8.8 bearing stick out from the housing into the mix, but there is no need to. That makes it simple.

I was worried about the axle hardness.  I know I don't have a tool to cut it. I was considering taking it to a local crank shop. If the bearing is 1.562" id, do I need to make the axle .001" or so bigger for a press fit? The "wedding ring" is what really holds it, but I expect there needs to be some interference on the bearing also.

[kb426]

All the bearings I do are press fit.

[enjenjo]

generally it's .0005 to .001 inch per inch of diameter press fit.

[Beck]

I would just duplicate the axle stick out you have now since you will be using the same brakes. Measure from the outside face of the axle to the housing mounting flange, and ignore any part of the bearing housing that sticks out past the flange.

I purchased a "Set 20" bearing today. That is the tapered roller for the 9" axle. I don't think that is going to work for me. The bearing is wider than the housing, so it extends past the brake mounting flange. That isn't a deal breaker since I can just measure the difference and cut the axle that much further. The real deal breaker is the seal diameter. The seal rides on a larger part of the shaft. My shaft is smaller than the seal ID. My only option using this bearing on my turned down axle would be to make a spacer to press on the axle. I don't think I have the ability to machine the sleeve smooth enough to not destroy the seal. I could install it oversized and have it ground when the shaft is machined.

There is also a ball bearing used in the 9". They didn't have one of those in stock. It will be there in the morning. I don't know how that one seals. There is an O-ring on the bearing OD. Is the bearing itself sealed good enough to hold the gear lube? I believe some of these axles used an internal seal. I don't know if my new ends will accept those.

[kb426]

The bearings I had on the Monarch rear in the 32 had the oring only. Those were small bearing ends. There is also Oldsmobile ends that use the oring. This is the bearings I used: https://www.summitracing.com/parts/msr-9507f-1/