Ford 4100 major oil leak from rear axle brake rod boot

[Pete O]

The old 4100 that I spent a lot of time on a year or so ago (rebuild thread here https://www.tractorbynet.com/forums/parts-repairs/386813-general-freshen-up-1967-ford.html ) has sprung a leak, it has dropped about 10 litres of oil over the past 6 weeks whilst sitting unused. I have had so much other stuff happening that I have just had to let it sit there and leak! I really need to get it fixed though as my paddock needs slashing. The oil is coming out of the rubber boot where the brake rod enters the right-hand rear axle. I did not strip the rear axle and brakes down at all during the rebuild so I'm not familiar with what is in there, wondering if anyone can advise where the source of the leak is likely to be- I am assuming the rubber boot is not supposed to have all that oil right behind it so there must be a seal somewhere further in that is allowing the diff oil into that chamber. I'd like to get a bit of an idea before I start stripping that side down.

 

[joecdeere]

A bad boot will give you quite a leak, very easy repair, a new one pops in from the outside after taking the rod apart.
If the rod is rough, polish it with some emery cloth before sliding the new one over it, some people put a couple of wraps of tape over the threads while sliding the new boot down. If you drive that side of the tractor up on a block of wood, you won’t have a leak while changing. If you’re down that much fluid, you may not leak anyway.

 

[ovrszd]

Yep, as Joe said, very easy fix. The boot is the seal. Kind of odd how it's designed. But works very well. Age probably finally destroyed your boot.

 

[Pete O]

Thanks for the replies, yes it does seem odd that the boot seals the axle oil in. It seemed to me more like something to keep the dirt out. Relieved that it doesn't involve a major strip down of the axle, I have way too much on at the moment so it looked like getting a contractor to slash my paddock.

 

[ovrszd]

You'll do this repair in a couple hours at the very most!!! Probably less than an hour.

 

[Sportsman762]

I think the seal part number is 82037652. Relative to the rest of the work you have done on this tractor, this job is easy.

 

[Pete O]

Thanks for the replies, very helpful info. I thought I was in for an axle strip-down to get to a seal behind the brakes or something. Still kind of surprised that the boot is there to contain an axle full of oil, I really assumed it was just a dust boot. Should be a super-easy fix. I'll be careful to ensure the bore and the rod have nice smooth surfaces for the boot to seal on.

 

[Pete O]

Ok interesting update on this; I contacted my dealer to order the boot and discussed with them whether it is supposed to have oil directly behind it. Their initial response was that no, it's just a dust boot- but on further discussion and throwing it around the staff they said that yes, there is oil in the chamber directly behind that boot but it shouldn't be up as high as the boot- so I have over-filled the diff. Which makes perfect sense, plus it makes this a self-solving problem as the excess oil is making it's way out of the axle via the boot!

 

[RickB]

Ok interesting update on this; I contacted my dealer to order the boot and discussed with them whether it is supposed to have oil directly behind it. Their initial response was that no, it's just a dust boot- but on further discussion and throwing it around the staff they said that yes, there is oil in the chamber directly behind that boot but it shouldn't be up as high as the boot- so I have over-filled the diff. Which makes perfect sense, plus it makes this a self-solving problem as the excess oil is making it's way out of the axle via the boot!

The update is more sad than interesting. Your dealer is wrong. Look at the oil level plug and the brake rod boot. The plug is higher than the boot. Must be a bunch of kids working there that don’t know anything about Fords.

 

[joecdeere]

Like Rick said, a quick look at the check plug location will show you these kids haven’t owned one or ever worked on one.
I’ve been around this style Ford my whole life, and have one outside, I promise you there’s oil behind that boot!