MTFCA Forum

Guys -
We have purchased the inner rear axle neoprene seals and have encountered a problem installing them. I have never installed these before, so I am a neoprene seal virgin. Be gentle with me.

There were no instructions or diagram included with the seals indicating the direction the rubber seal is supposed to face. Logic tells me that the conical shape of the seal would face outwards toward the wheel after slipping it over the axle and seating it behind the bearing sleeve. But when we do that, the roller bearing sticks out past the end of the axle almost one inch! Test "dry" assembling the other side by sliding the rubber seal into the bearing held in my hand, the parts mate well and the seal's metal washer fits flush with the bearing - with some pressure. But when the bearing is installed inside the sleeve, the roller bearings are compressed between the sleeve and the axle = now there is no room for the rubber boot to fit inside the bearing. That's why I believe the one bearing is sticking out and cannot be forced deeper into place, even though I removed the one thin washer behind the sleeve and drove the new seal washer inwards until it seated.
So, the question: Does the neoprene seal face outwards when installed as I described above, and if so, why won't the bearing slide all the way in? What did I do wrong THIS time???
Marshall

The raised cup goes inside first, away from the bearing. Turned around, the bearing would chew it up.
As pictured, those seals appear to have a thin washer base that might fit without sleeve trimming.
In the past, those seals had a thicker base & the sleeve had to be trimmed to sit in far enough to properly set the raised locking dimple in the axle housing. The sleeve should fit flush with the housing end.

Dan posted this about a decade ago. Note they have improved the seal as picture below.

Grease the axle so the seal slides on better

JTT3 wrote: ↑

Fri Jan 12, 2024 8:36 am

Dan posted this a few years ago.

The seal pictured on the axle fits way to tight as a seal. You can see that seal has to be streched quite a bit ti fit a 1.062" shaft.
I now cut off that tight band back to that raised radius-ed ridge.
I have yet to find one of those seals still intact functional as installed as pictured. The seal typically grabs & shreds itself or delaminates from the steel backing washer & spins.

Also when I put them in I place I put masking tape over the key way so it doesn't nick the seal. In addition, some ultra black RTV on the outer edge that will hit the axle tube to help seal it in place. A piece of PVC pipe is excellent to push it into place. I do not trim the seal lip, it will conform to the axle.

The seal adds some thickness, so don't be surprised if your outer Hyatt bearing sleeves stick out a bit past the end of the axle housing. If they do, remove the sleeves and grind a bit off of the inside edge until the outer edge fits flush with the housing.

Good hint on trimming the seal John, I’ll give that a try. I also put a bead of RTV on the outer edge of the seal.

Andy

Those style seals are usually an okay fit in ‘26-‘27 rear ends where there is room for them designed into the housings, but they are less than satisfactory on earlier housings.

Another method to protect the seal from being cut from the sharp edge of the axle keyway is to put a very small screwdriver in the keyway and pry the lip of the seal away from the keyway as you slide the seal on.

Those seals had been "modified" years ago to have a narrow ledge removed so as to not having to trim the sleeve.

I used electrical tape instead of masking tape and the Cantrell-Miller tool makes pushing it in and seating it easy.

Thanks, Guys. I knew something was wrong. I wish I had seen these photos and read this advice before starting what seemed to be a simple installation. Don't you think it would have been helpful if the manufacturer had put note in the package accompanying the parts, giving installation guidelines and tips (like in the above posts) to make a successful installation? Or is the installation supposed to be so intuitive that even an idiot like me would guess correctly with a 50-50 chance of installing the seals backwards? Whenever there's a 50-50 chance of guessing wrong on something, I'll guess wrong 80% of the time!
Now to try and dig out the one seal that I installed backwards! 'Tain't gonna' be easy...
Marshall

Marshall

Instructions may help, for this seal the metal washer is for the Hyatt bearing race to butt against, just like the washer for the outer felt seal. So metal out


A long pick with slight hook can grab that seal to remove, may have to pierce the plastic, likely wrecking that seal.