Hello, I have a L4200DT. There's a low pressure hydraulic leak at the bottom of my rear axle case. Right at the bottom of the case. I removed the wheel and successfully removed old worn liquid gasket. It appeared as if someone before me had done the same repair. I replaced the gasket with Permatex Ultra Black. I will admit that I laid it on thick, more like 3/8" instead of 1/8". I made sure to stay on the interior side of all the bolts. I let it dry. Then secured the axle case back on, fairly tight, but not crazy tight. My repair failed. The leak is still in the same spot at the bottom of the case. It leaks while the tractor is cold and sitting unused. It is a slow leak, but I need to fix it. I would like to attempt this again, but would like to know what the best option is for a gasket. Any tips would be greatly appreciated!
Seeking answer on best gasket material for rear axle case
- Thread starter Echo_Orchard
- Start date
kubotafreak
Well-known member
Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Kubota uses Gray factory. You sure there is not a cracked housing, or a bolt put in the wrong spot, and popped through the casting? Or stripped drain plug?
thanks for the tip on the kubota gray factory. I’ll order that for next attempt. Fairly certain the housing is not cracked. It’s more likely that there’s a non-factory bolt that is causing the leak.
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Improper application of these type sealants does not make them work better.
I believe Kubota uses Three Bond products but what you used seems appropriate for the application.
I believe Kubota uses Three Bond products but what you used seems appropriate for the application.
kubotafreak
Well-known member
Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
If that is the case, you can reseal the housing, and apply some pipe dope(Dont kill me GeoHorn) to the bolt threads. This is common with blind holes. Insert a bolt too long and it pops a little cap off on the inside. Then the oil seeps around the bolt threads. Give adequate cleaning/curing time for the sealer you choose. Installing oil wet, or too thick is asking for trouble. The inner squeeze out can and will fall off and float around the system.
Russel King sounds right about the branding. Gray sealer tends to be a little more dry if you will, and is very common amongst asian build. Black and blue, tend to be more slippery, and clear silicone like in nature. Unless it is great stuff" and it is between black and gray in cured consistency. If you were to pick one only, Id pick gray sealer.
Russel King sounds right about the branding. Gray sealer tends to be a little more dry if you will, and is very common amongst asian build. Black and blue, tend to be more slippery, and clear silicone like in nature. Unless it is great stuff" and it is between black and gray in cured consistency. If you were to pick one only, Id pick gray sealer.
Last edited:
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
You need to really,really,really CLEAN the mating surfaces AND 'deck' them. After you've cleaned them 4-5 times, run white paper towel over them...ANYTHING 'oily' shows up, clean again and again. Vertical B&S engine are bad for leaking(bolts 'wiggle' loose...), I spend an hour cleaning then use a quality gasketmaker,reassemble and have never had any return for leaks.
'decking' means running a KNOWN straigh edge ove rhte surface and filing as necessary to the the surfaces FLAT, leave with a slightly,lightly groove though, helps gasket material stick
BEFORE you goop and go, look real careful, bright light, different angles, to be 100% SURE the case doesn't have a hairline fracture. That could have been caused by over torquing the nuts or bolts in a previous repair.....
'decking' means running a KNOWN straigh edge ove rhte surface and filing as necessary to the the surfaces FLAT, leave with a slightly,lightly groove though, helps gasket material stick
BEFORE you goop and go, look real careful, bright light, different angles, to be 100% SURE the case doesn't have a hairline fracture. That could have been caused by over torquing the nuts or bolts in a previous repair.....
kubotafreak
Well-known member
Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Good point!
A honing stone works great for flattening out pry marks on the mating surfaces if the prior person got to vigorous.
I have repaired several of these. As others have sad cleanliness is the number one thing. I use brake clean. I use the Kubota branded 3 Bond. $20 a tube but well worth it. You can't have any oil on the surface period torque bolts to spec period.
whitetiger
Moderator
Staff member
Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
It appears your main problem is that you let your sealer harden before your reassembly. The housing should be reinstalled with the sealer fresh, then tighten the bolts to the correct torque.
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
I actually read the tube one day.. says 30 seconds ! yeesh ....guess it pays to read instructions once in awhile.
I now spread the goop, place case on, toss all bolts in holes, then torque down in 2 or 3 stages, being sure to evenly tighten them in the correct pattern...
I now spread the goop, place case on, toss all bolts in holes, then torque down in 2 or 3 stages, being sure to evenly tighten them in the correct pattern...
yep look for pry and beating marks
clean the old stuff off with a rotary wire brush in a drill.
some techs like to use tools that are considerably more "brash" and that's all I'm saying. They can damage the housing(s).
Does either part have a groove? If so, the groove needs to be completely cleaned out. I usually use a pick to get most of it and wire brush the remainder. It acts as an expansion groove, when silly-cone dries it it expands into the groove and seals it a little better
Next. Bolt holes. And I have actually DONE this. Some of the bolt holes are blind meaning they do not go all the way through. Now, when the housing is taken off, often there is some junk in the back of the bolt holes. "Junk" meaning it can be water, oil, or silicone. CLEAN IT ALL OUT. If for some reason there is any left behind, that stuff acts like a hydrualic ram. When you torque the bolt back in, there is sufficient force to break or crack the back of the housing and then you end up with a mystery leak. I learned this the hard way (cost me a case). One of the little details that I will never in my life forget, is to clean out the blind holes in whatever I'm bolting. Dad did it on an original Boss 302 block, water pump hole. Full of silicone, he runs the bolt in, it gets tight prematurely--he grabs a wrench and starts cranking on it. Pop. Back of the hole broke out. I won't repeat what his words were but you can use your imagination. It wasn't nice.
Ultra series silicone, you apply it to dry and CLEAN (and flat) surfaces, then assemble the parts hand tight only. Meaning, put the housing on, then just start the bolts. Soon as you see the stuff start to ooze out, stop. Let it sit one hour. Then tighten it all up and let it cure 24 hours. As long as the surfaces are prepped correctly it will not leak. Kubota uses Threebond 1206 I believe. Permatex ultra is just as good. In my case, I like to paint the cured liquid gasket that oozes out, makes for a more professional repair. Can't tell you how many customers have complimented on this, it only takes a minute and a few oz of gray paint to do, but just looks better. Then later on if you decide to sell it, only YOU will know. Some buyers are sensitive to silicone hanging out. Painted over, they don't see it as easily. Looks factory.
clean the old stuff off with a rotary wire brush in a drill.
some techs like to use tools that are considerably more "brash" and that's all I'm saying. They can damage the housing(s).
Does either part have a groove? If so, the groove needs to be completely cleaned out. I usually use a pick to get most of it and wire brush the remainder. It acts as an expansion groove, when silly-cone dries it it expands into the groove and seals it a little better
Next. Bolt holes. And I have actually DONE this. Some of the bolt holes are blind meaning they do not go all the way through. Now, when the housing is taken off, often there is some junk in the back of the bolt holes. "Junk" meaning it can be water, oil, or silicone. CLEAN IT ALL OUT. If for some reason there is any left behind, that stuff acts like a hydrualic ram. When you torque the bolt back in, there is sufficient force to break or crack the back of the housing and then you end up with a mystery leak. I learned this the hard way (cost me a case). One of the little details that I will never in my life forget, is to clean out the blind holes in whatever I'm bolting. Dad did it on an original Boss 302 block, water pump hole. Full of silicone, he runs the bolt in, it gets tight prematurely--he grabs a wrench and starts cranking on it. Pop. Back of the hole broke out. I won't repeat what his words were but you can use your imagination. It wasn't nice.
Ultra series silicone, you apply it to dry and CLEAN (and flat) surfaces, then assemble the parts hand tight only. Meaning, put the housing on, then just start the bolts. Soon as you see the stuff start to ooze out, stop. Let it sit one hour. Then tighten it all up and let it cure 24 hours. As long as the surfaces are prepped correctly it will not leak. Kubota uses Threebond 1206 I believe. Permatex ultra is just as good. In my case, I like to paint the cured liquid gasket that oozes out, makes for a more professional repair. Can't tell you how many customers have complimented on this, it only takes a minute and a few oz of gray paint to do, but just looks better. Then later on if you decide to sell it, only YOU will know. Some buyers are sensitive to silicone hanging out. Painted over, they don't see it as easily. Looks factory.