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Hi,
My B&S powered MTD ride on mower has busted the crank seal for the second time in a month (should that be a cause for concearn? or could it just be bad luck?)

Last time I took the engine out myself and had a friend install the new crank seal, but this time I want to try to do the whole job myself.

Therefore the question I'd like to ask is, when I put the new seal on do I need to lube and/or glue it?

Thanks in advance.

Normally they go in dry.
You clean everything , polish the shaft.
I lube the lip with Vasoline by filling the space between the inner lip and the outer dust lip with vasoline.

The question is why has it failed.
If it has blown out then there is something wrong with the breather or head gasket or both.
If some one took a wire brush to the hole whan the last one was done you might need some Loctite bearing seal.

Yes lube both crank and seal and make sure the inside of the seal doesn't roll up on you when you push down on it.....

Thanks for your help.

I have replaced the seal but after 10 minutes it is leaking again.

Interestingly, I noticed that with both the old seal and the new seal the crank does not appear to be centered, as can be seen from this foto of the old seal.

At this point would it be safe to assume the crank may be bent and/or the bearings need replacing?

The engine in question is a 11,5hp 28t707 1119 e1 model and is probably about 15 years old, other than this reoccuring oil leak it has been quite reliable.

Remove all the belts, and try to move the crankshaft back and forth. May need to rotate the crank to different position and try it all the way around. I have seen several engines that repeatedly not seal with a new seal egg shape the lower bearing in the sump, as well as wear a groove into the crankshaft. The belts pulling from the side especially if very tight will cause bearing failure and crank damage.

Thanks again for the assistance.

As instructed I have tried checking the crank but was able to detect any movement.

While I had the pully off I pushed the seal further in. I then had it running for 20 minutes at high rpms but as soon as I shut the engine off it started leaking again.


At this point is it safe to assume I need new bearings, at least.


Would that be a simple do it yourself job or would I be better off getting a professional mechanic to do the job? If it's just a case of taking the sump off and changing the bearing I should be able to do it, but if it's anything more complicated then I'd probably be out of my depth.


I really need this machine working, at least for a few days while I keep the grass down, so as a temporary fix could I wrap the crank in Teflon tape? (plumbers tape)


Again, thanks in advance! :thumbsup:

You probably don't have a bearing It would be a part of the lower sump. All the engines that i had this problem on where the twin cylinder engines, and when removing the sump found that both the sump and the crankshaft were worn and had to be replaced.

:thumbsup: Awesome, 100% correct!
After opening the engine it was discovered there is no bearing and both the sump and the crank are worn.
I have found replacement parts from a 28b707-1146-e1 engine and I believe they're the same as my 28t707-1119-e1.
Piston, cylender and valves all look good so I will procede to fit the replacement crank and sump.

I wonder why these parts have worn? Could it be a lubrification issue? Is there anything else to check/replace while the engine is open?

Aldo said:

:thumbsup: Awesome, 100% correct!
After opening the engine it was discovered there is no bearing and both the sump and the crank are worn.
I have found replacement parts from a 28b707-1146-e1 engine and I believe they're the same as my 28t707-1119-e1.
Piston, cylender and valves all look good so I will procede to fit the replacement crank and sump.

I wonder why these parts have worn? Could it be a lubrification issue? Is there anything else to check/replace while the engine is open?

View attachment 38586

View attachment 38585

Click to expand...

Primarily it is a lubrication problem.
The crank runs in the oil filled sump with all of the grit & acid by-products of combustion in it, so basically it is running in a micro grinding paste .
An engine with real replaceable bearings would have cost an additional $ 500, would you have paid the extra ?
No one else did so they stopped making them.
Add to that the fact that the crank is always being pulled back by the belts and pushed back by the pistons firing and you have a recepie for ovaling out the lower bush.
It is not new, been around for as long as vertical shaft engine have been made.
A few manufacturers down here tried mounting engines the other way round or even sideways but it made little difference to the service life but a big difference to the difficulty of servicing and the noise discomfort to the operator.
It is also the reason why most of the service techs here hammer in annual oil changes at a minimum.

Thanks for the detailed and interesting explanation :thumbsup:

You dudes have been invaluable. Thanks to you all!

Hi again,
Very last quick question before we close the engine.
For the timing, should the dots on the crank and cam align?

Aldo said:

Hi again,
Very last quick question before we close the engine.
For the timing, should the dots on the crank and cam align?

Click to expand...

those are the timing marks so they need to line up with each other.

IL Engine is correct..... To align the dots, IF they are not lined up when you turn the crank, Just slip the cam out gently and then align the cam dot to the crank dot......

The dot is in between the teeth so they will line up spot on perfect........ But turn the crank towards the cam shaft so it will be easier to pop the cam back in.....

Let us Know Mon Ami ~!~!

BTW........ The way those dots are lined up in the picture, the engine would be right at 180 degrees out of time......

Boudreaux In Eunice La. said:

BTW........ The way those dots are lined up in the picture, the engine would be right at 180 degrees out of time......

Click to expand...

Geared 2:1, those dots will come into alignment once every two turns of the crank. 180 degrees "out" is right on the money.

Awesome!
Have had it all back together for a couple of weeks now. Had about 10 hours usage out of it and it's going really well, no problems at all.
Thanks once again! :thumbsup: