Hydro Pump Gasket
 

I have a model 149 that I have split and replaced the hydro pump to rear end gasket three times! It continues to leak :angry:

I originally took it apart to repair the trunnion and replace all the seals. Upon putting it back together, I noticed Hytran leaking after two days. So I waited a while, then pulled it apart again. I was very careful to remove the old gasket and clean all surfaces thoroughly with paint thinner. I only use OEM gaskets and I tightened the bolts to spec with a torque wrench.

It was a PITA to take it apart again, but everything seemed okay—until two days later, when again it starts to leak. So I pull it apart again.

All three times it has been the same thing. I complete the repair, mow the lawn for an hour, park it over night, and no leak. A day or two later a wet spot appears under the tractor directly below where the pump meets the rear end.

Everything is clean, and it is not leaking from any of the seals I replaced or the relief valves. I inspected the housing for cracks, and did not see anything.

I did the same repair on my other 149, and she does not leak a drop…

Any suggestions? Should I double up on the gaskets?

If you have replaced it three times and it still leaks, that's probably not where the leak is. The suction tubes sometimes leak...... Are you SURE that it's leaking at that gasket, or there is just oil on the floor in the same location? :bigthink: Run it till you can look under the machine and see it dripping. Then pull the tunnel cover off and even fenders if you have to ..... I'd say you'll find it leaking somewhere else.

I was starting to think that might be the issue, but I wrapped the threads on the suction tubes with tread tape. Plus I can feel the Hytran on the face of the rear end, just below where that gasket is...

And why will it not leak for two days, then start leaking again?

check hydro valves they leak as well

Run it two more days and see if it quits..... :bigthink: :biggrin2::biggrin2:

did u ever get this to stop leaking id really like to know thanks ronnei

No. It is still leaking! What a pain.

I now believe it is leaking from the expansion plug, part #29 in the attached photo.

the reason im asking ive got a 782 that starts as a leek then just starts bleeding

I have actually pinpointed my leak to that expansion plug. I put some gasket sealer around the bottom of it, and it slowed the leak quite a bit. I will do a better repair next spring, because I have the thrower on it now and the leak is not too bad.

I don't know if you have the same rear end on your 682. I believe some of the later model 82 series did not have the cast iron rear end. I could be mistaken. I am not an expert.

If you have the cast iron rear end, then that plug is definitely something to check.

regarding replacing the expansion plug- do I need to tap on it from inside the gearbox to get it out?

Have my leak narrowed to this or the "hydro cork gasket" and going to do both since I have it all apart

thanks

If the expansion plug is not leaking do not mess with it. Only way to get them out is to drill a hole in them and pry them out good chance of getting metal chips into the bearings unless you are doing a total disassembly and rebuild. Read the manual.

Still leaking two years later
 

I cannot find the instructions for this procedure in the repair manual. Can you direct me to where these instructions are?

I specifically need to know how to remove the old plug and install the new one. I already know how to split the tractor...

leaking hydro
 

Replaced the hydro seal 2 years ago. No leaks untill last fall. Could not locate the leak,seemed to be from multiple sourced. Opened the fill plug on the rear cover,and pressure escaped from the fill hole,as well as approximatly 1/2 cup of fluid (and twice since then). I believe I filled the system correctly after the "split", and after describing this on the forum it was suggested the problem could an obstructed vent plug. It was described as a sintered metal plug on the top of the transaxle case. Mine is difficult to access since the tunnel cover is not removeable, but I can see it was painted over by the previous owner. I suspect that could be what is causing my leak, but I can't figure out how to clean or replace it without opening the rearend. Would love to clean or replace it, just to rule it out before I have to get into another "split". Good Luck. Steve

The expansion plug can be drilled and a screw inserted
to "pop" it out, usually they come out easily.
If not, progress to a larger drill/screw or small punch or screwdriver.

Do clean up the housing of any residue where the new plug will live.
Make sure it is not only clean, but free of oil and apply a thin coating of Yamabond, Hondabond or similar crankcase sealer to the plug and counterbore, it is situated in.
I don't like silly cone for this application.
place a long socket or similar larger punch in the center of the new expansion plug and whack it good one time, expanding it.
-------------2 times and most generally you loosen it.
Some applications require removing lines or linkages, cross shafts etc to access the expansion plug.
Order 2 plugs, shipping is expensive and you have one on hand for next time/project. :beerchug:

Repeated applications of Lacquer thinner or acetone to the sintered pourous bronze vent will usually soften/dissolve paint.
A small artist brush, swab etc will usually work.
It is worth a try.

This is from the 82 series service manual. One word of caution, when you drill the hole in the plug you are likely to get chips into the bearing behind it. You will need to make sure that it is absolutely clean before the put the new plug in or you stand the chance of a more serious failure.

I have a question on the sealant. We use a lot of Loctite 515 at work, would that work on the expansion plug? A nudder question on the Yamabond for George. I found there is Yamabond #4 & #5, which one do you use?

I'm thinking #4 on the yamahahahaha bond.
it holds up better than silly cone as silly will dissolve in oil/gas
Outboard ppl use their version of crankcase sealer as does harley-able-son :biggrin2:and just about all of them, as long as it is for crankcase sealing.
Silly cone works on crankcases, but being thicker, it tends to get in passages where it can cause problems with oil circulation, sometimes blocking passages totally.
Silly will allow easier separation of sealed parts during dissembly, the crankcase sealers takes more effort.
Well meaning ppl tend to apply it like tooth paste.
A light coat no thicker than a coat of paint will do the best job.
I can't emphasize too much, the need for surfaces to be clean and dry for any sealant.
udder wize it plum don't stick/seal! :biggrin2:
If ppl use a product and it works for them, great.
I tell what works for me, but always willing to learn!! :bigthink:
I wished I was familiar with loctite sealing products, as their thread lockers work very well when used in accordance with instructions.

One . Way to help when you drill dip drill in grease chip stick in gease

The 515 is a better choice for the expansion plug. I use the same thing, only in Permatex. Loctite brand is twice as much for the same stuff last time I priced it.

hydro leak
 

Ol'George; Thanks I'll try that. I had some concern that a solvent might only drive the paint deeper into the vent material, but it should get most of it off.

Permatex equivalent
 

Thanks for the information and tips!

BTW, what is the Permatex equivalent for Loctite 515?

It's just called "Permatex Anaerobic Flange Sealant (or gasket maker)"

Permatex #51813
 

Okay. I split the tractor again today, and I removed the expansion plug. I was very careful not to get any drill shavings into the bearing behind the plug.

I was able to find some Permatex #51813 anaerobic gasket maker. I am now waiting for the new expansion plug to arrive.