Hydraulic Pump Leaking

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Hydraulic Pump Leaking

Postby ricky racer » Sat Mar 21, 2009 11:22 am

I can't believe it, I noticed oil accumulating around the crank case filler tube (short tube) and wondered how that happened. Pulled out the dip stick and wouldn't you know it, the oil level was way to high. Hmm, that can only mean one of two things. Either coolant has entered the crank case and displaced the motor oil raising the oil level, that would be a bad thing, or the hydraulic pump is leaking into the crank case, that would be an inconvenience. I checked the coolant level in the radiator and it's where it should be, that a good thing, so that leaves the hyd. pump. I didn't rebuild the pump during my tractor rebuild but it was rebuilt by a very capable friend that I had let barrow it to use on his Cub while mine was down for repair.
My question is this, are the seals #9A and #11 in the picture below lip seals or o-rings? If the pump was just rebuilt what would possibly cause the seal to leak? Is it common for the shafts that the seals ride on to get grooved? If so can a speedy sleeve be used to correct the problem. I guess I could just go pull it off and tear it apart and find out myself but I figured I'd ask the experts first. What do you think guys.
Looking at the repair kit on TM's website, I see the instruction sheet also has a blow up of the pump assembly but it looks different than the one that I posted. It shows 2 seals in front of the cover bearing spring. What's up there?

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Re: Hydraulic Pump Leaking

Postby John *.?-!.* cub owner » Sat Mar 21, 2009 12:31 pm

The seal (9) may be either a seal (early version) or an O'ring (late version). Yes, the shaft beign grooved is a common problme. if you have the version with a seal, the new seal is shallower than the original and can be seated a different depth. If it is an o ring, there is not enoug room to install a redi-sleeve. You will need to replace it or take it to a machine shop for repairs. The other 2 items you listed are not standard o rings as I recall. Tm sells the kit with the o rings, gaskets, etc. You will probably need the rear gasket (par tof kit) since removing the lines form the block are the safest way to take pump off.

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Re: Hydraulic Pump Leaking

Postby Rick Prentice » Sat Mar 21, 2009 1:27 pm

My question is this, are the seals #9A and #11 in the picture below lip seals or o-rings?
Rick yes, 9A and 11 are "O"rings. Just for grins, I'd call your friend and ask if he remembered to replace the 9A(easily missed because it's hard to see, or if it had the lip seal (9)like John also talked about. Alot of times when you take a pump apart, it also has thin fibre shims that fit alongside the 11's that aren't even mentioned in the kits.

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Re: Hydraulic Pump Leaking

Postby ricky racer » Sat Mar 21, 2009 8:16 pm

Well, I pulled the pump off and took it apart. It had been properly rebuilt and everything was in it's proper place. I did find wear on the drive shaft where the o-ring rides on the sealing area. I think I'll take it to a machine shop that we deal with through work and get it chromed and reground to the proper diameter, install new seals and it should be good to go. The machine shop does quite a bit of work for our shop and sometimes I can get a little government work done as a freebe by them. I'll let you know how it goes.
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Re: Hydraulic Pump Leaking

Postby ricky racer » Wed Mar 25, 2009 7:19 pm

Well, plan "A" hasn't worked out like I thought it might. I had hoped to have a vendor from work do a little government job for me and chrome up the drive gear shaft and grind it back into spec. but the benevolance wasn't there. I got two quotes, one for $150 and one for $175. That's a little to steep for this poor Michigan boy.
Plan "B" will be a speedy sleeve and I'm going to explore machining the pump housing to accept a lip seal instead which would be much better than an o-ring to seal the pump. We'll see how that looks and if it is possible.
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Re: Hydraulic Pump Leaking

Postby John *.?-!.* cub owner » Wed Mar 25, 2009 9:40 pm

If you machine for seal you can seat at depth where it does not hit the groove. won't need sleeve then.
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Re: Hydraulic Pump Leaking

Postby ricky racer » Thu Mar 26, 2009 6:14 am

Looking over the seal catalog, the available seals that will fit are somewhat limited and the depth to seat the seal is somewhat limited due to the constraints of the pump housing. I'm afraid that the lip seal will end up falling into the same location that the o-ring ran so if I do attempt this, I think a speedi sleeve will be required. Right now I'm just measuring and exploring the options.
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Re: Hydraulic Pump Leaking

Postby ricky racer » Fri Mar 27, 2009 9:58 pm

Well, I "Got-R-Done". I installed a lip seal in the 53's hydraulic pump housing around the drive gear shaft, replacing the o-ring as a seal. My pump had been rebuilt during the restoration of the tractor and had about 20-30hrs. on it but began leaking past the o-ring into the crank case. Upon inspection I could see a slight score mark on the shaft where the o-ring ran causing the 0-ring to wear.
Discussions with a Fluid Power Engineer at work convinced me that, as he said, "the o-ring is a poor seal on a rotating shaft". It works well as a static seal but will wear much quicker than a lip type seal. We discussed a few options including a Speedi-Sleeve or turning down the shaft and making a sleeve to shrink onto the shaft to give the o-ring a new surface to ride on but in the end decided on installing a lip seal to hopefully last longer and it would allow the seal to ride on an unmolested portion of the shaft, Now I know that the o-rings have been used for years and if the shaft is in good shape may be fine. I was looking for an improvement and hopefully something that I won't have to bother with again and think that the lip seal is the right decision. Only time will tell.



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Last edited by ricky racer on Sat Nov 17, 2012 10:20 pm, edited 3 times in total.
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Re: Hydraulic Pump Leaking

Postby ricky racer » Fri Mar 27, 2009 10:18 pm

Rick,
Below is a copy of a post I made tonight regarding the lip seal upgrade on my hydraulic pump. I think this will be an improvement and if it works out, others may possibly want to do it. I have no interest in modifing pump housings but thought it would be right up your alley. It was a very easy modification to make. The seal I used was a SKF 4911 lip seal. I bored the housing out to .688" which is just a few thousands of an inch more than the existing o-ring groove. I bored down to the bottom land of the o-ring groove. The pictures show the seal pressed lower than where it currently is. It is currently installed flush with the top of the housing. That allowed the seal to ride on a good section of the shaft.
If someone wanted to make these modifications to other pump housings, by having an end mill ground to .688" it would only take maybe 20 minutes to indicate in the housing and plunge down to the lower o-ring land and clean up your mess. Just a thought. Maybe no one will be interested, but I know I read on a lot of posts about the o-ring leaking oil into the crank case. Maybe this will be a good fix. I guess we'll have to see what interest it generates.
Have a good weekend. Rick

ricky racer wrote:Well, I "Got-R-Done". I installed a lip seal in the 53's hydraulic pump housing around the drive gear shaft, replacing the o-ring as a seal. My pump had been rebuilt during the restoration of the tractor and had about 20-30hrs. on it but began leaking past the o-ring into the crank case. Upon inspection I could see a slight score mark on the shaft where the o-ring ran causing the 0-ring to wear.
Discussions with a Fluid Power Engineer at work convinced me that as he said, "the o-ring is a poor seal on a rotating shaft". It works well as a static seal but will wear much quicker than a lip type seal. We discussed a few options including a Speedi-Sleeve or turning down the shaft and making a sleeve to shrink onto the shaft to give the o-ring a new surface to ride on but in the end decided on installing a lip seal to hopefully last longer and it would allow the seal to ride on an unmolested portion of the shaft, Now I know that the o-rings have been used for years and if the shaft is in good shape may be fine. I was looking for an improvement and hopefully something that I won't have to bother with again and think that the lip seal is the right decision. Only time will tell.



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Last edited by ricky racer on Wed Feb 01, 2012 10:01 pm, edited 1 time in total.
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Re: Hydraulic Pump Leaking

Postby Rick Prentice » Sat Mar 28, 2009 7:08 am

Thanks Rick. Looks like an interesting and well done project. I'll have to see if I can make a special jig to fit onto my retainer jig. That would make quick work of things for me if I could do it on my lathe. Soon as I get a bigger shop, I'll get me a nice Bridgeport. Right now I only have a 15"Jet :shock:

Thanks again Rick,
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Re: Hydraulic Pump Leaking

Postby ryan_cook08 » Sat Oct 19, 2013 6:26 am

ok.
Just ripped this thing apart.
Was not supposed to touch it but was having the same thing with the hydraulic oil getting in the engine.
Are the housing covers different??
I guess so, but it looks like I have the bottom housing with the "9A" O-ring.
So that is probably not going to work.
Do you know how much an entire pump assembly would cost and whereto get it??
The whole thing looks pretty "chewed up".
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