Hurth Transmission output shaft seal leak

[KDH]

Our triumph at getting the coupling off the prop shaft was short lived as our output shaft seal (at least we think that is the problem) is now leaking. We've had absolutely no luck getting a mechanic to even come to the boat (still stuck in rural Ireland) to look at it so we are pressing onwards. Just not sure how to start! ZF 15 MIV (Hurth HBW 150 V) (perkins 4.108). Do I pull the output drive shaft forward into the boat, after loosening the nuts, replace the seal? If I am replacing the seals would it be a good idea to replace the bearings as well? Is there an easier way to do this? Anyone who wants a pic, please refer to the previous thread at http://www.cruisersforum.com/forums/...on-125990.html
as still can't upload. Many thanks!

[KDH]

Must be like taking the kids to the doctor...mechanic showed up just after I posted this. We are taking the whole thing to the shop. Thanks anyway!

[estop]

Your shaft coupler will have to be remove. The trans will have to be removed from the engine at the adapter plate. Remove it from the trans and you will have to split the two halfs keeping everything in the side of the shifter.. if you need more, I can get the books out. It has been 15 plus years. Send me a PM, be happy to help.

[wingless]

Frequently the root cause for the leaking problem is incorrect alignment.

The alignment for a vee drive transmission is difficult, time consuming and almost universally misunderstood.

There are not any good procedures that I have found posted on-line for aligning a vee drive transmission.

[Blue Stocking]

V-drive configurations just have to be the curse placed on sailors for past evil deeds against mankind.

[estop]

This V drive application is EZ to do. The coupler sets in front of you.
Also, very nice engine room! Clean!

[KDH]

Estop, if only that nice clean engine room was mine! Those pics were kindly uploaded by the guys who replied as I don't have enough bandwidth here to upload pics.

[botanybay]

Originally Posted by Blue Stocking

V-drive configurations just have to be the curse placed on sailors for past evil deeds against mankind.

Naw, that is exterior teak!

[Glenn.Brooks]

Just went through the same thing with a 2:1 Hurth tranny on a 25 hp universal diesel. Undoubtedly misalignment can cause shaft log leakage- IF the alignment is way out- like over 1/8th inch side load. This causes uneven wear on one side of the bearing and or seal along the shaft. Second most common problem is not changing out the Transmission fluid for years and years- enabling water/dirt/burned fluid to accumulate and eat up the shaft and seals. As the shaft corrodes and turns, the seal gets degraded until one day it leaks.

BTW, with a Hurth, the whole inside assembly is attached to,the output,shaft - so no such thing as pulling off the end plate and inserting a new seal- unfortunately. Once you pull the shaft, all the gears , spacers, and seals have to come off, then go back on the shaft new. Learned this the hard way. But they are nice, long running transmissions -mine was installed in 1985 and just rebuilt after thirty some years use.


Sent from my iPad using Cruisers Sailing Forum

[KDH]

Originally Posted by Glenn.Brooks

Just went through the same thing with a 2:1 Hurth tranny on a 25 hp universal diesel. Undoubtedly misalignment can cause shaft log leakage- IF the alignment is way out- like over 1/8th inch side load. This causes uneven wear on one side of the bearing and or seal along the shaft. Second most common problem is not changing out the Transmission fluid for years and years- enabling water/dirt/burned fluid to accumulate and eat up the shaft and seals. As the shaft corrodes and turns, the seal gets degraded until one day it leaks.

BTW, with a Hurth, the whole inside assembly is attached to,the output,shaft - so no such thing as pulling off the end plate and inserting a new seal- unfortunately. Once you pull the shaft, all the gears , spacers, and seals have to come off, then go back on the shaft new. Learned this the hard way. But they are nice, long running transmissions -mine was installed in 1985 and just rebuilt after thirty some years use.


Sent from my iPad using Cruisers Sailing Forum

Glenn, thanks for the response. The shaft looks fine with no corrosion. Now I am trying to decide on rebuild vs replace new. Did you rebuild the transmission yourself? Currently stuck in the marina in Lisbon trying to ransom my other engine parts from Fedex so not really eager to ship anything into Portugal again. Next port probably the Canaries, which I know from past experience, we can sail into to drop anchor if need be but ideally would like to sort this out before we leave. The transmission is still working, just leaking like a sieve!

[Glenn.Brooks]

Originally Posted by KDH

Glenn, thanks for the response. The shaft looks fine with no corrosion. Now I am trying to decide on rebuild vs replace new. Did you rebuild the transmission yourself? Currently stuck in the marina in Lisbon trying to ransom my other engine parts from Fedex so not really eager to ship anything into Portugal again. Next port probably the Canaries, which I know from past experience, we can sail into to drop anchor if need be but ideally would like to sort this out before we leave. The transmission is still working, just leaking like a sieve!

No, I had a local marine repair shop rebuild the Hurth. Could have/should have bought a new Hurth rather than have it rebuilt, but the new ones are 1" longer in the case. This requires shortening the shaft and probably rekeying it with a new flange, so opted for the path of least resistance and had the old one rebuilt.

Interesting that yours works well but leaks. Do you know the cause of the leak? If misalignment is a problem, as it was with mine, the bearings inside the tranny likely are burnished on one side and need replacement. This was caused by misalignment putting excessive wear on the side with the high centering misalignment. Also, if the old shaft in the tranny is worn, a shop can put a 1mm (not sure of the size- but very thin material) stainless sleeve around the shaft to tighten up the seal. That's what they did with mine, to save buying a new shaft.

BTW, after beating my head against the wall for weeks trying to resolve final engine alignment problems, I downloaded a digital carpenters level app onto my iPhone. The app reads angles to tenths of an inch. I found my athawrtships angle of the engine was off a tiny bit to stbd. So leveled the engine a tiny bit with the rear jack screw on one engine mount and it took out my high center problem. Then measured the prop shaft angle (12.7 degrees) and the engine/tranny angle (12.1 degrees). Soon as I raised the front jack screws three turns on the engine mounts to 12.6 degrees, the coupling and flange slipped right into place with less than .002" all around. I was amazed the digital level app worked so much better than screwing around with feeler gauges heads down in the engine compartment.

Also, second tip, if you take off the transmission for rebuild, check the spring loaded shaft plate bolted onto the back of the engine. This plate assembly is what connects the transmission to the engine output shaft. There should be no wear on the studs holding the six dampening springs that support the inner and outer plates of the coupling assembly. Usually, I am told, these studs wear, and often break by the time a tranny needs rebuilding. Mine needed replacement, and I was told most should be replaced when a Hurth gets rebuilt. So might be good to chedk yours and replace as needed. $100 part, but critical for health of the transmission.

[Glenn.Brooks]

Footnote: just realized you have a V drive. My only experiences (see comments above) are with straight in line engines and Hirth xmission, so not sure what may be different.

Here is a possible contact in the US for the shop that did my Hurth rebuild.

harbor Marine, in Everett Washington phone. 425-259-3285. Ask for Mike, the transmission shop foreman. They are very well respected throughout Puget Sound for Marine transmission repair. Also carry a dozen Hurth transmissions on the shelf for sale at any one time. They ship internationally to customers all over the Pacific, so could send you any parts or complete units you might need.

[Ostinato]

If you can replace do it. I've never had good luck with a rebuild and apparently I am not alone.

[bikesherpa]

In Italy, to rebuild a Hurth 150A (replacing the seals and the friction discs - excluding the replacement of the bearings) I was asked 1200 euro.
I then found a supplier that sold me a completely new gearbox for 1100 euro. The only downside was that I had to wait 2 months for the new gearbox to be delivered by the ZF factory

[KDH]

Have found the contact info for ZF rep in Portugal, here in Lisbon. Will be trying to track him down tomorrow. I don't have 2 months to wait for a new one though! Will update after I get a hold of the rep. If anyone has other contacts for Portugal or Spain (we are headed to the Canaries) please let me know.