Hurth 630 V-Drive Help

[Avenger]

Well a simple repair just became more invovled. I was tring to remove my propshaft and ended up having to heat the crap out of the coupler to remove it. I was trying very hard to not let the heat transfer to the v-drive or shaft. I was taking temp readings all over with my raytech while heating the coupler. The coupler did finally release and I cooled everything sufficiently so I thought. The next day when I returned to the boat there was transmission fluid in the bilge. It is dripping from the hole where the prop shaft goes through the Vdrive. Any ideas of what seal I may have damaged. Also is there a trick to removing the gear case from the bell housing I believe it is just a spline fit to the coupler, correct? Thanks for the help.

 

[fwebster]

What are you working on? How to remove the transmission, and even if you need to, depends a lot on how much room you have to work.

Generally, you have to remove the aft motor supports......mark every nut position because this affects engine alignment. To do so means you need to jack up the transmission end of the engine far enough for the transmission to clear any obstaclce. Sometimes this cannot be done (depends upon the boat) and in those cases, you have to remove the engine and transmission as a unit. If it will clear and can be removed, once the engine is blocked, remove all transmission oil cooler hoses, the starter, starter wiring, and transmission oil cooler. Then remove the bell housing bolts, but leave the top 2 in place. Next rig a lifting appliance of some sort to take the weight off the back of the transmission. NOw gradually remove the 2 remaining bolts. Use the lifting apparatus only to take the weight off the transmission and bell housing...keep the bell housing aligned with the gap between it and the engine equal all around the joint. When the last 2 bolts are out, gently rock the transmission while pulling it away from the engine. It should just slip away as the pilot shaft slips out of the coupler spline.

How to lift and handle the transimssion can be a challenge. I have done Hurth 800-IV and it is too heavy to man handle...perhaps you and 2 friends with strong backs can lift the 630-IV.

The output shaft of the transmission has seals on both sides of the hole where the shaft passes thru the transmission. You most likely damaged the aft one located behind the output flange. You will have to remove the output flange (probably requires a puller with hole spacing to fit this application) to access the seal boss and, if I were doing it, since there is a lot of work involved in getting to this point, I would replace both seals.

SInce I don't know what you are working on, I can't advise you, but If it is obvious that the rear seal is the source of the leak, it may be possible to remove the output flange and replace the seal without uncoupling the transmission and removing it from the boat.


Good luck with it..........

 

[Avenger]

Frank, Thanks for the fast response. I am helping the gentleman that purchased my last boat. It is a 96' 370 Dancer. This all started out with having to replace an oil pan due to a very small pin hole leak near the drain plug. My plan was to raise the engine enough so the oil pan would clear the oil pick up. I just needed to slip the shaft back out of the v drive to accomplish this. There is not much room to work between the VDrive and the Bulkhead so I will remove the Hurth and replace both seals on the bench. Being that I have not done this before I just wanted to make sure there were no inherant pitfalls. I was also not sure if I would have to split the case in order to replace the input and output seals. Thanks again for your help it is certainly appreciated.

 

[MasterFab]

Frank's got this one pretty much surrounded, so I won't add much, other than a few relevant points:

1 - You will need a specialty puller to remove the output flange from the transmission, to access the seal. This is an interesting puller. You will remove all the bolts from the coupler, except for 4 of them, located 180 degrees apart, which you will leave installed. Then, the puller bolts to the flange, and while you are backing out the last four remaining bolts, the puller draws the flange along with them. Remove them slowly and evenly, and the flange will pop right off. It is a relatively easy part to make - I have one made from a piece of 1/2" aluminum that I have used for years.

2 - Download a service manual for the transmission. Do a search online - they are easy to find, and the instructions are quite clear.

Dale

 

[Avenger]

Thanks Dale, BTW, The work you have done to your 340 is unbelievable!

 

[Avenger]

Update, I was able to elevate the engine and v-drive approximately three feet above its mounts. At that point I had clear access to the output seal that was leaking and was able to replace the seal with relative ease. I also replaced the oil pan and gasket. For the V-Drive parts Alan at Simplicity Marine in Florida was a great help with both both parts and overall knowledge. It is a huge relief to have the engine sitting back on it's mounts and everything dry! Thanks again for the help here.