Hurth/ZF 100 gearbox seal replacement

[neil1967]

The hurth/ZF 100 gearbox fitted to my Perkins 4108 has a slow leak. Although I can't identify the exact source, the fact that the oil absorbing pad underneath the engine has a red speckle over it suggests that it is the rear seal with oil being sprayed out, rather than a drip (?). How difficult is it to replace the seal? Can it be done in situ (access is reasonable) or would I have to remove it from the engine and prop shaft?

Thanks

Neil

 

[sailorman]

The hurth/ZF 100 gearbox fitted to my Perkins 4108 has a slow leak. Although I can't identify the exact source, the fact that the oil absorbing pad underneath the engine has a red speckle over it suggests that it is the rear seal with oil being sprayed out, rather than a drip (?). How difficult is it to replace the seal? Can it be done in situ (access is reasonable) or would I have to remove it from the engine and prop shaft?

Thanks

Neil

It might be the crap string seal on the aft end of the crank shaft ( in the bell housing) rather then the gearbox

 

[Slipstream 34]

It might be the crap string seal on the aft end of the crank shaft ( in the bell housing) rather then the gearbox

If the fluid leaking is red then it has to be ATF from the gearbox, not engine oil from the rear crank seal.

The seals are replaceable but you will need to remove the gearbox and crack it open. Might be worth trying some leak stop ATF fluid in the short term, plenty on the market if you google it.

 

[sailorman]

If the fluid leaking is red then it has to be ATF from the gearbox, not engine oil from the rear crank seal.

The seals are replaceable but you will need to remove the gearbox and crack it open. Might be worth trying some leak stop ATF fluid in the short term, plenty on the market if you google it.

Guess how i know about that crank seal

 

[doug748]

Check that the filler is tight and that any dipstick is fully home, first.

 

[Slipstream 34]

Guess how i know about that crank seal

I feel your pain! I am changing my rear seal this winter

 

[sailorman]

I feel your pain! I am changing my rear seal this winter

The TMP gearbox rebuild was the wincing bit. Thanks to Duffields poor marination that included copper tube

 

[Caer Urfa]

Hi Neil

Just a thought.

When did you last replace the oil in the gearbox? you will not be the first to find that the 'sealing washer' on the 'drain' bolt has not been replaced or dropped out after you removed the bolt to drain the oil.


Mike

 

[neil1967]

Mike

I've never replaced the oil - I've only had her running for just over a season and have just kept the oil topped up. I'll check when I'm down this weekend!

Thanks

Neil

 

[Caer Urfa]

Mike

I've never replaced the oil - I've only had her running for just over a season and have just kept the oil topped up. I'll check when I'm down this weekend!

Thanks

Neil

The sealing washer is very thin but there is one, sometimes it comes out with the bolt but othertimes it sticks to the underside of the gearbox when you take the bolt out then drops out later.

I had to change my box in 2011 and have a degree in the bloody things, also on advice from ZF to get the best life out the gearbox they recommend changing the oil every year or 100 hours.

Also may pay you to just check all the bolts are tight before anything else, it's not rocket science getting the gearbox out, just time and probably money.

Mike

 

[neil1967]

Checked the box today, and indeed the sealing washer is missing! Any ideas where I could get a replacement - I normally use ASAP, but they don't list one.

Thanks

Neil

 

[Caer Urfa]

Have you actually spoken to ASAP rather than just look in their cataloge, surprised they can not help you.

Try:

http://www.lancingmarine.com/
http://www.zf.com/corporate/en/products/spare_parts/transmissions_spare_parts/transmissions.jsp

Alternativly measure the washer from the other end and any good nut/bolt store should be able to suppply the soft washer


Mike