Richard T Posted November 8, 2012 Report Share Posted November 8, 2012 The PRM 150 gearbox on Dasque has had a small leak for sometime. This has now got worse - the seals to the selctor mechanism have been replaced and do not appear to be leaking. The leak is definetly at the output shaft end of the box. Despite having had a really good clean up I've not been able to track down the leak. Are the oil seals on the output shaft susceptible to leaks? What about the gaskets to the oil pump? Can any one make any suggestions as to where the leak is from or how to track it down? Link to comment Share on other sites More sharing options...
Iain_S Posted November 8, 2012 Report Share Posted November 8, 2012 Even if the selector "O" ring has been replaced, it's worth checking again. The PRM on Copperkins had to have it done twice: I suspect that the first time the new ring was slightly undersize. Our leak from the selector was difficult to spot : apart from a smear of oil left on a finger rubbed under the selector, and a very small amount on the casing, there was little trace of a leak, although it was enough to drop the gearbox oil level enough to stop the box working in about a week. Iain Link to comment Share on other sites More sharing options...
Keeping Up Posted November 8, 2012 Report Share Posted November 8, 2012 Also the selector shaft will continuously leak slightly if there is any pressure on the selector such as by a mis-adjusted cable trying to push it too far. Link to comment Share on other sites More sharing options...
RobinJ Posted November 9, 2012 Report Share Posted November 9, 2012 The PRM 150 gearbox on Dasque has had a small leak for sometime. This has now got worse - the seals to the selctor mechanism have been replaced and do not appear to be leaking. The leak is definetly at the output shaft end of the box. Despite having had a really good clean up I've not been able to track down the leak. Are the oil seals on the output shaft susceptible to leaks? What about the gaskets to the oil pump? Can any one make any suggestions as to where the leak is from or how to track it down? The simple answer is yes! Can I first confirm (due to changes over the years with names and numbers) that this is the sort of roundish lump? If so, they have no breather and therefore if worked hard or run in hot conditions tend to pressurise the seals! (Usually find this happens after a long river trip!) They only have two gaskets, which rarely leak, but a number of seals, inclduing the selector, output and input shafts, any number of which can 'blow'. Also the heat can exerbate the wear on the clutches, so if its over 5 years old, it may be worth going for a complete overhaul. The selector shaft is easy to change seals on, albeit fiddly, worst is the input shaft, output shaft may be easy if the drive flange will come off, otherwise both of these require a complete dismantling. Link to comment Share on other sites More sharing options...
n.b.Goldie Posted November 9, 2012 Report Share Posted November 9, 2012 The simple answer is yes! Can I first confirm (due to changes over the years with names and numbers) that this is the sort of roundish lump? If so, they have no breather and therefore if worked hard or run in hot conditions tend to pressurise the seals! (Usually find this happens after a long river trip!) They only have two gaskets, which rarely leak, but a number of seals, inclduing the selector, output and input shafts, any number of which can 'blow'. Also the heat can exerbate the wear on the clutches, so if its over 5 years old, it may be worth going for a complete overhaul. The selector shaft is easy to change seals on, albeit fiddly, worst is the input shaft, output shaft may be easy if the drive flange will come off, otherwise both of these require a complete dismantling. Are you sure? My Delta has a very small hole in the dipstick/filler cap as did the 150 in my previous boat. So small that i would think it easy to block with debris and if blocked might pressurise and cause seals to leak. Regards Ditchdabbler Link to comment Share on other sites More sharing options...
RLWP Posted November 9, 2012 Report Share Posted November 9, 2012 Are you sure? My Delta has a very small hole in the dipstick/filler cap as did the 150 in my previous boat. So small that i would think it easy to block with debris and if blocked might pressurise and cause seals to leak. Regards Ditchdabbler Beat me to it! Richard Link to comment Share on other sites More sharing options...
bizzard Posted November 9, 2012 Report Share Posted November 9, 2012 Two likely places that they tend to leak from are the hydraulic pumps securing bolts, situated next to the output flange, these have small copper washers under their heads which often leak i've found as a couple of them are not in blind threaded holes but are in open holes into the oil space. Also the oil coolers banjo pipe fitting underneath the box is also always suspect as its out of sight. Link to comment Share on other sites More sharing options...
RobinJ Posted November 9, 2012 Report Share Posted November 9, 2012 Are you sure? My Delta has a very small hole in the dipstick/filler cap as did the 150 in my previous boat. So small that i would think it easy to block with debris and if blocked might pressurise and cause seals to leak. I think they altered the design for the Delta (as many people had already drilled a hole!) Link to comment Share on other sites More sharing options...
RLWP Posted November 9, 2012 Report Share Posted November 9, 2012 I think they altered the design for the Delta (as many people had already drilled a hole!) Doesn't the Delta pre-date the 150? Richard Link to comment Share on other sites More sharing options...
RobinJ Posted November 9, 2012 Report Share Posted November 9, 2012 Doesn't the Delta pre-date the 150? Not sure when the Delta was introduced? Originally the Newage boxes all had numbers. PRM seem to have changed the numbers/names at least once? Link to comment Share on other sites More sharing options...
n.b.Goldie Posted November 9, 2012 Report Share Posted November 9, 2012 According to the Newage/PRM website the Delta preceded the 150. Regards Ditchdabbler Link to comment Share on other sites More sharing options...
RobinJ Posted November 9, 2012 Report Share Posted November 9, 2012 According to the Newage/PRM website the Delta preceded the 150. I have a Newage 150 series that has an original oil filter made in 1975! It is not the same as the PRM 150? Link to comment Share on other sites More sharing options...
n.b.Goldie Posted November 9, 2012 Report Share Posted November 9, 2012 (edited) The Delta is no longer in production, it ceased in February 1997 and was replaced by the PRM 150D Link to PRM website listing older models here: http://www.prm-marine.com/shop.php?sec=prod∏=28 Regards Ditchdabbler Edited to add link. Edited November 9, 2012 by ditchdabbler Link to comment Share on other sites More sharing options...
Keeping Up Posted November 9, 2012 Report Share Posted November 9, 2012 The PRM 150 gearbox certainly has the same small hole in the filler as does the (earlier) PRM Delta. Link to comment Share on other sites More sharing options...
bizzard Posted November 9, 2012 Report Share Posted November 9, 2012 They would all have a breather somewhere or other otherwise pressure would build up as the oil gets warm and expands. Link to comment Share on other sites More sharing options...
blackrose Posted November 9, 2012 Report Share Posted November 9, 2012 My PRM 150 has a small breather hole in the filler cap/dipstick. Did someone already mention that? My engine & gearbox have only done about 800 hours but most of that has been on the Thames including tidal so the gearbox has worked fairly hard. When these leaks happen can they be sudden and serious or do they occur gradually? I wouldn't know about a serious leak until I'd stopped and would hate to wreck my gearbox. Link to comment Share on other sites More sharing options...
RLWP Posted November 9, 2012 Report Share Posted November 9, 2012 If you have a very serious leak, eventually you will run out of oil and the gearbox will disengage. You'll know before you damage anything, it will be a pretty serious and obvious leak Richard Link to comment Share on other sites More sharing options...
nb Innisfree Posted November 9, 2012 Report Share Posted November 9, 2012 Our PRM 50 has always leaked, never have managed to trace it, mind you, regular topping up does save oil changes. Link to comment Share on other sites More sharing options...
Richard T Posted November 9, 2012 Author Report Share Posted November 9, 2012 Our PRM 50 has always leaked, never have managed to trace it, mind you, regular topping up does save oil changes. We don't change the oil because it leaks somewhere between 200 and 300ml every three days or so depending on use. The filler does have a small breather hole I will check that it is not blocked. Will look at and do a general tighten up of bolts around the hydraulic pump - this does appear to be a possible source of the leak. Thanks every body for comments. I'll let you know how we get on. Link to comment Share on other sites More sharing options...
steve hayes Posted November 10, 2012 Report Share Posted November 10, 2012 Our PRM150 started leaking from the selector at about 1,000 hours. I acquired a new O ring to swap, but was advised to check the breather first. I found it was blocked and tried to clean it out, but couldn't get it cleaned out there was something solid in the hole. So I drilled it out and found some brass swarf probably from the original drilling While I had the drill out I drilled a second hole opposite the original. The box has not leaked since 3 - 4 years and I still have the O ring Link to comment Share on other sites More sharing options...
blackrose Posted November 10, 2012 Report Share Posted November 10, 2012 Our PRM150 started leaking from the selector at about 1,000 hours. I acquired a new O ring to swap, but was advised to check the breather first. I found it was blocked and tried to clean it out, but couldn't get it cleaned out there was something solid in the hole. So I drilled it out and found some brass swarf probably from the original drilling While I had the drill out I drilled a second hole opposite the original. The box has not leaked since 3 - 4 years and I still have the O ring That's not a bad tip. I might drill a second hole in mine. Link to comment Share on other sites More sharing options...
Chas78 Posted March 15, 2018 Report Share Posted March 15, 2018 I have noticed yesterday when changing the oil on my PRM 260 that it was pressurized there were no leaks as yet and there is NO breather on my box or on the filler/dipstick nut i to will be drilling a hole in the filler/dipstick nut as previously mentioned to alleviate the pressure BEFORE it does cause some damage Link to comment Share on other sites More sharing options...
RLWP Posted March 15, 2018 Report Share Posted March 15, 2018 See the yellow blank here: That's where the breather should be Richard Link to comment Share on other sites More sharing options...
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