Grease nipples snapping on trailer bearings

Tireetim · 05 June 2012, 12:03

Hi, I've just bought a grease gun and tried to grease the bearings on my boat trailer (indespension). When I removed the grease gun the nipple snapped off. Having never used a grease gun before I rang the dealer to check I was doing it right (just push on, pull off with the grease gun). Anyway, I got a spare nipple from my spare set of bearing and just tried again but this time was super careful and even loosened the grease gun end (making it really easy to pull off) before removing it from the nipple to ensure the same thing didn't happen. It did ! Can anyone help please, this can't be normal. I must be doing something wrong. The nipples seem to be made of a really soft metal but even so .... I'm now left with one ungreased bearing and two unuseable spare hubs until I can find some more replacement nipples.
Thanks.
Tim.

Boats&Outboards · 05 June 2012, 12:14

Here's something like what you need, available in different sizes so check which you have.

Grease Nipple Fitting M6 x 1 Straight (10) - UK Made

http://bit.ly/L04yhz

Peter @ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

Tireetim · 05 June 2012, 12:30

Thanks Peter, I'm not sure what size I need but this seller has said that if I send one over they will check (not that I have a spare anymore).
The trouble is that so far I have not managed to grease a bearing without snapping the nipple which can't be normal.

Boats&Outboards · 05 June 2012, 12:46

Sounds more like an application issue rather than defective nipples. When removing position at slight angle and give it a sharp yank. If you still have problems unscrew it from the gun then the pressure should ease, making it easier to remove

Also have a look at the attachment on the gun as most are adjustable to suit different sizes. If yours if fully down it'll be a tight fit and may damage them pulling off, loosening it back may make it easier to remove, too much and it won't connect though

Or grease the nipple before use

Peter @ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

Bigmuz7 · 05 June 2012, 13:20

Is it snapping the head off the nipple (highly unusual) or pulling the whole nipple out of its socket ?

You cant really get this wrong, so perhaps the nipples are extremely brittle/soft ?

Getting replacements is easy enough though, perhaps the might be more resilient

Tireetim · 05 June 2012, 13:28

Peter, yes - the last one I unscrewed the end of the grease gun fully so that very little pressure was needed (just enough to stop grease coming out of the thread where the end joins the gun) and it still snapped. I'm beginning to think they are just rubbish quality.
Bgmuz, the nipple gets stuck in the grease gun and it leaves a bit of thread in the hub. Luckily these come out fairly easily. Going to try to find out thread size and get some replacements to see if they are stronger. Poor quality is all I can think of, seems I'm doing things correctly otherwise.

Bigmuz7 · 05 June 2012, 16:14

well if it puts it in perspective, I grease thousands of grease points all the time, and this has never happened to me unless its a 45° nipple that has the nipple inserted into a straight body.

New gun ends are often tight and slacken off over time after which they leak. When new its not uncommon for me to have to lever the push connector off the nipple, but even with this sort of force the nipples never break unless it was a special as above, and I got the angle wrong, so it sounds like the nipples are a bit poor

Tireetim · 05 June 2012, 17:02

Thanks Bigmuz, that's exactly what I wanted to hear and confirms what I thought.

Peter_C · 05 June 2012, 17:13

I have greased an insane amount of grease fittings and never had a nipple break off in a gun until recently. It was on my Chinese made Harbor Freight trailer. Quality standards are not always there and now both grease nipples have been replaced with some higher quality units.

Tireetim · 05 June 2012, 17:22

Thanks Peter. Is there an easy way to find out what thread the nipples are? I asked the boat dealer who didn't know but is sending a couple of spares (I guess they will be the same quality). So far my only option is to send a spare away to a company that sells them and let them work it out. Was going to ask indespension but they might not be the same as the original ones as I've only started trying to grease them since the originals were replaced.

chewy · 05 June 2012, 17:26

I tried greasing the steering on my Yam with a brand new grease gun and ut snapped the nipple straight off.

captnjack · 05 June 2012, 17:36

Just remove the threaded portion out of your hub and take it to an auto parts store. Then get some beefier looking ones with the same threading. (or take one of the spares being sent). They are typically just chromated steel (golden color) and you can look at how thick the neck is to gauge how robust they will be.

chrishowden · 11 July 2012, 13:18

Quote:

Originally Posted by Tireetim

Hi, I've just bought a grease gun and tried to grease the bearings on my boat trailer (indespension). When I removed the grease gun the nipple snapped off. Having never used a grease gun before I rang the dealer to check I was doing it right (just push on, pull off with the grease gun). Anyway, I got a spare nipple from my spare set of bearing and just tried again but this time was super careful and even loosened the grease gun end (making it really easy to pull off) before removing it from the nipple to ensure the same thing didn't happen. It did ! Can anyone help please, this can't be normal. I must be doing something wrong. The nipples seem to be made of a really soft metal but even so .... I'm now left with one ungreased bearing and two unuseable spare hubs until I can find some more replacement nipples.
Thanks.
Tim.

Hi tim

I have also got the same problem just out of interest what trailer do you have?

Cheers
Chris

Tireetim · 11 July 2012, 18:34

I think it's a coaster swing or similar. GVW 750Kgs. I rang everyone and even indespension who told me I needed some imperial size which I bought but didn't fit. In the end they turned out to be M6. I got some of these : Grease Nipple Fitting M6 x 1 Straight (10) - UK Made | eBay

So far so good, the fit perfectly and don't seem to snap like the originals. I think they are just very poor quality as so far all 4 original ones have snapped first time I used them (dealer sent me a couple of replacements that did the same).
Also, the bearing seem to need grease every time you launch as every time I re-grease a fair amount of water comes out the tiny hole in the centre of the bearing cap before grease comes through.
Hope that helps !
Tim.

Peter_C · 11 July 2012, 19:56

Quote:

Originally Posted by Tireetim

Also, the bearing seem to need grease every time you launch as every time I re-grease a fair amount of water comes out the tiny hole in the centre of the bearing cap before grease comes through.
Hope that helps !
Tim.

Yikes? If water was coming out of my bearings I would tear them down and rebuild them with new seals. Carefully inspecting the bearings and races after cleaning.

I was taught the best time to grease is right before you launch if you have trailered a fair distance heating up the bearings. What happens is the water cools them hubs and they suck water in.

Nos4r2 · 11 July 2012, 21:31

Quote:

Originally Posted by chewy

I tried greasing the steering on my Yam with a brand new grease gun and ut snapped the nipple straight off.

I've done the same on my Yam on the original nipples with a new gun.They seem to be an odd, quite weak alloy.
However,they unscrew easily when snapped.

No problems with the replacements though.