[Steering & Suspension] How to fit grease nipple on rear axle berlingo

[jj9]

. . .  Did you happen to notice if the axle pin has a seal on the outer end?

The outer trailing arm bearing is a cup design, there is no seal, the seal is made between the body of the trailing arm and the cup, there will be no ingress at this point.

The ideal location for a grease nipple would be through the end of the outer cup bearing, however the end of the axle pin is open with only a plastic bung in place . . .  you can see this lying at the bottom in the picture in post #7.

If you wanted to introduce a grease nipple to the bearing cup you would need to seal the end of the axle pin with a permanent seal, I' don't think the plastic bung (that may or not be in place) would be up to the job so something better would be advantageous, this would have to be fitted with the bearing cup or the swinging arm removed.

The "Bung" at the end of the axle pin would be no more than a disc to seal the pin that would stand up to the pressure of the grease being pumped in, this would then allow the grease to be pumped directly through the cup bearing, then along the gap between the axle pin and the spacer tube to exit through the inner bearing..... the ultimate set-up.

Can you tell that I've given this a bit of thought !  


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[cancunia]

Thanks again & yes I can tell you've given this some thought!

So what we have is a trailing arm with a plastic spacer / seal (probably) covering the void & an axle pin (probably) with a plastic seal at the end.
Does the spacer have a void around it in the middle, and if so is only tight at the bearing ends?
The plan is to drill through to the axle pin from underneath the trailing arm, tap the hole, fit the grease nipple and inject some grease. If there's a void around the centre of the spacer, then a lot of grease will simply go into the trailing arm as per Brajo's notes.
I'll report back when I find some more out.

Update:

I think this is perhaps where Marxxon got their info, not looked at the whole site yet but looks interesting. I'm now fairly sure that the spacer in the trailing arm is also intended as an inner seal for the bearings as it seems to cover a void in the middle. The pictures in this post and others show a gap around the seal in the middle:

http://balka405.com/en/lubricator.html

[jj9]

So what we have is a trailing arm with a plastic spacer / seal (probably) covering the void & an axle pin (probably) with a plastic seal at the end.
Does the spacer have a void around it in the middle, and if so is only tight at the bearing ends?

If there's a void around the centre of the spacer, then a lot of grease will simply go into the trailing arm as per Brajo's notes.

Yes, the spacer has a void around it and is only tight at the ends,  so yes you will be filling the trailing arm full of grease unless the end of the grease nipple contacts the plastic spacer tube.


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[cancunia]

Yes, the spacer has a void around it and is only tight at the ends,  so yes you will be filling the trailing arm full of grease unless the end of the grease nipple contacts the plastic spacer tube.

Problems is that, on ebay at least, I can only see standard grease nipples or longer nipples that are only threaded at the end. In any event getting the length just right will be a challenge.
How about drilling nearer to the inner bearing and going through the spacer/seal where it's tightly fitted to the trailing arm. The drilling point will of course get a bit critical and depend on the width of the spacer land.

It's just dawned on me that I can probably use a brake bleed nipple of the same thread size as the grease nipple. Grind the end flat, screw it up to the axle pin & fill with grease via the bleed holes. When it's done, take out the bleed nipple, replace with the grease nipple to seal the hole & confuse the person that buys it from me.

[jj9]

Yes that's the problem, the longer grease nipples are only threaded at the end, you could run a die down them to thread them over the full length.
It would be a case of trial and error to get the nipple fitted so it was just the right length, but that would just need a few measurements.

The brake bleed nipple idea may be an good option.

But after a bit more thought I think fitting the grease nipple at either the inner or outer bearing end of the trailing arm is probably a better option, and a standard grease nipple would work as you wouldn't be encountering any void.
As long as the hole drilled for the grease nipple missed the bearing it would be fine and the grease would go between the axle pin and the spacer and into the bearings like you want it to.

If I remember correctly the part of the inner bearing goes into the trailing arm is about 19mm in depth, the outer cup bearing is about the same. The machined area (land) at either end of the trailing arm is around 35mm so there's plenty of room to drill a hole, even if the hole misses the end of the plastic spacer it won't matter as the spacer is a tight fit onto the machined area.


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[jj9]

@ cancunia,

So which method are you going to go with?


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[cancunia]

@ cancunia,
So which method are you going to go with?

Hmm, well since you've asked...
The grease nipples have arrived but still waiting for the bleed nipple & won't know until it arrives if the grease gun will fit well enough.

Not decided on what to do yet so for now will go with the short term solution of some grease spray which is what I did to the previous Berlingo and then think about things for a while, probably until it gets warmer next year.

My preference is for the grease nipples drilled nearer the bearing as the seal will be good at that point but there are a couple of questions in my mind. Firstly is exactly where to drill and secondly will drilling the hole cause any weakness in the casting? The question of weakness is probably a non issue as there are several examples of drilling nipples to grease direct into the bearing, but I was advised by a friend with an engineering degree about this potential issue so it's worth thinking about.
The bleed nipple in the middle should do the trick but then there's the question about keeping things sealed afterwards, probably some extra grease into the void would take care of that.

[jj9]

I think the grease nipple fitted close to the bearing is the best option as then the grease will definitely be delivered between the plastic spacer and the axle pin with no grease finding the voids., you would only need 1 grease nipple fitted at either the inner or outer bearing end.

The swinging arm is a casting so there isn't just a void around the axle pin area, the void extends down the length of the arm to the wheel area, hence the plastic spacer to seal off that area, if the grease is delivered into the void you will have to fill up the whole trailing arm.

As we know and can see in the picture in post #7 the inner bearing seal starts to fail after a given time allowing the weather in corroding the bearings and axle pin, if you fill the area with grease the weather won't be able to get in, the grease will also give lubrication to the bearings but keeping the weather out is the priority.

Regarding where to drill the hole and possible weakness... 

I would be looking to drill the hole 25-30mm in from the end of the trailing arm, split the difference, call it 27mm. 

As for any weakness created by drilling a hole, I would imagine your mate could come up with all sorts of equations and formulas to baffle us on that one, but in the real world it won't make the slightest difference.


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[cancunia]

I think the grease nipple fitted close to the bearing is the best option as then the grease will definitely be delivered between the plastic spacer and the axle pin with no grease finding the voids., you would only need 1 grease nipple fitted at either the inner or outer bearing end.

I thought so too but it's interesting all the same that the only non DIY solutions I can find show a grease nipple in the middle. I'm no genius so I wonder why no one has thought of it before.

The swinging arm is a casting so there isn't just a void around the axle pin area, the void extends down the length of the arm to the wheel area, hence the plastic spacer to seal off that area, if the grease is delivered into the void you will have to fill up the whole trailing arm.

Totally agree, was just thinking that a bit of extra grease around the hole in the seal might help, but if the whole bearing space is packed with grease it probably won't matter.

I would be looking to drill the hole 25-30mm in from the end of the trailing arm, split the difference, call it 27mm. 

Just over an inch from the end, sounds about right but it would be good to see some accurate measurements of the bearings to be sure.

As for any weakness created by drilling a hole, I would imagine your mate could come up with all sorts of equations and formulas to baffle us on that one, but in the real world it won't make the slightest difference.

Reminds me of your comments on the sump mod thread
My friend has a lot of real world experience and recognised straight away why the ends are thicker, it's because they are load bearing.
However, I tend to agree that in this case it's probably not an issue to put a 6mm hole in that part of the casting.

[jj9]

I thought so too but it's interesting all the same that the only non DIY solutions I can find show a grease nipple in the middle. I'm no genius so I wonder why no one has thought of it before.

Probably because they aren't as good at thinking as we are   . . .   they aren't considering that the grease will be able to go into the voids of the trailing arm if the grease nipple doesn't contact the plastic spacer, and they probably don't care anyway.

Look at the video in the link below, there is a grease nipple at either end and the grease comes out through the bearings, the tube has been bored out to take the larger diameter bearings.

https://youtu.be/jIQVIJ8zPfE?t=348

Totally agree, was just thinking that a bit of extra grease around the hole in the seal might help, but if the whole bearing space is packed with grease it probably won't matter.

No it won't matter, but filling the whole trailing arm down to the wheel is a bit silly if you don't have to.

Just over an inch from the end, sounds about right but it would be good to see some accurate measurements of the bearings to be sure.

Unfortunately my old bearings have been mistakenly thrown out      but I know I measured them at the time and the measurements are as I've posted. 
There may be a diagram on the internet somewhere showing the bearing dimensions.

Reminds me of your comments on the sump mod thread
My friend has a lot of real world experience and recognised straight away why the ends are thicker, it's because they are load bearing.
However, I tend to agree that in this case it's probably not an issue to put a 6mm hole in that part of the casting.

Aye I just say what I think    

Yeah your mate may have a lot of real world experience but he's also been trained to weigh up all of the possibilities no matter how unlikely, sometimes you are better off just doing things and they work even when they shouldn't.

On the sump mod thread there were concerns that the sump may distort or split when trying to pull the recess out, (that was weighing it up)  in the real world none of that happened and the recess pulled out with no problem. . .  you can often weigh things up too much!

The Russians (like in the video above) bore the bearing tube out from the standard 58mm to 62mm so it accepts the larger diameter bearings, then they drill holes through it for the grease nipples,  so they are obviously quite confident in its load bearing ability . . .  Nah,  a 5 or 6mm hole is not worth worrying about in my opinion  


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