TAP SIZE AND DRILL BIT 8MM GREASE NIPPLE.

[brendy]

Hi, need some advice on fitting grease nipples to a recond Berlingo rear axle that i hope to fit in the next week or so. The size of grease nipple i am fitting is 8mm . What drill bit size and tap size do i need to use. Do i need a starter tap then a finish tap. Thanks . Brendy.

[Tree]

if its an M8 thread then you'll need a 6.8 drill - if its an 8 mm ball i've no idea what the thread would be

[Gravity]

As your Berlingo is front wheel drive, I am curious as to why you need grease nipples in the rear beam axle.

Bear in mind that when you drill and tap there will be swarf, so you'll need to contain this. One way of doing it is to load the drillbit with grease as you drill. Apologies if I'm preaching to the converted!

Gravity

[geoff]

Drilling into steel ??

6.8mm is the " correct " size but if you don't have 6.8 don't be tempted to use 6.5mm as it will be too tight and a snapped tap / ugly thread is likely. Better to use a 17/64th if you have one or 7.0mm at a push.

You will only be tapping for a grease nipple so no need for finish / plug tap I'd be using an intermediate / 2nd tap only with a partial depth used whilst checking with the nipple for degree of fit. Nipples often have only a very short thread so be careful !

edit : use some PTFE tape on the thread to help keep water etc out of your new axle !! Apply the tape clockwise to the thread and not the other way around !

[brendy]

As your Berlingo is front wheel drive, I am curious as to why you need grease nipples in the rear beam axle.

Bear in mind that when you drill and tap there will be swarf, so you'll need to contain this. One way of doing it is to load the drillbit with grease as you drill. Apologies if I'm preaching to the converted!

Gravity

Berlingos have a horrible reputation for  rear axle problems  The  rear axle has torsion bars fitted which acts as the suspension. The bearings fitted to the trailing arm are prone to collaspe , and very few berlingos will be immune, and   will need  recond axle or new bearings fitted at some point.  If got in time you get away with just replacing the bearings.  If not noticed quickly , the axle shaft is damaged beyond repair.  Hence a small industry has developed in repair kits, new  and fully recond units.Citoren have known about this , ( some say deliberate money spinner) for years yet but did   nothing  about it. Many axle recond suppliers fit grease nipple on their recond axles Mechanics i have spoken to all agree that  had Citoren used  heavier bearings and grease nipples, this problem would  barely exist. Fitting grease nipples allows the new  bearings to be greased regularly, furthering their lifespan. This problem is not  unique to Berlingos but i common in  Citroen , Renault,Peugeot models, as they all use similar axle type. The old Pegeot 405 was a classic example of this simlar type  of axle suspension , rarely did they get beyond 80 thousand mls on the clock till a recond axle was fitted. Never knew anyone who had a 405 inclunding myself who did not  replace the compleate axle  at some point. Had my problem been  my old Ford Transit my mechanic told me it was a £70 fix . Now with recond axle , new wheel bearings and others bits and pieces it will into approx £400, and that not counting my time. I decided to do it myself after getting quotes from £650  and above. Their are numerous YouTube videos on Berlingo  axle repair.  on this very subject.  A visible  sign the bearing have collapsed is the wheel or wheels will lie in at the top  when viewed from rear. Brendy

[Tomcat3]

There is a How to on this very subject on the site.

[brendy]

Drilling into steel ??  

6.8mm is the " correct " size but if you don't have 6.8 don't be tempted to use 6.5mm as it will be too tight and a snapped tap / ugly thread is likely. Better to use a 17/64th if you have one or 7.0mm at a push.

You will only be tapping for a grease nipple so no need for finish / plug tap I'd be using an intermediate / 2nd tap only with a partial depth used whilst checking with the nipple for degree of fit. Nipples often have only a very short thread so be careful !

edit : use some PTFE tape on the thread to help keep water etc out of your new axle !!  Apply the tape clockwise to the thread and not the other way around !

I have just got a message from a friend and he said that the tap i need is a M8x1mm pitch metric fine, would you second this.

[Gravity]

Great - thanks for that info. Now I know. Wonder if this weakness is the same for both B9 and M59?

Why not get a thread pitch guide (a couple of pounds, Ebay). Then you can confirm the thread pitch on the grease nipples before you drill and tap.

Gravity

[Gravity]

edit : use some PTFE tape on the thread to help keep water etc out of your new axle !!  Apply the tape clockwise to the thread and not the other way around !

... Depends which way you view the thread. The nipple screws in clockwise, so the ptfe tape needs to be applied anticlockwise viewed from the same aspect. If you hold the nipple with the thread uppermost - that is, facing you - the tape will be applied clockwise.

Just sayin' ...

Gravity

[jj9]

@ Gravity,

The M59 & B9 have completely different rear suspension set ups so the axle bearing problem that the M59 suffers doesn't exist on the B9.


Grease Nipples,....

Most screw in grease nipples that I've seen are of a tapered design, (the thread diameter increases towards the base of the nipple) so they tighten up as they are screwed into the hole.

For this reason the hole needs to be smaller than the thread at the base of the nipple, and make sure not to over tighten it as it will snap off, when it gets tight stop even if it isn't fully home.

If you have the tapered type you could more than likely get away without tapping the hole, just drill the hole a size so the first few threads of the nipple will fit in and as you screw it in the threads will cut into the steel enough to keep it tightly in place.


.