Needle bearing removal woes

[onthames]

I'm having to remove needle bearings on quite a regular basis from throttle bodies. Mostly from classic BMWs. They all seem to have an interesting design where the bearing is in a blind hole with a lip.
Here is the situation I'm in, quite often. The bore is in black, bearing in red, puller in blue - side profile.
I've heated the outside, freeze sprayed the inside, everything. I'm not keen on welding anything in because these throttle bodies are aluminium and I don't want to damage them. I can't use the grease method as the hole goes through into the throttle body bore, is not tapped, and I can't get a tap in there to tap and plug it.

The result of using one of these pullers:

I've used these pullers in situations where I can get to the back of the bearing, shown at the bottom of the diagram, and they work fine - every time. Now this seems a little odd as you are essentially pulling on the lip, as you would on the top lip, but for whatever reason they are stronger in that direction. The solution I use when this lip does break off is I cut through two sides of the outer race and then collapse it on itself so I can get pliers on it to pull it out. Unfortunately as cutting through the race you do slightly nick the bore which I'd like to avoid doing. This is why I need a tool that works for removing these!

Does anyone have a suggestion for a tool to buy/make for this scenario? I was thinking of breaking the lip off on purpose, then using a tap to tap thread into the outer race, add a threaded rod and use a puller on the rod.
The era of parts I work on it all tends to have the same needle bearing - INA HK08122RS

 

[john.k]

With steel in ally,the only viable method is heating in boiling water ...and Ive found that at 100C ,the bearing is normally a sliding fit and will come out.....so dont distort the race ,and it will come out easily.

 

[ratbldr427]

Those are drawn cup bearings and installed in your application I don't know any easy way other than what you have tried. I use a lot of them but so far most are not in blind holes. They are a light press fit.

I use a lot of those same bearings in some small aluminum hub poly coated wheels I make. An 8mm bore bearing I think I would use a miniture torch after pulling the needles out . The shell will heat quick and I don't think the aluminum will be hurt. Heat and cool quick a few times and maybe you can anneal them so as to tap them,they are very hard. I wouldn't break the lip off if you find the right pitch tap then you would have one thread to pull on. I have used that method on a lot of bushings, sometimes just scoring the surface will do, a full thread is not necessary. Remember that any internal pressure will just lock the bearing tighter.

 

[jccaclimber]

I wonder if throwing the entire assembly in the oven for a while would result in the bearing becoming a slip fit, or at least enough looser that the puller would work.
Not quite the same thing, but I've pulled a few valve guides out of older air cooled motorcycle cylinder heads. I figured they would be designed in a way that they don't get loose hot, but after leaving them at (I don't remember the temperature), we flipped the heads over and the valve guides simply fell out. The new ones dropped in, and once cooled we were good to ream them.

 

[john.k]

Unfortunately ,with bearing steel SAE 52100,there is no viable way of softening the steel...........Its important to thoroughly heat the ally,water has a vey high specific heat ,and cant cause any damage.

 

[mark costello]

If You could cut a square groove tap with a fine pitch thread You might be able to use both edges to spread the force out.

 

[onthames]

Thank you for the replies guys - I will try getting the part in some water on a rolling boil (heat the water up with the part as to avoid thermal shock) and then try the puller with the part sitting in the water. Will update

 

[Peter from Holland]

I have good experience with the hydraulic methode But with a cup like that you have to use a thick paste like clay No grease That leaks too much And it needs a impact from a hammer
Then use a floating plug that seals the bore and the bearing too as good as possible Drill a hole in that plug and a crosshole or 2-3
Hold it in position one way or the other With a bridge or flange at the top of some sort
Fill it Put a plunjer in the hole and smack it with a hammer

Peter

 

[angelw]

I have good experience with the hydraulic methode But with a cup like that you have to use a thick paste like clay No grease That leaks too much And it needs a impact from a hammer
Then use a floating plug that seals the bore and the bearing too as good as possible Drill a hole in that plug and a crosshole or 2-3
Hold it in position one way or the other With a bridge or flange at the top of some sort
Fill it Put a plunjer in the hole and smack it with a hammer

Peter

Peter's method, but use Bread and a little oil as the compressive material.
Another method is:
1. clean and degrease the inside of the bearing
2. place plasticine in the bore up to just entering the bottom of the bearing
3. use a bolt, or threaded rod, the OD of which is circa 1mm radial clearance in the needle roller bearing
4. mix some high strength epoxy, coat the inside of the bearing, making sure you force the epoxy in to the drawn cup and enough so that when the bolt is placed in the bore of the bearing, down to the plasticine, some of the epoxy is extruded, so there are no air gaps.
5. once the epoxy has cured, heat the body and using whatever puller arrangement you can muster, or a slide hammer, pull the bearing out.
6. if you can approach the bearing from the opposite end, complete steps 1 and 2 above, then simply fill the bearing, with epoxy, ensuring that the epoxy is forced into the drawn cup. Once the epoxy is cured, use a punch from the other side of the throttle body to drive the bearing out.

Regards,

Bill

 

[Scottl]

It's hard to completely visualize the situation from the photos, but when you say "I can't use the grease method as the hole goes through into the throttle body bore, is not tapped, and I can't get a tap in there to tap and plug it" I wonder if you could machine a plug to be a close fit in the throttle body bore with O-rings and then try the grease method (actually thicker paste as others have mentioned. No doubt some might squirt past the O-rings but it might back it out enough for better puller access.

Might be totally un-doable but I thought it was worth a mention.

 

[jim rozen]

Everyone knows that real classic BMWs don't have any needle bearing!

 

[Dan from Oakland]

Why not use 5 minute epoxy and glue a threaded stud into the bearing, let it cure and jack it out with a sleeve and a nut?

 

[Conrad Hoffman]

They don't look very big, so the amount of differential expansion you can get by heating and cooling is very small. I like the epoxy idea. Most epoxy also shrinks when it cures, so that might help.

 

[Scottl]

Why not use 5 minute epoxy and glue a threaded stud into the bearing, let it cure and jack it out with a sleeve and a nut?

IMO it would at least be worth a try as a possible cheap and easy method since the OP needs to do this often.

 

[MrWhoopee]

Isn't alum used to remove broken taps in aluminum?

 

[onthames]

Well it looks like I found a solution. Boiling water did not work. I had some new cheap chinese internal pullers arrive, I took the 9mm one (the bearing ID is 8mm) and I filed off approx .5mm. Now there is a small gap between each prong, allowing me to push the prongs together and get this puller into the hole and under the lip - without using the expanding rod. See video here: https://streamable.com/y2gah0
I then heated the bore area for 5 minutes using a MAP gas torch. Before I had only heated for 1-2 minutes using a butane flame, believing this was enough. Well, low and behold, this in combination with using a oversized bearing puller and no expansion rod worked. The advantage of having it grip the edge without the rod was that if the bearing was not going to come out yet (not enough thermal expansion from surrounding bore) then instead of ripping the lip off the bearing and giving me a hell of a job, it would simply pop out leaving it undamaged. Most of the time it worked 1st try, a few it didn't which lead me to heat for longer, which made it work. Thanks for the help and ideas guys.



(the 2 cut races in this photo are from having the lip break off trying other methods like boiling water etc)

 

[Scottl]

Excellent! Thanks for posting the follow up in case anyone encounters a similar situation.