Bushing install?

Need some advice on OME 40mm lift kit install. 

The new bushings for the control arm are 1.6mm larger than the ID in the control arm. (It's normal for the new bushings to be about 1mm larger than the ID to compensate for worn ID on the control arms.) Instead of deburring the control arm ID by .5mm. As spelled out in the instructions. The machine shop wants to reduce the OD on the bushing by .8mm. So the bushing will be .8mm larger than the ID on the control arm. But still fit. And stay in.  

The instructions say to deburr the ID on the control arm by .5mm.  Is this a problem?

Their excuse is that reducing the control arm ID will make the control arm unsafe. That it will make the walls around the bushing to thin. And they will get blamed if it breaks.  

I'm in the Phillipines. I know this sounds like a sh*t show. But it's what I'm dealing with. The mechanic has the lift kit half installed. And I'm running control arms back and forth to the local machine shop.

I checked with the mechanic who is installing the lift and he agrees that reducing the OD on the bushings is fine.  

Advice?

I'm confused someone is wanting to turn down the od of a polyurethane bushing to make it less of an interference fit? Or are they metalastic bushes with an outer bonded steel face? I've not done castor bushes but on the normal ones I have done i just ran a flap sanding wheel inside the radius arms hole to remove the surface rust and pushed the new bushes in?

There is no issue reducing the bushing. The machinist is correct about which is the safer choice.

The reason the instructions tell you to ream the control arm instead is that anyone can do that with a simple tool, while few DIY installers would have a lathe handy to turn down the bush. But the latter is the better way.

Wise of you to ask first though.

Good luck

Hang on there. The instructions only say debur as necessary. To debur is to simply remove any high spots and or sharp edges there is no mention of resizing either the bushes or the radius arms, just an instruction to get the inner surface cleaned up and any sharp bits smoothed out.

Old man emu are not going to sell a kit to the general public that needs significant machine shop intervention.

Apparently the bushings are normally made 1mm large to compensate for any wear from the original bushing or manufacturing tolarances. It's also apparently typical to expand the ID in the control arm by up to .5mm. This gives you extra tolerance so you can reduce to the size you need. Meaning take away material. Whereas adding additional material to the bushings or control arms is impossible.

I tend to agree that if for some reason either part is made unusable in this scenario - increasing the control arm ID vs reducing the bushings OD. I'd rather replace the bushings than the control arm.

But let's hope this works just fine.

They were far more comfortable machining either than deburring. I don't know what their reason was. But it's a regional machine shop in the province. All of their machines are old manuals. Nothing is computerized here. And they weren't confident deburring wouldn't end up with an elongated hole. So they were going to machine that as well if they had agreed to do it.

They aren't doing it until the morning. And the tolerance is .8mm oversized on the bushings. So that should be a tight fit. And they should stay in place.

And honestly I have a hard time disagreeing that machining the bushings seems safer than machining the control arms. Not to mention it's four holes in the control arms.

It was a shit show though. Language barrier even tho my gf was there. But woman behind the desk with no clue what she was doing started refusing right away. After one of the dummy employees that looks like all he can handle is the press said it couldn't be done. I pointed out in the instructions about deburring. She refused. And then stated all they would do is reduce the bushings to the same size as the ID in the control arms. That's when her and I got off to a bit if a heated disagreement. Other more knowledgeable employees could see my point - that pressing in same size OD into a same size ID made no sense.

But then the boss finally came out. Saw my caliper measurements. Remeasured. And agreed that some reduction was needed but not 100%. Lol.

We agreed the difference was 1.6mm between the two. And matching half of that off the bushings would work. Only then did I agree to have it done.

Again it made sense to machine the bushings not the control arms. As long as it was 50% and not 100%! I was like "what's the purpose of a press then?" I could tap them in with a screwdriver but they weren't going to stay in place to long.

Further conferred back at my mechanics shop with him. He agreed the machining of the bushings was fine.

I also sent an email to the ARB distributer here in the Phillipines that sold me the lift. Waiting for their response.

But so far I still feel like this is the way to go.

If I had it all to do over again I would have taken a 2 days ferry ride to a larger town that has actual 4x4 shops with experience with lifts. This is a commercial/civilian suspension shop. Nothing about this install should be that complicated.

But I'm still open to all advice.