Lower control arm bolt stuck

[Kavadarci]

Hi,
Due to ball joints clunks I’m replacing the lower control arms.
While the passenger side went smooth the driver side is a major issue.
I can not remove the front bolt of the lower control arm as it appears to be “stuck”, welded like no matter what I do.
See photo for the bolt.

heated hammered on blasted and using power tools and hands.
The issue is that the welded nut is inside the subframe and can only access to tiny crack on the subframe to spray some on blaster.
After 3 hours on this bolt I gave up and I’m at a stand still.
I appreciate any input.

thank you

 

[edmaz]

Try a 2+ foot breaker bar with a 6-8 foot pipe slipped over it. When you pull on that lever, something will give, and hopefully it will not be the captive nut that breaks loose.

 

[Kavadarci]

I’m afraid of anything giving up.
If the bolt gives up how do I take the rest out of the subframe?
If the welded nut gives up I need new subframe?
I can’t cut it, I can’t drill it.
Horrifying

 

[edmaz]

I’m afraid of anything giving up.....

Well included in 'anything' is of course the good outcome of the bolt simply coming out with no damage. Unfortunately at this point I don't think you have any choice other than taking a deep breath and giving it a go, because driving with one new and one worn out LCA would probably be worse than the 2 old ones were. Having a worst case outcome of needing to replace the subframe is not that big a deal IMO, unless you're seeing some rust issue which would make that job really problematic.

 

[Kavadarci]

Understood but it’s my friends car.
If I break the bolt he is without a car and has only one. Not ideal I know.
I have replaced many parts and rebuild engines but this design is kind of dumb as the nut is welded inside a subframe with no access and moisture will off course rust the bolt.
You can’t even heat up.

To replace subframe because of this is plain silly.
I will let it soak in pb bluster and try again.
Appreciate the feedback.

 

[negusm]

Do you have an impact?

Impacts make a world of difference.

Barring an impact, get that 2 foot breaker bar on it and as you apply more and more torque, have your friend with a big hammer WHACK it in line with the bolt. The shock can usually jar the threads loose.

 

[edmaz]

Understood but it’s my friends car.
If I break the bolt he is without a car and has only one. Not ideal I know.....

Yes, definitely much worse than if it were your own vehicle.

.... this design is kind of dumb as the nut is welded inside a subframe with no access and moisture will off course rust the bolt. ....

I think this 'hidden' nut is becoming more common across auto makes - monkey see, monkey do I guess. Every student in engineering school should have a required class where they have to make repairs on rustmobiles. If they did that, most of these stupid maintenance-unfriendly designs would disappear.

... To replace subframe because of this is plain silly. ...

Most definitely true. Good luck, and I hope it doesn't come to that for you on this one.

 

[Kavadarci]

First of all, what a friendly forum. I love it. Thank you.
Yes I have big impact gun and have never ever not have been able to remove a bolt - until now.

I have big breaker bar and two of us were on it and started to bend.
Hitting it with a hammer is something I didn’t try.

I’m getting new bolt tomorrow in case we break it.
I have drilled broken bolts and rethreaded but you can’t even get to do that here if it breaks.

yes totally agree that engenders today do not repair cars and don’t think in long terms.

I still have German cars from the 70s (merc and Porsche) and they were engineered to be worked on and replace parts multiple times but you he nee ones which I also have not so much.

 

[AnthonyVerde]

First of all, what a friendly forum. I love it. Thank you.
Yes I have big impact gun and have never ever not have been able to remove a bolt - until now.

I have big breaker bar and two of us were on it and started to bend.
Hitting it with a hammer is something I didn’t try.

I’m getting new bolt tomorrow in case we break it.
I have drilled broken bolts and rethreaded but you can’t even get to do that here if it breaks.

yes totally agree that engenders today do not repair cars and don’t think in long terms.

I still have German cars from the 70s (merc and Porsche) and they were engineered to be worked on and replace parts multiple times but you he nee ones which I also have not so much.

I had this same issue last year. I tried it all — impact wrench, breaker bar (even with a 4 foot piece of steel pipe over the end) — with no luck. Problem is there's a metal sleeve in the busing that the bolt goes through. Moisture and corrosion seized the bolt in that bushing, so whenever I'd try to turn the bolt, I'd be putting torque on the sleeve and the bushing as well. No way it was coming out. Fortunately, I was able to pick up a new LCA and bolt and take the van to a mechanic down the road to have them cut the bolt out and replace. Rust and corrosion are a pain with these vehicles.

 

[tj4fa2003P5]

Ran into the same issue as you while working yesterday on my son's 2003 Protege5 removing the Lower Control Arms for new replacements to follow lots of other work.

The P5 has a different setup than your Mazda5 but same deal, bolts do/did not want to bulge.

The bolts on the P5 are vertically mounted just past the rear of the engine bay and also can't get access to do anything with the captured nuts inside the body.

Best I could do is spray PB blaster up in small hole of crevice near on the bolt head and hope to get some on the buried captured nut then using a 6' pipe over my 1/2" breaker bar...pray that if/when the bolt gives, it breaks free not in two.
I got lucky...(this time).

The attached photos show the bolts from both the Driver and Passenger Side that I let sit in some Coca Cola overnight to get some of the oily sand and rust crud off.

-Not sure if it's a dissimilar metal thing going on or just its because its just another of those Mazda things.

-Good luck with yours.

 

[Kavadarci]

I appreciate the feedback.

It makes so much more sense now as I was starting to doubt my capabilities.
I did another round today and short of cutting I see not giving up so we will take it to a mechanic shop.
If it was mine I would cut it but will have to be at the shop now.
This would go at the top of the list of the worst designs I have seen in a long time.

 

[Kavadarci]

Sooooo
Here is the bolt (which didn’t break) and as described the bolt was rusted inside the sleeve.
My mechanic had to burn the bushings first (was so cloudy with smoke) and I’m glad I didn’t do it in my garage. Then cut the control arm out, then cut under one angle one piece came out then cut again for another piece snd finally could get to the inner sleeve.
Then heated it to cherry red and still wouldn’t give up.
Hammering and trying one more time finally gave up.
He was tired and sweaty and said yes this is a Mazda thing and no way you would have done this at home without the tools they have at the shop.

mom glad is over and will never take on this work at home
Thank you For all your help.

 

[AnthonyVerde]

Sooooo
Here is the bolt (which didn’t break) and as described the bolt was rusted inside the sleeve.
My mechanic had to burn the bushings first (was so cloudy with smoke) and I’m glad I didn’t do it in my garage. Then cut the control arm out, then cut under one angle one piece came out then cut again for another piece snd finally could get to the inner sleeve.
Then heated it to cherry red and still wouldn’t give up.
Hammering and trying one more time finally gave up.
He was tired and sweaty and said yes this is a Mazda thing and no way you would have done this at home without the tools they have at the shop.

mom glad is over and will never take on this work at home
Thank you For all your help.

Awesome. Glad this got fixed!

That's exactly how my mechanic went about removing the stuck LCA bolt in our 5. Funny enough, that job left such an impression on them that they cringed when I showed up a month later asking to get the other LCA replaced.

 

[edmaz]

... Then cut the control arm out, then cut under one angle one piece came out then cut again for another piece snd finally could get to the inner sleeve.
Then heated it to cherry red and still wouldn’t give up.
Hammering and trying one more time finally gave up. ....

Bottom line, it's done and out of your hair! But one thing I'm not understanding is why he didn't just cut through the bolt/sleeve, once he got to that point, instead of doing all of that extra work to free it up. This exact same thing (bolt corrosion-welded to the sleeve) happened to me (non-Mazda though), and I just cut through the bolt in a couple places, and then turned it out of the frame. But I wasn't looking over his shoulder, so perhaps there was something different with this one from my situation, and cutting/turning it out wasn't possible for him to do.

 

[Kavadarci]

My guess, if you cut the bolt you might not be able to unbolt it (wise grips or like) as the nut is inside the frame.
The owner now complains of vibrations and car pulling , who knows why

 

[edmaz]

My guess, if you cut the bolt you might not be able to unbolt it (wise grips or like) as the nut is inside the frame. ....

Yes, that's probably why he did it that way.

.... The owner now complains of vibrations and car pulling , who knows why

Two possibilities that come to mind are that an LCA was not preloaded before final torque; or that one or more bolts are loose.

 

[Kavadarci]

How does it have to be pre loaded?

 

[edmaz]

The exact procedure varies by vehicle, but with the ones I've worked on, you leave the front LCA bolt loose, then lower the vehicle so the control arm rests on jackstands, and then tightening the front bolt to spec.

However, when I just took a look at the FSM for the CX-5, I was surprised to see that there is no preloading procedure provided for the LCA installation. So apparently Mazda doesn't feel preloading is necessary (for this vehicle anyway).

 

[Kavadarci]

Thank you

 

[topFC3Sman]

New control arms likely will mean that the car needs an alignment - this could explain the pulling and vibrations