Help! Captive nut on forward LCA bolt is loose.

Replaced the LCAs, and when installing the front bolt on the LCA, I knocked the captive nut out and now it floating around in the sub-frame.

The sub-frame looks pretty impossible for me to remove. What next?

There is a how-to here about cutting a window and using a wrench and then welding the nut I believe.

I had this happen to me. Luckily I had another subframe and we switched them out.

It was still a PITA to cut into the subframe and hold that nut so I could get the LCA off to have a spare set to be able to install bushing into ahead of time for next LCA bushing refresh.

Oldpoopie is the one that had that thread on cutting the window in the LCA.

Edit:

HERE it is.

I knocked the nut off putting the new LCA in, and its completely loose, so at least the LCA will come out easily.

I wonder how much it will cost to have a garage replace the subframe?

I happened to have a used subframe and a lift here at home.

FYI I was suprised at the cost of a new one. I'm thinking 300-400 and for some reason I though it would be worse.

You're gonna have to have it towed too.

We were swapping 01m's, replacing rear main seal(with 215k on it for kicks) rebuilding the axles, and replacing the Mehle LCA's with 40k that the rear bushing was going bad in already so we already had a lot of stuff undone so it wasn't that big of a deal and I was planning on alignment anyways.

Might be a bit expensive labor wise to have a shop do.

A suggestion. Don't use air tools on the bolts that go into those captive nuts. I suspect my problem was from when I had someone else install the Mehle LCA's. I was able to remove the bolts but the threads were compromised on the bolt. Upon reinstall(with a new bolt) got part way in and the nut broke loose.

Wasn't a happy day at all.

I have the frame laying outside with the window I cut into it with a grinder. If that may help you after you found the how-to PM me and I'll try and get you some pics.

Thanks. But Pittsburgh is over 400 mi away. I don't have much choice. Bummer. Guess I'll get it put back together to the point where it can be towed, at least.

Got the press fit nut out via the opening in the rear. Can't find oldpoopie thread on cutting a window in the sub-frame. I wonder how they get these press fit nuts into the subframe when they're manufactured?

I linked that thread in Post #3.

As pointed out in that link I do believe the nut is round - to add "extra fun".

Also it looks like in that link the subframe was out of the car - the same way I did mine.

On the car I'm thinking this fix wouldn't be much fun at all.

Sorry this happened. This is by exact fear when replacing the control arm bushings. I'll be facing this fear in a couple of months, already got all the parts and new ball joints too, since I will be in there. I actually think if an impact wrench is used to remove the front control arm bolt, there may less chance of the nut coming loose. If a namual wrench or socket is used, the lower speed/higher torque turning may break the nut free inside the subframe. Now when installing the front bolt, DO NOT knock it through the front control arm bushing with a hammer, because when it bottoms out against the nut, it may pop it off the inside of the subframe. Also, use a wrench/socket to lightly tighten it and finish up with a torque wrench. DO NOT use an impact wrench to install.

Anyone else think the impact wrench is the way to go to remove the front bolt? Or have you had good luck with manually wrenching it off? I could go either way for removing the bolt. Any advice would be appreciated.

--Nate

FWIW this particular fail was of my own making. I knocked the new bolt through with a hammer, and dislodged the nut. Instead of taking more time to line up the hole.

Took the old bolt out with an impact wrench.

I could imagine an impact wrench pushing out the nut if it generated axial impacts as well as rotational. It seems to me that my HF electric impact gun works better when there's a lot of forward pressure on it, so I lean on it pretty hard. In hindsight, forward pressure, at this location, whether removing or inserting the nut, might be risky.

PDJetta said:

Anyone else think the impact wrench is the way to go to remove the front bolt? Or have you had good luck with manually wrenching it off? I could go either way for removing the bolt. Any advice would be appreciated.
--Nate

Click to expand...

I just did mine last weekend and had no issues. I did not use an impact wrench, but didn't need one. Not much road salt use in this area so all the bolts were in fairly good condition (no rust at all). I'm sure that has something to do with it. Soaked them as best I could with PB ahead of time. I just pulled on the wrench harder and harder until the bolt began to loosen. When putting everything back together, I also made sure I made a couple of turns by hand only before any tools made it even remotely close to the bolt.

Just did this today for the second time! First time I put an access hole in the subframe with a hole saw. This time I put a square hole in with a cutoff wheel on my dremel. It's not too bad. Nuts are attached by some technique where they're spun until they 'weld' to the subframe before it is assembled. BTW, dremel method worked better. Good luck!

I've done 2, one on my sons car at 208,xxx and mine at 230,xxx original on both cars. I used hand tools for removeal and install, no issues.

I also have done 3 cars , never had the nut loosen up. but didn't use impact either

Gingerly drove to the garage this morning with the front LCA bolt duct taped in place, and called at 9 to learn the car was repaired! $95 included fixing the captive nut, and a wheel alignment. They cut a window into the subframe. To quote Lorenzo "not a big deal, its happened before"

I never cease to be amazed at how much more efficient professionals are than an amature like me. For anyone that's interested in the garage:

Romeo's Automotive
Denville, NJ

A happy ending!!

mine came loose on first LCA bushing replacement, did nothign bad to it.

Though a little opening below the nut, I work with a piece of wire and tweezers to hold it in place until the bolt could grab it... Was lots of fun for hours to catch it.

My fear... knowing that nut is loose when I do the LCA bushings again.. moot point, TDI still in pieces after turbo went :-(

This happened to me today and was horrified. Cussed at vw engineers but that did not get me anywhere. Here's what I did that was unbelievably easy and cheap!
Tools:
1) magnetic pickup tool with magnet tip small enough to fit round hole
2) one of the pick and hooks from harbor freight item 66836, currently on sale for under $2. Use the pick with squirly tip
3) mirror to help you see inside where nut is so you can understand what you are dealing with.
Procedure:
Before following steps below, make sure lca is easily insertable with rear part of lca already inserted. Jack up knuckle so the ball joint is out of the way during the procedure.
1) insert magnet through round hole to attract nut. If nut is not reachable, it has rolled out of reach from the round hole. Insert the magnet through the opening where the front lca bushing goes into. When nut is caught use pick to roll nut to round hole area so that it can be accessed from there. There are
many holes in the lca from which to get this done. Be imaginative
2) with nut in round hole vicinity, insert magnet and catch the nut. The nut being rounded is a blessing. The magnet catches nut in such a way that it is easy to position nut for screwing in bolt. Use the pick to adjust nut position and pin nut against wall
3) insert bolt and screw in lca bolt until it catches
4) when bolt catches, pull on bolt and pin the nut with the pick. Remove bolt while keeping nut pinned against wall.
5) here's where dexterity comes in. Make sure the lca is easily insertable into the subframe. This means the ball joint is not in play at all. Jack up knuckle so it is not the way if you have to. Insert the lca while keeping nut pinned by the
pick. Insert bolt and hope that it screws into nut. Keep nut pinned while you screw in bolt. In my case, the bolt tightened without the nut spinning. I hope you have the same luck as I did.
I hope this helps. Just wanted to contribute to a site that has provided so much help with keeping my 2 mk4 TDIs on the road.

Thanks everyone.

After agonizing about this I decided to drill a 1/4" pilot hole and then use a 1" hole saw. I figured I could always weld a cap on the hole. Also a round hole has less stress than one with corners. The process was quick. The agnoy of deciding which approach was tough.

I did the job outside in January and the highs were in the low 20's. I didn't think the bushing was that bad but it failed state inspection. The year before they failed the car for a tiny chip missing on the bottom end of a rear spring. About 1/4". It had been that way since 98. Anything for a repair opportunity.

Doing two more sets of LCA on other Jettas this summer.