Subframe front re-install question. Hope we can post info about how to. Replace steering rack

[GreenMagicMan]

Hi:

I've got a 150K 2005 V50 P1 (P One) Volvo chassis.

I had to replace a rotted PS rack metal pipe that mounts on top of the rack directly. The other pipe looked to be on it's way out. Sourced a 80K miles S40 rack locally for $116 with inner and outer tie rods all in good shape with the two metal pipes.

I dropped the front sub frame. Quite easy!!! and not too long to do either. My first sub frame drop and I was quite stunned how much of a non issue this was. I garnered my courage watching this superb Youtoobs video here:

https://www.youtube.com/embed/z37IIgp_f ... s94XjSnVuC

Fantastic how to with excellent diagrams.

My question though: is the alignment for reinstall. I was able to easily jack it back and hit the first bolt in place, and second and third (the two rear mount points with the 21mm and 13mm (2) small bolted bracket) and one of the front upper 15mm bolts.
However, the fourth and final mount spot is lined up where it should be according to dust / grime marks but the bolt is not true or wanting to go in perfectly perpendicular to unibody frame and not parallel to the sub frame mounting hole.
In fact - there is a lot of play at all these mount points. I was excepting a demanding precision placement and a lot of wriggling and heaving and swearing where none of that was needed at all.

Thoughts?
There seems to be just about no information out there about this.

And a note: I have been historically intimidated to touch / replace a steering rack. This is fairly easy peasy stuff. It's not difficult in the least and wriggling the rack to the passenger side first in order to clear the driver side sway bar in the way and then drag it back out the backside of the driver side was actually quite easy. I took a video of that process which the guy above unfortunately did not shoot video of - it's the one part that's a bit vague and not well explained in the excellent video so I will likely post that small portion to my YouTube channel and put the link in this post.

I do see there are sort of alignment holes - both in the subframe itself and in the above unibody frame of the car. The unibody has two stacked holes in it - obviously to align the single subframe hole up I suppose. I am looking into getting a proper sized tube to insert there. But I don't think it will change anything. It's pretty easy to see it's lined up where it was before on all four major mount points, especially the front upper 15mm spots where the road dirt is and isn't.

[scot850]

Have you left the other 3 mounts loose when fitting up the subframe or have you already tightened them? If you have tightened them up loosen them to take the tension off and then try seeing if the last bolt then lines up with the old witness marks. It could be if you tightened the other bolts up first it is skewing the sub-frame bushes.

Neil.

[GreenMagicMan]

I did make sure to loosen up the other 3 mount spots. I'll try to make them even looser today.
I took some sockets for measuring - and inserted them into the open alignment holes.
Going to go get an old ski pole and saw it in half to use on both sides for 'alignment pins' or whatever they might be referred to as.
But honestly I don't think either of these strategies will make a difference. It's like the bolt is going in sloppy / diagonal anyway so I don't understand why.

ALSO, uh, could be a bad question. These openings on the top / front of the subframe - they should have (tight) bushings in them right?
I don't see anything at all there. It's like a 1 3/4" open sized hole if I recall that right. About to work on this again and hope to get it all back together.

Also, note: This 2005 V50 T5 has the PS reservoir behind the passenger side headlight. I can see one tube with clamp attached to it, so far not a second one. I assume it's like a normal system with a return and supply hose. This seems to be the place to flush the system out. The replacement rack has more of a reddish PS fluid in it, whereas my V50 system clearly had the greenish (Pentosin) looking fluid. So I want to get as much of the red stuff out of the replacement rack as I've read these two fluid are not compatible (true?).

[GreenMagicMan]

I am going to go verify - but I think one of the issues is that my subframe has no bushings at all installed in it.
The 15mm bolt on the front upper mount has a 'funny' tapered extra wide lock washer looking thing - the bolt just goes thru an enormous open steel hole in the subframe.
There's absolutely no bushing there. Ah... isn't that a problem? EDIT: There are bushings in all the bolt in spots. They are significantly wider than the width of the bolt.

The car is a bit loud for my perspective with little to compare to save 2004, 2005, 2007 Volvo XC70 cars which are quiet and very solid feeling. This V50 is lighter and more active feeling, louder, and more vibration / harshness but not super high amounts of that either.
?

[GreenMagicMan]

The passenger side 15mm upper sub frame bolt is not going in straight. It's also closing in on tightening up the sub frame (it's not yet) and the bolt is seizing up. with a 16" cheater bar and a lot of force it's stuck solid and won't tighten in anymore.
This is the kind of force that could shear off a bolt (ask me how I know).
I can post some pictures of the issue.

[GreenMagicMan]

Here's some pictures:

IMG_7317.jpeg (192.82 KiB) Viewed 2644 times

Here's how the subframe sits without pulling it over a bit.

IMG_7322.jpeg (190.83 KiB) Viewed 2644 times

Slop around the bolt - should the bushing be tight(er) here? There's a lot of play as you can see. The bolt had not been started in the bore, just being held by hand at an angle

As bolted in slightly how things want to line up without pulling things hard.

THIS seems to be THE PROBLEM. How the bolt does not bolt in true / flush as it should. Why on earth does it keep going in diagonally?

The bolt will not tighten past a certain spot - it's close to starting to tighten on the subframe bore but not there yet. Major force would be required to try to proceed. Shearing force type of force I am sure.

[GreenMagicMan]

I removed both 15mm bolts to compare the threads and swap them and see if the one that went in fine will mount on the passenger side.
It's unfortunately easy to tell which bolt is which: the stuck sideways one was very much of a pain to remove, fighting me most of the way out.
The first three thread rings on the tip of the stuck bolt are slightly damaged. I guess this bolt is definitely cross threading into the frame - or the receiver nut end of the frame is damaged and damaging this bolt.

I shot the opening full of PB Blaster. I may make thread chaser out of this bad bolt and try to clean the threads of the car frame. I may also shove aside the sub frame and try to carefully drive this bolt in straight to try to save the inner frame threads first and then re-try with the frame in place.

I've read that the bolts can stretch and cause some issues. But both bolts lined up together seem to have a similar thread pitch.

[GreenMagicMan]

Minor follow up:
I unbolted and dropped subframe again to get more access to unibody frame boot in area.
The nut / insert welded up in the car frame is clearly and visibly damaged.


The bolt drives in correctly about 3-4 turns and then abruptly is forced toward center of the car.

The nut misshapen so it’s internally “tilted” towards the center of the car about five threads up. Never seen something like this but was easy to see with subframe out of way and examining closely with a very bright light.

There was gunk up there too. Shot it heavily with PB Blaster with small directional nozzle all over 2x.
Removed sludge but still a problem.

I just located and ordered a M12 x 1.75 pitch tap from Grainger for $4.79.
Will try to tap the damaged area but not 100% even this will work.
If it does not my next plan is to cut off about 3-4 full threads of the bolt and then simply have 4 turns of bolt into the frame before it bottoms out into the damaged twisted thread.

Should be back to car work Sunday or Monday.

[GreenMagicMan]

Hmmm. I updated this but don't see the post.
About 2 weeks ago (?) I DID tap out the messed up frame insert with that M12 1.25 pitch tap. Cut a lot of metal out.
The bolt finger tightens in all the way very easily. Too easily in my experience working on cars and motorcycles. But the driver 'good' side also went in by hand. Used both original bolts as I special ordered a bolt for the bad side and it was too short - apparently there is a longer bolt for ONLY the AWD cars. That's almost impossible to figure that out online.
So, currently trying to source a replacement longer 12mm (14mm head) bolt to swap in with blue Loctite on the new bolt is the plan.

[GreenMagicMan]

Found it on my other thread so am doing a cut n paste here in case someone is reading this thread:
Post by GreenMagicMan » June 19th, 2024, 8:54 pm

Finished it a few days ago.
I used the Grainger tap to clean out and cut threads in the cross threaded mess.
The bolt finger spun in the whole way. But it also did on the other front upper 15mm bolt that I cleaned up.

I torqued the 'good' front upper 15mm bolt in at 88 ft/lbs. I didn't dare go that forceful on the 'bad' re-cut side, so I winced and hoped as I torqued it to 60 ft/lbs.

Have been driving the car a few trips. Steering is back and fine

Next plan is to probably source a proper length longer AWD new bolt and douse it in thread locker blue Loctite, and torque it to.... not sure. Will do at least 60 but not sure I can trust not blowing out the chopped up threads all the way to 80+

I torqued the back lower 21mm bolts to 120 ft/ lbs. I mis-read my notes and recalled later those were the TTY torque to yield bolts of 103 ft/lbs + 120 degrees. So although the 120 ft lbs felt like a sh*t load of force on those bolts, I am guessing those are ok.

Thoughts?

And those two on a side little 13mm bolts get torqued to 37 ft/lbs according to my notes which I did.