Suspension Bushing/Mount Refresh + Oil Pan & Steering

[LockDots]

I ended up snapping just about all of those header to midpipe studs when I went to remove the nut. If I had to do it over again, I'd use a ton of heat - like, a MAP or propane torch until the nuts were glowing hot, then a long breaker bar so as to not break the stud. It was a serious nut roll trying to remove the studs, whether by air hammer or by drilling. They're not some normal steel stud, they'll eat up most drill bits and fight you the whole way.

I believe this is because over the years they become fused and heat treated. I ended up holding up that section with one nut on each pipe and brought it to an exhaust shop. They hammered out all the studs and replaced them with stainless bolts and copper nuts.

[TostitoBandito]

Yeah I may just end up skipping the guibo for now, or see if I can get enough access to it by just letting the midpipe hang/droop.

On to the next piece of fun, rear diff bushings. What did everyone use to get these things out? I just tried pressing one out using a diy tool (threaded rod, socket, pipe, etc...) and it pushed the metal center section a fair distance but the rubber just flexed and the outer sleeve didn't move. I was thinking of trying a drill next between the inner/outer sleeve to cut them, and then try the press again.

[NoLastName]

Threaded rod sucks for pressing things. If you don't have access to a hydraulic press get a ball joint press. It's a heavy duty c-clamp with acme threads. I have one of these for small press jobs and I've used it many times over the years: https://www.harborfreight.com/ball-j...les-63279.html

If you don't want to buy one they're available for rent at some auto parts stores. The rubber in the bushings will stretch a lot but they'll eventually come out. You just need enough room in the receptacle end of your press.

[TostitoBandito]

Yeah, I'll go borrow one of those and see how it goes.

Status update, I've got the front subframe and control arms all connected and torqued, and the motor is now sitting on the new Vorshlag mounts. The main belt is being a PITA as I expected, so I'm in the process of pulling out my CAI so I can reach the top driver's side corner of the belt/pulleys from above. From below I couldn't pull hard enough on the belt to free up enough slack to slide it around the tensioner while working the tensioner with the other hand. I've also got my new steering rack out of the box and ready to install as soon as I tighten up the tie rod ends. I've measured both new and old racks a number of times between the tie rod stud and the nearest mounting bolt hole (where rack bolts to subframe) and I have them about as close as I can get with a tape measure. It should at least have a driveable toe setting. After the rack goes in, just need to put the x-brace, sway bar, and underpanel back on. And hopefully remember to put oil in the engine.

For the rear end, I need to replace the diff ear bushings as I mentioned, replace the rear ball joints, and replace the poly RTAB's with OEM + limiters (I have the BMW tool for this so it should be fast). Then I can put the subframe back onto the diff (which is still connected to the half shafts and trailing arms). Loosely connect up the upper and lower control arms, and then I can wheel the beast back over to the rear of my car and jack it up into place.

Of course, this has all taken far longer than anticipated. Partly because I'm being very cautious and OCD about all the stuff I've never done before (especially the oil pan stuff), and partly because real life keeps preventing me from spending an entire day in the garage on the weekends.

[pbonsalb]

It always takes much longer than you think the first time and most of us DIYers won’t be doing this job 2 or 3 times. A full suspension overhaul is a lot of work but really transforms the car. The ride becomes supple again and the rear end stops shifting.

Tensioner needs to be fully turned. Use a longer handle tool for leverage and maybe use part of your body to push it so you have 2 hands free. Obviously if you have UD pulleys you need a longer belt than stock.

[JitteryJoe]

Yeah I may just end up skipping the guibo for now, or see if I can get enough access to it by just letting the midpipe hang/droop.

On to the next piece of fun, rear diff bushings. What did everyone use to get these things out? I just tried pressing one out using a diy tool (threaded rod, socket, pipe, etc...) and it pushed the metal center section a fair distance but the rubber just flexed and the outer sleeve didn't move. I was thinking of trying a drill next between the inner/outer sleeve to cut them, and then try the press again.

Eric, I think I used my rear end bush removal kit to get those out. You are welcome to come by and use.

[TostitoBandito]

All rear ball joints have been replaced. Through some amount of trial and error I discovered:

• 3/8" threaded rod isn't enough, 7/16" is highly recommended. Some people use 1/2", but that requires drilling out the ball joints which I didn't want to do.
• My initial method of removing the old ones was to get it moving using the giant auto parts store loaner ball joint tool along with a race from an old front wheel bearing to get it started (it tapered so it could only press about 1/4 inch). Then I'd switch to the threaded rod with copper pipe fitting as a pusher. That got me through removing 2 and a half ball joints before the rod gave up.
• The 7/16" rod was able to remove the last bushings easily enough with the copper fitting, and also easily pressed in 3 of the 4 ball joints
• The last ball joint was tighter and the 7/16 rod was a little bent by then, so it kept wanting to go in crooked (and mangled my copper pipe). I ended up finding a big socket which fit nicely over one end and just pounded it in with a sledgehammer. Slow and loud, but it went in straight. Could probably have pressed them all in via the "hammer method" in hindsight.
• I had my new ball joints in the freezer for a couple days prior to installation, which seemed to help as most went in quite smoothly.
• It's mandatory IMO to remove the parking brake and unbolt the backing plate, and it only takes a couple minutes. Without doing this you are severely limited in the length/size of your tools, and likely have to bend the hell out of the backing plate since every ball joint is angled towards the plate at one end or the other.

Some long overdue pictures:

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[TostitoBandito]

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[TostitoBandito]

Rear diff bushings are now done as well. I ended up deciding it was easiest to just take off the diff cover so I'd have room to get the giant ball joint tool in there. With the diff assembled it'd hit the CV joint. I had it drained already so it was only a few minutes of time to remove the 8 bolts and I'll have to clean up the joint and put some new permatex stuff on it prior to reassembly. The bushings pressed out fairly easily using a big (36mm I think) socket as a press and a piece of pipe around my adjustable wrench to torque the tool while standing on the diff cover.

Now I get to bolt everything together this weekend, which should hopefully be fairly straightforward. I've got the rear rotors and parking brake hardware off at the moment, so I'm hoping that it'll be easier to balance the giant rear assembly (diff/subframe, upper/lower control arms, half shafts, trailing arms/hubs) while jacking it up into position than it was when I removed it. Almost all the weight should be in the center above the jack now. The rotors and parking brake stuff are easy enough to bolt back on after the suspension is on the car.

[TostitoBandito]

Front of the car is 100% done. Haven't started the car yet, but everything is on the car and there's oil in the motor. Just need to fill the empty power steering system once I do start the car. Getting the steering flex coupler pounded the correct distance onto the steering rack was a PITA due to the slight change in angle between the steering column and the rack. Took a lot of hammering in various places on the coupler, while holding/flexing it to the proper angle with one hand.

I got my bolts today for the front diff bolt replacement. I'm going to need to grind off some of the diff case material next to where the back side of the hole is in order to allow space for the nut/washer to sit there. That's my project for tomorrow morning. I'm assuming the cast iron diff case is pretty thick, so there should be plenty of material. Hopefully my dremel is up to the task.

[TostitoBandito]

Woohoo! Rear suspension assembly is finally back on the car. I ended up borrowing a second floor jack from a friend so I could control the angle enough to get it onto the front studs. I had one jack under the rear edge of the diff, and another jack propped up on top of the wheels of the first jack and under the bottom of the subframe near the front of the diff. That arrangement got me just high enough to start getting nuts/bolts on. I ended up just pushing the driveshaft to the side out of the way rather than going through the trouble of dropping the midpipe and CSB. Today I'll have to briefly unbolt the diff and slide it back in order to get the diff flange onto the drive shaft. I figured that was easier than dropping the shaft.

I got the springs back in, shocks reconnected, RTAB's torqued at something resembling the correct angle (used a steel bar and aimed it a bit above the lower caliper bracket hole), and trailing arms loosely attached pending a quick and dirty toe alignment. Still need to put the parking brakes back together, along with a few other small things. Can hopefully finish it up this weekend.

[TostitoBandito]

Everything is back on except for the sway bars, front underpanel, and some of the CAI hardware in the engine bay (for belt and power steering access). I tried to start it last night and predictably my 8ish year old battery (which was on its way out anyway) is stone dead after not running for 2 months. I tried to jump it but the most I could get is it to crank a little (like one crank at the most) but no ignition. Seems like there wasn't enough juice for the starter, fuel pump, and ignition simultaneously. I might have been able to get it charged enough if I left it hooked up to a running car for a while, but I'll just go get a new battery tonight. While it was being jumped I turned the key and got it power long enough to check for any codes, and there were none for what it's worth.

[TostitoBandito]

IT LIVES.



New battery installed, and it started right up. Oil pressure light went off within 3 seconds. I let it run for about 10 minutes and looked for any issues, and let it charge the new battery a bit. No CEL codes or strange noises. The poly motor mounts are noticeably a little rougher at idle, but it goes away and smooths out as soon as the engine is revved at all. I'll finish bleeding the steering, button up the underpanel and get the car on the ground, and then it's off to get an alignment.

I did notice what looks like a small coolant leak which has probably existed for a while coming from the passenger side of the thermostat housing. It's running down the underside of the big hose coming out of that side of the thermostat housing which connects to the bottom of the radiator, and dripping a little onto the AC belt below it. I haven't noticed any measurable drop in coolant level for years, so it must be small. Jostling the engine around while the pan was off may have made it temporarily worse though. In any case, I'll address that next. I'll get a new housing, new thermostat, and probably some radiator hoses for good measure, and keep an eye on it until then.

[NoLastName]

Nice work! It's a great feeling when it fires up again after having guts out on the bench.

Bonus points for 2x valve cover and 2x coil cover bolt caps in place upon completion. Extra credit if you were missing caps before and bought new ones to complete this job. Attention to detail...

[TostitoBandito]

Nice work! It's a great feeling when it fires up again after having guts out on the bench.

Bonus points for 2x valve cover and 2x coil cover bolt caps in place upon completion. Extra credit if you were missing caps before and bought new ones to complete this job. Attention to detail...

LOL, yeah those things used to go missing half the time I'd take my car in to the shop to get worked on. Now that I don't really do that anymore, I've replaced them. It drove me crazy.

I've been so paranoid over the last couple weeks since I put the oil pan on that I screwed something up somehow, it wouldn't crank, and I'd have to take the whole thing apart again. Glad that's over. Something to be said for being super OCD and careful and taking a (long) time to do it mostly right. I did manage to put my inner upper control arm bolts in the wrong way. Seemed like the right way when I had the subframe out since the bolts could be removed without removing the diff, but as I was tightening them under the car I realized that there's no way to get the bolts out without removing the subframe since the trunk or fuel tank is in the way. I figure it's not a big deal because a) I never plan to have to remove them again, and b) if I do have to, the subframe probably needs to come out anyways. That'll teach me not to think I'm smarter than the realoem diagrams.

[TostitoBandito]

Oh, and let me add that I had forgotten how much of a pain in the ass putting the x-brace on was. The frame rails are ever-so-slightly closer together than the crossmember is wide, so the second one of those bolts is very difficult to get in cleanly. I damaged the threads in one of them and had to clean it up with a chaser, and was eventually able to get both bolts in after spending like 90 minutes messing with it. Then I managed to get all the little ones torqued without spinning any more of the nutserts (or at least they got to 20 ft/lb if they were spinning). For a while I thought I was totally screwed and I was going to have to drill out those holes to M12 and tap them. Thankfully I avoided that.

[pbonsalb]

I have the same problem. I have ground out the x brace holes a bit and still have to leave the brace loose while I get all bolts started and use washers under the bolt heads for the holes I opened up.

[TostitoBandito]

It drives. No new leaks I didn't already know about. Steering and suspension alignment are a disaster, but that's why I'm taking it into the alignment shop in the morning.

First impressions on the suspension/mounts:

• Significant additional vibration from the motor mounts at idle, mostly diminishing at higher RPM's
• Fantastic engine noise in the cabin at WOT, and a bit louder all around
• A bit more shifting/clutch noise from the transmission, especially at low speed in low gears, kind of like what you hear shifting in a racecar except not nearly that loud and annoying
• A little bit more noise from the diff, not a drone but more like occasional faint clunks when you give it power suddenly
• Rest of the suspension feels reasonable, tighter, not overly harsh. Should have a better idea after it's aligned.

Torquing the poly motor/trans mounts is somewhat of a black art, so I think there's still improvements to be made there. I have mine pretty loose so as not to squish the poly too much, so it's possible they are too loose. I basically tightened them slightly past the nut making solid contact with the plate at the top of the mount. I'll be taking a look at them again. If anyone from Vorshlag is here and would like to chime in, feel free.

[pbonsalb]

What is your idle speed? If stock and you hold at 850-900 rpm does the idle nvh decrease? I run a higher idle in my tune. Poly gets hard with too much torque but I cannot remember the spec for vorshlag red poly.

[TostitoBandito]

My idle is the stock setting, looks to be around 700 rpm (maybe less). Yes if I rev up to 800-900 and hold it significantly decreases. My speculation is that perhaps I need to snug up the stiffer motor mounts because the whole mount stacks might be vibrating between the motor and subframe at those low frequencies. I think the transmission mounts are ok, but they're significantly softer and similar to rubber. I wish the driver's side motor mount wasn't such a pain to get to or they'd be a piece of cake to adjust.

There were no issues on my 15 mile drive to my alignment shop, other than having to deal with my steering wheel kinked 10 degrees to the left to go straight (they're gonna straighten out the coupler for me during the alignment). I did notice a bit of a diff whine from the rear end poly, but only between 45-55mph. Nothing concerning.

[NoLastName]

Steering wheel to one side is usually the rear thrust angle out of whack. Entirely expected because you reworked the entire rear suspension. They may not need to mess with the steering coupler if you marked it before disassembly and put it back on the same spline where it was before. If you didn't mark the coupler/spline interface and just reconnected it randomly then it's possible the rack itself is not centered. These are things a good tech should be able to check and fix as needed. A good tech - not a standard issue shop monkey.

The vibrations and new noises are standard issue with stiffer mounts. You'll either get used to it or it'll bother you and you'll long for the days of stock rubber everything. I've tried many combinations of bushing and pivot materials in different locations over 10 years. In my experience, transmission mounts have the biggest effect on NVH. The stiffer you go with those (and particularly if you use a straight bolt-through design) the more racket you're going to hear and feel inside the cabin.

[TostitoBandito]

Steering wheel to one side is usually the rear thrust angle out of whack. Entirely expected because you reworked the entire rear suspension. They may not need to mess with the steering coupler if you marked it before disassembly and put it back on the same spline where it was before. If you didn't mark the coupler/spline interface and just reconnected it randomly then it's possible the rack itself is not centered. These are things a good tech should be able to check and fix as needed. A good tech - not a standard issue shop monkey.

The vibrations and new noises are standard issue with stiffer mounts. You'll either get used to it or it'll bother you and you'll long for the days of stock rubber everything. I've tried many combinations of bushing and pivot materials in different locations over 10 years. In my experience, transmission mounts have the biggest effect on NVH. The stiffer you go with those (and particularly if you use a straight bolt-through design) the more racket you're going to hear and feel inside the cabin.

Turns out I actually got the steering coupling dead on and the rack and wheel are aligned (my shop was impressed), but the front left was just horrendously toed in. I knew the toe was bad but it was close enough to drive and I didn't have time to try and adjust it before my appointment. Anyways, alignment and steering are perfect now. I really like the E46 ZHP rack I put in. No center dead zone anymore and it's a little bit quicker but not annoyingly so.

Driving home from the shop I noticed some driveline lash/vibration a couple times on the freeway when I'd be on the throttle and then release it quickly and it'd feel like going over a mild rumble strip or lane divider for a second or so. That indicates to me that there's too much movement of components in the driveline under torque, most likely from my mounts being too loose as I'd already speculated. I'm going to tighten them up along with checking everything else back to and including the diff just to make sure nothing is coming loose. I imagine that will clear up the issue with the drive shaft getting pissed at me, and might also make a small improvement in vibrations at idle (which is the only place they're a concern to be honest). My transmission mounts are bolt-through but they're only 80A which feels in the same ballpark as the rubber mounts I removed.

Aside from that, the extra engine sound in the cabin is really growing on me. It's funny because I noticed immediately that it feels like my car is faster not because it is, but because every time I come around a corner and accelerate now I subconsciously give it more throttle than I used to because the sound is so reaffirming. The engine/induction/exhaust sound at anything over about 50% throttle is amazing to both hear and feel.

The suspension in general is rock solid. Much more composed feeling than before with all the worn out ball joints and ancient bushings.

[TostitoBandito]

Tightened up the mounts and I still have the odd vibration when lifting off the throttle while in gear. It's subtle at low speeds and more noticeable at high speeds. I was thinking maybe the drive shaft (or guibo/CSB/u-joint), but I find it odd that acceleration is smooth and it only occurs right after I lift. I'd expect that to cause vibrations anytime it's spinning. At freeway speeds is vibrates like a mild rumble strip for about half a second after lifting.

Any ideas? Is this just normal engine braking transmission noise which I'm now feeling for the first time due to the stiff mounts?

[LockDots]

Does it happen the instant you accelerate as well? I'm wondering if the trailing arms are moving.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[TostitoBandito]

Does it happen the instant you accelerate as well? I'm wondering if the trailing arms are moving.

Sent from my SAMSUNG-SM-G920A using Tapatalk

No, acceleration is smooth as far as I can tell. I also just got it aligned so I'm confident the trailing arms are firmly in place.