Suspension Bushing/Mount Refresh + Oil Pan & Steering

[TostitoBandito]

I'm writing this post to solicit advice on things I might have missed or that might bite me when I start the work (in mid-late February probably). I know many of you have done the same work, so I'd certainly love to hear from you if I've got anything wrong. I'll also update this thread once I start the work with any thing I come across, pictures, and so forth.

All the work is going to be done at once. I'm going to strip all this stuff off the car on a weekend, work on it then and during the following week, and hopefully finish and get everything reassembled the following weekend.

Here is a list of everything I'm doing, from front to rear:

• Steering - replace rack with Z3 or E46 ZHP rack, replace steering guibo, replace reservoir and refill with ATF fluid
• Engine - drop oil pan and swap in reinforced pump/pickup, wire/loctite oil pump nut, replace pan gasket, replace oil/filter
• Front Subframe - get motor mount reinforcements welded on front subframe, clean and paint
• Mounts - replace motor and transmission mounts (95A/80A poly Vorshlag)
• Front Suspension - replace FCAB's (95A poly), replace both ball joints in each front control arm
• Drive Shaft - replace flex disc (OEM)
• Rear Subframe - get swaybar tab reinforcements welded on subframe, clean and paint, replace subframe bushings (95A poly)
• Rear Suspension - replace RTAB's (OEM+limiters), replace diff bushings (95A poly), replace upper and lower outer ball joints, replace inner upper control arm bushings (lower control arms and inner bushings are new)

My basic plan of attack is to lower the rear subframe on a jack with trailing arms and diff as a unit, and then tear it down once it's off the car and on the floor. I'm gonna try disconnecting the parking brake cable from the cabin so I can pull it out that way, and I'll detach the rear brake lines from the trailing arms and hang the rear calipers from the chassis so I don't have to flush the brakes. I've got tools to do the RTAB's and rear ball joints, and I'll load the suspension to remove RTAB preload when installing. I'll burn/drill out the subframe and diff bushings, or modify my RTAB/ball joint tools to help with them if needed. For the front end I'll support the engine from above and rip everything off. I'll have to press/burn/drill the FCAB's out. For the control arm ball joints I'll use a shop or a friend with a 20 ton press. The steering rack and oil pan stuff should be pretty straightforward bolt-on stuff, though getting the pan off and back on is going to be a PITA.

Then once it's back together I'll drive it to my alignment shop, go home, and relax for a while.

[JitteryJoe]

You'll get many opinions regarding Poly vs. rubber. I bought poly motor mounts then went with Bimmerworld Group N reps.
I may also swap out my RTAB poly for HD Meyle rubber. I do have poly in other areas but motor mounts and RTAB I've heard too many negative comments.
Anyway, expect many opinions here.
I have a set of new AKG poly motor mounts you can have for cheap and I'm in the area. May have a few other poly pieces as well.
Steering, I went with a ZHP rack plus new flex joint. Some folks prefer the non-rubber steering joint (don't recall which model it is sourced).
Probably a bunch of small stuff you missed (e.g. new diff mount bushings?). I just did all of this and more. Seems endless once you start.

[Team Neverlift]

Steering, I went with a ZHP rack plus new flex joint. Some folks prefer the non-rubber steering joint (don't recall which model it is sourced).

E34 steering coupler, I am running one w/ a Z3 1.9L rack, I really like it... but I also like poly motor mounts... You will want to replace your inner & outer tie rods at the same time imo, some racks come w/ new inners already.

[pbonsalb]

Looks like a good comprehensive list and plan of attack. I have done all of it. Bushing choices look fine. You will love the supple but firm ride and stable rear end when you are done. Big project, but there really is no easy way unless maybe you have all the factory bushing tools and most of us DIYing this job do not.

[TostitoBandito]

You'll get many opinions regarding Poly vs. rubber. I bought poly motor mounts then went with Bimmerworld Group N reps.
I may also swap out my RTAB poly for HD Meyle rubber. I do have poly in other areas but motor mounts and RTAB I've heard too many negative comments.
Anyway, expect many opinions here.
I have a set of new AKG poly motor mounts you can have for cheap and I'm in the area. May have a few other poly pieces as well.
Steering, I went with a ZHP rack plus new flex joint. Some folks prefer the non-rubber steering joint (don't recall which model it is sourced).
Probably a bunch of small stuff you missed (e.g. new diff mount bushings?). I just did all of this and more. Seems endless once you start.

Yeah already done all that research and have the parts. Vorshlag motor/trans mounts (which are beautifully designed/fabricated), OEM RTAB, and revshift 95A for all the poly bushings and diff mounts. Never heard of the non-rubber steering joint, but I feel comfortable going with the new OEM one I have. It's not a full track car.

You will want to replace your inner & outer tie rods at the same time imo, some racks come w/ new inners already.

Yeah I plan on getting the rack from rackdoctor which comes with inners, and I'll have them throw on new outers at the same time to make things simple.

[pbonsalb]

I recently bought and installed a Z3 Non-M rack with lifetime warranty from Detroit Axle on Amazon (also on EBay). Cost $238, I think and no core charge. I like it. Noticeably quicker once off center. Thought about the E46 330i Purple Tag, but it required some mods to fit while the Z3 was direct fit. The only thing I would not mind is a heavier on center feel - I think the E46 rack may be variable in feel and if it does give a heavier on center feel than the Z3, I would probably buy it instead were I doing this now.

[TostitoBandito]

I recently bought and installed a Z3 Non-M rack with lifetime warranty from Detroit Axle on Amazon (also on EBay). Cost $238, I think and no core charge. I like it. Noticeably quicker once off center. Thought about the E46 330i Purple Tag, but it required some mods to fit while the Z3 was direct fit. The only thing I would not mind is a heavier on center feel - I think the E46 rack may be variable in feel and if it does give a heavier on center feel than the Z3, I would probably buy it instead were I doing this now.

I believe the E46 ZHP (yellow tag) rack is the one that's very close to the Z3 rack and a bit cheaper. I'll probably just spring for the Z3 rack though, since a $40 or $50 price difference isn't the end of the world compared to everything else I'm doing.

[JitteryJoe]

I believe the E46 ZHP (yellow tag) rack is the one that's very close to the Z3 rack and a bit cheaper. I'll probably just spring for the Z3 rack though, since a $40 or $50 price difference isn't the end of the world compared to everything else I'm doing.

My understanding is that the ZHP rack is between the stock M3 rack & the Z3 rack responsiveness-wise. I got mine from the RackDoctor fully built with end links. I've heard the Z3 rack can be a bit twitchy for the street so I opt'ed for the middle ground. Don't recall any price difference at the time.

[TostitoBandito]

My understanding is that the ZHP rack is between the stock M3 rack & the Z3 rack responsiveness-wise. I got mine from the RackDoctor fully built with end links. I've heard the Z3 rack can be a bit twitchy for the street so I opt'ed for the middle ground. Don't recall any price difference at the time.

Yeah that's my understanding as well. It's linear like the Z3 rack but with more turns lock-to-lock (but still less than stock M3). You do make a valid point, I'll have to think about that more. Right now the ZHP yellow tag is $280 and the Z3 is $360 at rackdoctor, both with a $150 core (which will probably be only partially refunded since I'm sending in an M3 core).

[pbonsalb]

I have not found the Z3 non M rack ton be twitchy but have put only about 1000 street miles on it. Some of that was with 255 fronts before the winter wheels went on. Perhaps if you had wide fronts and a zero tie alignment it would move more but I have just a little less than stock front toe.

I liked the $238 shipped price for a rebuilt lifetime warranty Z3 non-M rack from Detroit Axle.

[Team Neverlift]

I would agree, the z3 1.9L rack is not twitchy, its just direct, and immediate. I have never had a need to put toe into my alignment specs, and have probably 8k street miles on the z3 rack & e34 coupler.

As for purchasing a 1.9L rack from Detroit Axle, or anywhere for that matter... test the rack as soon as it arrives, to ensure that it is 2.8 LTL, and not 3.2 LTL... Detroit Axle sent my buddy 2 racks w/ the 3.2 LTL despite their store showing 2 separate part #'s, and him ordering the 2.8 LTL rack.

He recommended I use RockAuto (A1 Cardone), for a reman'd ZF rack that showed 2.8 LTL on the spec sheet that should be provided. They also charged a core fee, but I returned a blown M3 rack that I sourced locally for $20. It was probably $80-100 more in total vs the Detroit Axle cost, all said and done.

[TostitoBandito]

Good info guys. I took a look at Detroit axle and it looks like they don't charge for cores but only warranty if you send them one. I dunno, I'll probably just pay a bit more and go with rackdoctor for peace of mind, since they break out all the different parts within each car model.

Also, I might throw on some Achilles Motorsport oil pan baffles now that I found a friend to weld all my stuff at his shop. Looks like it would take about 5 minutes. Might as well do everything I can in that pan and then never take it off again.

[pbonsalb]

They took my M3 core in return for the lifetime warranty but did not give me a $25 credit for it. They gave me a shipping label so I did not pay to ship. But rack doctor has a good reputation and you would be supporting a popular and helpful vendor.

[NeilM]

You don't say what your driving use is for this car. Daily, track, mixed, what?

Replace both hoses that connect to the PS reservoir. Use screw hose clamps on them.

If this is a car you drive on the street:
- Stick with new stock rubber diff bushings. Any benefit from reduced driveline wind-up from poly is negligible, but the increase in NVH is real.
- Ditto for motor mounts. Most poly motor mounts are crap. They either have through bolts that defeat the purpose of a resilient mount, or they don't and can shear. If you insist of harder mounts use these (http://www.rogueengineering.com/Rogu...unts_p_78.html).
- Stick with rubber trans bushings like these (http://www.rogueengineering.com/Rogu...nts_p_137.html) unless you love gearbox whine in the cabin.

Inspect/replace the rear shock mounts (these last forever: http://www.rogueengineering.com/Rogu...E46_p_270.html).

Since you're going to refinish the rear subframe anyway, use a blowtorch to remove the bushings. Play the flame all around the outside of the each metal ring until you see the first wisps of smoke from the bushing rubber as its outer layer melts. At that point you can simply push the bushing out with a screwdriver, length of wooden dowel, whatever.

Only use poly subframe bushings that have a central metal sleeve against which the mounting bolt is torqued down. PowerFlex are good (they fixed the flimsy washer problem long ago), or there are others.

Disclaimers: Based on my experience, YMMV, don't stick beans up your nose...

Neil

[JitteryJoe]

Good info guys. I took a look at Detroit axle and it looks like they don't charge for cores but only warranty if you send them one. I dunno, I'll probably just pay a bit more and go with rackdoctor for peace of mind, since they break out all the different parts within each car model.

Also, I might throw on some Achilles Motorsport oil pan baffles now that I found a friend to weld all my stuff at his shop. Looks like it would take about 5 minutes. Might as well do everything I can in that pan and then never take it off again.

Achilles baffle is a nice product. Had one welded into my pan. It is about a 5 minute job. Also had them rebuild my oil pump. The turnaround was very fast and, visually anyway, a very nice job. They do away with the nut and replace it with a bolts tapped into a new shaft. The bolt has a wire lock drill out. You can see it on my build journal.

[NeilM]

You don't say what your driving use is for this car. Daily, track, mixed, what?

Replace both hoses that connect to the PS reservoir. Use screw hose clamps on them.

If this is a car you drive on the street:
- Stick with new stock rubber diff bushings. Any benefit from reduced driveline wind-up from poly is negligible, but the increase in NVH is real.
- Ditto for motor mounts. Most poly motor mounts are crap. They either have through bolts that defeat the purpose of a resilient mount, or they don't and can shear. If you insist of harder mounts use these (http://www.rogueengineering.com/Rogu...unts_p_78.html).
- Stick with rubber trans bushings like these (http://www.rogueengineering.com/Rogu...nts_p_137.html) unless you love gearbox whine in the cabin.

Inspect/replace the rear shock mounts (these last forever: http://www.rogueengineering.com/Rogu...E46_p_270.html).

Since you're going to refinish the rear subframe anyway, use a blowtorch to remove the bushings. Play the flame all around the outside of the each metal ring until you see the first wisps of smoke from the bushing rubber as its outer layer melts. At that point you can simply push the bushing out with a screwdriver, length of wooden dowel, whatever.

Only use poly subframe bushings that have a central metal sleeve against which the mounting bolt is torqued down. PowerFlex are good (they fixed the flimsy washer problem long ago), or there are others.

Disclaimers: Based on my experience, YMMV, don't stick beans up your nose...

I just did all of this and more. Seems endless once you start.

Truth!

Neil

[TostitoBandito]

Achilles baffle is a nice product. Had one welded into my pan. It is about a 5 minute job. Also had them rebuild my oil pump. The turnaround was very fast and, visually anyway, a very nice job. They do away with the nut and replace it with a bolts tapped into a new shaft. The bolt has a wire lock drill out. You can see it on my build journal.

Yeah I'll be getting the reinforced pickup and oil pump from Achilles as well. I like that they convert the pump to use a hollow shaft with a (wired) bolt that screws into it rather than the nut.

You don't say what your driving use is for this car. Daily, track, mixed, what?

Replace both hoses that connect to the PS reservoir. Use screw hose clamps on them.

The car is daily driven less than 3000 miles per year, and used for fun on the track in the summer. It's already got some degree of mods which compromise on NVH and street use like the GC suspension with linear springs, 3.46 diff, and wide aggressive track tires in the summer. My goal is to keep it in this middle ground where it's tolerable (to me, not necessarily the wife) on the street, while holding together nicely on road courses.

Good advice on the PS hoses and clamps, I'll do that. I was thinking about it when I ordered the reservoir the other day. Should be simple enough to do since it's all coming off.

Only use poly subframe bushings that have a central metal sleeve against which the mounting bolt is torqued down. PowerFlex are good (they fixed the flimsy washer problem long ago), or there are others.

Yeah I came to the same conclusion after doing my research. I went with Revshift for the subframe, diff, and FCAB's. The subframe bushings have the central metal sleeve similar to powerflex, and I can attest that the two halves fit REALLY tightly together as I had to use a screwdriver and a lot of twisting to get them separated.

[TostitoBandito]

One other question that I'd like to clarify.

As far as I can tell you don't need to, but is there any reason to replace any of the oil pan or front/rear subframe bolts? None of them have ever been off the car as far as I know. Are there any other bolts/hardware that I'll need to remove during this exercise which I should replace? The new ball joints and engine/trans mounts all came with new hardware (and self locking nuts), and I have aftermarket rear camber arms so those bolts are new.

[NoLastName]

You shouldn't need to replace oil pan bolts unless they're extremely rusty and might break. Remember there are 2 "hidden" oil pan bolts at the back. They're accessed through holes in the transmission bellhousing. If you forget those and try to pry the pan off you'll be in trouble.

I don't recall it being mandatory to replace subframe bolts or nuts either. Having said that, I often replace fasteners myself just for peace of mind. And yes, some of those buggers are expensive.

I have Revshift 75D rear subframe bushings. One tip: be careful you don't cross thread the rear subframe bolts. Mine didn't line up exactly perfect by hand. A little misalignment is possible when you have a very stiff bushing material with metal inserts or all-metal bushings. TMS aluminum bushings come with one hole slotted to allow some wiggle room for assembly. Revshift are not slotted. So on my car the holes were just a couple mm off, enough to prevent hand-starting of the 2nd bolt. It kept trying to cross thread until I thought about it and figured out a solution. The bolts are long and have pointed ends with a smooth starter section. I was able to thread one bolt in loosely, then smack the other firmly with a hammer so the point centered the bolt in the threads. Then the bolt went in easily and straight after that.

Another tip from memory: I think it's best to torque the front inner control arm ball joints to the subframe before bolting the subframe to the body. The top nuts are difficult to access with engine and accessories in the way. If you do it off the car you won't have to use super long extensions and u-joints. Easier to get a good torque reading.

[JitteryJoe]

My recollection is that the front mounts of the rear subframe, the nuts are locking. But my recall is a bit sketchy. I tend to replace fasteners "while I'm in there".
My bill for OEM nuts and bolts is stupid.

[Braymond141]

Nuts that are pinch (stover) should be replaced, however it isn’t absolutely necessary. Unfortunately all new bolts from BMW is 3-5x more expensive now versus 4 years ago. I purchased all new for my 96 and then had them restored on my 98.

I’d encourage you to not use poly. I’m undoing all of that learned lesson.

[TostitoBandito]

My recollection is that the front mounts of the rear subframe, the nuts are locking. But my recall is a bit sketchy. I tend to replace fasteners "while I'm in there".
My bill for OEM nuts and bolts is stupid.

According to realoem they are just ordinary M12x1.5 collar nuts, so I think they should be ok.

You shouldn't need to replace oil pan bolts unless they're extremely rusty and might break. Remember there are 2 "hidden" oil pan bolts at the back. They're accessed through holes in the transmission bellhousing. If you forget those and try to pry the pan off you'll be in trouble.

I don't recall it being mandatory to replace subframe bolts or nuts either. Having said that, I often replace fasteners myself just for peace of mind. And yes, some of those buggers are expensive.

I have Revshift 75D rear subframe bushings. One tip: be careful you don't cross thread the rear subframe bolts. Mine didn't line up exactly perfect by hand. A little misalignment is possible when you have a very stiff bushing material with metal inserts or all-metal bushings. TMS aluminum bushings come with one hole slotted to allow some wiggle room for assembly. Revshift are not slotted. So on my car the holes were just a couple mm off, enough to prevent hand-starting of the 2nd bolt. It kept trying to cross thread until I thought about it and figured out a solution. The bolts are long and have pointed ends with a smooth starter section. I was able to thread one bolt in loosely, then smack the other firmly with a hammer so the point centered the bolt in the threads. Then the bolt went in easily and straight after that.

Another tip from memory: I think it's best to torque the front inner control arm ball joints to the subframe before bolting the subframe to the body. The top nuts are difficult to access with engine and accessories in the way. If you do it off the car you won't have to use super long extensions and u-joints. Easier to get a good torque reading.

My 95A bushings are considerably softer than your 75D so hopefully they will be more compliant in lining up right. Thanks for the tip though, and also for the idea to bolt the control arms onto the front subframe before installation. I wouldn't have thought of that, but it makes sense.

I did find a self-locking nut in the rear end that's used on both ends of the upper control arms and on the RTAB bolt on the trailing arm.
https://www.fcpeuro.com/products/bmw...ut-33326760668

They're cheap and I'll probably replace all 6 of those.

[mitch500]

Rubber all the way, Poly blows. I had some Poly from uuc a while back and it all broke apart within a year. Trans mount bolts pulled out of the poly too.

I now have rubber everywhere

[LockDots]

Rubber all the way, Poly blows. I had some Poly from uuc a while back and it all broke apart within a year. Trans mount bolts pulled out of the poly too.

I now have rubber everywhere

UUC hasn't exactly had the best track record either when it comes to their bushings though. For what it's worth I love their short shifter and for Poly (anywhere I used it) I went with AKG 95A and I love it. Feels a little tighter than OE rubber but I don't think it added any harshness or noise. Keep in mind, that I wasn't replacing fresh rubber with Poly so I'm sure it's not AS silent and soft as OE rubber but I'm ok with that.

[NoLastName]

Over the years I've seen the stories of UUC transmission mount failures. And yet, for the past 5 years I've been hammering a set of super old UUC reds on track with absolutely no issues. They've been great for me. I'm sure they'll wear out eventually like any other mount.

On the street there's nothing better than OEM rubber mounts all around. I keep wanting to buy another M3 and restore the suspension to perfect, stock street condition just to enjoy the smoothness.