Can M5/ e32 740i trailing arms be installed on a 525i Touring?

[xcastaway]

I've been reading through every RTAB and rear wheel bearing thread I can find, getting ready for the next part of my Touring repairs, finishing up my rear suspension. I've replaced both half shafts and my sub frame bushings so far. I finally narrowed those rumbling noises on cornering down to bad rear wheel bearings, which I'm about to order. Since I already will have to pull the half shafts to replace these, I would really like to do the RTABs at the same time.

From what I found through my reading, I have high confidence that I can swap the wheel bearings in a reasonable amount of time, using Autozone loaner tools. I also am pretty certain I could, one way or another, cut/burn/ press out the original RTABs. If I was going to use poly rtabs, they would be simple enough to install too. But I have had issues with polyurethane bushings on other cars in the past that distorted and squeaked and didn't hold up well, so I'm not going that route. Which leaves either replacing the original bushings, or using M5/E32 slide bearings, though I haven't been able to find a definitive answer as to whether the slide bearings will fit my trailing arms. I'm pretty sure they will, but I hate operating under pretty sure when dealing with my only transportation. Some threads say installing either of these types is no problem, and others say they are a huge problem that will break several sets of tools in the process, and that I may not be able to manage to DIY at all. Which would leave me stranded while I figured it out, and I have a major aversion to stranded.

The best option I can come up with to avoid taking the car off the road for more than a day would be to get another set of trailing arms and install the rtabs and wheel bearings into them, then just yank and replace both trailing arms, which should be easily done in a day. SO, I checked the inventory at the local junkyard to see what I could come up with.

There is an E32 740i there that uses the same trailing arms as the M5, complete with the slide bushings. These, from my readings do not wear very much, so I could conceivably get away without replacing them, at least for the time being. I've checked ReaolOem regarding the differences between those arms and the ones on my touring. The arms seem the same, though with different numbers. I believe the arms themselves are just heavier duty. The M5/740 uses all the same components except for the side shaft and drive flange at the wheel. My question is: will my touring's side shaft and drive flange mate with the e32's trailing arms? The fact that they use the same bearings leads me to believe they will, but I'd prefer being at least pretty sure before going through the effort of going to the junkyard and pulling them. Does anyone know or have a good guess as to whether it is worth trying to mate 93 e32 trailing arms to 92 525i touring by swapping those 2 components? 1 and 5 in diagram. My touring uses

SIDE SHAFT

33411134883

and drive flange 33411136299 instead.

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No.	Description	Supp.	Qty	From	Up To	Part Number	Price		Notes
01	SIDE SHAFT		2			33411134877	$211.02
02	Inner hex bolt	M8X12	2			34111123072	$1.32
03	Lock Ring	80X2,5	2			07119934749	$0.96
04	Angular ball bearing	42X80X42	2			33411134549	$83.67
05	DRIVE FLANGE		2			33411131063	$93.58
06	Collar nut	M27X1,5	2			33411123428	$7.76
07	Securing plate		2			33411123973	$0.88

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[moroza]

All E32 and E34 bare trailing arms, except 525i sedans (and some Euro models), are identical, as are their wheel bearings. 525i sedans have a smaller wheelbearing and trailing arms to match. Other than 525i sedans, the different part numbers reflect that the arms come, if bought brand new from BMW, assembled with different RTABs - normal rubber bushings for non-M E34 and 735, slide bearings (still encased in rubber) on M5, 740, and 750. Both are 44mm OD (source: I measured both myself) and will fit either arm, but both are *very* tight and will break most tools. The geometry of the trailing arm prevents fitment in a normal H-frame press, but a special narrow press bed can accommodate them. I'm currently working on making one but need a welder. If you have or can borrow a decent welder, PM me and I'll do the press work on your arms in exchange for welder use.

The slide bearings last a long time but are not invincible. I pulled the arms off the brown 740 in Portland South and its bearings had a lot of slop. They cost a fortune, $70/each or more, and OE Lemförder is your only option. The rubber RTABs are also expensive - usually ~$45/ea for genuine, though EEuroparts has them for ~25/ea (I just bought a set), and there are aftermarket options.

E32 trailing arms from a junkyard (t.i. not from the dealer) come with E32-specific hubs (part No.1 in the diagram), which space the wheel mounting surface 7mm further outboard. For this reason they also have specific brake rotors, though calipers are shared with 540i.

All E32 trailing arms except late 735 use a bigger axle drive flange (inner hub flange, part No.5). See the "diff know-how" thread for more details. To answer your question: yes, you with a 525i wagon (not sedan) have the correct parts to make it all work.

The wheelbearings are difficult to replace with Autozone tools without removing the arms from the car. The hard part is actually reassembly, pressing the outer hub into the bearing. Attempting to draw the hub into the bearing using its own collar nut usually results in destruction of the nut, the hub (which then has to come back out, likely destroying the bearing), or both. Recommend taking out the arm and doing it correctly on a press. Bearings are ~50/ea for German-made SKF, last I checked. RTABs are probably old, but replacing them is a whole 'nother project if all you're trying to fix is rumbly wheelbearings.

Unless you want to space out your rear track and upgrade your brakes, there is no point in buying E32 arms. Chances are, their RTABs are just as bad as yours, and the hubs are nearly impossible to swap without destroying the wheelbearing (my success rate: 1 out of 6). EDIT: I see you want to minimize downtime. In that case, your plan is solid, just beware that Autozone rental tools aren't going to cut it, and that you'll need your 525iT's inner and outer hubs.

[xcastaway]

Oh, wow! Thank you for the time and effort you put into your reply! Not to mention your sharing of some of your accumulated knowledge. I was hoping you would stop by, most of the threads that got me tantalizingly close to having this figured out for myself had you prominently involved.

I will take your advice and do the bearings and rtabs with the trailing arms off the car, using the right tools. I still think, given my aversion to being stranded, that I'll try to pick up a set of trailing arms and get the bearings and bushings pressed into them, and then swap out the arms. My 5 speed swap, complete with dislocated shoulder blade soon after putting the gearbox into place, added several miserable days to the project and left me traumatized about being left without transportation. I'm willing to go through the extra expense and hassle of getting the arms to avoid doing that again. I do hate wasting the time of pulling a set and the expense, too. I'm also afraid one or more of the bolts will strip out at the yard, , leaving me with nothing to show for the effort.

I sold my welder a couple of years ago, to a friend who drank his way into losing it and everything else he owned, or I'd be delighted to take you up on your offer. When you manage to get your press built, I'll be happy to pay you to press in the bushings. The YouTube videos made it seem possible to do at home, if you have the right tools, but a number of threads I've read have said the opposite. The polyurethane bushings could be managed as a DIY project, but they caused me nothing but grief on the 2 '57 Chevy wagons I used them on.

I found some German made (Hamburg Technic) slide bearings I thought worth trying, for considerably less than the Lemforder version. $127 for the 4 bearings. I'd rather try these than just replace the standard bushings. I'm already way beyond my car repair budget for the year, and cannot justify springing for the Lemforders.

I ordered wheel bearings yesterday, so I'll have to wait for the slow boat from Groton to arrive before tackling that problem. I bought FAG bearings, which I have had excellent luck with on several cars over the years. I have a set of nib front wheel bearings from them, awaiting my locating a thinwall 46mm socket to install them.

There are several deep cracks visible on both of my outboard RTABs, which is the main reason the rear suspension is next on my repair agenda. I'm also nearing the point of being too old for this merde, which makes completing the major repairs while I am still able so pressing. I'm also trying to get as much done as possible before the rains return. I still need to replace the clutch, since I ran out of money and had to install the used one from my donor car, knowing it was a mistake but lacking any choice. I think I can baby that until next spring, in hopes of finding a ZF gearbox and driveline parts before I tackle it. My Getrag is a notchy, whiny, POS with a second gear crunch unless you shift it slowly enough. There is no way it will last the 15-20 more years I'm hoping to get out of the car.

Again, thank you so much for sharing your knowledge so freely.

[moroza]

Hamburg Technic made in Germany? You sure? China, last I checked. Having had both the normal RTABs and later the slide bearings in my 544iT, I would not bother with the latter, just get a set of genuine regular bushings for $98 shipped, less than the aftermarket bearings you're eyeing (and given how beastly this job is, I would not mess with aftermarket at all). Unlike front control arm bushings, the rears seem to last a good 20 years before they start squeaking.

I still think, given my aversion to being stranded, that I'll try to pick up a set of trailing arms and get the bearings and bushings pressed into them, and then swap out the arms.

In that case, get them from an E34 (other than a 525i sedan), so it'll come with the correct outer hubs at least (inner hubs are easier to swap later and on the car). Unless you want to space out your rear track and upgrade the brakes, in which case, go for whole E32 arms with brakes. I'm doing the latter myself.

[xcastaway]

It is pretty hard to figure out exactly where the Hamburg Technic bearings are made from their website. The company is definitely based out of Germany. I'll check before ordering, should I decide to go that route. Most recommendations I've read say either go with the polyurethane or the slide bearings, given what a pain they are to do. If I do go with the rubber bushings, I probably will go with OEM, as rubber parts are one area where I've found big quality differences from different manufacturing locations. Metal parts I haven't noticed as much variance due to where they were made. The exception to that was my Meyle HD front sway bar links, both of which were trash well within 20k miles. I replaced them with very inexpensive Karlyn units that are far superior in every way, and have already outlasted one of the Meyles.

I definitely don't want to widen my rear track, I don't even like what the 3mm extra offset of these e38 style 5's did to the feel of the car. It felt much more nimble with the bottle caps on. My first upgrade to the car was swapping boneyard e32/e38 calipers (per e34.net) and new 540i rotors onto it, since it's rotors were deeply grooved when I bought it, and I didn't want to replace them twice.

Sherwood has a 540i that already has the brakes and shocks removed for me, if I'm guessing right from the stuff that showed up on CL recently. I may head there in the morning to snag the trailing arms. The only reason I was looking at the 740 arms was due to the slide bearings, hoping it would be a low mile well maintained car and I could get off cheap with an upgrade and be able to avoid messing with the rtabs altogether. If it appears to meet those criteria, that is still a possibility. It may depend on which car the rotor retaining screws will come out of, and whether the axle bolts have been stripped out or not.

[Wishno87]

I wouldn't mind getting in on this. I have been planning on doing the e32 t/a bearings as well and have access to a welder.

[moroza]

"Based in Germany" means a few white collars in Germany paying dirt to lowest-bidder blue collars, mostly in Asia, earning revenue from selling an illusion of German product quality while incurring low labor costs, then complaining that their blue collar neighbors lining up at unemployment offices are "lazy" and "want to be poor".

In addition to actual product quality problems (especially rubber parts from India, IME), such business practices earn my boycott - my vote-by-dollar - wherever I can reasonably apply it. I've been having a bad week with this - Lemförder subframe mounts, Sachs rear strut mounts, and this Lincoln welder I just bought, all on their reputations for get-what-you-pay-for quality... China, China, and Mexico, respectively. Funny how the parts still cost (me) what they did when they were made in Germany or Ohio...

So yeah, I now have a welder, but the metal place that sold me steel tubing before now said no. Wasted my Friday afternoon driving out there. There's now three of us within an hour's drive who need RTABs pressed. Someone help me source materials and we can get this going sooner.

[xcastaway]

I can relate to your frustration over wasted time. I ended up going to Sherwood twice to get trailing arms, and still don't have them. They took out one row of cars on Thursday. Both the 740 and the 540 just happened to be in that row. The 740 still shows it's there on their website, I had to recheck today in case I somehow missed it after going thru everything twice. I did get a bunch of little odds and ends, anyway. I had to go back to grab a hood for my girlfriends car today, and tried to pull the trailing arms off a 535i. Everything went fine until I went to pull the axles. The parking brake wouldn't hold, and the transmission would still spin in park, and nothing I tried would keep the thing from turning. I should have tried to enlist somebody to step on the brakes long enough to break the 12 bolts loose, if I was going to manage it. Arrgghhh. I did get her hood, anyway.

I've never shopped for metal around here, so I'll be doing an internet search to see if there is anyplace around that carries metal and sells to the public. What exactly are you looking for?

Alas, that is just the way global capitalism works these days. And, there are companies that build total crap, and companies that make pretty good stuff in every country. The stamping machines for metal parts are pretty much the same worldwide, the difference is in the materials they stamp in them and the quality of the assembly afterwards. Parts made on the same machines using the same materials should be pretty much the same made in Germany or Lower Botswana, if they use a properly trained workforce. The consumer has to guess who does what where and how well. And yes, the rich will get richer, and the poor won't.

That said, I read a lot of reviews for Hamburg Technic parts since posting, and they were less than stellar. Way less. So it's back to the modern day drawing board, searching the internet. I may end up with poly bushings in spite of myself. Sure would like to try the slide bearings, though you are undoubtedly right that the difference they will make will be barely noticeable. I'm fairly sensitive to little things like that though. It would be a pretty expensive little bit. Given how bad the current rtabs look, the stock replacements should be a huge improvement. And on the other hand, going with poly I wouldn't need trailing arms since it would be possible to get back on the road in a reasonable amount of time, and are doable at home. I'd still have to figure out whose poly bushings to get. Or whether Chinese or Turkish Lemforders are any better than Chinese or Turkish Meyles or Rein if I go with stock replacements. Decisions, decisions.
.

[moroza]

Move to PM?

See above re: $98 shipped for a set of four genuine BMW RTABs

[xcastaway]

A slight update. I made one last stab at finding the slide bearings at a reasonable price, and lo and behold, Bavauto has Lemforder's version for $20 each. I couldn't resist, so have a set on their way.

https://www.bavauto.com/bmw-trailing...ushing-1330901.

[moroza]

Boogerwelds notwithstanding, it works.

[ross1]

Just skimmed but saw mention of "Hamburg Technic".
DON'T, just DON'T. No matter how cheap.
wanna do this bitch of a job over gain? Buy Hamburg Technic.
Hamburg, my ass

[xcastaway]

Just skimmed but saw mention of "Hamburg Technic".
DON'T, just DON'T. No matter how cheap.
wanna do this bitch of a job over gain? Buy Hamburg Technic.
Hamburg, my ass

Went Lemforder after reading some reviews on Hamburg Technic, which pretty much matched yours! And, I got the Lemforders for less. Sometimes you get lucky.

Nice, Moroza! Function is way more important than esthetics. Now the x frame you mentioned makes sense to me. My parts should be showing up sometime on Tuesday, according to the tracking numbers.